diff --git a/src/mzscheme/cmdline.inc b/src/mzscheme/cmdline.inc
index c92002c3f7..a8036a941f 100644
--- a/src/mzscheme/cmdline.inc
+++ b/src/mzscheme/cmdline.inc
@@ -906,6 +906,7 @@ static int run_from_cmd_line(int argc, char *_argv[],
 	  break;
 	case '-':
 	  no_more_switches = 1;
+          was_config_flag = 1;
 	  break;
 	case 'j':
 	  scheme_set_startup_use_jit(0);
diff --git a/src/mzscheme/include/mzscheme.exp b/src/mzscheme/include/mzscheme.exp
index 2a42cfd036..3d818ebd4d 100644
--- a/src/mzscheme/include/mzscheme.exp
+++ b/src/mzscheme/include/mzscheme.exp
@@ -205,6 +205,7 @@ scheme_make_prim
 scheme_make_noneternal_prim
 scheme_make_prim_w_arity
 scheme_make_folding_prim
+scheme_make_immed_prim
 scheme_make_noncm_prim
 scheme_make_noneternal_prim_w_arity
 scheme_make_prim_w_everything
diff --git a/src/mzscheme/include/mzscheme3m.exp b/src/mzscheme/include/mzscheme3m.exp
index 15bf60e8e9..0e765ddf95 100644
--- a/src/mzscheme/include/mzscheme3m.exp
+++ b/src/mzscheme/include/mzscheme3m.exp
@@ -215,6 +215,7 @@ scheme_make_prim
 scheme_make_noneternal_prim
 scheme_make_prim_w_arity
 scheme_make_folding_prim
+scheme_make_immed_prim
 scheme_make_noncm_prim
 scheme_make_noneternal_prim_w_arity
 scheme_make_prim_w_everything
diff --git a/src/mzscheme/include/mzwin.def b/src/mzscheme/include/mzwin.def
index c95a780f6e..4e9c41cd81 100644
--- a/src/mzscheme/include/mzwin.def
+++ b/src/mzscheme/include/mzwin.def
@@ -193,6 +193,7 @@ EXPORTS
  scheme_make_noneternal_prim
  scheme_make_prim_w_arity
  scheme_make_folding_prim
+ scheme_make_immed_prim
  scheme_make_noncm_prim
  scheme_make_noneternal_prim_w_arity
  scheme_make_prim_w_everything
diff --git a/src/mzscheme/include/mzwin3m.def b/src/mzscheme/include/mzwin3m.def
index 1ec30af225..80d06b7a94 100644
--- a/src/mzscheme/include/mzwin3m.def
+++ b/src/mzscheme/include/mzwin3m.def
@@ -207,6 +207,7 @@ EXPORTS
  scheme_make_noneternal_prim
  scheme_make_prim_w_arity
  scheme_make_folding_prim
+ scheme_make_immed_prim
  scheme_make_noncm_prim
  scheme_make_noneternal_prim_w_arity
  scheme_make_prim_w_everything
diff --git a/src/mzscheme/include/scheme.h b/src/mzscheme/include/scheme.h
index 52aa7becdf..b0758ce03c 100644
--- a/src/mzscheme/include/scheme.h
+++ b/src/mzscheme/include/scheme.h
@@ -612,26 +612,31 @@ typedef struct Scheme_Offset_Cptr
 
 /* Constants for flags in Scheme_Primitive_[Closed]_Proc.
    Do not use them directly. */
-#define SCHEME_PRIM_IS_FOLDING 1
-#define SCHEME_PRIM_IS_PRIMITIVE 2
-#define SCHEME_PRIM_IS_STRUCT_INDEXED_GETTER 4
-#define SCHEME_PRIM_IS_STRUCT_PRED 8
-#define SCHEME_PRIM_IS_PARAMETER 16
-#define SCHEME_PRIM_IS_STRUCT_OTHER 32
-#define SCHEME_PRIM_STRUCT_OTHER_TYPE_MASK (64 | 128)
-#define SCHEME_PRIM_IS_MULTI_RESULT 256
-#define SCHEME_PRIM_IS_BINARY_INLINED 512
-#define SCHEME_PRIM_IS_USER_PARAMETER 1024
-#define SCHEME_PRIM_IS_METHOD 2048
-#define SCHEME_PRIM_IS_CLOSURE 4096
-#define SCHEME_PRIM_IS_NONCM 8192
+#define SCHEME_PRIM_OPT_MASK (1 | 2)
+#define SCHEME_PRIM_IS_PRIMITIVE 4
+#define SCHEME_PRIM_IS_STRUCT_INDEXED_GETTER 8
+#define SCHEME_PRIM_IS_STRUCT_PRED 16
+#define SCHEME_PRIM_IS_PARAMETER 32
+#define SCHEME_PRIM_IS_STRUCT_OTHER 64
+#define SCHEME_PRIM_STRUCT_OTHER_TYPE_MASK (128 | 256)
+#define SCHEME_PRIM_IS_MULTI_RESULT 512
+#define SCHEME_PRIM_IS_BINARY_INLINED 1024
+#define SCHEME_PRIM_IS_USER_PARAMETER 2048
+#define SCHEME_PRIM_IS_METHOD 4096
+#define SCHEME_PRIM_IS_CLOSURE 8192
 #define SCHEME_PRIM_IS_UNARY_INLINED 16384
 #define SCHEME_PRIM_IS_MIN_NARY_INLINED 32768
 
+/* Values with SCHEME_PRIM_OPT_MASK, earlier implies later: */
+#define SCHEME_PRIM_OPT_FOLDING    3
+#define SCHEME_PRIM_OPT_IMMEDIATE  2
+#define SCHEME_PRIM_OPT_NONCM      1
+
+/* Values with SCHEME_PRIM_STRUCT_OTHER_TYPE_MASK */
 #define SCHEME_PRIM_STRUCT_TYPE_INDEXLESS_GETTER 0
-#define SCHEME_PRIM_STRUCT_TYPE_CONSTR 64
-#define SCHEME_PRIM_STRUCT_TYPE_INDEXLESS_SETTER 128
-#define SCHEME_PRIM_STRUCT_TYPE_INDEXED_SETTER (64 | 128)
+#define SCHEME_PRIM_STRUCT_TYPE_CONSTR           128
+#define SCHEME_PRIM_STRUCT_TYPE_INDEXLESS_SETTER 256
+#define SCHEME_PRIM_STRUCT_TYPE_INDEXED_SETTER   (128 | 256)
 
 #define SCHEME_PRIM_IS_STRUCT_PROC (SCHEME_PRIM_IS_STRUCT_INDEXED_GETTER | SCHEME_PRIM_IS_STRUCT_PRED | SCHEME_PRIM_IS_STRUCT_OTHER)
 
diff --git a/src/mzscheme/src/char.c b/src/mzscheme/src/char.c
index addddc6dfa..f360763ebd 100644
--- a/src/mzscheme/src/char.c
+++ b/src/mzscheme/src/char.c
@@ -246,7 +246,7 @@ void scheme_init_char (Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("make-known-char-range-list", 
-			     scheme_make_noncm_prim(char_map_list, 
+			     scheme_make_immed_prim(char_map_list, 
 						    "make-known-char-range-list", 
 						    0, 0),
 			     env);
diff --git a/src/mzscheme/src/cstartup.inc b/src/mzscheme/src/cstartup.inc
index 95e2e69817..cd8f145ece 100644
--- a/src/mzscheme/src/cstartup.inc
+++ b/src/mzscheme/src/cstartup.inc
@@ -1,68 +1,72 @@
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,8,51,46,57,57,46,48,46,57,50,0,0,0,1,0,0,6,0,9,
-0,14,0,18,0,23,0,28,0,32,0,39,0,42,0,55,0,62,0,69,0,
-78,0,84,0,98,0,112,0,115,0,119,0,121,0,132,0,134,0,148,0,155,
-0,177,0,179,0,193,0,203,0,209,0,232,0,33,1,43,1,60,1,93,1,
-126,1,185,1,230,1,52,2,97,2,102,2,122,2,252,2,16,3,64,3,130,
-3,13,4,155,4,198,4,209,4,32,5,0,0,50,7,0,0,65,98,101,103,
-105,110,29,11,11,64,108,101,116,42,63,108,101,116,64,119,104,101,110,64,99,
-111,110,100,63,97,110,100,66,108,101,116,114,101,99,62,111,114,72,112,97,114,
-97,109,101,116,101,114,105,122,101,66,100,101,102,105,110,101,66,117,110,108,101,
-115,115,68,104,101,114,101,45,115,116,120,65,113,117,111,116,101,29,94,2,14,
-68,35,37,112,97,114,97,109,122,11,29,94,2,14,68,35,37,107,101,114,110,
-101,108,11,62,105,102,63,115,116,120,61,115,70,108,101,116,45,118,97,108,117,
-101,115,61,120,73,108,101,116,114,101,99,45,118,97,108,117,101,115,66,108,97,
-109,98,100,97,1,20,112,97,114,97,109,101,116,101,114,105,122,97,116,105,111,
-110,45,107,101,121,61,118,73,100,101,102,105,110,101,45,118,97,108,117,101,115,
-95,8,240,48,117,0,0,11,16,0,95,8,193,11,16,0,96,35,11,93,159,
-2,16,34,35,16,2,2,13,161,2,2,35,2,13,2,2,2,13,97,10,34,
-11,94,159,2,15,34,34,159,2,16,34,34,16,20,2,9,2,2,2,3,2,
-2,2,4,2,2,2,5,2,2,2,10,2,2,2,7,2,2,2,8,2,2,
-2,6,2,2,2,11,2,2,2,12,2,2,13,16,4,34,29,11,11,2,2,
-11,18,98,64,104,101,114,101,8,31,8,30,8,29,8,28,8,27,27,248,22,
-178,3,195,249,22,171,3,80,158,37,34,251,22,73,2,17,248,22,88,199,12,
-249,22,63,2,1,248,22,90,201,27,248,22,178,3,195,249,22,171,3,80,158,
-37,34,251,22,73,2,17,248,22,88,199,249,22,63,2,1,248,22,90,201,12,
-27,248,22,65,248,22,178,3,196,28,248,22,71,193,20,15,159,35,34,35,28,
-248,22,71,248,22,65,194,248,22,64,193,249,22,171,3,80,158,37,34,251,22,
-73,2,17,248,22,64,199,249,22,63,2,7,248,22,65,201,11,18,100,10,8,
-31,8,30,8,29,8,28,8,27,16,4,11,11,2,18,3,1,7,101,110,118,
-54,55,55,56,16,4,11,11,2,19,3,1,7,101,110,118,54,55,55,57,27,
-248,22,65,248,22,178,3,196,28,248,22,71,193,20,15,159,35,34,35,28,248,
-22,71,248,22,65,194,248,22,64,193,249,22,171,3,80,158,37,34,250,22,73,
-2,20,248,22,73,249,22,73,248,22,73,2,21,248,22,64,201,251,22,73,2,
-17,2,21,2,21,249,22,63,2,9,248,22,65,204,18,100,11,8,31,8,30,
-8,29,8,28,8,27,16,4,11,11,2,18,3,1,7,101,110,118,54,55,56,
-49,16,4,11,11,2,19,3,1,7,101,110,118,54,55,56,50,248,22,178,3,
-193,27,248,22,178,3,194,249,22,63,248,22,73,248,22,64,196,248,22,65,195,
-27,248,22,65,248,22,178,3,196,249,22,171,3,80,158,37,34,28,248,22,51,
-248,22,172,3,248,22,64,197,27,249,22,2,32,0,89,162,8,36,35,41,9,
-222,33,39,248,22,178,3,248,22,88,199,250,22,73,2,22,248,22,73,249,22,
-73,248,22,73,248,22,64,203,250,22,74,2,23,249,22,2,22,64,203,248,22,
-90,205,249,22,63,248,22,64,201,249,22,2,22,88,199,250,22,74,2,20,249,
-22,2,32,0,89,162,34,35,45,9,222,33,40,248,22,178,3,248,22,64,201,
-248,22,65,198,27,248,22,178,3,194,249,22,63,248,22,73,248,22,64,196,248,
-22,65,195,27,248,22,65,248,22,178,3,196,249,22,171,3,80,158,37,34,250,
-22,74,2,22,249,22,2,32,0,89,162,34,35,45,9,222,33,42,248,22,178,
-3,248,22,64,201,248,22,65,198,27,248,22,65,248,22,178,3,196,27,248,22,
-178,3,248,22,64,195,249,22,171,3,80,158,38,34,28,248,22,71,195,250,22,
-74,2,20,9,248,22,65,199,250,22,73,2,4,248,22,73,248,22,64,199,250,
-22,74,2,3,248,22,65,201,248,22,65,202,27,248,22,65,248,22,178,3,196,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,9,51,46,57,57,46,48,46,49,49,50,0,0,0,1,0,0,6,0,
+9,0,14,0,18,0,23,0,36,0,41,0,45,0,52,0,55,0,62,0,69,
+0,78,0,84,0,98,0,112,0,115,0,119,0,121,0,132,0,134,0,148,0,
+155,0,177,0,179,0,193,0,203,0,209,0,232,0,33,1,43,1,60,1,99,
+1,138,1,212,1,1,2,94,2,139,2,144,2,164,2,54,3,74,3,124,3,
+190,3,75,4,238,4,25,5,36,5,115,5,0,0,133,7,0,0,65,98,101,
+103,105,110,29,11,11,64,108,101,116,42,63,108,101,116,64,119,104,101,110,72,
+112,97,114,97,109,101,116,101,114,105,122,101,64,99,111,110,100,63,97,110,100,
+66,108,101,116,114,101,99,62,111,114,66,100,101,102,105,110,101,66,117,110,108,
+101,115,115,68,104,101,114,101,45,115,116,120,65,113,117,111,116,101,29,94,2,
+14,68,35,37,112,97,114,97,109,122,11,29,94,2,14,68,35,37,107,101,114,
+110,101,108,11,62,105,102,63,115,116,120,61,115,70,108,101,116,45,118,97,108,
+117,101,115,61,120,73,108,101,116,114,101,99,45,118,97,108,117,101,115,66,108,
+97,109,98,100,97,1,20,112,97,114,97,109,101,116,101,114,105,122,97,116,105,
+111,110,45,107,101,121,61,118,73,100,101,102,105,110,101,45,118,97,108,117,101,
+115,95,8,240,48,117,0,0,11,16,0,95,8,193,11,16,0,96,35,11,93,
+159,2,16,34,35,16,2,2,13,161,2,2,35,2,13,2,2,2,13,97,10,
+34,11,94,159,2,15,34,34,159,2,16,34,34,16,20,2,10,2,2,2,3,
+2,2,2,4,2,2,2,5,2,2,2,6,2,2,2,7,2,2,2,8,2,
+2,2,9,2,2,2,11,2,2,2,12,2,2,13,16,4,34,29,11,11,2,
+2,11,18,98,64,104,101,114,101,8,31,8,30,8,29,8,28,8,27,27,248,
+22,178,3,23,196,1,249,22,171,3,80,158,37,34,251,22,73,2,17,248,22,
+88,23,200,2,12,249,22,63,2,1,248,22,90,23,202,1,27,248,22,178,3,
+23,196,1,249,22,171,3,80,158,37,34,251,22,73,2,17,248,22,88,23,200,
+2,249,22,63,2,1,248,22,90,23,202,1,12,27,248,22,65,248,22,178,3,
+23,197,1,28,248,22,71,23,194,2,87,94,23,193,1,20,15,159,35,34,35,
+28,248,22,71,248,22,65,23,195,2,248,22,64,193,249,22,171,3,80,158,37,
+34,251,22,73,2,17,248,22,64,23,200,2,249,22,63,2,8,248,22,65,23,
+202,1,11,18,100,10,8,31,8,30,8,29,8,28,8,27,16,4,11,11,2,
+18,3,1,7,101,110,118,54,57,49,51,16,4,11,11,2,19,3,1,7,101,
+110,118,54,57,49,52,27,248,22,65,248,22,178,3,23,197,1,28,248,22,71,
+23,194,2,87,94,23,193,1,20,15,159,35,34,35,28,248,22,71,248,22,65,
+23,195,2,248,22,64,193,249,22,171,3,80,158,37,34,250,22,73,2,20,248,
+22,73,249,22,73,248,22,73,2,21,248,22,64,23,202,2,251,22,73,2,17,
+2,21,2,21,249,22,63,2,10,248,22,65,23,205,1,18,100,11,8,31,8,
+30,8,29,8,28,8,27,16,4,11,11,2,18,3,1,7,101,110,118,54,57,
+49,54,16,4,11,11,2,19,3,1,7,101,110,118,54,57,49,55,248,22,178,
+3,193,27,248,22,178,3,194,249,22,63,248,22,73,248,22,64,196,248,22,65,
+195,27,248,22,65,248,22,178,3,23,197,1,249,22,171,3,80,158,37,34,28,
+248,22,51,248,22,172,3,248,22,64,23,198,2,27,249,22,2,32,0,89,162,
+8,44,35,41,9,222,33,39,248,22,178,3,248,22,88,23,200,2,250,22,73,
+2,22,248,22,73,249,22,73,248,22,73,248,22,64,23,204,2,250,22,74,2,
+23,249,22,2,22,64,23,204,2,248,22,90,23,206,2,249,22,63,248,22,64,
+23,202,1,249,22,2,22,88,23,200,1,250,22,74,2,20,249,22,2,32,0,
+89,162,42,35,45,9,222,33,40,248,22,178,3,248,22,64,201,248,22,65,198,
+27,248,22,178,3,194,249,22,63,248,22,73,248,22,64,196,248,22,65,195,27,
+248,22,65,248,22,178,3,23,197,1,249,22,171,3,80,158,37,34,250,22,74,
+2,22,249,22,2,32,0,89,162,42,35,45,9,222,33,42,248,22,178,3,248,
+22,64,201,248,22,65,198,27,248,22,65,248,22,178,3,196,27,248,22,178,3,
+248,22,64,195,249,22,171,3,80,158,38,34,28,248,22,71,195,250,22,74,2,
+20,9,248,22,65,199,250,22,73,2,4,248,22,73,248,22,64,199,250,22,74,
+2,3,248,22,65,201,248,22,65,202,27,248,22,65,248,22,178,3,23,197,1,
 27,249,22,1,22,77,249,22,2,22,178,3,248,22,178,3,248,22,64,199,249,
 22,171,3,80,158,38,34,251,22,73,1,22,119,105,116,104,45,99,111,110,116,
 105,110,117,97,116,105,111,110,45,109,97,114,107,2,24,250,22,74,1,23,101,
 120,116,101,110,100,45,112,97,114,97,109,101,116,101,114,105,122,97,116,105,111,
 110,21,95,1,27,99,111,110,116,105,110,117,97,116,105,111,110,45,109,97,114,
 107,45,115,101,116,45,102,105,114,115,116,11,2,24,201,250,22,74,2,20,9,
-248,22,65,203,27,248,22,65,248,22,178,3,196,28,248,22,71,193,20,15,159,
-35,34,35,249,22,171,3,80,158,37,34,27,248,22,178,3,248,22,64,197,28,
-249,22,137,8,62,61,62,248,22,172,3,248,22,88,196,250,22,73,2,20,248,
-22,73,249,22,73,21,93,2,25,248,22,64,199,250,22,74,2,6,249,22,73,
-2,25,249,22,73,248,22,97,203,2,25,248,22,65,202,251,22,73,2,17,28,
-249,22,137,8,248,22,172,3,248,22,64,200,64,101,108,115,101,10,248,22,64,
-197,250,22,74,2,20,9,248,22,65,200,249,22,63,2,6,248,22,65,202,99,
+248,22,65,203,27,248,22,65,248,22,178,3,23,197,1,28,248,22,71,23,194,
+2,87,94,23,193,1,20,15,159,35,34,35,249,22,171,3,80,158,37,34,27,
+248,22,178,3,248,22,64,23,198,2,28,249,22,138,8,62,61,62,248,22,172,
+3,248,22,88,23,197,2,250,22,73,2,20,248,22,73,249,22,73,21,93,2,
+25,248,22,64,199,250,22,74,2,7,249,22,73,2,25,249,22,73,248,22,97,
+203,2,25,248,22,65,202,251,22,73,2,17,28,249,22,138,8,248,22,172,3,
+248,22,64,23,201,2,64,101,108,115,101,10,248,22,64,23,198,2,250,22,74,
+2,20,9,248,22,65,23,201,1,249,22,63,2,7,248,22,65,23,203,1,99,
 8,31,8,30,8,29,8,28,8,27,16,4,11,11,2,18,3,1,7,101,110,
-118,54,56,48,52,16,4,11,11,2,19,3,1,7,101,110,118,54,56,48,53,
+118,54,57,51,57,16,4,11,11,2,19,3,1,7,101,110,118,54,57,52,48,
 18,158,94,10,64,118,111,105,100,8,47,27,248,22,65,248,22,178,3,196,249,
 22,171,3,80,158,37,34,28,248,22,51,248,22,172,3,248,22,64,197,250,22,
 73,2,26,248,22,73,248,22,64,199,248,22,88,198,27,248,22,172,3,248,22,
@@ -75,187 +79,187 @@
 6,2,7,2,8,2,9,2,10,2,11,2,12,16,10,11,11,11,11,11,11,
 11,11,11,11,16,10,2,3,2,4,2,5,2,6,2,7,2,8,2,9,2,
 10,2,11,2,12,34,44,16,11,16,5,93,2,13,20,15,159,34,34,34,34,
-20,102,159,34,16,0,16,1,33,32,10,16,5,93,2,12,89,162,8,36,35,
+20,102,159,34,16,0,16,1,33,32,10,16,5,93,2,12,89,162,8,44,35,
 51,9,223,0,33,33,34,20,102,159,34,16,1,20,25,159,35,2,2,2,13,
-16,0,11,16,5,93,2,5,89,162,8,36,35,51,9,223,0,33,34,34,20,
-102,159,34,16,1,20,25,159,35,2,2,2,13,16,0,11,16,5,93,2,7,
-89,162,8,36,35,51,9,223,0,33,35,34,20,102,159,34,16,1,20,25,159,
-35,2,2,2,13,16,1,33,36,11,16,5,93,2,9,89,162,8,36,35,54,
+16,0,11,16,5,93,2,5,89,162,8,44,35,51,9,223,0,33,34,34,20,
+102,159,34,16,1,20,25,159,35,2,2,2,13,16,0,11,16,5,93,2,8,
+89,162,8,44,35,51,9,223,0,33,35,34,20,102,159,34,16,1,20,25,159,
+35,2,2,2,13,16,1,33,36,11,16,5,93,2,10,89,162,8,44,35,54,
 9,223,0,33,37,34,20,102,159,34,16,1,20,25,159,35,2,2,2,13,16,
-1,33,38,11,16,5,93,2,4,89,162,8,36,35,56,9,223,0,33,41,34,
+1,33,38,11,16,5,93,2,4,89,162,8,44,35,56,9,223,0,33,41,34,
 20,102,159,34,16,1,20,25,159,35,2,2,2,13,16,0,11,16,5,93,2,
-8,89,162,8,36,35,51,9,223,0,33,43,34,20,102,159,34,16,1,20,25,
-159,35,2,2,2,13,16,0,11,16,5,93,2,3,89,162,8,36,35,52,9,
+9,89,162,8,44,35,51,9,223,0,33,43,34,20,102,159,34,16,1,20,25,
+159,35,2,2,2,13,16,0,11,16,5,93,2,3,89,162,8,44,35,52,9,
 223,0,33,44,34,20,102,159,34,16,1,20,25,159,35,2,2,2,13,16,0,
-11,16,5,93,2,10,89,162,8,36,35,53,9,223,0,33,45,34,20,102,159,
-34,16,1,20,25,159,35,2,2,2,13,16,0,11,16,5,93,2,6,89,162,
-8,36,35,56,9,223,0,33,46,34,20,102,159,34,16,1,20,25,159,35,2,
-2,2,13,16,1,33,48,11,16,5,93,2,11,89,162,8,36,35,52,9,223,
+11,16,5,93,2,6,89,162,8,44,35,53,9,223,0,33,45,34,20,102,159,
+34,16,1,20,25,159,35,2,2,2,13,16,0,11,16,5,93,2,7,89,162,
+8,44,35,56,9,223,0,33,46,34,20,102,159,34,16,1,20,25,159,35,2,
+2,2,13,16,1,33,48,11,16,5,93,2,11,89,162,8,44,35,52,9,223,
 0,33,49,34,20,102,159,34,16,1,20,25,159,35,2,2,2,13,16,0,11,
 16,0,94,2,16,2,15,93,2,16,9,0};
-    EVAL_ONE_SIZED_STR((char *)expr, 1964);
+    EVAL_ONE_SIZED_STR((char *)expr, 2048);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,8,51,46,57,57,46,48,46,57,61,0,0,0,1,0,0,3,0,16,
-0,21,0,38,0,53,0,71,0,87,0,97,0,115,0,135,0,151,0,169,0,
-200,0,229,0,251,0,9,1,15,1,29,1,34,1,44,1,52,1,80,1,112,
-1,157,1,202,1,226,1,9,2,11,2,20,2,71,2,87,3,96,3,126,3,
-170,4,242,4,58,5,146,5,158,5,201,5,217,5,204,6,218,6,69,7,8,
-8,202,8,209,8,215,8,75,9,87,9,155,9,1,10,14,10,36,10,170,10,
-36,11,37,12,45,12,53,12,79,12,159,12,0,0,210,15,0,0,29,11,11,
-72,112,97,116,104,45,115,116,114,105,110,103,63,64,98,115,98,115,76,110,111,
-114,109,97,108,45,99,97,115,101,45,112,97,116,104,74,45,99,104,101,99,107,
-45,114,101,108,112,97,116,104,77,45,99,104,101,99,107,45,99,111,108,108,101,
-99,116,105,111,110,75,99,111,108,108,101,99,116,105,111,110,45,112,97,116,104,
-69,45,102,105,110,100,45,99,111,108,77,99,104,101,99,107,45,115,117,102,102,
-105,120,45,99,97,108,108,79,112,97,116,104,45,114,101,112,108,97,99,101,45,
-115,117,102,102,105,120,75,112,97,116,104,45,97,100,100,45,115,117,102,102,105,
-120,77,108,111,97,100,47,117,115,101,45,99,111,109,112,105,108,101,100,1,29,
-102,105,110,100,45,108,105,98,114,97,114,121,45,99,111,108,108,101,99,116,105,
-111,110,45,112,97,116,104,115,1,27,112,97,116,104,45,108,105,115,116,45,115,
-116,114,105,110,103,45,62,112,97,116,104,45,108,105,115,116,1,20,102,105,110,
-100,45,101,120,101,99,117,116,97,98,108,101,45,112,97,116,104,73,101,109,98,
-101,100,100,101,100,45,108,111,97,100,65,113,117,111,116,101,29,94,2,17,68,
-35,37,112,97,114,97,109,122,11,64,108,111,111,112,69,101,120,101,99,45,102,
-105,108,101,67,119,105,110,100,111,119,115,6,25,25,112,97,116,104,32,111,114,
-32,118,97,108,105,100,45,112,97,116,104,32,115,116,114,105,110,103,6,29,29,
-126,97,58,32,105,110,118,97,108,105,100,32,114,101,108,97,116,105,118,101,32,
-112,97,116,104,58,32,126,115,6,42,42,126,97,58,32,99,111,108,108,101,99,
-116,105,111,110,32,110,111,116,32,102,111,117,110,100,58,32,126,115,32,105,110,
-32,97,110,121,32,111,102,58,32,126,115,6,42,42,112,97,116,104,32,40,102,
-111,114,32,97,110,121,32,115,121,115,116,101,109,41,32,111,114,32,118,97,108,
-105,100,45,112,97,116,104,32,115,116,114,105,110,103,6,21,21,115,116,114,105,
-110,103,32,111,114,32,98,121,116,101,32,115,116,114,105,110,103,6,36,36,99,
-97,110,110,111,116,32,97,100,100,32,97,32,115,117,102,102,105,120,32,116,111,
-32,97,32,114,111,111,116,32,112,97,116,104,58,32,5,0,68,35,37,107,101,
-114,110,101,108,27,20,14,159,80,158,35,49,250,80,158,38,50,249,22,27,11,
-80,158,40,49,22,137,12,10,248,22,186,4,195,28,248,22,164,5,193,12,87,
-94,248,22,140,8,193,248,80,159,36,53,35,195,28,248,22,71,194,9,27,248,
-22,64,195,27,28,248,22,182,12,194,193,28,248,22,181,12,194,249,22,183,12,
-195,250,80,158,41,47,248,22,133,13,2,20,11,10,250,80,158,39,47,248,22,
-133,13,2,20,196,10,28,192,249,22,63,248,22,185,12,249,22,183,12,197,247,
-22,134,13,27,248,22,65,199,28,248,22,71,193,9,27,248,22,64,194,27,28,
-248,22,182,12,194,193,28,248,22,181,12,194,249,22,183,12,195,250,80,158,46,
-47,248,22,133,13,2,20,11,10,250,80,158,44,47,248,22,133,13,2,20,196,
-10,28,192,249,22,63,248,22,185,12,249,22,183,12,197,247,22,134,13,248,80,
-159,44,52,35,248,22,65,198,248,80,159,42,52,35,248,22,65,196,27,248,22,
-65,197,28,248,22,71,193,9,27,248,22,64,194,27,28,248,22,182,12,194,193,
-28,248,22,181,12,194,249,22,183,12,195,250,80,158,44,47,248,22,133,13,2,
-20,11,10,250,80,158,42,47,248,22,133,13,2,20,196,10,28,192,249,22,63,
-248,22,185,12,249,22,183,12,197,247,22,134,13,248,80,159,42,52,35,248,22,
-65,198,248,80,159,40,52,35,248,22,65,196,249,80,159,36,37,35,2,7,195,
-27,248,22,158,12,194,28,192,192,28,248,22,133,6,194,27,248,22,180,12,195,
-28,192,192,248,22,181,12,195,11,87,94,28,28,248,22,159,12,194,10,27,248,
-22,158,12,195,28,192,192,28,248,22,133,6,195,27,248,22,180,12,196,28,192,
-192,248,22,181,12,196,11,12,250,22,167,8,76,110,111,114,109,97,108,45,112,
-97,116,104,45,99,97,115,101,6,42,42,112,97,116,104,32,40,102,111,114,32,
-97,110,121,32,115,121,115,116,101,109,41,32,111,114,32,118,97,108,105,100,45,
-112,97,116,104,32,115,116,114,105,110,103,196,28,28,248,22,159,12,194,249,22,
-137,8,248,22,160,12,196,2,21,249,22,137,8,247,22,152,7,2,21,27,28,
-248,22,133,6,195,194,248,22,142,7,248,22,163,12,196,28,249,22,146,13,0,
-21,35,114,120,34,94,91,92,92,93,91,92,92,93,91,63,93,91,92,92,93,
-34,194,28,248,22,133,6,195,248,22,166,12,195,194,27,248,22,172,6,194,249,
-22,167,12,248,22,145,7,250,22,152,13,0,6,35,114,120,34,47,34,28,249,
-22,146,13,0,22,35,114,120,34,91,47,92,92,93,91,46,32,93,43,91,47,
-92,92,93,42,36,34,200,198,250,22,152,13,0,19,35,114,120,34,91,32,46,
-93,43,40,91,47,92,92,93,42,41,36,34,201,6,2,2,92,49,80,158,42,
-35,2,21,28,248,22,133,6,194,248,22,166,12,194,193,87,94,28,27,248,22,
-158,12,195,28,192,192,28,248,22,133,6,195,27,248,22,180,12,196,28,192,192,
-248,22,181,12,196,11,12,250,22,167,8,195,2,22,196,28,248,22,180,12,194,
-12,248,22,182,10,249,22,191,9,248,22,162,6,250,22,181,6,2,23,199,200,
-247,22,23,87,94,28,27,248,22,158,12,195,28,192,192,28,248,22,133,6,195,
-27,248,22,180,12,196,28,192,192,248,22,181,12,196,11,12,250,22,167,8,195,
-2,22,196,28,248,22,180,12,194,12,248,22,182,10,249,22,191,9,248,22,162,
-6,250,22,181,6,2,23,199,200,247,22,23,87,94,87,94,28,27,248,22,158,
-12,195,28,192,192,28,248,22,133,6,195,27,248,22,180,12,196,28,192,192,248,
-22,181,12,196,11,12,250,22,167,8,195,2,22,196,28,248,22,180,12,194,12,
-248,22,182,10,249,22,191,9,248,22,162,6,250,22,181,6,2,23,199,200,247,
-22,23,249,22,3,89,162,34,35,48,9,223,2,33,36,196,248,22,182,10,249,
-22,157,10,195,247,22,23,87,94,87,94,249,80,159,36,37,35,2,7,195,249,
-22,3,80,159,36,51,35,196,251,80,159,38,40,35,2,7,32,0,89,162,34,
-35,43,9,222,33,38,197,198,32,40,89,162,34,40,57,65,99,108,111,111,112,
-222,33,41,28,248,22,71,198,248,195,251,22,181,6,2,24,198,28,248,22,71,
-202,200,250,22,1,22,176,12,203,204,197,27,249,22,176,12,248,22,64,201,198,
-28,248,22,171,12,193,27,250,22,1,22,176,12,196,201,28,248,22,171,12,193,
-192,27,248,22,65,201,28,248,22,71,193,248,198,251,22,181,6,2,24,201,28,
-248,22,71,205,203,250,22,1,22,176,12,206,23,15,200,27,249,22,176,12,248,
-22,64,196,201,28,248,22,171,12,193,27,250,22,1,22,176,12,196,204,28,248,
-22,171,12,193,192,253,2,40,203,204,205,206,23,15,248,22,65,201,253,2,40,
-202,203,204,205,206,248,22,65,200,27,248,22,65,200,28,248,22,71,193,248,197,
-251,22,181,6,2,24,200,28,248,22,71,204,202,250,22,1,22,176,12,205,206,
-199,27,249,22,176,12,248,22,64,196,200,28,248,22,171,12,193,27,250,22,1,
-22,176,12,196,203,28,248,22,171,12,193,192,253,2,40,202,203,204,205,206,248,
-22,65,201,253,2,40,201,202,203,204,205,248,22,65,200,27,247,22,135,13,253,
-2,40,198,199,200,201,202,198,87,95,28,28,248,22,159,12,193,10,27,248,22,
-158,12,194,28,192,192,28,248,22,133,6,194,27,248,22,180,12,195,28,192,192,
-248,22,181,12,195,11,12,252,22,167,8,199,2,25,34,197,198,28,28,248,22,
-133,6,194,10,248,22,185,6,194,12,252,22,167,8,199,2,26,35,197,198,91,
-159,37,11,90,161,37,34,11,248,22,179,12,196,87,94,28,192,12,250,22,168,
-8,200,2,27,198,249,22,7,194,195,91,159,36,11,90,161,36,34,11,87,95,
-28,28,248,22,159,12,195,10,27,248,22,158,12,196,28,192,192,28,248,22,133,
-6,196,27,248,22,180,12,197,28,192,192,248,22,181,12,197,11,12,252,22,167,
-8,2,10,2,25,34,199,200,28,28,248,22,133,6,196,10,248,22,185,6,196,
-12,252,22,167,8,2,10,2,26,35,199,200,91,159,37,11,90,161,37,34,11,
-248,22,179,12,198,87,94,28,192,12,250,22,168,8,2,10,2,27,200,249,22,
-7,194,195,27,249,22,168,12,250,22,151,13,0,18,35,114,120,35,34,40,91,
-46,93,91,94,46,93,42,124,41,36,34,248,22,164,12,200,28,248,22,133,6,
-202,249,22,145,7,203,8,63,201,28,248,22,159,12,198,248,22,160,12,198,247,
-22,161,12,28,248,22,158,12,194,249,22,176,12,195,194,192,91,159,36,11,90,
-161,36,34,11,87,95,28,28,248,22,159,12,195,10,27,248,22,158,12,196,28,
-192,192,28,248,22,133,6,196,27,248,22,180,12,197,28,192,192,248,22,181,12,
-197,11,12,252,22,167,8,2,11,2,25,34,199,200,28,28,248,22,133,6,196,
-10,248,22,185,6,196,12,252,22,167,8,2,11,2,26,35,199,200,91,159,37,
-11,90,161,37,34,11,248,22,179,12,198,87,94,28,192,12,250,22,168,8,2,
-11,2,27,200,249,22,7,194,195,27,249,22,168,12,249,22,131,7,250,22,152,
-13,0,9,35,114,120,35,34,91,46,93,34,248,22,164,12,202,6,1,1,95,
-28,248,22,133,6,201,249,22,145,7,202,8,63,200,28,248,22,159,12,198,248,
-22,160,12,198,247,22,161,12,28,248,22,158,12,194,249,22,176,12,195,194,192,
-249,247,22,184,5,194,11,248,80,158,35,45,9,27,247,22,137,13,249,80,158,
-37,46,28,194,27,248,22,150,7,6,11,11,80,76,84,67,79,76,76,69,67,
-84,83,28,192,192,6,0,0,6,0,0,27,28,195,250,22,176,12,248,22,133,
-13,69,97,100,100,111,110,45,100,105,114,247,22,148,7,6,8,8,99,111,108,
-108,101,99,116,115,11,27,248,80,159,40,52,35,249,22,77,201,248,22,73,248,
-22,133,13,72,99,111,108,108,101,99,116,115,45,100,105,114,28,193,249,22,63,
-195,194,192,32,49,89,162,34,37,49,2,19,222,33,50,27,249,22,144,13,196,
-197,28,192,27,248,22,88,194,27,250,2,49,198,199,248,22,97,198,28,249,22,
-191,6,195,2,28,249,22,77,197,194,249,22,63,248,22,167,12,196,194,28,249,
-22,191,6,197,2,28,249,22,77,195,9,249,22,63,248,22,167,12,198,9,87,
-95,28,28,248,22,185,6,194,10,248,22,133,6,194,12,250,22,167,8,2,14,
-6,21,21,98,121,116,101,32,115,116,114,105,110,103,32,111,114,32,115,116,114,
-105,110,103,196,28,28,248,22,72,195,249,22,4,22,158,12,196,11,12,250,22,
-167,8,2,14,6,13,13,108,105,115,116,32,111,102,32,112,97,116,104,115,197,
-250,2,49,197,195,28,248,22,133,6,197,248,22,144,7,197,196,32,52,89,162,
-8,36,38,56,2,19,222,33,55,32,53,89,162,8,36,37,53,70,102,111,117,
-110,100,45,101,120,101,99,222,33,54,28,192,91,159,37,11,90,161,37,34,11,
-248,22,179,12,198,27,28,197,27,248,22,184,12,200,28,249,22,139,8,194,201,
-11,28,248,22,180,12,193,250,2,53,200,201,249,22,176,12,199,197,250,2,53,
-200,201,195,11,28,192,192,27,28,248,22,158,12,195,27,249,22,176,12,197,200,
-28,28,248,22,171,12,193,10,248,22,170,12,193,192,11,11,28,192,192,28,198,
-11,27,248,22,184,12,201,28,249,22,139,8,194,202,11,28,248,22,180,12,193,
-250,2,53,201,202,249,22,176,12,200,197,250,2,53,201,202,195,194,28,248,22,
-71,196,11,27,248,22,183,12,248,22,64,198,27,249,22,176,12,195,196,28,248,
-22,170,12,193,250,2,53,198,199,195,27,248,22,65,199,28,248,22,71,193,11,
-27,248,22,183,12,248,22,64,195,27,249,22,176,12,195,199,28,248,22,170,12,
-193,250,2,53,201,202,195,27,248,22,65,196,28,248,22,71,193,11,27,248,22,
-183,12,248,22,64,195,27,249,22,176,12,195,202,28,248,22,170,12,193,250,2,
-53,204,205,195,251,2,52,204,205,206,248,22,65,199,87,95,28,27,248,22,158,
-12,195,28,192,192,28,248,22,133,6,195,27,248,22,180,12,196,28,192,192,248,
-22,181,12,196,11,12,250,22,167,8,2,15,6,25,25,112,97,116,104,32,111,
-114,32,115,116,114,105,110,103,32,40,115,97,110,115,32,110,117,108,41,196,28,
-28,194,28,27,248,22,158,12,196,28,192,192,28,248,22,133,6,196,27,248,22,
-180,12,197,28,192,192,248,22,181,12,197,11,248,22,180,12,195,11,10,12,250,
-22,167,8,2,15,6,29,29,35,102,32,111,114,32,114,101,108,97,116,105,118,
-101,32,112,97,116,104,32,111,114,32,115,116,114,105,110,103,197,28,28,248,22,
-180,12,194,91,159,37,11,90,161,37,34,11,248,22,179,12,197,249,22,137,8,
-194,68,114,101,108,97,116,105,118,101,11,27,248,22,150,7,6,4,4,80,65,
-84,72,251,2,52,198,199,200,28,196,27,249,80,158,42,46,199,9,28,249,22,
-137,8,247,22,152,7,2,21,249,22,63,248,22,167,12,5,1,46,194,192,9,
-27,248,22,183,12,195,28,248,22,170,12,193,250,2,53,198,199,195,11,250,80,
-158,37,47,196,197,11,250,80,158,37,47,196,11,11,87,94,249,22,189,5,247,
-22,166,4,195,248,22,140,5,249,22,151,3,34,249,22,135,3,197,198,27,248,
-22,133,13,2,20,27,249,80,158,38,47,195,11,27,27,248,22,154,3,198,28,
-192,192,34,27,27,248,22,154,3,200,28,192,192,34,27,249,22,183,4,197,89,
-162,8,36,34,46,9,224,4,3,33,59,27,248,22,170,4,194,87,94,248,22,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,9,51,46,57,57,46,48,46,49,49,61,0,0,0,1,0,0,3,0,
+16,0,21,0,38,0,53,0,71,0,87,0,97,0,115,0,135,0,151,0,169,
+0,200,0,229,0,251,0,9,1,15,1,29,1,34,1,44,1,52,1,80,1,
+112,1,157,1,202,1,226,1,9,2,11,2,20,2,71,2,87,3,96,3,126,
+3,170,4,242,4,58,5,146,5,158,5,201,5,217,5,204,6,218,6,69,7,
+8,8,202,8,209,8,215,8,75,9,87,9,155,9,1,10,14,10,36,10,170,
+10,36,11,37,12,45,12,53,12,79,12,158,12,0,0,209,15,0,0,29,11,
+11,72,112,97,116,104,45,115,116,114,105,110,103,63,64,98,115,98,115,76,110,
+111,114,109,97,108,45,99,97,115,101,45,112,97,116,104,74,45,99,104,101,99,
+107,45,114,101,108,112,97,116,104,77,45,99,104,101,99,107,45,99,111,108,108,
+101,99,116,105,111,110,75,99,111,108,108,101,99,116,105,111,110,45,112,97,116,
+104,69,45,102,105,110,100,45,99,111,108,77,99,104,101,99,107,45,115,117,102,
+102,105,120,45,99,97,108,108,79,112,97,116,104,45,114,101,112,108,97,99,101,
+45,115,117,102,102,105,120,75,112,97,116,104,45,97,100,100,45,115,117,102,102,
+105,120,77,108,111,97,100,47,117,115,101,45,99,111,109,112,105,108,101,100,1,
+29,102,105,110,100,45,108,105,98,114,97,114,121,45,99,111,108,108,101,99,116,
+105,111,110,45,112,97,116,104,115,1,27,112,97,116,104,45,108,105,115,116,45,
+115,116,114,105,110,103,45,62,112,97,116,104,45,108,105,115,116,1,20,102,105,
+110,100,45,101,120,101,99,117,116,97,98,108,101,45,112,97,116,104,73,101,109,
+98,101,100,100,101,100,45,108,111,97,100,65,113,117,111,116,101,29,94,2,17,
+68,35,37,112,97,114,97,109,122,11,64,108,111,111,112,69,101,120,101,99,45,
+102,105,108,101,67,119,105,110,100,111,119,115,6,25,25,112,97,116,104,32,111,
+114,32,118,97,108,105,100,45,112,97,116,104,32,115,116,114,105,110,103,6,29,
+29,126,97,58,32,105,110,118,97,108,105,100,32,114,101,108,97,116,105,118,101,
+32,112,97,116,104,58,32,126,115,6,42,42,126,97,58,32,99,111,108,108,101,
+99,116,105,111,110,32,110,111,116,32,102,111,117,110,100,58,32,126,115,32,105,
+110,32,97,110,121,32,111,102,58,32,126,115,6,42,42,112,97,116,104,32,40,
+102,111,114,32,97,110,121,32,115,121,115,116,101,109,41,32,111,114,32,118,97,
+108,105,100,45,112,97,116,104,32,115,116,114,105,110,103,6,21,21,115,116,114,
+105,110,103,32,111,114,32,98,121,116,101,32,115,116,114,105,110,103,6,36,36,
+99,97,110,110,111,116,32,97,100,100,32,97,32,115,117,102,102,105,120,32,116,
+111,32,97,32,114,111,111,116,32,112,97,116,104,58,32,5,0,68,35,37,107,
+101,114,110,101,108,27,20,14,159,80,158,35,49,250,80,158,38,50,249,22,27,
+11,80,158,40,49,22,138,12,10,248,22,186,4,195,28,248,22,164,5,193,12,
+87,94,248,22,141,8,193,248,80,159,36,53,35,195,28,248,22,71,194,9,27,
+248,22,64,195,27,28,248,22,183,12,194,193,28,248,22,182,12,194,249,22,184,
+12,195,250,80,158,41,47,248,22,134,13,2,20,11,10,250,80,158,39,47,248,
+22,134,13,2,20,196,10,28,192,249,22,63,248,22,186,12,249,22,184,12,197,
+247,22,135,13,27,248,22,65,199,28,248,22,71,193,9,27,248,22,64,194,27,
+28,248,22,183,12,194,193,28,248,22,182,12,194,249,22,184,12,195,250,80,158,
+46,47,248,22,134,13,2,20,11,10,250,80,158,44,47,248,22,134,13,2,20,
+196,10,28,192,249,22,63,248,22,186,12,249,22,184,12,197,247,22,135,13,248,
+80,159,44,52,35,248,22,65,198,248,80,159,42,52,35,248,22,65,196,27,248,
+22,65,197,28,248,22,71,193,9,27,248,22,64,194,27,28,248,22,183,12,194,
+193,28,248,22,182,12,194,249,22,184,12,195,250,80,158,44,47,248,22,134,13,
+2,20,11,10,250,80,158,42,47,248,22,134,13,2,20,196,10,28,192,249,22,
+63,248,22,186,12,249,22,184,12,197,247,22,135,13,248,80,159,42,52,35,248,
+22,65,198,248,80,159,40,52,35,248,22,65,196,249,80,159,36,37,35,2,7,
+195,27,248,22,159,12,194,28,192,192,28,248,22,133,6,194,27,248,22,181,12,
+195,28,192,192,248,22,182,12,195,11,87,94,28,28,248,22,160,12,194,10,27,
+248,22,159,12,195,28,192,192,28,248,22,133,6,195,27,248,22,181,12,196,28,
+192,192,248,22,182,12,196,11,12,250,22,168,8,76,110,111,114,109,97,108,45,
+112,97,116,104,45,99,97,115,101,6,42,42,112,97,116,104,32,40,102,111,114,
+32,97,110,121,32,115,121,115,116,101,109,41,32,111,114,32,118,97,108,105,100,
+45,112,97,116,104,32,115,116,114,105,110,103,196,28,28,248,22,160,12,194,249,
+22,138,8,248,22,161,12,196,2,21,249,22,138,8,247,22,152,7,2,21,27,
+28,248,22,133,6,195,194,248,22,142,7,248,22,164,12,196,28,249,22,147,13,
+0,21,35,114,120,34,94,91,92,92,93,91,92,92,93,91,63,93,91,92,92,
+93,34,194,28,248,22,133,6,195,248,22,167,12,195,194,27,248,22,172,6,194,
+249,22,168,12,248,22,145,7,250,22,153,13,0,6,35,114,120,34,47,34,28,
+249,22,147,13,0,22,35,114,120,34,91,47,92,92,93,91,46,32,93,43,91,
+47,92,92,93,42,36,34,200,198,250,22,153,13,0,19,35,114,120,34,91,32,
+46,93,43,40,91,47,92,92,93,42,41,36,34,201,6,2,2,92,49,80,158,
+42,35,2,21,28,248,22,133,6,194,248,22,167,12,194,193,87,94,28,27,248,
+22,159,12,195,28,192,192,28,248,22,133,6,195,27,248,22,181,12,196,28,192,
+192,248,22,182,12,196,11,12,250,22,168,8,195,2,22,196,28,248,22,181,12,
+194,12,248,22,183,10,249,22,128,10,248,22,162,6,250,22,181,6,2,23,199,
+200,247,22,23,87,94,28,27,248,22,159,12,195,28,192,192,28,248,22,133,6,
+195,27,248,22,181,12,196,28,192,192,248,22,182,12,196,11,12,250,22,168,8,
+195,2,22,196,28,248,22,181,12,194,12,248,22,183,10,249,22,128,10,248,22,
+162,6,250,22,181,6,2,23,199,200,247,22,23,87,94,87,94,28,27,248,22,
+159,12,195,28,192,192,28,248,22,133,6,195,27,248,22,181,12,196,28,192,192,
+248,22,182,12,196,11,12,250,22,168,8,195,2,22,196,28,248,22,181,12,194,
+12,248,22,183,10,249,22,128,10,248,22,162,6,250,22,181,6,2,23,199,200,
+247,22,23,249,22,3,89,162,34,35,48,9,223,2,33,36,196,248,22,183,10,
+249,22,158,10,195,247,22,23,87,94,87,94,249,80,159,36,37,35,2,7,195,
+249,22,3,80,159,36,51,35,196,251,80,159,38,40,35,2,7,32,0,89,162,
+34,35,43,9,222,33,38,197,198,32,40,89,162,34,40,57,65,99,108,111,111,
+112,222,33,41,28,248,22,71,198,248,195,251,22,181,6,2,24,198,28,248,22,
+71,202,200,250,22,1,22,177,12,203,204,197,27,249,22,177,12,248,22,64,201,
+198,28,248,22,172,12,193,27,250,22,1,22,177,12,196,201,28,248,22,172,12,
+193,192,27,248,22,65,201,28,248,22,71,193,248,198,251,22,181,6,2,24,201,
+28,248,22,71,205,203,250,22,1,22,177,12,206,23,15,200,27,249,22,177,12,
+248,22,64,196,201,28,248,22,172,12,193,27,250,22,1,22,177,12,196,204,28,
+248,22,172,12,193,192,253,2,40,203,204,205,206,23,15,248,22,65,201,253,2,
+40,202,203,204,205,206,248,22,65,200,27,248,22,65,200,28,248,22,71,193,248,
+197,251,22,181,6,2,24,200,28,248,22,71,204,202,250,22,1,22,177,12,205,
+206,199,27,249,22,177,12,248,22,64,196,200,28,248,22,172,12,193,27,250,22,
+1,22,177,12,196,203,28,248,22,172,12,193,192,253,2,40,202,203,204,205,206,
+248,22,65,201,253,2,40,201,202,203,204,205,248,22,65,200,27,247,22,136,13,
+253,2,40,198,199,200,201,202,198,87,95,28,28,248,22,160,12,193,10,27,248,
+22,159,12,194,28,192,192,28,248,22,133,6,194,27,248,22,181,12,195,28,192,
+192,248,22,182,12,195,11,12,252,22,168,8,199,2,25,34,197,198,28,28,248,
+22,133,6,194,10,248,22,185,6,194,12,252,22,168,8,199,2,26,35,197,198,
+91,159,37,11,90,161,37,34,11,248,22,180,12,196,87,94,28,192,12,250,22,
+169,8,200,2,27,198,249,22,7,194,195,91,159,36,11,90,161,36,34,11,87,
+95,28,28,248,22,160,12,195,10,27,248,22,159,12,196,28,192,192,28,248,22,
+133,6,196,27,248,22,181,12,197,28,192,192,248,22,182,12,197,11,12,252,22,
+168,8,2,10,2,25,34,199,200,28,28,248,22,133,6,196,10,248,22,185,6,
+196,12,252,22,168,8,2,10,2,26,35,199,200,91,159,37,11,90,161,37,34,
+11,248,22,180,12,198,87,94,28,192,12,250,22,169,8,2,10,2,27,200,249,
+22,7,194,195,27,249,22,169,12,250,22,152,13,0,18,35,114,120,35,34,40,
+91,46,93,91,94,46,93,42,124,41,36,34,248,22,165,12,200,28,248,22,133,
+6,202,249,22,145,7,203,8,63,201,28,248,22,160,12,198,248,22,161,12,198,
+247,22,162,12,28,248,22,159,12,194,249,22,177,12,195,194,192,91,159,36,11,
+90,161,36,34,11,87,95,28,28,248,22,160,12,195,10,27,248,22,159,12,196,
+28,192,192,28,248,22,133,6,196,27,248,22,181,12,197,28,192,192,248,22,182,
+12,197,11,12,252,22,168,8,2,11,2,25,34,199,200,28,28,248,22,133,6,
+196,10,248,22,185,6,196,12,252,22,168,8,2,11,2,26,35,199,200,91,159,
+37,11,90,161,37,34,11,248,22,180,12,198,87,94,28,192,12,250,22,169,8,
+2,11,2,27,200,249,22,7,194,195,27,249,22,169,12,249,22,131,7,250,22,
+153,13,0,9,35,114,120,35,34,91,46,93,34,248,22,165,12,202,6,1,1,
+95,28,248,22,133,6,201,249,22,145,7,202,8,63,200,28,248,22,160,12,198,
+248,22,161,12,198,247,22,162,12,28,248,22,159,12,194,249,22,177,12,195,194,
+192,249,247,22,184,5,194,11,248,80,158,35,45,9,27,247,22,138,13,249,80,
+158,37,46,28,194,27,248,22,150,7,6,11,11,80,76,84,67,79,76,76,69,
+67,84,83,28,192,192,6,0,0,6,0,0,27,28,195,250,22,177,12,248,22,
+134,13,69,97,100,100,111,110,45,100,105,114,247,22,148,7,6,8,8,99,111,
+108,108,101,99,116,115,11,27,248,80,159,40,52,35,249,22,77,201,248,22,73,
+248,22,134,13,72,99,111,108,108,101,99,116,115,45,100,105,114,28,193,249,22,
+63,195,194,192,32,49,89,162,34,37,49,2,19,222,33,50,27,249,22,145,13,
+196,197,28,192,27,248,22,88,194,27,250,2,49,198,199,248,22,97,198,28,249,
+22,191,6,195,2,28,249,22,77,197,194,249,22,63,248,22,168,12,196,194,28,
+249,22,191,6,197,2,28,249,22,77,195,9,249,22,63,248,22,168,12,198,9,
+87,95,28,28,248,22,185,6,194,10,248,22,133,6,194,12,250,22,168,8,2,
+14,6,21,21,98,121,116,101,32,115,116,114,105,110,103,32,111,114,32,115,116,
+114,105,110,103,196,28,28,248,22,72,195,249,22,4,22,159,12,196,11,12,250,
+22,168,8,2,14,6,13,13,108,105,115,116,32,111,102,32,112,97,116,104,115,
+197,250,2,49,197,195,28,248,22,133,6,197,248,22,144,7,197,196,32,52,89,
+162,8,36,38,56,2,19,222,33,55,32,53,89,162,8,36,37,53,70,102,111,
+117,110,100,45,101,120,101,99,222,33,54,28,192,91,159,37,11,90,161,37,34,
+11,248,22,180,12,198,27,28,197,27,248,22,185,12,200,28,249,22,140,8,194,
+201,11,28,248,22,181,12,193,250,2,53,200,201,249,22,177,12,199,197,250,2,
+53,200,201,195,11,28,192,192,27,28,248,22,159,12,195,27,249,22,177,12,197,
+200,28,28,248,22,172,12,193,10,248,22,171,12,193,192,11,11,28,192,192,28,
+198,11,27,248,22,185,12,201,28,249,22,140,8,194,202,11,28,248,22,181,12,
+193,250,2,53,201,202,249,22,177,12,200,197,250,2,53,201,202,195,194,28,248,
+22,71,196,11,27,248,22,184,12,248,22,64,198,27,249,22,177,12,195,196,28,
+248,22,171,12,193,250,2,53,198,199,195,27,248,22,65,199,28,248,22,71,193,
+11,27,248,22,184,12,248,22,64,195,27,249,22,177,12,195,199,28,248,22,171,
+12,193,250,2,53,201,202,195,27,248,22,65,196,28,248,22,71,193,11,27,248,
+22,184,12,248,22,64,195,27,249,22,177,12,195,202,28,248,22,171,12,193,250,
+2,53,204,205,195,251,2,52,204,205,206,248,22,65,199,87,95,28,27,248,22,
+159,12,195,28,192,192,28,248,22,133,6,195,27,248,22,181,12,196,28,192,192,
+248,22,182,12,196,11,12,250,22,168,8,2,15,6,25,25,112,97,116,104,32,
+111,114,32,115,116,114,105,110,103,32,40,115,97,110,115,32,110,117,108,41,196,
+28,28,194,28,27,248,22,159,12,196,28,192,192,28,248,22,133,6,196,27,248,
+22,181,12,197,28,192,192,248,22,182,12,197,11,248,22,181,12,195,11,10,12,
+250,22,168,8,2,15,6,29,29,35,102,32,111,114,32,114,101,108,97,116,105,
+118,101,32,112,97,116,104,32,111,114,32,115,116,114,105,110,103,197,28,28,248,
+22,181,12,194,91,159,37,11,90,161,37,34,11,248,22,180,12,197,249,22,138,
+8,194,68,114,101,108,97,116,105,118,101,11,27,248,22,150,7,6,4,4,80,
+65,84,72,251,2,52,198,199,200,28,196,27,249,80,158,42,46,199,9,28,249,
+22,138,8,247,22,152,7,2,21,249,22,63,248,22,168,12,5,1,46,194,192,
+9,27,248,22,184,12,195,28,248,22,171,12,193,250,2,53,198,199,195,11,250,
+80,158,37,47,196,197,11,250,80,158,37,47,196,11,11,87,94,249,22,189,5,
+247,22,166,4,195,248,22,140,5,249,22,151,3,34,249,22,135,3,197,198,27,
+248,22,134,13,2,20,27,249,80,158,38,47,195,11,27,27,248,22,154,3,198,
+28,192,192,34,27,27,248,22,154,3,200,28,192,192,34,27,249,22,183,4,197,
+89,162,34,34,46,9,224,4,3,33,59,27,248,22,170,4,194,87,94,248,22,
 134,4,21,94,2,17,2,29,248,80,159,41,53,35,193,159,34,20,102,159,34,
 16,1,20,24,65,98,101,103,105,110,16,0,83,158,40,20,99,134,67,35,37,
 117,116,105,108,115,2,1,11,10,10,10,10,10,41,80,158,34,34,20,102,159,
@@ -288,7 +292,7 @@
 16,2,32,0,89,162,34,35,42,2,12,222,33,46,80,159,34,44,35,83,158,
 34,16,2,83,158,37,20,96,95,2,13,89,162,34,34,41,9,223,0,33,47,
 89,162,34,35,51,9,223,0,33,48,80,159,34,45,35,83,158,34,16,2,27,
-248,22,140,13,248,22,144,7,27,28,249,22,137,8,247,22,152,7,2,21,6,
+248,22,141,13,248,22,144,7,27,28,249,22,138,8,247,22,152,7,2,21,6,
 1,1,59,6,1,1,58,250,22,181,6,6,14,14,40,91,94,126,97,93,42,
 41,126,97,40,46,42,41,195,195,89,162,34,36,46,2,14,223,0,33,51,80,
 159,34,46,35,83,158,34,16,2,83,158,37,20,96,96,2,15,89,162,8,36,
@@ -299,160 +303,160 @@
     EVAL_ONE_SIZED_STR((char *)expr, 4194);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,8,51,46,57,57,46,48,46,57,7,0,0,0,1,0,0,6,0,19,
-0,34,0,48,0,62,0,76,0,0,0,253,0,0,0,65,113,117,111,116,101,
-29,94,2,1,67,35,37,117,116,105,108,115,11,29,94,2,1,69,35,37,110,
-101,116,119,111,114,107,11,29,94,2,1,68,35,37,112,97,114,97,109,122,11,
-29,94,2,1,68,35,37,101,120,112,111,98,115,11,29,94,2,1,68,35,37,
-107,101,114,110,101,108,11,159,34,20,102,159,34,16,1,20,24,65,98,101,103,
-105,110,16,0,83,158,40,20,99,134,69,35,37,98,117,105,108,116,105,110,29,
-11,11,10,10,18,94,11,97,10,34,11,97,159,2,2,34,34,159,2,3,34,
-34,159,2,4,34,34,159,2,5,34,34,159,2,6,34,34,16,0,18,94,11,
-95,35,11,16,0,10,18,94,11,95,8,240,48,117,0,0,11,16,0,34,80,
-158,34,34,20,102,159,34,16,0,16,0,11,11,16,0,34,11,11,11,16,0,
-16,0,16,0,34,34,11,11,16,0,16,0,16,0,34,34,11,11,16,0,16,
-0,16,0,34,34,16,0,16,0,98,2,6,2,5,29,94,2,1,69,35,37,
-102,111,114,101,105,103,110,11,2,4,2,3,2,2,9,9,0};
-    EVAL_ONE_SIZED_STR((char *)expr, 289);
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,9,51,46,57,57,46,48,46,49,49,7,0,0,0,1,0,0,6,0,
+19,0,34,0,48,0,62,0,76,0,0,0,253,0,0,0,65,113,117,111,116,
+101,29,94,2,1,67,35,37,117,116,105,108,115,11,29,94,2,1,69,35,37,
+110,101,116,119,111,114,107,11,29,94,2,1,68,35,37,112,97,114,97,109,122,
+11,29,94,2,1,68,35,37,101,120,112,111,98,115,11,29,94,2,1,68,35,
+37,107,101,114,110,101,108,11,159,34,20,102,159,34,16,1,20,24,65,98,101,
+103,105,110,16,0,83,158,40,20,99,134,69,35,37,98,117,105,108,116,105,110,
+29,11,11,10,10,18,94,11,97,10,34,11,97,159,2,2,34,34,159,2,3,
+34,34,159,2,4,34,34,159,2,5,34,34,159,2,6,34,34,16,0,18,94,
+11,95,35,11,16,0,10,18,94,11,95,8,240,48,117,0,0,11,16,0,34,
+80,158,34,34,20,102,159,34,16,0,16,0,11,11,16,0,34,11,11,11,16,
+0,16,0,16,0,34,34,11,11,16,0,16,0,16,0,34,34,11,11,16,0,
+16,0,16,0,34,34,16,0,16,0,98,2,6,2,5,29,94,2,1,69,35,
+37,102,111,114,101,105,103,110,11,2,4,2,3,2,2,9,9,0};
+    EVAL_ONE_SIZED_STR((char *)expr, 290);
   }
   {
-    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,8,51,46,57,57,46,48,46,57,52,0,0,0,1,0,0,3,0,14,
-0,41,0,47,0,60,0,74,0,96,0,122,0,134,0,152,0,172,0,184,0,
-200,0,223,0,3,1,8,1,13,1,18,1,23,1,54,1,58,1,66,1,74,
-1,82,1,163,1,199,1,216,1,245,1,17,2,47,2,57,2,87,2,97,2,
-104,2,178,3,190,3,209,3,33,4,45,4,173,4,185,4,30,5,36,5,50,
-5,77,5,148,5,150,5,203,5,93,10,152,10,184,10,0,0,119,13,0,0,
-29,11,11,70,100,108,108,45,115,117,102,102,105,120,1,25,100,101,102,97,117,
-108,116,45,108,111,97,100,47,117,115,101,45,99,111,109,112,105,108,101,100,65,
-113,117,111,116,101,29,94,2,4,67,35,37,117,116,105,108,115,11,29,94,2,
-4,68,35,37,112,97,114,97,109,122,11,1,20,100,101,102,97,117,108,116,45,
-114,101,97,100,101,114,45,103,117,97,114,100,1,24,45,109,111,100,117,108,101,
-45,104,97,115,104,45,116,97,98,108,101,45,116,97,98,108,101,71,45,112,97,
-116,104,45,99,97,99,104,101,77,45,108,111,97,100,105,110,103,45,102,105,108,
-101,110,97,109,101,79,45,108,111,97,100,105,110,103,45,112,114,111,109,112,116,
-45,116,97,103,71,45,112,114,101,118,45,114,101,108,116,111,75,45,112,114,101,
-118,45,114,101,108,116,111,45,100,105,114,1,21,115,112,108,105,116,45,114,101,
-108,97,116,105,118,101,45,115,116,114,105,110,103,1,34,109,97,107,101,45,115,
-116,97,110,100,97,114,100,45,109,111,100,117,108,101,45,110,97,109,101,45,114,
-101,115,111,108,118,101,114,64,98,111,111,116,64,115,97,109,101,64,119,101,97,
-107,64,108,111,111,112,1,29,115,116,97,110,100,97,114,100,45,109,111,100,117,
-108,101,45,110,97,109,101,45,114,101,115,111,108,118,101,114,63,108,105,98,67,
-105,103,110,111,114,101,100,249,22,14,195,80,158,36,44,249,80,159,36,47,35,
-195,10,27,28,194,28,249,22,137,8,196,80,158,37,45,80,158,35,46,27,248,
-22,149,4,196,28,248,22,158,12,193,91,159,37,11,90,161,37,34,11,248,22,
-179,12,196,87,95,83,160,36,11,80,158,39,45,198,83,160,36,11,80,158,39,
-46,192,192,11,11,28,192,192,27,247,22,185,5,28,192,192,247,22,134,13,20,
-14,159,80,158,34,38,250,80,158,37,39,249,22,27,11,80,158,39,38,22,185,
-5,28,248,22,158,12,197,196,247,22,134,13,247,194,250,22,176,12,196,198,249,
-80,158,41,37,197,5,3,46,122,111,252,22,176,12,198,200,6,6,6,110,97,
-116,105,118,101,247,22,153,7,249,80,158,43,37,199,80,158,43,34,27,193,27,
-250,22,129,13,196,11,32,0,89,162,8,44,34,39,9,222,11,28,192,249,22,
-63,195,194,11,27,248,194,195,27,250,22,129,13,196,11,32,0,89,162,8,44,
-34,39,9,222,11,28,192,249,22,63,195,194,11,249,247,22,139,13,248,22,64,
-195,195,27,248,194,195,27,250,22,129,13,196,11,32,0,89,162,8,44,34,39,
-9,222,11,28,192,249,22,63,195,194,11,249,247,22,183,5,248,22,64,195,195,
-249,247,22,183,5,194,195,87,94,28,248,80,158,35,36,194,12,250,22,167,8,
-77,108,111,97,100,47,117,115,101,45,99,111,109,112,105,108,101,100,6,25,25,
-112,97,116,104,32,111,114,32,118,97,108,105,100,45,112,97,116,104,32,115,116,
-114,105,110,103,196,91,159,40,11,90,161,35,34,11,28,248,22,182,12,200,199,
-27,247,22,185,5,28,192,249,22,183,12,202,194,200,90,161,37,35,11,248,22,
-179,12,193,90,161,35,38,11,28,249,22,137,8,195,68,114,101,108,97,116,105,
-118,101,2,17,193,90,161,35,39,11,247,22,136,13,27,89,162,34,35,48,62,
-122,111,225,7,5,3,33,27,27,89,162,34,35,50,9,225,8,6,4,33,28,
-27,249,22,5,89,162,34,35,46,9,223,5,33,29,202,27,28,194,27,249,22,
-5,89,162,34,35,46,9,223,5,33,30,204,27,28,195,11,193,28,192,192,28,
-193,28,195,28,249,22,147,3,248,22,65,196,248,22,65,198,193,11,11,11,11,
-28,192,249,80,159,46,53,35,202,89,162,34,34,44,9,224,14,2,33,31,27,
-28,196,27,249,22,5,89,162,34,35,46,9,223,7,33,32,205,27,28,196,11,
-193,28,192,192,28,193,28,196,28,249,22,147,3,248,22,65,196,248,22,65,199,
-193,11,11,11,11,28,192,249,80,159,47,53,35,203,89,162,34,34,44,9,224,
-15,2,33,33,249,80,159,47,53,35,203,89,162,34,34,43,9,224,15,7,33,
-34,32,36,89,162,34,35,53,2,19,222,33,38,0,17,35,114,120,34,94,40,
-46,42,63,41,47,40,46,42,41,36,34,27,249,22,144,13,2,37,195,28,192,
-249,22,63,248,22,88,195,27,248,22,97,196,27,249,22,144,13,2,37,195,28,
-192,249,22,63,248,22,88,195,27,248,22,97,196,27,249,22,144,13,2,37,195,
-28,192,249,22,63,248,22,88,195,248,2,36,248,22,97,196,248,22,73,194,248,
-22,73,194,248,22,73,194,32,39,89,162,34,35,53,2,19,222,33,40,28,248,
-22,71,248,22,65,194,249,22,7,9,248,22,64,195,91,159,36,11,90,161,36,
-34,11,27,248,22,65,196,28,248,22,71,248,22,65,194,249,22,7,9,248,22,
-64,195,91,159,36,11,90,161,36,34,11,27,248,22,65,196,28,248,22,71,248,
-22,65,194,249,22,7,9,248,22,64,195,91,159,36,11,90,161,36,34,11,248,
-2,39,248,22,65,196,249,22,7,249,22,63,248,22,64,199,196,195,249,22,7,
-249,22,63,248,22,64,199,196,195,249,22,7,249,22,63,248,22,64,199,196,195,
-27,248,2,36,194,28,194,192,248,2,39,193,87,95,28,248,22,147,4,195,12,
-250,22,167,8,2,20,6,20,20,114,101,115,111,108,118,101,100,45,109,111,100,
-117,108,101,45,112,97,116,104,197,28,207,248,208,195,12,27,27,250,22,126,80,
-158,40,41,248,22,162,13,247,22,146,11,11,28,192,192,27,247,22,120,87,94,
-250,22,125,80,158,41,41,248,22,162,13,247,22,146,11,195,192,250,22,125,195,
-198,66,97,116,116,97,99,104,251,211,197,198,199,10,28,192,250,22,166,8,11,
-196,195,248,22,164,8,194,28,249,22,139,6,194,6,1,1,46,2,17,28,249,
-22,139,6,194,6,2,2,46,46,62,117,112,192,28,249,22,139,8,248,22,65,
-199,196,28,249,22,137,8,248,22,64,199,195,251,22,164,8,2,20,6,26,26,
-99,121,99,108,101,32,105,110,32,108,111,97,100,105,110,103,32,97,116,32,126,
-101,58,32,126,101,199,249,22,2,22,65,248,22,78,249,22,63,205,201,12,12,
-247,192,20,14,159,80,158,38,43,249,22,63,247,22,146,11,196,20,14,159,80,
-158,38,38,250,80,158,41,39,249,22,27,11,80,158,43,38,22,131,4,195,249,
-247,22,184,5,197,248,22,52,248,22,162,12,197,87,94,28,28,248,22,158,12,
-196,10,248,22,152,4,196,12,28,197,250,22,166,8,11,6,15,15,98,97,100,
-32,109,111,100,117,108,101,32,112,97,116,104,200,250,22,167,8,2,20,6,19,
-19,109,111,100,117,108,101,45,112,97,116,104,32,111,114,32,112,97,116,104,198,
-28,28,248,22,61,196,249,22,137,8,248,22,64,198,2,4,11,248,22,148,4,
-248,22,88,197,28,28,248,22,61,196,249,22,137,8,248,22,64,198,66,112,108,
-97,110,101,116,11,87,94,28,207,12,20,14,159,80,158,36,38,250,80,158,39,
-39,249,22,27,11,80,158,41,38,22,146,11,196,90,161,35,34,10,249,22,132,
-4,21,94,2,21,6,18,18,112,108,97,110,101,116,47,114,101,115,111,108,118,
-101,114,46,115,115,1,27,112,108,97,110,101,116,45,109,111,100,117,108,101,45,
-110,97,109,101,45,114,101,115,111,108,118,101,114,12,251,211,199,200,201,202,27,
-89,162,34,35,44,79,115,104,111,119,45,99,111,108,108,101,99,116,105,111,110,
-45,101,114,114,223,6,33,44,27,28,248,22,51,198,27,250,22,126,80,158,42,
-42,249,22,63,203,247,22,135,13,11,28,192,192,91,159,36,11,90,161,36,34,
-11,249,80,159,43,47,35,248,22,54,203,11,27,251,80,158,46,49,2,20,201,
-28,248,22,71,198,198,248,22,64,198,28,248,22,71,198,9,248,22,65,198,249,
-22,176,12,194,28,248,22,71,196,6,7,7,109,97,105,110,46,115,115,249,22,
-156,6,198,6,3,3,46,115,115,28,248,22,133,6,198,27,248,80,159,40,54,
-35,200,27,250,22,126,80,158,43,42,249,22,63,204,198,11,28,192,192,91,159,
-36,11,90,161,36,34,11,249,80,159,44,47,35,203,11,250,22,1,22,176,12,
-198,249,22,77,249,22,2,32,0,89,162,8,36,35,42,9,222,33,45,199,248,
-22,73,199,28,248,22,158,12,198,28,248,22,181,12,198,197,248,22,73,6,26,
-26,32,40,97,32,112,97,116,104,32,109,117,115,116,32,98,101,32,97,98,115,
-111,108,117,116,101,41,28,249,22,137,8,248,22,64,200,2,21,27,250,22,126,
-80,158,42,42,249,22,63,203,247,22,135,13,11,28,192,192,91,159,37,11,90,
-161,36,34,11,249,80,159,44,47,35,248,22,88,204,11,90,161,35,36,11,28,
-248,22,71,248,22,90,203,28,248,22,71,193,249,22,146,13,0,8,35,114,120,
-34,91,46,93,34,195,11,10,27,27,28,196,249,22,77,28,248,22,71,248,22,
-90,23,15,21,93,6,5,5,109,122,108,105,98,249,22,1,22,77,249,22,2,
-80,159,50,55,35,248,22,90,23,18,196,28,248,22,71,195,248,22,73,196,194,
-251,80,158,48,49,2,20,203,248,22,64,197,248,22,65,197,249,22,176,12,194,
-28,197,196,28,248,22,71,196,6,7,7,109,97,105,110,46,115,115,28,249,22,
-146,13,0,8,35,114,120,34,91,46,93,34,198,196,249,22,156,6,198,6,3,
-3,46,115,115,28,249,22,137,8,248,22,64,200,64,102,105,108,101,249,22,183,
-12,248,22,88,200,248,80,159,41,54,35,201,12,87,94,28,28,248,22,158,12,
-193,10,248,22,155,7,193,12,28,199,250,22,166,8,67,114,101,113,117,105,114,
-101,249,22,181,6,6,17,17,98,97,100,32,109,111,100,117,108,101,32,112,97,
-116,104,126,97,28,197,248,22,64,198,6,0,0,202,250,22,167,8,2,20,249,
-22,181,6,6,13,13,109,111,100,117,108,101,32,112,97,116,104,126,97,28,197,
-248,22,64,198,6,0,0,200,27,28,248,22,155,7,194,249,22,160,7,195,34,
-249,22,185,12,248,22,186,12,196,11,27,28,248,22,155,7,195,249,22,160,7,
-196,35,248,80,158,41,50,194,91,159,37,11,90,161,37,34,11,28,248,22,155,
-7,198,250,22,7,2,22,249,22,160,7,202,36,2,22,248,22,179,12,197,27,
-28,248,22,155,7,199,249,22,160,7,200,37,249,80,158,46,51,196,5,0,27,
-28,248,22,155,7,200,249,22,160,7,201,38,248,22,148,4,199,27,27,250,22,
-126,80,158,50,41,248,22,162,13,247,22,146,11,11,28,192,192,27,247,22,120,
-87,94,250,22,125,80,158,51,41,248,22,162,13,247,22,146,11,195,192,87,95,
-28,23,16,27,250,22,126,196,197,11,28,192,12,87,95,27,27,28,248,22,17,
-80,158,50,44,80,158,49,44,247,22,19,250,22,25,248,22,23,196,80,158,52,
-43,195,27,247,22,146,11,249,22,3,89,162,34,35,53,9,226,12,11,2,3,
-33,46,195,248,28,248,22,17,80,158,49,44,32,0,89,162,34,35,40,9,222,
-33,47,80,159,48,56,35,89,162,34,34,49,9,227,14,9,8,4,3,33,48,
-250,22,125,196,197,10,12,28,28,248,22,155,7,201,11,27,248,22,133,6,23,
-15,28,192,192,28,248,22,61,23,15,249,22,137,8,248,22,64,23,17,2,21,
-11,250,22,125,80,158,49,42,28,248,22,133,6,23,17,249,22,63,23,18,248,
-80,159,52,54,35,23,20,249,22,63,23,18,247,22,135,13,252,22,157,7,23,
-15,206,204,202,201,12,193,91,159,36,10,90,161,35,34,10,11,90,161,35,35,
-10,83,158,37,20,96,96,2,20,89,162,8,36,35,49,9,224,2,0,33,42,
+    static MZCOMPILED_STRING_FAR unsigned char expr[] = {35,126,9,51,46,57,57,46,48,46,49,49,52,0,0,0,1,0,0,3,0,
+14,0,41,0,47,0,60,0,74,0,96,0,122,0,134,0,152,0,172,0,184,
+0,200,0,223,0,3,1,8,1,13,1,18,1,23,1,54,1,58,1,66,1,
+74,1,82,1,163,1,199,1,216,1,245,1,17,2,47,2,57,2,87,2,97,
+2,104,2,178,3,190,3,209,3,33,4,45,4,173,4,185,4,30,5,36,5,
+50,5,77,5,148,5,150,5,203,5,93,10,151,10,183,10,0,0,118,13,0,
+0,29,11,11,70,100,108,108,45,115,117,102,102,105,120,1,25,100,101,102,97,
+117,108,116,45,108,111,97,100,47,117,115,101,45,99,111,109,112,105,108,101,100,
+65,113,117,111,116,101,29,94,2,4,67,35,37,117,116,105,108,115,11,29,94,
+2,4,68,35,37,112,97,114,97,109,122,11,1,20,100,101,102,97,117,108,116,
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+195,27,248,2,36,194,28,194,192,248,2,39,193,87,95,28,248,22,147,4,195,
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+100,117,108,101,45,112,97,116,104,197,28,207,248,208,195,12,27,27,250,22,126,
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+198,28,28,248,22,61,196,249,22,138,8,248,22,64,198,2,4,11,248,22,148,
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+108,97,110,101,116,11,87,94,28,207,12,20,14,159,80,158,36,38,250,80,158,
+39,39,249,22,27,11,80,158,41,38,22,147,11,196,90,161,35,34,10,249,22,
+132,4,21,94,2,21,6,18,18,112,108,97,110,101,116,47,114,101,115,111,108,
+118,101,114,46,115,115,1,27,112,108,97,110,101,116,45,109,111,100,117,108,101,
+45,110,97,109,101,45,114,101,115,111,108,118,101,114,12,251,211,199,200,201,202,
+27,89,162,34,35,44,79,115,104,111,119,45,99,111,108,108,101,99,116,105,111,
+110,45,101,114,114,223,6,33,44,27,28,248,22,51,198,27,250,22,126,80,158,
+42,42,249,22,63,203,247,22,136,13,11,28,192,192,91,159,36,11,90,161,36,
+34,11,249,80,159,43,47,35,248,22,54,203,11,27,251,80,158,46,49,2,20,
+201,28,248,22,71,198,198,248,22,64,198,28,248,22,71,198,9,248,22,65,198,
+249,22,177,12,194,28,248,22,71,196,6,7,7,109,97,105,110,46,115,115,249,
+22,156,6,198,6,3,3,46,115,115,28,248,22,133,6,198,27,248,80,159,40,
+54,35,200,27,250,22,126,80,158,43,42,249,22,63,204,198,11,28,192,192,91,
+159,36,11,90,161,36,34,11,249,80,159,44,47,35,203,11,250,22,1,22,177,
+12,198,249,22,77,249,22,2,32,0,89,162,8,36,35,42,9,222,33,45,199,
+248,22,73,199,28,248,22,159,12,198,28,248,22,182,12,198,197,248,22,73,6,
+26,26,32,40,97,32,112,97,116,104,32,109,117,115,116,32,98,101,32,97,98,
+115,111,108,117,116,101,41,28,249,22,138,8,248,22,64,200,2,21,27,250,22,
+126,80,158,42,42,249,22,63,203,247,22,136,13,11,28,192,192,91,159,37,11,
+90,161,36,34,11,249,80,159,44,47,35,248,22,88,204,11,90,161,35,36,11,
+28,248,22,71,248,22,90,203,28,248,22,71,193,249,22,147,13,0,8,35,114,
+120,34,91,46,93,34,195,11,10,27,27,28,196,249,22,77,28,248,22,71,248,
+22,90,23,15,21,93,6,5,5,109,122,108,105,98,249,22,1,22,77,249,22,
+2,80,159,50,55,35,248,22,90,23,18,196,28,248,22,71,195,248,22,73,196,
+194,251,80,158,48,49,2,20,203,248,22,64,197,248,22,65,197,249,22,177,12,
+194,28,197,196,28,248,22,71,196,6,7,7,109,97,105,110,46,115,115,28,249,
+22,147,13,0,8,35,114,120,34,91,46,93,34,198,196,249,22,156,6,198,6,
+3,3,46,115,115,28,249,22,138,8,248,22,64,200,64,102,105,108,101,249,22,
+184,12,248,22,88,200,248,80,159,41,54,35,201,12,87,94,28,28,248,22,159,
+12,193,10,248,22,155,7,193,12,28,199,250,22,167,8,67,114,101,113,117,105,
+114,101,249,22,181,6,6,17,17,98,97,100,32,109,111,100,117,108,101,32,112,
+97,116,104,126,97,28,197,248,22,64,198,6,0,0,202,250,22,168,8,2,20,
+249,22,181,6,6,13,13,109,111,100,117,108,101,32,112,97,116,104,126,97,28,
+197,248,22,64,198,6,0,0,200,27,28,248,22,155,7,194,249,22,160,7,195,
+34,249,22,186,12,248,22,187,12,196,11,27,28,248,22,155,7,195,249,22,160,
+7,196,35,248,80,158,41,50,194,91,159,37,11,90,161,37,34,11,28,248,22,
+155,7,198,250,22,7,2,22,249,22,160,7,202,36,2,22,248,22,180,12,197,
+27,28,248,22,155,7,199,249,22,160,7,200,37,249,80,158,46,51,196,5,0,
+27,28,248,22,155,7,200,249,22,160,7,201,38,248,22,148,4,199,27,27,250,
+22,126,80,158,50,41,248,22,163,13,247,22,147,11,11,28,192,192,27,247,22,
+120,87,94,250,22,125,80,158,51,41,248,22,163,13,247,22,147,11,195,192,87,
+95,28,23,16,27,250,22,126,196,197,11,28,192,12,87,95,27,27,28,248,22,
+17,80,158,50,44,80,158,49,44,247,22,19,250,22,25,248,22,23,196,80,158,
+52,43,195,27,247,22,147,11,249,22,3,89,162,34,35,53,9,226,12,11,2,
+3,33,46,195,248,28,248,22,17,80,158,49,44,32,0,89,162,34,35,40,9,
+222,33,47,80,159,48,56,35,89,162,34,34,49,9,227,14,9,8,4,3,33,
+48,250,22,125,196,197,10,12,28,28,248,22,155,7,201,11,27,248,22,133,6,
+23,15,28,192,192,28,248,22,61,23,15,249,22,138,8,248,22,64,23,17,2,
+21,11,250,22,125,80,158,49,42,28,248,22,133,6,23,17,249,22,63,23,18,
+248,80,159,52,54,35,23,20,249,22,63,23,18,247,22,136,13,252,22,157,7,
+23,15,206,204,202,201,12,193,91,159,36,10,90,161,35,34,10,11,90,161,35,
+35,10,83,158,37,20,96,96,2,20,89,162,34,35,49,9,224,2,0,33,42,
 89,162,34,37,47,9,223,1,33,43,89,162,34,38,8,30,9,225,2,3,0,
-33,49,208,87,95,248,22,130,4,248,80,158,36,48,247,22,146,11,248,22,184,
-5,80,158,35,35,248,22,132,12,80,159,35,40,35,159,34,20,102,159,34,16,
+33,49,208,87,95,248,22,130,4,248,80,158,36,48,247,22,147,11,248,22,184,
+5,80,158,35,35,248,22,133,12,80,159,35,40,35,159,34,20,102,159,34,16,
 1,20,24,65,98,101,103,105,110,16,0,83,158,40,20,99,134,66,35,37,98,
 111,111,116,2,1,11,10,10,10,10,10,36,80,158,34,34,20,102,159,38,16,
 19,30,2,1,2,2,193,30,2,1,2,3,193,30,2,5,72,112,97,116,104,
diff --git a/src/mzscheme/src/env.c b/src/mzscheme/src/env.c
index 0824d225cd..f60a82febb 100644
--- a/src/mzscheme/src/env.c
+++ b/src/mzscheme/src/env.c
@@ -54,7 +54,7 @@ int scheme_get_allow_set_undefined() { return scheme_allow_set_undefined; }
 
 int scheme_starting_up;
 
-Scheme_Object *scheme_local[MAX_CONST_LOCAL_POS][2];
+Scheme_Object *scheme_local[MAX_CONST_LOCAL_POS][2][3];
 
 #define MAX_CONST_TOPLEVEL_DEPTH 16
 #define MAX_CONST_TOPLEVEL_POS 16
@@ -256,30 +256,33 @@ Scheme_Env *scheme_basic_env()
 
 
   {
-    int i, k;
+    int i, k, cor;
 
 #ifndef USE_TAGGED_ALLOCATION
     GC_CAN_IGNORE Scheme_Local *all;
 
-    all = (Scheme_Local *)scheme_malloc_eternal(sizeof(Scheme_Local) * 2 * MAX_CONST_LOCAL_POS);
+    all = (Scheme_Local *)scheme_malloc_eternal(sizeof(Scheme_Local) * 3 * 2 * MAX_CONST_LOCAL_POS);
 # ifdef MEMORY_COUNTING_ON
-    scheme_misc_count += sizeof(Scheme_Local) * 2 * MAX_CONST_LOCAL_POS;
+    scheme_misc_count += sizeof(Scheme_Local) * 3 * 2 * MAX_CONST_LOCAL_POS;
 # endif    
 #endif
 
     for (i = 0; i < MAX_CONST_LOCAL_POS; i++) {
       for (k = 0; k < 2; k++) {
-	Scheme_Object *v;
-	
+        for (cor = 0; cor < 3; cor++) {
+          Scheme_Object *v;
+          
 #ifndef USE_TAGGED_ALLOCATION
-	v = (Scheme_Object *)(all++);
+          v = (Scheme_Object *)(all++);
 #else
-	v = (Scheme_Object *)scheme_malloc_eternal_tagged(sizeof(Scheme_Local));
+          v = (Scheme_Object *)scheme_malloc_eternal_tagged(sizeof(Scheme_Local));
 #endif
-	v->type = k + scheme_local_type;
-	SCHEME_LOCAL_POS(v) = i;
-	
-	scheme_local[i][k] = v;
+          v->type = k + scheme_local_type;
+          SCHEME_LOCAL_POS(v) = i;
+          SCHEME_LOCAL_FLAGS(v) = cor;
+          
+          scheme_local[i][k][cor] = v;
+        }
       }
     }
   }
@@ -1541,7 +1544,7 @@ Scheme_Object *scheme_register_stx_in_prefix(Scheme_Object *var, Scheme_Comp_Env
   if (rec && rec[drec].dont_mark_local_use) {
     /* Make up anything; it's going to be ignored. */
     l = (Scheme_Local *)scheme_malloc_atomic_tagged(sizeof(Scheme_Local));
-    l->so.type = scheme_compiled_quote_syntax_type;
+    l->iso.so.type = scheme_compiled_quote_syntax_type;
     l->position = 0;
 
     return (Scheme_Object *)l;
@@ -1556,7 +1559,7 @@ Scheme_Object *scheme_register_stx_in_prefix(Scheme_Object *var, Scheme_Comp_Env
   pos = cp->num_stxes;
 
   l = (Scheme_Local *)scheme_malloc_atomic_tagged(sizeof(Scheme_Local));
-  l->so.type = scheme_compiled_quote_syntax_type;
+  l->iso.so.type = scheme_compiled_quote_syntax_type;
   l->position = pos;
 
   cp->num_stxes++;
@@ -1582,23 +1585,40 @@ static Scheme_Object *alloc_local(short type, int pos)
   return (Scheme_Object *)v;
 }
 
-Scheme_Object *scheme_make_local(Scheme_Type type, int pos)
+Scheme_Object *scheme_make_local(Scheme_Type type, int pos, int flags)
 {
   int k;
-  Scheme_Object *v;
+  Scheme_Object *v, *key;
 
   k = type - scheme_local_type;
-
-  if (pos < MAX_CONST_LOCAL_POS) {
-    if (pos >= 0)
-      return scheme_local[pos][k];
+  
+  /* Helper for reading bytecode: make sure flags is a valid value */
+  switch (flags) {
+  case 0:
+    break;
+  case SCHEME_LOCAL_CLEAR_ON_READ:
+    break;
+  default:
+  case SCHEME_LOCAL_OTHER_CLEARS:
+    flags  = SCHEME_LOCAL_OTHER_CLEARS;
+    break;
   }
 
-  v = scheme_hash_get(locals_ht[k], scheme_make_integer(pos));
+  if (pos < MAX_CONST_LOCAL_POS) {
+    return scheme_local[pos][k][flags];
+  }
+
+  key = scheme_make_integer(pos);
+  if (flags) {
+    key = scheme_make_pair(scheme_make_integer(flags), key);
+  }
+
+  v = scheme_hash_get(locals_ht[k], key);
   if (v)
     return v;
 
   v = alloc_local(type, pos);
+  SCHEME_LOCAL_FLAGS(v) = flags;
 
   if (locals_ht[k]->count > TABLE_CACHE_MAX_SIZE) {
     Scheme_Hash_Table *ht;
@@ -1606,7 +1626,7 @@ Scheme_Object *scheme_make_local(Scheme_Type type, int pos)
     locals_ht[k] = ht;
   }
 
-  scheme_hash_set(locals_ht[k], scheme_make_integer(pos), v);
+  scheme_hash_set(locals_ht[k], key, v);
 
   return v;
 }
@@ -1642,7 +1662,7 @@ static Scheme_Local *get_frame_loc(Scheme_Comp_Env *frame,
   
   COMPILE_DATA(frame)->use[i] = u;
 
-  return (Scheme_Local *)scheme_make_local(scheme_local_type, p + i);
+  return (Scheme_Local *)scheme_make_local(scheme_local_type, p + i, 0);
 }
 
 Scheme_Object *scheme_hash_module_variable(Scheme_Env *env, Scheme_Object *modidx, 
@@ -2384,7 +2404,7 @@ scheme_lookup_binding(Scheme_Object *find_id, Scheme_Comp_Env *env, int flags,
               *_lexical_binding_id = val;
             }
 	    if (flags & SCHEME_DONT_MARK_USE)
-	      return scheme_make_local(scheme_local_type, 0);
+	      return scheme_make_local(scheme_local_type, 0, 0);
 	    else
 	      return (Scheme_Object *)get_frame_loc(frame, i, j, p, flags);
 	  }
@@ -2970,7 +2990,7 @@ Scheme_Object *scheme_optimize_reverse(Optimize_Info *info, int pos, int unless_
     if (info->use && info->use[pos])
       return NULL;
 
-  return scheme_make_local(scheme_local_type, pos + delta);
+  return scheme_make_local(scheme_local_type, pos + delta, 0);
 }
 
 int scheme_optimize_is_used(Optimize_Info *info, int pos)
@@ -3063,7 +3083,7 @@ static Scheme_Object *do_optimize_info_lookup(Optimize_Info *info, int pos, int
 	if (!n) {
 	  /* Return shifted reference to other local: */
 	  delta += scheme_optimize_info_get_shift(info, pos);
-	  n = scheme_make_local(scheme_local_type, pos + delta);
+	  n = scheme_make_local(scheme_local_type, pos + delta, 0);
 	}
       }
       return n;
@@ -3386,7 +3406,8 @@ static int resolve_info_lookup(Resolve_Info *info, int pos, int *flags, Scheme_O
             vec = scheme_make_vector(sz + 1, NULL);
             for (i = 0; i < sz; i++) {
               loc = scheme_make_local(scheme_local_type,
-                                      posmap[i] + offset + shifted);
+                                      posmap[i] + offset + shifted,
+                                      0);
               if (boxmap) {
                 if (boxmap[i / BITS_PER_MZSHORT] & ((mzshort)1 << (i & (BITS_PER_MZSHORT - 1))))
                   loc = scheme_box(loc);
@@ -4641,16 +4662,29 @@ static Scheme_Object *write_local(Scheme_Object *obj)
   return scheme_make_integer(SCHEME_LOCAL_POS(obj));
 }
 
+static Scheme_Object *do_read_local(Scheme_Type t, Scheme_Object *obj)
+{
+  int n, flags;
+
+  if (SCHEME_PAIRP(obj)) {
+    flags = SCHEME_INT_VAL(SCHEME_CAR(obj));
+    obj = SCHEME_CDR(obj);
+  } else
+    flags = 0;
+
+  n = SCHEME_INT_VAL(obj);
+
+  return scheme_make_local(t, n, flags);
+}
+
 static Scheme_Object *read_local(Scheme_Object *obj)
 {
-  return scheme_make_local(scheme_local_type,
-			   SCHEME_INT_VAL(obj));
+  return do_read_local(scheme_local_type, obj);
 }
 
 static Scheme_Object *read_local_unbox(Scheme_Object *obj)
 {
-  return scheme_make_local(scheme_local_unbox_type,
-			   SCHEME_INT_VAL(obj));
+  return do_read_local(scheme_local_unbox_type, obj);
 }
 
 static Scheme_Object *write_resolve_prefix(Scheme_Object *obj)
@@ -4753,6 +4787,7 @@ static void register_traversers(void)
   GC_REG_TRAV(scheme_rt_comp_env, mark_comp_env);
   GC_REG_TRAV(scheme_rt_resolve_info, mark_resolve_info);
   GC_REG_TRAV(scheme_rt_optimize_info, mark_optimize_info);
+  GC_REG_TRAV(scheme_rt_sfs_info, mark_sfs_info);
 }
 
 END_XFORM_SKIP;
diff --git a/src/mzscheme/src/eval.c b/src/mzscheme/src/eval.c
index 24588f4076..fe0d9fb608 100644
--- a/src/mzscheme/src/eval.c
+++ b/src/mzscheme/src/eval.c
@@ -829,8 +829,10 @@ int scheme_omittable_expr(Scheme_Object *o, int vals, int fuel, int resolved)
   vtype = SCHEME_TYPE(o);
 
   if ((vtype > _scheme_compiled_values_types_) 
-      || (vtype == scheme_local_type)
-      || (vtype == scheme_local_unbox_type)
+      || ((vtype == scheme_local_type)
+          && !(SCHEME_LOCAL_FLAGS(o) & SCHEME_LOCAL_CLEAR_ON_READ))
+      || ((vtype == scheme_local_unbox_type)
+          && !(SCHEME_LOCAL_FLAGS(o) & SCHEME_LOCAL_CLEAR_ON_READ))
       || (vtype == scheme_unclosed_procedure_type)
       || (vtype == scheme_compiled_unclosed_procedure_type)
       || (vtype == scheme_case_lambda_sequence_type)
@@ -1067,9 +1069,11 @@ static Scheme_Object *make_application(Scheme_Object *v)
 
     f = SCHEME_CAR(v);
 
-    if ((SCHEME_PRIMP(f) && (((Scheme_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_IS_FOLDING))
+    if ((SCHEME_PRIMP(f) && ((((Scheme_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_OPT_MASK)
+                             == SCHEME_PRIM_OPT_FOLDING))
 	|| (SCHEME_CLSD_PRIMP(f) 
-	    && (((Scheme_Closed_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_IS_FOLDING))
+	    && ((((Scheme_Closed_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_OPT_MASK)
+                == SCHEME_PRIM_OPT_FOLDING))
 	|| (SAME_TYPE(SCHEME_TYPE(f), scheme_closure_type)
 	    && (foldable_body(f)))) {
       f = try_apply(f, SCHEME_CDR(v));
@@ -1282,12 +1286,22 @@ static Scheme_Object *resolve_application(Scheme_Object *o, Resolve_Info *orig_i
 
 static Scheme_Object *resolve_application3(Scheme_Object *o, Resolve_Info *orig_info, int already_resolved_arg_count);
 
+static void set_app2_eval_type(Scheme_App2_Rec *app)
+{
+  short et;
+
+  et = scheme_get_eval_type(app->rand);
+  et = et << 3;
+  et += scheme_get_eval_type(app->rator);
+  
+  SCHEME_APPN_FLAGS(app) = et;
+}
+
 static Scheme_Object *resolve_application2(Scheme_Object *o, Resolve_Info *orig_info, int already_resolved_arg_count)
 {
   Resolve_Info *info;
   Scheme_App2_Rec *app;
   Scheme_Object *le;
-  short et;
 
   app = (Scheme_App2_Rec *)o;
 
@@ -1347,16 +1361,12 @@ static Scheme_Object *resolve_application2(Scheme_Object *o, Resolve_Info *orig_
   } else
     already_resolved_arg_count--;
 
-  et = scheme_get_eval_type(app->rand);
-  et = et << 3;
-  et += scheme_get_eval_type(app->rator);
-  
-  SCHEME_APPN_FLAGS(app) = et;
-  
   info->max_let_depth += 1;
   if (orig_info->max_let_depth < info->max_let_depth)
     orig_info->max_let_depth = info->max_let_depth;
 
+  set_app2_eval_type(app);
+
   return (Scheme_Object *)app;
 }
 
@@ -1374,12 +1384,24 @@ static int eq_testable_constant(Scheme_Object *v)
   return 0;
 }
 
+static void set_app3_eval_type(Scheme_App3_Rec *app)
+{
+  short et;
+
+  et = scheme_get_eval_type(app->rand2);
+  et = et << 3;
+  et += scheme_get_eval_type(app->rand1);
+  et = et << 3;
+  et += scheme_get_eval_type(app->rator);
+  
+  SCHEME_APPN_FLAGS(app) = et;
+}
+
 static Scheme_Object *resolve_application3(Scheme_Object *o, Resolve_Info *orig_info, int already_resolved_arg_count)
 {
   Resolve_Info *info;
   Scheme_App3_Rec *app;
   Scheme_Object *le;
-  short et;
 
   app = (Scheme_App3_Rec *)o;
 
@@ -1445,13 +1467,7 @@ static Scheme_Object *resolve_application3(Scheme_Object *o, Resolve_Info *orig_
     app->rator = scheme_eq_prim;
   }
 
-  et = scheme_get_eval_type(app->rand2);
-  et = et << 3;
-  et += scheme_get_eval_type(app->rand1);
-  et = et << 3;
-  et += scheme_get_eval_type(app->rator);
-  
-  SCHEME_APPN_FLAGS(app) = et;
+  set_app3_eval_type(app);
 
   info->max_let_depth += 2;
   if (orig_info->max_let_depth < info->max_let_depth)
@@ -1828,7 +1844,8 @@ Scheme_Object *scheme_resolve_expr(Scheme_Object *expr, Resolve_Info *info)
         return scheme_make_local((flags & SCHEME_INFO_BOXED) 
                                  ? scheme_local_unbox_type
                                  : scheme_local_type,
-                                 pos);
+                                 pos,
+                                 0);
       }
     }
   case scheme_compiled_syntax_type:
@@ -2094,9 +2111,11 @@ uncompile(int argc, Scheme_Object *argv[])
 static Scheme_Object *try_optimize_fold(Scheme_Object *f, Scheme_Object *o, Optimize_Info *info)
 {
   if ((SCHEME_PRIMP(f) 
-       && (((Scheme_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_IS_FOLDING))
+       && ((((Scheme_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_OPT_MASK)
+           == SCHEME_PRIM_OPT_FOLDING))
       || (SCHEME_CLSD_PRIMP(f) 
-	  && (((Scheme_Closed_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_IS_FOLDING))) {
+	  && ((((Scheme_Closed_Primitive_Proc *)f)->pp.flags & SCHEME_PRIM_OPT_MASK)
+              == SCHEME_PRIM_OPT_FOLDING))) {
     Scheme_Object *args;
     
     switch (SCHEME_TYPE(o)) {
@@ -2250,7 +2269,9 @@ Scheme_Object *optimize_for_inline(Optimize_Info *info, Scheme_Object *le, int a
   }
 
   if (le && SCHEME_PRIMP(le)) {
-    if (((Scheme_Prim_Proc_Header *)le)->flags & SCHEME_PRIM_IS_NONCM)
+    int opt;
+    opt = ((Scheme_Prim_Proc_Header *)le)->flags & SCHEME_PRIM_OPT_MASK;
+    if (opt > SCHEME_PRIM_OPT_NONCM)
       *_flags = (CLOS_PRESERVES_MARKS | CLOS_SINGLE_RESULT);
   }
   
@@ -2289,7 +2310,7 @@ static Scheme_Object *check_app_let_rator(Scheme_Object *app, Scheme_Object *rat
         
         reset_rator(app, scheme_false);
         app = scheme_optimize_shift(app, 1, 0);
-        reset_rator(app, scheme_make_local(scheme_local_type, 0));
+        reset_rator(app, scheme_make_local(scheme_local_type, 0, 0));
 
         clv->body = app;
         
@@ -2804,7 +2825,7 @@ Scheme_Object *scheme_optimize_expr(Scheme_Object *expr, Optimize_Info *info)
 
       delta = scheme_optimize_info_get_shift(info, pos);
       if (delta)
-	expr = scheme_make_local(scheme_local_type, pos + delta);
+	expr = scheme_make_local(scheme_local_type, pos + delta, 0);
 
       return expr;
     }
@@ -2898,7 +2919,7 @@ Scheme_Object *scheme_optimize_clone(int dup_ok, Scheme_Object *expr, Optimize_I
       if (pos >= closure_depth) {
 	expr = scheme_optimize_reverse(info, pos + delta - closure_depth, 0);
 	if (closure_depth)
-	  expr = scheme_make_local(scheme_local_type, SCHEME_LOCAL_POS(expr) + closure_depth);
+	  expr = scheme_make_local(scheme_local_type, SCHEME_LOCAL_POS(expr) + closure_depth, 0);
       }
       return expr;
     }
@@ -3088,7 +3109,7 @@ Scheme_Object *scheme_optimize_shift(Scheme_Object *expr, int delta, int after_d
     {
       int pos = SCHEME_LOCAL_POS(expr);
       if (pos >= after_depth) {
-        expr = scheme_make_local(t, SCHEME_LOCAL_POS(expr) + delta);
+        expr = scheme_make_local(t, SCHEME_LOCAL_POS(expr) + delta, 0);
       }
       return expr;
     }
@@ -3224,6 +3245,821 @@ Scheme_Object *scheme_optimize_shift(Scheme_Object *expr, int delta, int after_d
   return NULL;
 }
 
+/*========================================================================*/
+/*                                  sfs                                   */
+/*========================================================================*/
+
+/* For debugging and measuring the worst-case cost of sfs clears: */
+#define MAX_SFS_CLEARING 0
+
+#define SFS_LOG(x) /* nothing */
+
+Scheme_Object *scheme_sfs(Scheme_Object *o, SFS_Info *info, int max_let_depth)
+{
+  int init, i;
+
+  if (!info) {
+    info = scheme_new_sfs_info(max_let_depth);
+  }
+
+  info->pass = 0;
+  info->ip = 1;
+  info->saved = scheme_null;
+  info->min_touch = -1;
+  info->max_touch = -1;
+  info->tail_pos = 1;
+  init = info->stackpos;
+  o = scheme_sfs_expr(o, info, -1);
+
+  if (info->seqn)
+    scheme_signal_error("ended in the middle of an expression?");
+
+# if MAX_SFS_CLEARING
+  info->max_nontail = info->ip;
+# endif
+
+  for (i = info->depth; i-- > init; ) {
+    info->max_calls[i] = info->max_nontail;
+  }
+
+  {
+    Scheme_Object *v;
+    v = scheme_reverse(info->saved);
+    info->saved = v;
+  }
+
+  info->pass = 1;
+  info->seqn = 0;
+  info->ip = 1;
+  info->tail_pos = 1;
+  info->stackpos = init;
+  o = scheme_sfs_expr(o, info, -1);
+
+  return o;
+}
+
+SFS_Info *scheme_new_sfs_info(int depth)
+{
+  SFS_Info *info;
+  int *max_used, *max_calls;
+
+  info = MALLOC_ONE_RT(SFS_Info);
+  SET_REQUIRED_TAG(info->type = scheme_rt_sfs_info);
+
+  info->depth = depth;
+  info->stackpos = depth;
+  info->tlpos = depth;
+
+  max_used = (int *)scheme_malloc_atomic(sizeof(int) * depth);
+  max_calls = (int *)scheme_malloc_atomic(sizeof(int) * depth);
+
+  memset(max_used, 0, sizeof(int) * depth);
+  memset(max_calls, 0, sizeof(int) * depth);
+
+  info->max_used = max_used;
+  info->max_calls = max_calls;
+
+  return info;
+}
+
+static void scheme_sfs_save(SFS_Info *info, Scheme_Object *v)
+{
+  if (info->pass)
+    scheme_signal_error("internal error: wrong pass to save info");
+  v = scheme_make_pair(v, info->saved);
+  info->saved = v;
+}
+
+static Scheme_Object *scheme_sfs_next_saved(SFS_Info *info)
+{
+  Scheme_Object *v;
+
+  if (!info->pass)
+    scheme_signal_error("internal error: wrong pass to get saved info");
+  if (!SCHEME_PAIRP(info->saved))
+    scheme_signal_error("internal error: no saved info");
+
+  v = SCHEME_CAR(info->saved);
+  info->saved = SCHEME_CDR(info->saved);
+  return v;
+}
+
+void scheme_sfs_start_sequence(SFS_Info *info, int cnt, int last_is_tail)
+{
+  info->seqn += (cnt - (last_is_tail ? 1 : 0));
+}
+
+void scheme_sfs_push(SFS_Info *info, int cnt, int track)
+{
+  info->stackpos -= cnt;
+
+  if (info->stackpos < 0)
+    scheme_signal_error("internal error: pushed too deep");
+
+  if (track) {
+    while (cnt--) {
+      scheme_sfs_used(info, cnt);
+    }
+  }
+}
+
+void scheme_sfs_used(SFS_Info *info, int pos)
+{
+  if (info->pass)
+    return;
+
+  pos += info->stackpos;
+
+  if ((pos < 0) || (pos >= info->depth)) {
+    scheme_signal_error("internal error: stack use out of bounds");
+  }
+  if (pos == info->tlpos)
+    scheme_signal_error("internal error: misuse of toplevel pointer");
+
+  SFS_LOG(printf("touch %d %d\n", pos, info->ip));
+  
+  if ((info->min_touch == -1)
+      || (pos < info->min_touch))
+    info->min_touch = pos;
+  if (pos > info->max_touch)
+    info->max_touch = pos;
+
+  info->max_used[pos] = info->ip;
+}
+
+Scheme_Object *scheme_sfs_add_clears(Scheme_Object *expr, Scheme_Object *clears, int pre)
+{
+  int len, i;
+  Scheme_Object *loc;
+  Scheme_Sequence *s;
+
+  if (SCHEME_NULLP(clears))
+    return expr;
+
+  len = scheme_list_length(clears);
+
+  s = malloc_sequence(len + 1);
+  s->so.type = (pre ? scheme_sequence_type : scheme_begin0_sequence_type);
+  s->count = len + 1;
+  s->array[pre ? len : 0] = expr;
+
+  for (i = 0; i < len; i++) {
+    loc = scheme_make_local(scheme_local_type,
+                            SCHEME_INT_VAL(SCHEME_CAR(clears)),
+                            SCHEME_LOCAL_CLEAR_ON_READ);
+    s->array[i + (pre ? 0 : 1)] = loc;
+    clears = SCHEME_CDR(clears);    
+  }
+
+  if (pre)
+    return (Scheme_Object *)s;
+  else
+    return scheme_make_syntax_resolved(BEGIN0_EXPD, (Scheme_Object *)s);
+}
+
+static void sfs_note_app(SFS_Info *info, Scheme_Object *rator)
+{
+  if (!info->pass) {
+    if (!info->tail_pos) {
+      if (SCHEME_PRIMP(rator)) {
+        int opt;
+        opt = ((Scheme_Prim_Proc_Header *)rator)->flags & SCHEME_PRIM_OPT_MASK;
+        if (opt >= SCHEME_PRIM_OPT_IMMEDIATE)
+          /* Don't need to clear stack before an immediate/folding call */
+          return;
+      }
+      info->max_nontail = info->ip;
+    } else {
+      if (!MAX_SFS_CLEARING && (info->selfpos >= 0)) {
+        if (SAME_TYPE(SCHEME_TYPE(rator), scheme_local_type)) {
+          if ((SCHEME_LOCAL_POS(rator) + info->stackpos) == info->selfpos) {
+            /* No point in clearing out any of the closure before the
+               tail call. */
+            int i;
+            for (i = info->selflen; i--; ) {
+              if ((info->selfstart + i) != info->tlpos)
+                scheme_sfs_used(info, (info->selfstart - info->stackpos) + i);
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
+static Scheme_Object *sfs_application(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Object *orig, *naya = NULL;
+  Scheme_App_Rec *app;
+  int i, n;
+
+  app = (Scheme_App_Rec *)o;
+  n = app->num_args + 1;
+
+  scheme_sfs_start_sequence(info, n, 0);
+  scheme_sfs_push(info, n-1, 0);
+
+  for (i = 0; i < n; i++) {
+    orig = app->args[i];
+    naya = scheme_sfs_expr(orig, info, -1);
+    app->args[i] = naya;
+  }
+
+  sfs_note_app(info, app->args[0]);
+
+  scheme_finish_application(app);
+
+  return o;
+}
+
+static Scheme_Object *sfs_application2(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_App2_Rec *app;
+  Scheme_Object *nrator, *nrand;
+
+  app = (Scheme_App2_Rec *)o;
+
+  scheme_sfs_start_sequence(info, 2, 0);
+  scheme_sfs_push(info, 1, 0);
+
+  nrator = scheme_sfs_expr(app->rator, info, -1);
+  nrand = scheme_sfs_expr(app->rand, info, -1);
+  app->rator = nrator;
+  app->rand = nrand;
+
+  sfs_note_app(info, app->rator);
+
+  set_app2_eval_type(app);
+  
+  return o;
+}
+
+static Scheme_Object *sfs_application3(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_App3_Rec *app;
+  Scheme_Object *nrator, *nrand1, *nrand2;
+
+  app = (Scheme_App3_Rec *)o;
+
+  scheme_sfs_start_sequence(info, 3, 0);
+  scheme_sfs_push(info, 2, 0);
+
+  nrator = scheme_sfs_expr(app->rator, info, -1);
+  nrand1 = scheme_sfs_expr(app->rand1, info, -1);
+  nrand2 = scheme_sfs_expr(app->rand2, info, -1);
+  
+  app->rator = nrator;
+  app->rand1 = nrand1;
+  app->rand2 = nrand2;
+
+  sfs_note_app(info, app->rator);
+
+  set_app3_eval_type(app);
+
+  return o;
+}
+
+static Scheme_Object *sfs_sequence(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Object *orig, *naya;
+  Scheme_Sequence *seq;
+  int i, n;
+
+  seq = (Scheme_Sequence *)o;
+  n = seq->count;
+
+  scheme_sfs_start_sequence(info, n, 1);
+
+  for (i = 0; i < n; i++) {
+    orig = seq->array[i];
+    naya = scheme_sfs_expr(orig, info, -1);
+    seq->array[i] = naya;
+  }
+
+  return o;
+}
+
+#define SFS_BRANCH_W 4
+
+static Scheme_Object *sfs_one_branch(SFS_Info *info, int ip, 
+                                     Scheme_Object *vec, int delta,
+                                     Scheme_Object *tbranch)
+{
+  int t_min_t, t_max_t, t_cnt, n, stackpos, i, save_nt, b_end, nt;
+  Scheme_Object *t_vec, *o;
+  Scheme_Object *clears = scheme_null;
+
+  info->min_touch = -1;
+  info->max_touch = -1;
+  save_nt = info->max_nontail;
+
+  SFS_LOG(printf("%d %d %s %d\n", info->pass, ip, (delta ? "else" : "then"), ip));
+
+  if (info->pass) {
+    /* Re-install max_used entries that refer to the branch */
+    o = SCHEME_VEC_ELS(vec)[delta * SFS_BRANCH_W];
+    t_min_t = SCHEME_INT_VAL(o);
+    o = SCHEME_VEC_ELS(vec)[(delta * SFS_BRANCH_W) + 2];
+    nt = SCHEME_INT_VAL(o);
+    if (nt > info->max_nontail)
+      info->max_nontail = nt;
+    if (t_min_t > -1) {
+      t_vec = SCHEME_VEC_ELS(vec)[(delta * SFS_BRANCH_W) + 1];
+      t_cnt = SCHEME_VEC_SIZE(t_vec);
+      for (i = 0; i < t_cnt; i++) {
+        o = SCHEME_VEC_ELS(t_vec)[i];
+        if (SCHEME_INTP(o)) {
+          n = SCHEME_INT_VAL(o);
+          SFS_LOG(printf(" @%d %d\n", i + t_min_t, n));
+          if (info->max_used[i + t_min_t] < n) {
+            SFS_LOG(printf(" |%d %d\n", i + t_min_t, n));
+            info->max_used[i + t_min_t] = n;
+            info->max_calls[i + t_min_t] = info->max_nontail;
+          }
+        }
+      }
+    }
+    /* If the other branch has last use for something not used in this
+       branch, and if there's a non-tail call in this branch
+       of later, then we'll have to start with explicit clears. 
+       Note that it doesn't matter whether the other branch actually
+       clears them (i.e., the relevant non-tail call might be only
+       in this branch). */
+    o = SCHEME_VEC_ELS(vec)[((1 - delta) * SFS_BRANCH_W) + 3];
+    b_end = SCHEME_INT_VAL(o);
+    if (((nt > ip) && (nt < b_end)) /* => non-tail call in branch */
+        || (ip < save_nt)) { /* => non-tail call after branches */
+      o = SCHEME_VEC_ELS(vec)[(1 - delta) * SFS_BRANCH_W];
+      t_min_t = SCHEME_INT_VAL(o);
+      if (t_min_t > -1) {
+        int at_ip, pos;
+        t_vec = SCHEME_VEC_ELS(vec)[((1 - delta) * SFS_BRANCH_W) + 1];
+        t_cnt = SCHEME_VEC_SIZE(t_vec);
+        o = SCHEME_VEC_ELS(vec)[((1 - delta) * SFS_BRANCH_W) + 2];
+        nt = SCHEME_INT_VAL(o);
+        o = SCHEME_VEC_ELS(vec)[((1 - delta) * SFS_BRANCH_W) + 3];
+        b_end = SCHEME_INT_VAL(o);
+        for (i = 0; i < t_cnt; i++) {
+          o = SCHEME_VEC_ELS(t_vec)[i];
+          if (SCHEME_INTP(o)) {
+            n = SCHEME_INT_VAL(o);
+            pos = i + t_min_t;
+            at_ip = info->max_used[pos];
+            SFS_LOG(printf(" ?%d %d %d\n", pos, n, at_ip));
+            if (((!delta && (at_ip == ip))
+                 || (delta && (at_ip == n)))
+                && (at_ip < info->max_calls[pos])) {
+              /* Add clear */
+              SFS_LOG(printf(" !%d %d %d\n", pos, n, at_ip));
+              pos -= info->stackpos;
+              clears = scheme_make_pair(scheme_make_integer(pos), 
+                                        clears);
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stackpos = info->stackpos;
+
+  tbranch = scheme_sfs_expr(tbranch, info, -1);
+
+  if (info->pass)
+    info->max_nontail = save_nt;
+# if MAX_SFS_CLEARING
+  else
+    info->max_nontail = info->ip;
+# endif
+
+  tbranch = scheme_sfs_add_clears(tbranch, clears, 1);
+
+  if (!info->pass) {
+    t_min_t = info->min_touch;
+    t_max_t = info->max_touch;
+    if (t_min_t < stackpos)
+      t_min_t = stackpos;
+    if (t_max_t < stackpos)
+      t_max_t = -1;
+    SFS_LOG(printf("%d %s %d [%d,%d] /%d\n", info->pass, (delta ? "else" : "then"), ip, 
+                   t_min_t, t_max_t, stackpos));
+    if (t_max_t < 0) {
+      t_min_t = -1;
+      t_vec = scheme_false;
+    } else {
+      t_cnt = t_max_t - t_min_t + 1;
+      t_vec = scheme_make_vector(t_cnt, NULL);
+      for (i = 0; i < t_cnt; i++) {
+        n = info->max_used[i + t_min_t];
+        SFS_LOG(printf("%d %s %d %d -> %d/%d\n", info->pass, (delta ? "else" : "then"), ip, 
+                       i + t_min_t, n, info->max_calls[i+ t_min_t]));
+        if (n > ip) {
+          SCHEME_VEC_ELS(t_vec)[i] = scheme_make_integer(n);
+          info->max_used[i + t_min_t] = ip;
+        } else {
+          SCHEME_VEC_ELS(t_vec)[i] = scheme_false;
+        }
+      }
+    }
+    SCHEME_VEC_ELS(vec)[delta * SFS_BRANCH_W] = scheme_make_integer(t_min_t);
+    SCHEME_VEC_ELS(vec)[(delta * SFS_BRANCH_W) + 1] = t_vec;
+    SCHEME_VEC_ELS(vec)[(delta * SFS_BRANCH_W) + 2] = scheme_make_integer(info->max_nontail);
+    SCHEME_VEC_ELS(vec)[(delta * SFS_BRANCH_W) + 3] = scheme_make_integer(info->ip);
+  }
+
+  info->stackpos = stackpos;
+
+  return tbranch;
+}
+
+static Scheme_Object *sfs_branch(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Branch_Rec *b;
+  Scheme_Object *t, *tb, *fb, *vec;
+  int ip, min_t, max_t;
+
+  b = (Scheme_Branch_Rec *)o;
+
+  scheme_sfs_start_sequence(info, 1, 0);
+
+  t = scheme_sfs_expr(b->test, info, -1);
+
+  ip = info->ip;
+  info->ip++;
+  /* Use ip to represent all uses in the two branches.
+     Use ip+1 to represent all non-tail calls in the two branches. */
+
+  min_t = info->min_touch;
+  max_t = info->max_touch;
+
+  SFS_LOG(printf(" after test: %d %d\n", min_t, max_t));
+
+  if (!info->pass) {
+    vec = scheme_make_vector(SFS_BRANCH_W * 2, NULL);
+    scheme_sfs_save(info, vec);
+  } else {
+    vec = scheme_sfs_next_saved(info);
+  }
+
+  tb = sfs_one_branch(info, ip, vec, 0, b->tbranch);
+
+  if (!info->pass) {
+    if ((min_t == -1)
+        || ((info->min_touch > -1) && (info->min_touch < min_t)))
+      min_t = info->min_touch;
+    if (info->max_touch > max_t)
+      max_t = info->max_touch;
+    if (info->max_nontail > ip + 1)
+      info->max_nontail = ip + 1;
+  }
+
+  fb = sfs_one_branch(info, ip, vec, 1, b->fbranch);
+
+  if (!info->pass) {
+    if ((min_t == -1)
+        || ((info->min_touch > -1) && (info->min_touch < min_t)))
+      min_t = info->min_touch;
+    if (info->max_touch > max_t)
+      max_t = info->max_touch;
+    if (info->max_nontail > ip + 1)
+      info->max_nontail = ip + 1;
+  }
+
+  SFS_LOG(printf(" done if: %d %d\n", min_t, max_t));
+  
+  info->min_touch = min_t;
+  info->max_touch = max_t;
+  
+  b->test = t;
+  b->tbranch = tb;
+  b->fbranch = fb;
+
+  return o;
+}
+
+static Scheme_Object *sfs_let_value(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Let_Value *lv = (Scheme_Let_Value *)o;
+  Scheme_Object *body, *rhs, *clears = scheme_null;
+  int i, pos;
+
+  scheme_sfs_start_sequence(info, 2, 1);
+
+  rhs = scheme_sfs_expr(lv->value, info, -1);
+
+  if (!info->pass
+      || (info->ip < info->max_nontail)) {
+    for (i = 0; i < lv->count; i++) {
+      pos = lv->position + i;
+      if (!info->pass)
+        scheme_sfs_used(info, pos);
+      else {
+        int spos;
+        spos = pos + info->stackpos;
+        if ((info->max_used[spos] == info->ip)
+            && (info->max_calls[spos] > info->ip)) {
+          /* No one is using the id after we set it.
+             We still need to set it, in case it's boxed and shared,
+             but then remove the binding or box. */
+          clears = scheme_make_pair(scheme_make_integer(pos),
+                                    clears);
+        }
+      }
+    }
+  }
+
+  body = scheme_sfs_expr(lv->body, info, -1);
+
+  body = scheme_sfs_add_clears(body, clears, 1);
+
+  lv->value = rhs;
+  lv->body = body;
+  
+  return o;
+}
+
+static Scheme_Object *sfs_let_one(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Let_One *lo = (Scheme_Let_One *)o;
+  Scheme_Object *body, *rhs, *vec;
+  int pos, save_mnt;
+
+  scheme_sfs_start_sequence(info, 2, 1);
+
+  scheme_sfs_push(info, 1, 1);
+  pos = info->stackpos;
+  save_mnt = info->max_nontail;
+
+  if (!info->pass) {
+    vec = scheme_make_vector(3, NULL);
+    scheme_sfs_save(info, vec);
+  } else {
+    vec = scheme_sfs_next_saved(info);
+    if (SCHEME_VEC_SIZE(vec) != 3)
+      scheme_signal_error("internal error: bad vector length");
+    info->max_used[pos] = SCHEME_INT_VAL(SCHEME_VEC_ELS(vec)[0]);
+    info->max_calls[pos] = SCHEME_INT_VAL(SCHEME_VEC_ELS(vec)[1]);
+    info->max_nontail = SCHEME_INT_VAL(SCHEME_VEC_ELS(vec)[2]);
+  }
+
+  rhs = scheme_sfs_expr(lo->value, info, -1);
+  body = scheme_sfs_expr(lo->body, info, -1);
+
+# if MAX_SFS_CLEARING
+  if (!info->pass)
+    info->max_nontail = info->ip;
+# endif
+  
+  if (!info->pass) {
+    int n;
+    info->max_calls[pos] = info->max_nontail;
+    n = info->max_used[pos];
+    SCHEME_VEC_ELS(vec)[0] = scheme_make_integer(n);
+    n = info->max_calls[pos];
+    SCHEME_VEC_ELS(vec)[1] = scheme_make_integer(n);
+    SCHEME_VEC_ELS(vec)[2] = scheme_make_integer(info->max_nontail);
+  } else {
+    info->max_nontail = save_mnt;
+  }
+
+  lo->value = rhs;
+  lo->body = body;
+
+  return o;
+}
+
+static Scheme_Object *sfs_let_void(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Let_Void *lv = (Scheme_Let_Void *)o;
+  Scheme_Object *body;
+  int i, pos;
+  Scheme_Object *vec;
+    
+  scheme_sfs_push(info, lv->count, 1);
+  pos = info->stackpos;
+
+  if (!info->pass) {
+    vec = scheme_make_vector(lv->count + 1, NULL);
+    scheme_sfs_save(info, vec);
+  } else {
+    vec = scheme_sfs_next_saved(info);
+    if (!SCHEME_VECTORP(vec))
+      scheme_signal_error("internal error: not a vector");
+    for (i = 0; i < lv->count; i++) {
+      info->max_used[pos + i] = SCHEME_INT_VAL(SCHEME_VEC_ELS(vec)[i]);
+      info->max_calls[pos + i] = SCHEME_INT_VAL(SCHEME_VEC_ELS(vec)[lv->count]);
+    }
+  }
+
+  body = scheme_sfs_expr(lv->body, info, -1);
+
+# if MAX_SFS_CLEARING
+  if (!info->pass)
+    info->max_nontail = info->ip;
+# endif
+
+  if (!info->pass) {
+    int n;
+    SCHEME_VEC_ELS(vec)[lv->count] = scheme_make_integer(info->max_nontail);
+    for (i = 0; i < lv->count; i++) {
+      n = info->max_used[pos + i];
+      SCHEME_VEC_ELS(vec)[i] = scheme_make_integer(n);
+    }
+  }
+
+  lv->body = body;
+
+  return o;
+}
+
+static Scheme_Object *sfs_letrec(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_Letrec *lr = (Scheme_Letrec *)o;
+  Scheme_Object **procs, *v, *clears = scheme_null;
+  int i, count;
+
+  count = lr->count;
+
+  scheme_sfs_start_sequence(info, count + 1, 1);
+
+  procs = lr->procs;
+
+  for (i = 0; i < count; i++) { 
+    v = scheme_sfs_expr(procs[i], info, i);
+
+    if (SAME_TYPE(SCHEME_TYPE(v), scheme_syntax_type)
+        && (SCHEME_PINT_VAL(v) == BEGIN0_EXPD)) {
+      /* Some clearing actions were added to the closure.
+         Lift them out. */
+      int j;
+      Scheme_Sequence *cseq = (Scheme_Sequence *)SCHEME_IPTR_VAL(v);
+      for (j = 1; j < cseq->count; j++) {
+        int pos;
+        pos = SCHEME_LOCAL_POS(cseq->array[j]);
+        clears = scheme_make_pair(scheme_make_integer(pos), clears);
+      }
+      v = cseq->array[0];
+    }
+    procs[i] = v;
+  }
+
+  v = scheme_sfs_expr(lr->body, info, -1);
+
+  v = scheme_sfs_add_clears(v, clears, 1);
+
+  lr->body = v;
+
+  return o;
+}
+
+static Scheme_Object *sfs_wcm(Scheme_Object *o, SFS_Info *info)
+{
+  Scheme_With_Continuation_Mark *wcm = (Scheme_With_Continuation_Mark *)o;
+  Scheme_Object *k, *v, *b;
+
+  scheme_sfs_start_sequence(info, 3, 1);
+
+  k = scheme_sfs_expr(wcm->key, info, -1);
+  v = scheme_sfs_expr(wcm->val, info, -1);
+  b = scheme_sfs_expr(wcm->body, info, -1);
+  
+  wcm->key = k;
+  wcm->val = v;
+  wcm->body = b;
+
+  return o;
+}
+
+Scheme_Object *scheme_sfs_expr(Scheme_Object *expr, SFS_Info *info, int closure_self_pos)
+{
+  Scheme_Type type = SCHEME_TYPE(expr);
+  int seqn, stackpos, tp;
+
+  seqn = info->seqn;
+  stackpos = info->stackpos;
+  tp = info->tail_pos;
+  if (seqn) {
+    info->seqn = 0;
+    info->tail_pos = 0;
+  }
+  info->ip++;
+
+  switch (type) {
+  case scheme_local_type:
+  case scheme_local_unbox_type:
+    if (!info->pass)
+      scheme_sfs_used(info, SCHEME_LOCAL_POS(expr));
+    else {
+      int pos, at_ip;
+      pos = SCHEME_LOCAL_POS(expr);
+      at_ip = info->max_used[info->stackpos + pos];
+      if (at_ip < info->max_calls[info->stackpos + pos]) {
+        if (at_ip == info->ip) {
+          /* Clear on read: */
+          expr = scheme_make_local(type, pos, SCHEME_LOCAL_CLEAR_ON_READ);
+        } else {
+          /* Someone else clears it: */
+          expr = scheme_make_local(type, pos, SCHEME_LOCAL_OTHER_CLEARS);
+        }
+      } else {
+# if MAX_SFS_CLEARING
+        scheme_signal_error("should have been cleared somewhere");
+# endif
+      }
+    }
+    break;
+  case scheme_syntax_type:
+    {
+      Scheme_Syntax_SFSer f;
+      Scheme_Object *orig, *naya;
+      
+      f = scheme_syntax_sfsers[SCHEME_PINT_VAL(expr)];
+      orig = SCHEME_IPTR_VAL(expr);
+      naya = f(orig, info);
+      if (!SAME_OBJ(orig, naya))
+        expr = naya;
+    }
+    break;
+  case scheme_application_type:
+    expr = sfs_application(expr, info);
+    break;
+  case scheme_application2_type:
+    expr = sfs_application2(expr, info);
+    break;
+  case scheme_application3_type:
+    expr = sfs_application3(expr, info);
+    break;
+  case scheme_sequence_type:
+    expr = sfs_sequence(expr, info);
+    break;
+  case scheme_branch_type:
+    expr = sfs_branch(expr, info);
+    break;
+  case scheme_with_cont_mark_type:
+    expr = sfs_wcm(expr, info);
+    break;
+  case scheme_unclosed_procedure_type:
+    expr = scheme_sfs_closure(expr, info, closure_self_pos);
+    break;
+  case scheme_let_value_type:
+    expr = sfs_let_value(expr, info);
+    break;
+  case scheme_let_void_type:
+    expr = sfs_let_void(expr, info);
+    break;
+  case scheme_letrec_type:
+    expr = sfs_letrec(expr, info);
+    break;
+  case scheme_let_one_type:
+    expr = sfs_let_one(expr, info);
+    break;
+  case scheme_closure_type:
+    {
+      Scheme_Closure *c = (Scheme_Closure *)expr;
+      if (ZERO_SIZED_CLOSUREP(c)) {
+        Scheme_Object *code;
+	code = scheme_sfs_closure((Scheme_Object *)c->code, info, closure_self_pos);
+        if (SAME_TYPE(SCHEME_TYPE(code), scheme_syntax_type)
+            && (SCHEME_PINT_VAL(code) == BEGIN0_EXPD)) {
+          Scheme_Sequence *seq = (Scheme_Sequence *)SCHEME_IPTR_VAL(code);
+          c->code = (Scheme_Closure_Data *)seq->array[0];
+          seq->array[0] = expr;
+          expr = code;
+        } else {
+          c->code = (Scheme_Closure_Data *)code;
+        }
+      }
+    }
+    break;
+  case scheme_toplevel_type:
+    {
+      int c = SCHEME_TOPLEVEL_DEPTH(expr);
+      if (info->stackpos + c != info->tlpos)
+        scheme_signal_error("toplevel access not at expected place");
+    }
+    break;
+  case scheme_case_closure_type:
+    {
+      /* FIXME: maybe need to handle eagerly created closure */
+    }
+    break;
+  default:
+    break;
+  }
+
+  info->ip++;
+
+  if (seqn) {
+    info->seqn = seqn - 1;
+    memset(info->max_used + info->stackpos, 0, (stackpos - info->stackpos) * sizeof(int));
+    memset(info->max_calls + info->stackpos, 0, (stackpos - info->stackpos) * sizeof(int));
+    info->stackpos = stackpos;
+    info->tail_pos = tp;
+  }
+
+  return expr;
+}
+
 /*========================================================================*/
 /*                                  JIT                                   */
 /*========================================================================*/
@@ -3936,6 +4772,7 @@ static void *compile_k(void)
       scheme_enable_expression_resolve_lifts(ri);
 
       o = scheme_resolve_expr(o, ri);
+      o = scheme_sfs(o, NULL, ri->max_let_depth);
 
       o = scheme_merge_expression_resolve_lifts(o, rp, ri);
 
@@ -6777,12 +7614,12 @@ scheme_do_eval(Scheme_Object *obj, int num_rands, Scheme_Object **rands,
       case scheme_local_type:
 	{
 	  v = RUNSTACK[SCHEME_LOCAL_POS(obj)];
-	  goto returnv_never_multi;
+          goto returnv_never_multi;
 	}
       case scheme_local_unbox_type:
 	{
 	  v = SCHEME_ENVBOX_VAL(RUNSTACK[SCHEME_LOCAL_POS(obj)]);
-	  goto returnv_never_multi;
+          goto returnv_never_multi;
 	}
       case scheme_syntax_type:
 	{
@@ -8491,6 +9328,61 @@ void scheme_pop_prefix(Scheme_Object **rs)
 #define VALID_VAL 1
 #define VALID_BOX 2
 #define VALID_TOPLEVELS 3
+#define VALID_VAL_NOCLEAR 4
+#define VALID_BOX_NOCLEAR 5
+
+typedef struct Validate_Clearing {
+  MZTAG_IF_REQUIRED
+  int stackpos, stacksize;
+  int *stack;
+  int ncstackpos, ncstacksize;
+  int *ncstack;
+  int self_pos, self_count, self_start;
+} Validate_Clearing;
+
+static struct Validate_Clearing *make_clearing_stack()
+{
+  Validate_Clearing *vc;
+  vc = MALLOC_ONE_RT(Validate_Clearing);
+  SET_REQUIRED_TAG(vc->type = scheme_rt_validate_clearing);
+  vc->self_pos = -1;
+  return vc;
+}
+
+static void reset_clearing(struct Validate_Clearing *vc)
+{
+  vc->stackpos = 0;
+  vc->ncstackpos = 0;
+}
+
+static void clearing_stack_push(struct Validate_Clearing *vc, int pos, int val)
+{
+  if (vc->stackpos + 2 > vc->stacksize) {
+    int *a, sz;
+    sz = (vc->stacksize ? 2 * vc->stacksize : 32);
+    a = (int *)scheme_malloc_atomic(sizeof(int) * sz);
+    memcpy(a, vc->stack, vc->stacksize * sizeof(int));
+    vc->stacksize = sz;
+    vc->stack = a;
+  }
+  vc->stack[vc->stackpos] = pos;
+  vc->stack[vc->stackpos + 1] = val;
+  vc->stackpos += 2;
+}
+
+static void noclear_stack_push(struct Validate_Clearing *vc, int pos)
+{
+  if (vc->ncstackpos + 1 > vc->ncstacksize) {
+    int *a, sz;
+    sz = (vc->ncstacksize ? 2 * vc->ncstacksize : 32);
+    a = (int *)scheme_malloc_atomic(sizeof(int) * sz);
+    memcpy(a, vc->ncstack, vc->ncstacksize * sizeof(int));
+    vc->ncstacksize = sz;
+    vc->ncstack = a;
+  }
+  vc->ncstack[vc->ncstackpos] = pos;
+  vc->ncstackpos += 1;
+}
 
 void scheme_validate_code(Mz_CPort *port, Scheme_Object *code,
                           int depth, 
@@ -8499,6 +9391,7 @@ void scheme_validate_code(Mz_CPort *port, Scheme_Object *code,
 {
   char *stack;
   int delta;
+  struct Validate_Clearing *vc;
   Validate_TLS tls;
 
   depth += ((num_toplevels || num_stxes || num_lifts) ? 1 : 0);
@@ -8514,22 +9407,27 @@ void scheme_validate_code(Mz_CPort *port, Scheme_Object *code,
 
   tls = MALLOC_N(mzshort*, num_lifts);
 
+  vc = make_clearing_stack();
+
   if (code_vec) {
     int i, cnt;
     cnt = SCHEME_VEC_SIZE(code);
     for (i = 0; i < cnt; i++) {
+      reset_clearing(vc);
       scheme_validate_expr(port, SCHEME_VEC_ELS(code)[i], 
                            stack, tls,
                            depth, delta, delta, 
                            num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0,
+                           vc, 1);
     }
   } else {
     scheme_validate_expr(port, code, 
                          stack, tls,
                          depth, delta, delta, 
                          num_toplevels, num_stxes, num_lifts,
-                         NULL, 0);
+                         NULL, 0, 0,
+                         vc, 1);
   }
 }
 
@@ -8542,16 +9440,18 @@ static Scheme_Object *validate_k(void)
   int *args = (int *)(((void **)p->ku.k.p5)[0]);
   Scheme_Object *app_rator = (Scheme_Object *)(((void **)p->ku.k.p5)[1]);
   Validate_TLS tls = (Validate_TLS)(((void **)p->ku.k.p5)[2]);
+  struct Validate_Clearing *vc = (struct Validate_Clearing *)p->ku.k.p4;
   
   p->ku.k.p1 = NULL;
   p->ku.k.p2 = NULL;
   p->ku.k.p3 = NULL;
+  p->ku.k.p4 = NULL;
   p->ku.k.p5 = NULL;
 
   scheme_validate_expr(port, expr, stack, tls,
                        args[0], args[1], args[2],
                        args[3], args[4], args[5],
-                       app_rator, args[6]);
+                       app_rator, args[6], args[7], vc, args[8]);
 
   return scheme_true;
 }
@@ -8654,11 +9554,13 @@ static int argument_to_arity_error(Scheme_Object *app_rator, int proc_with_refs_
 
 void scheme_validate_closure(Mz_CPort *port, Scheme_Object *expr, 
                              char *closure_stack, Validate_TLS tls,
-                             int num_toplevels, int num_stxes, int num_lifts)
+                             int num_toplevels, int num_stxes, int num_lifts,
+                             int self_pos_in_closure)
 {
   Scheme_Closure_Data *data = (Scheme_Closure_Data *)expr;
   int i, sz, cnt, base, base2;
   char *new_stack;
+  struct Validate_Clearing *vc;
 
   sz = data->max_let_depth;
   new_stack = scheme_malloc_atomic(sz);
@@ -8684,18 +9586,124 @@ void scheme_validate_closure(Mz_CPort *port, Scheme_Object *expr,
     new_stack[i + base] = closure_stack[i];
   }
 
+  vc = make_clearing_stack();
+  if (self_pos_in_closure >= 0) {
+    vc->self_pos = base + self_pos_in_closure;
+    vc->self_count = data->closure_size;
+    vc->self_start = base;
+  }
+
   scheme_validate_expr(port, data->code, new_stack, tls, sz, sz, base, num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, 1);
+}
+
+
+static void validate_unclosed_procedure(Mz_CPort *port, Scheme_Object *expr, 
+                                        char *stack, Validate_TLS tls,
+                                        int depth, int delta, 
+                                        int num_toplevels, int num_stxes, int num_lifts,
+                                        Scheme_Object *app_rator, int proc_with_refs_ok,
+                                        int self_pos)
+{
+  Scheme_Closure_Data *data = (Scheme_Closure_Data *)expr;
+  int i, cnt, q, p, sz, base, vld, self_pos_in_closure = -1;
+  mzshort *map;
+  char *closure_stack;
+      
+  if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
+    sz = data->closure_size + data->num_params;
+  } else {
+    sz = data->closure_size;
+  }
+  map = data->closure_map;
+      
+  if (sz)
+    closure_stack = scheme_malloc_atomic(sz);
+  else
+    closure_stack = NULL;
+
+  if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
+    cnt = data->num_params;
+    base = sz - cnt;
+    for (i = 0; i < cnt; i++) {
+      int bit = ((mzshort)1 << (i & (BITS_PER_MZSHORT - 1)));
+      if (map[data->closure_size + (i / BITS_PER_MZSHORT)] & bit)
+        vld = VALID_BOX;
+      else
+        vld = VALID_VAL;
+      closure_stack[i + base] = vld;
+    }
+  } else {
+    base = sz;
+  }
+
+  cnt = data->closure_size;
+  base = base - cnt;
+
+  for (i = 0; i < cnt; i++) {
+    q = map[i];
+    if (q == self_pos)
+      self_pos_in_closure = i;
+    p = q + delta;
+    if ((q < 0) || (p > depth) || (stack[p] == VALID_NOT))
+      scheme_ill_formed_code(port);
+    vld = stack[p];
+    if (vld == VALID_VAL_NOCLEAR)
+      vld = VALID_VAL;
+    else if (vld == VALID_BOX_NOCLEAR)
+      vld = VALID_BOX;
+    closure_stack[i + base] = vld;
+  }
+
+  if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
+    if ((proc_with_refs_ok != 1)
+        && !argument_to_arity_error(app_rator, proc_with_refs_ok))
+      scheme_ill_formed_code(port);
+  }
+      
+  if (SCHEME_RPAIRP(data->code)) {
+    /* Delay validation */
+    Scheme_Object *vec;
+    vec = scheme_make_vector(7, NULL);
+    SCHEME_VEC_ELS(vec)[0] = SCHEME_CAR(data->code);
+    SCHEME_VEC_ELS(vec)[1] = (Scheme_Object *)closure_stack;
+    SCHEME_VEC_ELS(vec)[2] = (Scheme_Object *)tls;
+    SCHEME_VEC_ELS(vec)[3] = scheme_make_integer(num_toplevels);
+    SCHEME_VEC_ELS(vec)[4] = scheme_make_integer(num_stxes);
+    SCHEME_VEC_ELS(vec)[5] = scheme_make_integer(num_lifts);
+    SCHEME_VEC_ELS(vec)[6] = scheme_make_integer(self_pos_in_closure);
+    SCHEME_CAR(data->code) = vec;
+  } else
+    scheme_validate_closure(port, expr, closure_stack, tls, num_toplevels, num_stxes, num_lifts, self_pos_in_closure);
+}
+
+static void check_self_call_valid(Scheme_Object *rator, Mz_CPort *port, struct Validate_Clearing *vc, 
+                                  int delta, char *stack)
+{
+  if ((vc->self_pos >= 0)
+      && SAME_TYPE(SCHEME_TYPE(rator), scheme_local_type)
+      && !(SCHEME_LOCAL_FLAGS(rator) & SCHEME_LOCAL_CLEARING_MASK)
+      && ((SCHEME_LOCAL_POS(rator) + delta) == vc->self_pos)) {
+    /* For a self call, the JIT needs the closure data to be intact. */
+    int i, pos;
+    for (i = vc->self_count; i--; ) {
+      pos = i + vc->self_start;
+      if (stack[pos] == VALID_NOT)
+        scheme_ill_formed_code(port);
+    }
+  }
 }
 
 void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr, 
                           char *stack, Validate_TLS tls,
 			  int depth, int letlimit, int delta, 
 			  int num_toplevels, int num_stxes, int num_lifts,
-                          Scheme_Object *app_rator, int proc_with_refs_ok)
+                          Scheme_Object *app_rator, int proc_with_refs_ok,
+                          int result_ignored,
+                          struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Type type;
-  int did_one = 0;
+  int did_one = 0, vc_merge = 0, vc_merge_start = 0;
 
 #ifdef DO_STACK_CHECK
 # include "mzstkchk.h"
@@ -8704,11 +9712,12 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
     void **pr;
     int *args;
 
-    args = MALLOC_N_ATOMIC(int, 7);
+    args = MALLOC_N_ATOMIC(int, 8);
 
     p->ku.k.p1 = (void *)port;
     p->ku.k.p2 = (void *)expr;
     p->ku.k.p3 = (void *)stack;
+    p->ku.k.p4 = (void *)vc;
 
     args[0] = depth;
     args[1] = letlimit;
@@ -8717,6 +9726,7 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
     args[4] = num_stxes;
     args[5] = num_lifts;
     args[6] = proc_with_refs_ok;
+    args[7] = result_ignored;
 
     pr = MALLOC_N(void*, 3);
     pr[0] = (void *)args;
@@ -8797,16 +9807,37 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       if ((q < 0) || (p >= depth))
 	scheme_ill_formed_code(port);
       
-      if (stack[p] != VALID_VAL) {
-        if ((proc_with_refs_ok >= 2) && (stack[p] == VALID_BOX)
-            && scheme_validate_rator_wants_box(app_rator, proc_with_refs_ok - 2, 1,
-                                               tls, num_toplevels, num_stxes, num_lifts)) {
+      if ((stack[p] != VALID_VAL) && (stack[p] != VALID_VAL_NOCLEAR)) {
+        if (result_ignored && ((stack[p] == VALID_BOX) || (stack[p] == VALID_BOX_NOCLEAR))) {
+          /* ok to look up and ignore box */
+        } else if ((proc_with_refs_ok >= 2) 
+                   && ((stack[p] == VALID_BOX) || (stack[p] == VALID_BOX_NOCLEAR))
+                   && scheme_validate_rator_wants_box(app_rator, proc_with_refs_ok - 2, 1,
+                                                      tls, num_toplevels, num_stxes, num_lifts)) {
           /* It's ok - the function wants us to pass it a box, and
              we did. */
           app_rator = NULL;
         } else
           scheme_ill_formed_code(port);
       }
+
+      if (SCHEME_LOCAL_FLAGS(expr) & SCHEME_LOCAL_CLEAR_ON_READ) {
+        if ((stack[p] == VALID_VAL_NOCLEAR) || (stack[p] == VALID_BOX_NOCLEAR))
+          scheme_ill_formed_code(port);
+        if (p >= letlimit)
+          clearing_stack_push(vc, p, stack[p]);
+        stack[p] = VALID_NOT;
+      } else if (!(SCHEME_LOCAL_FLAGS(expr) & SCHEME_LOCAL_OTHER_CLEARS)) {
+        if (stack[p] == VALID_BOX) {
+          if (p >= letlimit)
+            noclear_stack_push(vc, p);
+          stack[p] = VALID_BOX_NOCLEAR;
+        } else if (stack[p] == VALID_VAL) {
+          if (p >= letlimit)
+            noclear_stack_push(vc, p);
+          stack[p] = VALID_VAL_NOCLEAR;
+        }
+      }
     }
     break;
   case scheme_local_unbox_type:
@@ -8814,8 +9845,23 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       int q = SCHEME_LOCAL_POS(expr);
       int p = q + delta;
 
-      if ((q < 0) || (p >= depth) || (stack[p] != VALID_BOX))
+      if ((q < 0) || (p >= depth) || ((stack[p] != VALID_BOX)
+                                      && (stack[p] != VALID_BOX_NOCLEAR)))
 	scheme_ill_formed_code(port);
+
+      if (SCHEME_LOCAL_FLAGS(expr) & SCHEME_LOCAL_CLEAR_ON_READ) {
+        if (stack[p] == VALID_BOX_NOCLEAR)
+          scheme_ill_formed_code(port);
+        if (p >= letlimit)
+          clearing_stack_push(vc, p, stack[p]);
+        stack[p] = VALID_NOT;
+      } else if (!(SCHEME_LOCAL_FLAGS(expr) & SCHEME_LOCAL_OTHER_CLEARS)) {
+        if (stack[p] == VALID_BOX) {
+          if (p >= letlimit)
+            noclear_stack_push(vc, p);
+          stack[p] = VALID_BOX_NOCLEAR;
+        }
+      }
     }
     break;
   case scheme_syntax_type:
@@ -8827,7 +9873,8 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
 	scheme_ill_formed_code(port);
 
       f = scheme_syntax_validaters[p];
-      f((Scheme_Object *)SCHEME_IPTR_VAL(expr), port, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts);
+      f((Scheme_Object *)SCHEME_IPTR_VAL(expr), port, stack, tls, depth, letlimit, delta, 
+        num_toplevels, num_stxes, num_lifts, vc, tailpos);
     }
     break;
   case scheme_application_type:
@@ -8844,8 +9891,11 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
 
       for (i = 0; i < n; i++) {
 	scheme_validate_expr(port, app->args[i], stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                             i ? app->args[0] : NULL, i + 1);
+                             i ? app->args[0] : NULL, i + 1, 0, vc, 0);
       }
+
+      if (tailpos)
+        check_self_call_valid(app->args[0], port, vc, delta, stack);
     }
     break;
   case scheme_application2_type:
@@ -8858,9 +9908,12 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       stack[delta] = VALID_NOT;
 
       scheme_validate_expr(port, app->rator, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                           NULL, 1);
+                           NULL, 1, 0, vc, 0);
       scheme_validate_expr(port, app->rand, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                           app->rator, 2);
+                           app->rator, 2, 0, vc, 0);
+
+      if (tailpos)
+        check_self_call_valid(app->rator, port, vc, delta, stack);
     }
     break;
   case scheme_application3_type:
@@ -8874,11 +9927,14 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       stack[delta+1] = VALID_NOT;
 
       scheme_validate_expr(port, app->rator, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                           NULL, 1);
+                           NULL, 1, 0, vc, 0);
       scheme_validate_expr(port, app->rand1, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                           app->rator, 2);
+                           app->rator, 2, 0, vc, 0);
       scheme_validate_expr(port, app->rand2, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts, 
-                           app->rator, 3);
+                           app->rator, 3, 0, vc, 0);
+
+      if (tailpos)
+        check_self_call_valid(app->rator, port, vc, delta, stack);
     }
     break;
   case scheme_sequence_type:
@@ -8891,7 +9947,7 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
 	  
       for (i = 0; i < cnt - 1; i++) {
 	scheme_validate_expr(port, seq->array[i], stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                             NULL, 0);
+                             NULL, 0, 1, vc, 0);
       }
 
       expr = seq->array[cnt - 1];
@@ -8901,15 +9957,44 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
   case scheme_branch_type:
     {
       Scheme_Branch_Rec *b;
+      int vc_pos, vc_ncpos;
+
       b = (Scheme_Branch_Rec *)expr;
       scheme_validate_expr(port, b->test, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0, vc, 0);
       /* This is where letlimit is useful. It prevents let-assignment in the
 	 "then" branch that could permit bad code in the "else" branch (or the
 	 same thing with either branch affecting later code in a sequence). */
       letlimit = delta;
+      vc_pos = vc->stackpos;
+      vc_ncpos = vc->ncstackpos;
       scheme_validate_expr(port, b->tbranch, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, result_ignored, vc, tailpos);
+
+      /* Rewind clears and noclears, but also save the clears,
+         so that the branches' effects can be merged. */
+      {
+        int i, j;
+
+        if (!vc_merge) {
+          vc_merge = 1;
+          vc_merge_start = vc_pos;
+        }
+        
+        for (i = vc->stackpos - 2; i >= vc_pos; i -= 2) {
+          stack[vc->stack[i]] = vc->stack[i + 1];
+        }
+
+        for (i = vc->ncstackpos - 1; i >= vc_ncpos; i--) {
+          j = vc->ncstack[i];
+          if (stack[j] == VALID_VAL_NOCLEAR)
+            stack[j] = VALID_VAL;
+          else if (stack[j] == VALID_BOX_NOCLEAR)
+            stack[j] = VALID_BOX;
+        }
+        vc->ncstackpos = vc_ncpos;
+      }
+
       expr = b->fbranch;
       goto top;
     }
@@ -8919,9 +10004,9 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       Scheme_With_Continuation_Mark *wcm = (Scheme_With_Continuation_Mark *)expr;
       
       scheme_validate_expr(port, wcm->key, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0, vc, 0);
       scheme_validate_expr(port, wcm->val, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0, vc, 0);
       expr = wcm->body;
       goto top;
     }
@@ -8943,68 +10028,9 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
     break;
   case scheme_unclosed_procedure_type:
     {
-      Scheme_Closure_Data *data = (Scheme_Closure_Data *)expr;
-      int i, cnt, q, p, sz, base, vld;
-      mzshort *map;
-      char *closure_stack;
-      
-      if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
-        sz = data->closure_size + data->num_params;
-      } else {
-        sz = data->closure_size;
-      }
-      map = data->closure_map;
-      
-      if (sz)
-        closure_stack = scheme_malloc_atomic(sz);
-      else
-        closure_stack = NULL;
-
-      if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
-        cnt = data->num_params;
-        base = sz - cnt;
-        for (i = 0; i < cnt; i++) {
-          int bit = ((mzshort)1 << (i & (BITS_PER_MZSHORT - 1)));
-          if (map[data->closure_size + (i / BITS_PER_MZSHORT)] & bit)
-            vld = VALID_BOX;
-          else
-            vld = VALID_VAL;
-          closure_stack[i + base] = vld;
-        }
-      } else {
-        base = sz;
-      }
-
-      cnt = data->closure_size;
-      base = base - cnt;
-
-      for (i = 0; i < cnt; i++) {
-        q = map[i];
-        p = q + delta;
-        if ((q < 0) || (p > depth) || (stack[p] == VALID_NOT))
-          scheme_ill_formed_code(port);
-        closure_stack[i + base] = stack[p];
-      }
-
-      if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_REF_ARGS) {
-        if ((proc_with_refs_ok != 1)
-            && !argument_to_arity_error(app_rator, proc_with_refs_ok))
-          scheme_ill_formed_code(port);
-      }
-      
-      if (SCHEME_RPAIRP(data->code)) {
-        /* Delay validation */
-        Scheme_Object *vec;
-        vec = scheme_make_vector(6, NULL);
-        SCHEME_VEC_ELS(vec)[0] = SCHEME_CAR(data->code);
-        SCHEME_VEC_ELS(vec)[1] = (Scheme_Object *)closure_stack;
-        SCHEME_VEC_ELS(vec)[2] = (Scheme_Object *)tls;
-        SCHEME_VEC_ELS(vec)[3] = scheme_make_integer(num_toplevels);
-        SCHEME_VEC_ELS(vec)[4] = scheme_make_integer(num_stxes);
-        SCHEME_VEC_ELS(vec)[5] = scheme_make_integer(num_lifts);
-        SCHEME_CAR(data->code) = vec;
-      } else
-        scheme_validate_closure(port, expr, closure_stack, tls, num_toplevels, num_stxes, num_lifts);
+      validate_unclosed_procedure(port, expr, stack, tls,
+                                  depth, delta, num_toplevels, num_stxes, num_lifts,
+                                  app_rator, proc_with_refs_ok, -1);
     }
     break;
   case scheme_let_value_type:
@@ -9013,7 +10039,7 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       int q, p, c, i;
 
       scheme_validate_expr(port, lv->value, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0, vc, 0);
       memset(stack, VALID_NOT, delta);
 
       c = lv->count;
@@ -9023,13 +10049,17 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       for (i = 0; i < c; i++, p++) {
 	if ((q < 0) 
 	    || (SCHEME_LET_AUTOBOX(lv) && ((p >= depth)
-					   || (stack[p] != VALID_BOX)))
+					   || ((stack[p] != VALID_BOX)
+                                               && (stack[p] != VALID_BOX_NOCLEAR))))
 	    || (!SCHEME_LET_AUTOBOX(lv) && ((p >= letlimit)
-					    || ((stack[p] != VALID_VAL) && (stack[p] != VALID_NOT)))))
+					    || ((stack[p] != VALID_VAL) 
+                                                && (stack[p] != VALID_VAL_NOCLEAR) 
+                                                && (stack[p] != VALID_NOT)))))
 	  scheme_ill_formed_code(port);
 
 	if (!SCHEME_LET_AUTOBOX(lv)) {
-	  stack[p] = VALID_VAL;
+          if (stack[p] != VALID_VAL_NOCLEAR)
+            stack[p] = VALID_VAL;
 	}
       }
 
@@ -9081,8 +10111,9 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       }
 
       for (i = 0; i < c; i++) {
-	scheme_validate_expr(port, l->procs[i], stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                             NULL, 0);
+	validate_unclosed_procedure(port, l->procs[i], stack, tls, 
+                                    depth, delta, num_toplevels, num_stxes, num_lifts,
+                                    NULL, 0, i);
       }
 
       expr = l->body;
@@ -9099,7 +10130,7 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
       stack[delta] = VALID_NOT;
 
       scheme_validate_expr(port, lo->value, stack, tls, depth, letlimit, delta, num_toplevels, num_stxes, num_lifts,
-                           NULL, 0);
+                           NULL, 0, 0, vc, 0);
       stack[delta] = VALID_VAL;
 
       expr = lo->body;
@@ -9129,6 +10160,15 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
     if (scheme_validate_rator_wants_box(app_rator, proc_with_refs_ok - 2, 0,
                                         tls, num_toplevels, num_stxes, num_lifts))
       scheme_ill_formed_code(port);
+
+  if (vc_merge) {
+    /* Re-clear to merge effects from branches */
+    int i, p;
+    for (i = vc_merge_start; i < vc->stackpos; i += 2) {
+      p = vc->stack[i];
+      stack[p] = VALID_NOT;
+    }
+  }
 }
 
 void scheme_validate_toplevel(Scheme_Object *expr, Mz_CPort *port,
@@ -9143,7 +10183,8 @@ void scheme_validate_toplevel(Scheme_Object *expr, Mz_CPort *port,
   scheme_validate_expr(port, expr, stack, tls, 
                        depth, delta, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, skip_refs_check ? 1 : 0);
+                       NULL, skip_refs_check ? 1 : 0, 0,
+                       make_clearing_stack(), 0);
 }
 
 void scheme_validate_boxenv(int p, Mz_CPort *port, char *stack, int depth, int delta)
@@ -9245,6 +10286,19 @@ static Scheme_Object *write_syntax(Scheme_Object *obj)
   idx = scheme_make_integer(c);
   protect_after = scheme_syntax_protect_afters[c];
 
+  if (c == BEGIN0_EXPD) {
+    Scheme_Object *v;
+    v = SCHEME_PTR_VAL(obj);
+    switch (SCHEME_TYPE(v)) {
+    case scheme_sequence_type:
+    case scheme_begin0_sequence_type:
+      break;
+    default:
+      *(long *)0x0 = 1;
+      break;
+    }
+  }
+
   l = rest = (Scheme_Object *)SCHEME_IPTR_VAL(obj);
   if (protect_after == -2) {
     /* -2 => protect first element of vector */
@@ -9389,6 +10443,7 @@ static void register_traversers(void)
 {
   GC_REG_TRAV(scheme_rt_compile_info, mark_comp_info);
   GC_REG_TRAV(scheme_rt_saved_stack, mark_saved_stack);
+  GC_REG_TRAV(scheme_rt_validate_clearing, mark_validate_clearing);
 }
 
 END_XFORM_SKIP;
diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index ada5325a3b..7adda10005 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -647,8 +647,7 @@ scheme_make_folding_prim(Scheme_Prim *fun, const char *name,
 {
   return make_prim_closure(fun, 1, name, mina, maxa,
 			   (folding 
-			    ? (SCHEME_PRIM_IS_FOLDING
-			       | SCHEME_PRIM_IS_NONCM)
+			    ? SCHEME_PRIM_OPT_FOLDING
 			    : 0),
 			   1, 1,
 			   0, 0, NULL);
@@ -660,9 +659,22 @@ scheme_make_noncm_prim(Scheme_Prim *fun, const char *name,
 {
   /* A non-cm primitive leaves the mark stack unchanged when it returns,
      it can't return multiple values or a tail call, and it cannot
-     use its third argument (i.e., the closure pointer) */
+     use its third argument (i.e., the closure pointer). */
   return make_prim_closure(fun, 1, name, mina, maxa,
-			   SCHEME_PRIM_IS_NONCM,
+			   SCHEME_PRIM_OPT_NONCM,
+			   1, 1,
+			   0, 0, NULL);
+}
+
+Scheme_Object *
+scheme_make_immed_prim(Scheme_Prim *fun, const char *name,
+		       mzshort mina, mzshort maxa)
+{
+  /* An immediate primitive is a non-cm primitive, and it doesn't
+     extend the continuation in a way that interacts with space safety, except
+     maybe to raise an exception. */
+  return make_prim_closure(fun, 1, name, mina, maxa,
+			   SCHEME_PRIM_OPT_IMMEDIATE,
 			   1, 1,
 			   0, 0, NULL);
 }
@@ -693,7 +705,7 @@ Scheme_Object *scheme_make_folding_prim_closure(Scheme_Primitive_Closure_Proc *p
 {
   return make_prim_closure((Scheme_Prim *)prim, 1, name, mina, maxa,
 			   (functional
-			    ? SCHEME_PRIM_IS_FOLDING
+			    ? SCHEME_PRIM_OPT_FOLDING
 			    : 0),
 			   1, 1,
 			   1, size, vals);
@@ -721,7 +733,7 @@ scheme_make_closed_prim_w_everything(Scheme_Closed_Prim *fun,
   prim->name = name;
   prim->mina = mina;
   prim->maxa = maxa;
-  prim->pp.flags = ((folding ? SCHEME_PRIM_IS_FOLDING : 0)
+  prim->pp.flags = ((folding ? SCHEME_PRIM_OPT_FOLDING : 0)
 		    | (scheme_defining_primitives ? SCHEME_PRIM_IS_PRIMITIVE : 0)
 		    | (hasr ? SCHEME_PRIM_IS_MULTI_RESULT : 0));
 
@@ -908,7 +920,8 @@ void scheme_delay_load_closure(Scheme_Closure_Data *data)
                               (Validate_TLS)SCHEME_VEC_ELS(vinfo)[2], 
                               SCHEME_INT_VAL(SCHEME_VEC_ELS(vinfo)[3]),
                               SCHEME_INT_VAL(SCHEME_VEC_ELS(vinfo)[4]),
-                              SCHEME_INT_VAL(SCHEME_VEC_ELS(vinfo)[5]));
+                              SCHEME_INT_VAL(SCHEME_VEC_ELS(vinfo)[5]),
+                              SCHEME_INT_VAL(SCHEME_VEC_ELS(vinfo)[6]));
     }
   }
 }
@@ -1024,6 +1037,98 @@ Scheme_Object *scheme_shift_closure_compilation(Scheme_Object *_data, int delta,
   return _data;
 }
 
+Scheme_Object *scheme_sfs_closure(Scheme_Object *expr, SFS_Info *info, int self_pos)
+{
+  Scheme_Closure_Data *data = (Scheme_Closure_Data *)expr;
+  Scheme_Object *code;
+  int i, size, has_tl = 0;
+
+  size = data->closure_size;
+  if (size) {
+    if (info->stackpos + data->closure_map[size - 1] == info->tlpos) {
+      has_tl = 1;
+      --size;
+    }
+  }
+
+  if (!info->pass) {
+    for (i = size; i--; ) {
+      scheme_sfs_used(info, data->closure_map[i]);
+    }
+  } else {
+    /* Check whether we need to zero out any stack positions
+       after capturing them in a closure: */
+    Scheme_Object *clears = scheme_null;
+
+    if (info->ip < info->max_nontail) {
+      int pos, ip;
+      for (i = size; i--; ) {
+        pos = data->closure_map[i] + info->stackpos;
+        if (pos < info->depth) {
+          ip = info->max_used[pos];
+          if ((ip == info->ip)
+              && (ip < info->max_calls[pos])) {
+            pos -= info->stackpos;
+            clears = scheme_make_pair(scheme_make_integer(pos),
+                                      clears);
+          }
+        }
+      }
+    }
+
+    return scheme_sfs_add_clears(expr, clears, 0);
+  }
+
+  if (!(SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_SFS)) {
+    SCHEME_CLOSURE_DATA_FLAGS(data) |= CLOS_SFS;
+    info = scheme_new_sfs_info(data->max_let_depth);
+    scheme_sfs_push(info, data->closure_size + data->num_params, 1);
+
+    if (has_tl)
+      info->tlpos = info->stackpos + data->closure_size - 1;
+
+    if (self_pos >= 0) {
+      for (i = size; i--; ) {
+        if (data->closure_map[i] == self_pos) {
+          info->selfpos = info->stackpos + i;
+          info->selfstart = info->stackpos;
+          info->selflen = data->closure_size;
+          break;
+        }
+      }
+    }
+    
+    code = scheme_sfs(data->code, info, data->max_let_depth);
+    
+    /* If any arguments go unused, and if there's a non-tail,
+       non-immediate call in the body, then we flush the
+       unused arguments at the start of the body. We assume that
+       the closure values are used (otherwise they wouldn't
+       be in the closure). */
+    if (info->max_nontail) {
+      int i, pos, cnt;
+      Scheme_Object *clears = scheme_null;
+
+      cnt = data->num_params;
+      for (i = 0; i < cnt; i++) {
+        pos = data->max_let_depth - (cnt - i);
+        if (!info->max_used[pos]) {
+          pos = i + data->closure_size;
+          clears = scheme_make_pair(scheme_make_integer(pos),
+                                    clears);
+        }
+      }
+      
+      if (SCHEME_PAIRP(clears))
+        code = scheme_sfs_add_clears(code, clears, 1);
+    }
+
+    data->code = code;
+  }
+
+  return expr;
+}
+
 int scheme_closure_body_size(Scheme_Closure_Data *data, int check_assign)
 {
   int i;
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index 545363315c..5f0070afdf 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -857,6 +857,19 @@ static int mz_is_closure(mz_jit_state *jitter, int i, int arity, int *_flags)
   return 0;
 }
 
+static int stack_safety(mz_jit_state *jitter, int cnt, int offset)
+{
+  /* To preserve space safety, we must initialize any stack room
+     that we make, so that whatever happens to be there isn't
+     traversed in case of a GC. */
+  int i;
+  for (i = 0; i < cnt; i++) {
+    jit_stxi_p(WORDS_TO_BYTES(i+offset), JIT_RUNSTACK, JIT_RUNSTACK);
+    CHECK_LIMIT();
+  }
+  return 1;
+}
+
 #define mz_pushr_p(x) mz_pushr_p_it(jitter, x)
 #define mz_popr_p(x) mz_popr_p_it(jitter, x)
 
@@ -1275,8 +1288,12 @@ static int inlined_nary_prim(Scheme_Object *o, Scheme_Object *_app)
 static int is_noncm(Scheme_Object *a, mz_jit_state *jitter, int depth, int stack_start)
 {
   if (SCHEME_PRIMP(a)) {
-    if (((Scheme_Prim_Proc_Header *)a)->flags & SCHEME_PRIM_IS_NONCM)
-      return 1;
+    int opts;
+    opts = ((Scheme_Prim_Proc_Header *)a)->flags & SCHEME_PRIM_OPT_MASK;
+    if (opts >= SCHEME_PRIM_OPT_NONCM)
+      /* Structure-type predicates are handled specially, so don't claim NONCM: */
+      if (!(((Scheme_Prim_Proc_Header *)a)->flags & SCHEME_PRIM_IS_STRUCT_PRED))
+        return 1;
   }
 
   if (depth 
@@ -1409,6 +1426,82 @@ static int is_simple(Scheme_Object *obj, int depth, int just_markless, mz_jit_st
   return (type > _scheme_values_types_);
 }
 
+static int is_non_gc(Scheme_Object *obj, int depth)
+{
+  /* Return 1 if evaluating `obj' can't trigger a GC. */
+  Scheme_Type type;
+
+  type = SCHEME_TYPE(obj);
+
+  switch (type) {
+  case scheme_syntax_type:
+    break;
+
+  case scheme_branch_type:
+    if (depth) {
+      Scheme_Branch_Rec *b = (Scheme_Branch_Rec *)obj;
+      return (is_non_gc(b->test, depth - 1)
+	      && is_non_gc(b->tbranch, depth - 1)
+	      && is_non_gc(b->fbranch, depth - 1));
+    }
+    break;
+    
+  case scheme_let_value_type:
+    if (depth) {
+      Scheme_Let_Value *lv = (Scheme_Let_Value *)obj;
+      if (SCHEME_LET_AUTOBOX(lv))
+        return 0;
+      return is_non_gc(lv->body, depth - 1);
+    }
+    break;
+  case scheme_let_one_type:
+    if (depth) {
+      return (is_non_gc(((Scheme_Let_One *)obj)->value, depth - 1)
+              && is_non_gc(((Scheme_Let_One *)obj)->body, depth - 1));
+    }
+    break;
+  case scheme_let_void_type:
+    if (depth) {
+      Scheme_Let_Void *lv = (Scheme_Let_Void *)obj;
+      if (SCHEME_LET_AUTOBOX(lv))
+        return 0;
+      return is_non_gc(lv->body, depth - 1);
+    }
+    break;
+  case scheme_letrec_type:
+    break;
+
+  case scheme_application_type:
+    break;
+  case scheme_application2_type:
+    break;
+  case scheme_application3_type:
+    break;
+
+  case scheme_toplevel_type:
+    break;
+  case scheme_unclosed_procedure_type:
+    break;
+
+  case scheme_quote_syntax_type:
+  case scheme_local_type:
+  case scheme_local_unbox_type:
+    return 1;
+    break;
+  }
+
+  return (type > _scheme_values_types_);
+}
+
+static int ok_to_move_local(Scheme_Object *obj)
+{
+  if (SAME_TYPE(SCHEME_TYPE(obj), scheme_local_type)
+      && !(SCHEME_LOCAL_FLAGS(obj) & SCHEME_LOCAL_CLEARING_MASK)) {
+    return 1;
+  } else
+    return 0;
+}
+
 static int is_constant_and_avoids_r1(Scheme_Object *obj)
 {
   Scheme_Type t = SCHEME_TYPE(obj);
@@ -1417,7 +1510,7 @@ static int is_constant_and_avoids_r1(Scheme_Object *obj)
     return ((SCHEME_TOPLEVEL_FLAGS(obj) & SCHEME_TOPLEVEL_CONST)
             ? 1
             : 0);
-  } else if (SAME_TYPE(t, scheme_local_type)) {
+  } else if (SAME_TYPE(t, scheme_local_type) && ok_to_move_local(obj)) {
     return 1;
   } else
     return (t >= _scheme_compiled_values_types_);
@@ -2085,10 +2178,10 @@ static int is_a_procedure(Scheme_Object *v, mz_jit_state *jitter)
 static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_rands, 
 			mz_jit_state *jitter, int is_tail, int multi_ok)
 {
-  int i, offset;
+  int i, offset, need_safety = 0;
   int direct_prim = 0, need_non_tail = 0, direct_native = 0, direct_self = 0;
   int proc_already_in_place = 0;
-  Scheme_Object *rator, *v;
+  Scheme_Object *rator, *v, *arg;
   int reorder_ok = 0;
   int args_already_in_place = 0;
   START_JIT_DATA();
@@ -2106,7 +2199,7 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
   } else {
     Scheme_Type t;
     t = SCHEME_TYPE(rator);
-    if (t == scheme_local_type) {
+    if ((t == scheme_local_type) && ok_to_move_local(rator)) {
       /* We can re-order evaluation of the rator. */
       reorder_ok = 1;
 
@@ -2181,7 +2274,8 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
     mz_runstack_skipped(jitter, num_rands);
     for (i = 0; i < num_rands; i++) {
       v = (alt_rands ? alt_rands[i+1] : app->args[i+1]);
-      if (SAME_TYPE(SCHEME_TYPE(v), scheme_local_type)) {
+      if (SAME_TYPE(SCHEME_TYPE(v), scheme_local_type)
+          && !(SCHEME_LOCAL_FLAGS(v) & SCHEME_LOCAL_OTHER_CLEARS)) {
         int pos;
         pos = mz_remap(SCHEME_LOCAL_POS(v));
         if (pos == (jitter->depth + args_already_in_place))
@@ -2202,6 +2296,7 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
   if (num_rands) {
     if (!direct_prim || (num_rands > 1)) {
       jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(num_rands));
+      need_safety = num_rands;
       CHECK_RUNSTACK_OVERFLOW();
       mz_runstack_pushed(jitter, num_rands);
     } else {
@@ -2224,6 +2319,12 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
     offset = 0;
 
   if (!direct_prim && !reorder_ok && !direct_self) {
+    if (need_safety && !is_non_gc(rator, INIT_SIMPLE_DEPTH)) {
+      stack_safety(jitter, need_safety, offset);
+      CHECK_LIMIT();
+      need_safety = 0;
+    }
+
     generate_non_tail(rator, jitter, 0, !need_non_tail);
     CHECK_LIMIT();
 
@@ -2239,8 +2340,11 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
 	   can move the proc directly to V1. */
 	jit_movr_p(JIT_V1, JIT_R0);
 	proc_already_in_place = 1;
-      } else
+      } else {
 	jit_stxi_p(WORDS_TO_BYTES(num_rands - 1 + offset), JIT_RUNSTACK, JIT_R0);
+        if (need_safety)
+          need_safety--;
+      }
     } else {
       jit_movr_p(JIT_V1, JIT_R0);
     }
@@ -2248,10 +2352,15 @@ static int generate_app(Scheme_App_Rec *app, Scheme_Object **alt_rands, int num_
 
   for (i = 0; i < num_rands; i++) {
     PAUSE_JIT_DATA();
-    generate_non_tail((alt_rands 
-                       ? alt_rands[i+1+args_already_in_place] 
-                       : app->args[i+1+args_already_in_place]), 
-                      jitter, 0, !need_non_tail);
+    arg = (alt_rands 
+           ? alt_rands[i+1+args_already_in_place] 
+           : app->args[i+1+args_already_in_place]);
+    if (need_safety && !is_non_gc(arg, INIT_SIMPLE_DEPTH)) {
+      stack_safety(jitter, need_safety - i, offset + i);
+      CHECK_LIMIT();
+      need_safety = 0;
+    }
+    generate_non_tail(arg, jitter, 0, !need_non_tail);
     RESUME_JIT_DATA();
     CHECK_LIMIT();
     if ((i == num_rands - 1) && !direct_prim && !reorder_ok && !direct_self && !proc_already_in_place) {
@@ -2694,9 +2803,9 @@ static int generate_arith(mz_jit_state *jitter, Scheme_Object *rator, Scheme_Obj
       rand = rand2;
       rand2 = NULL;
       reversed = 1;
-    } else if ((SAME_TYPE(SCHEME_TYPE(rand2), scheme_local_type)
+    } else if ((ok_to_move_local(rand2)
 		|| SCHEME_INTP(rand2))
-	       && !(SAME_TYPE(SCHEME_TYPE(rand), scheme_local_type)
+	       && !(ok_to_move_local(rand)
 		    || SCHEME_INTP(rand))) {
       /* Second expression is side-effect-free, unlike the first; 
 	 swap order and use the fast path for when the first arg is
@@ -2715,7 +2824,7 @@ static int generate_arith(mz_jit_state *jitter, Scheme_Object *rator, Scheme_Obj
   }
 
   if (rand2) {
-    simple_rand = (SAME_TYPE(SCHEME_TYPE(rand), scheme_local_type)
+    simple_rand = (ok_to_move_local(rand)
 		   || SCHEME_INTP(rand));
   } else
     simple_rand = 0;
@@ -2728,11 +2837,13 @@ static int generate_arith(mz_jit_state *jitter, Scheme_Object *rator, Scheme_Obj
   mz_runstack_skipped(jitter, skipped);
 
   if (rand2 && !simple_rand) {
+    mz_runstack_skipped(jitter, 1);
+    generate_non_tail(rand, jitter, 0, 1);
+    mz_runstack_unskipped(jitter, 1);
+    CHECK_LIMIT();
     jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
     CHECK_RUNSTACK_OVERFLOW();
     mz_runstack_pushed(jitter, 1);
-    generate_non_tail(rand, jitter, 0, 1);
-    CHECK_LIMIT();
     jit_str_p(JIT_RUNSTACK, JIT_R0);
   }
 
@@ -3618,14 +3729,16 @@ static int generate_two_args(Scheme_Object *rand1, Scheme_Object *rand2, mz_jit_
 
       mz_runstack_unskipped(jitter, 2);
     } else {
+      mz_runstack_skipped(jitter, 2);
+      generate_non_tail(rand1, jitter, 0, 1);
+      mz_runstack_unskipped(jitter, 2);
+      CHECK_LIMIT();
+
       jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
       CHECK_RUNSTACK_OVERFLOW();
       mz_runstack_pushed(jitter, 1);
-      mz_runstack_skipped(jitter, 1);
-
-      generate_non_tail(rand1, jitter, 0, 1);
-      CHECK_LIMIT();
       jit_str_p(JIT_RUNSTACK, JIT_R0);
+      mz_runstack_skipped(jitter, 1);
 
       generate_non_tail(rand2, jitter, 0, 1);
       CHECK_LIMIT();
@@ -3810,7 +3923,7 @@ static int generate_inlined_binary(mz_jit_state *jitter, Scheme_App3_Rec *app, i
       __END_SHORT_JUMPS__(branch_short);
     } else {
       /* Two complex expressions: */
-      generate_two_args(a1, a2, jitter, 0);
+      generate_two_args(a2, a1, jitter, 0);
       
       __START_SHORT_JUMPS__(branch_short);
 
@@ -3902,15 +4015,18 @@ static int generate_inlined_binary(mz_jit_state *jitter, Scheme_App3_Rec *app, i
 	mz_runstack_skipped(jitter, 1);
 
       if (!simple) {
-	jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
-        CHECK_RUNSTACK_OVERFLOW();
-	mz_runstack_pushed(jitter, 1);
+        mz_runstack_skipped(jitter, 1);
       }
 
       generate_non_tail(app->rand1, jitter, 0, 1);
       CHECK_LIMIT();
 
       if (!simple) {
+        mz_runstack_unskipped(jitter, 1);
+	jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
+        CHECK_RUNSTACK_OVERFLOW();
+	mz_runstack_pushed(jitter, 1);
+
 	jit_str_p(JIT_RUNSTACK, JIT_R0);
 
 	generate_non_tail(app->rand2, jitter, 0, 1);
@@ -4104,6 +4220,8 @@ static int generate_inlined_nary(mz_jit_state *jitter, Scheme_App_Rec *app, int
 	jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(pushed));
         CHECK_RUNSTACK_OVERFLOW();
 	mz_runstack_pushed(jitter, pushed);
+        stack_safety(jitter, pushed, 0);
+        CHECK_LIMIT();
       }
 
       generate_non_tail(app->args[1], jitter, 0, 1);
@@ -4568,12 +4686,15 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
       /* Other parts of the JIT rely on this code modifying R0, only */
       int pos;
       START_JIT_DATA();
-      LOG_IT(("local\n"));
       pos = mz_remap(SCHEME_LOCAL_POS(obj));
+      LOG_IT(("local %d [%d]\n", pos, SCHEME_LOCAL_FLAGS(obj)));
       if (pos || (mz_CURRENT_STATUS() != mz_RS_R0_HAS_RUNSTACK0)) {
         jit_ldxi_p(JIT_R0, JIT_RUNSTACK, WORDS_TO_BYTES(pos));
         VALIDATE_RESULT(JIT_R0);
       }
+      if (SCHEME_LOCAL_FLAGS(obj) & SCHEME_LOCAL_CLEAR_ON_READ) {
+        jit_stxi_p(WORDS_TO_BYTES(pos), JIT_RUNSTACK, JIT_RUNSTACK);
+      }
       END_JIT_DATA(2);
       return 1;
     }
@@ -4586,6 +4707,10 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
       pos = mz_remap(SCHEME_LOCAL_POS(obj));
       jit_ldxi_p(JIT_R0, JIT_RUNSTACK, WORDS_TO_BYTES(pos));
       jit_ldr_p(JIT_R0, JIT_R0);
+      if (SCHEME_LOCAL_FLAGS(obj) & SCHEME_LOCAL_CLEAR_ON_READ) {
+        LOG_IT(("clear-on-read\n"));
+        jit_stxi_p(WORDS_TO_BYTES(pos), JIT_RUNSTACK, JIT_RUNSTACK);
+      }
       VALIDATE_RESULT(JIT_R0);
 
       END_JIT_DATA(3);
@@ -5036,6 +5161,7 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
       nsrs = jitter->need_set_rs;
       PAUSE_JIT_DATA();
       LOG_IT(("...then...\n"));
+      FOR_LOG(++jitter->log_depth);
       g1 = generate(branch->tbranch, jitter, is_tail, multi_ok);
       RESUME_JIT_DATA();
       CHECK_LIMIT();
@@ -5077,7 +5203,9 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
       }
       __END_SHORT_JUMPS__(then_short_ok);
       PAUSE_JIT_DATA();
+      FOR_LOG(jitter->log_depth--);
       LOG_IT(("...else\n"));
+      FOR_LOG(++jitter->log_depth);
       g2 = generate(branch->fbranch, jitter, is_tail, multi_ok);
       RESUME_JIT_DATA();
       CHECK_LIMIT();
@@ -5094,6 +5222,7 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
 	mz_patch_ucbranch(ref2);
 	__END_SHORT_JUMPS__(else_short_ok);
       }
+      FOR_LOG(jitter->log_depth--);
 
       END_JIT_DATA(12);
 
@@ -5218,6 +5347,7 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
 
       jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(c));
       CHECK_RUNSTACK_OVERFLOW();
+      stack_safety(jitter, c, 0);
       mz_runstack_pushed(jitter, c);
 
       if (SCHEME_LET_AUTOBOX(lv)) {
@@ -5301,14 +5431,19 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
 
       LOG_IT(("leto...\n"));
 
-      jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
-      CHECK_RUNSTACK_OVERFLOW();
-      mz_runstack_pushed(jitter, 1);
+      mz_runstack_skipped(jitter, 1);
 
       PAUSE_JIT_DATA();
       generate_non_tail(lv->value, jitter, 0, 1);
       RESUME_JIT_DATA();
       CHECK_LIMIT();
+      
+      mz_runstack_unskipped(jitter, 1);
+
+      jit_subi_p(JIT_RUNSTACK, JIT_RUNSTACK, WORDS_TO_BYTES(1));
+      CHECK_RUNSTACK_OVERFLOW();
+      mz_runstack_pushed(jitter, 1);
+
       jit_str_p(JIT_RUNSTACK, JIT_R0);
 	
       END_JIT_DATA(17);
@@ -5329,7 +5464,7 @@ static int generate(Scheme_Object *obj, mz_jit_state *jitter, int is_tail, int m
       /* Key: */
       generate_non_tail(wcm->key, jitter, 0, 1);
       CHECK_LIMIT();
-      if (SCHEME_TYPE(obj) > _scheme_values_types_) {
+      if (SCHEME_TYPE(wcm->val) > _scheme_values_types_) {
 	/* No need to push mark onto value stack: */
 	jit_movr_p(JIT_V1, JIT_R0);
 	generate_non_tail(wcm->val, jitter, 0, 1);
@@ -6596,7 +6731,9 @@ static int do_generate_closure(mz_jit_state *jitter, void *_data)
     }
   }
 
-  LOG_IT(("PROC: %s\n", (data->name ? scheme_format_utf8("~s", 2, 1, &data->name, NULL) : "???")));
+  LOG_IT(("PROC: %s, %d args\n", 
+          (data->name ? scheme_format_utf8("~s", 2, 1, &data->name, NULL) : "???"),
+          data->num_params));
   FOR_LOG(jitter->log_depth++);
 
   jitter->self_data = data;
diff --git a/src/mzscheme/src/list.c b/src/mzscheme/src/list.c
index 5e948b37b6..95a49dc3b4 100644
--- a/src/mzscheme/src/list.c
+++ b/src/mzscheme/src/list.c
@@ -155,19 +155,19 @@ scheme_init_list (Scheme_Env *env)
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant ("mcons", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_mcar, "mcar", 1, 1);
+  p = scheme_make_immed_prim(scheme_checked_mcar, "mcar", 1, 1);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
   scheme_add_global_constant ("mcar", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_mcdr, "mcdr", 1, 1);
+  p = scheme_make_immed_prim(scheme_checked_mcdr, "mcdr", 1, 1);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
   scheme_add_global_constant ("mcdr", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_set_mcar, "set-mcar!", 2, 2);
+  p = scheme_make_immed_prim(scheme_checked_set_mcar, "set-mcar!", 2, 2);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant ("set-mcar!", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_set_mcdr, "set-mcdr!", 2, 2);
+  p = scheme_make_immed_prim(scheme_checked_set_mcdr, "set-mcdr!", 2, 2);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant ("set-mcdr!", p, env);
 
@@ -176,17 +176,17 @@ scheme_init_list (Scheme_Env *env)
   scheme_add_global_constant ("null?", p, env);
 
   scheme_add_global_constant ("list?",
-			      scheme_make_noncm_prim(list_p_prim,
+			      scheme_make_immed_prim(list_p_prim,
 						     "list?",
 						     1, 1),
 			      env);
   scheme_add_global_constant ("list",
-			      scheme_make_noncm_prim(list_prim,
+			      scheme_make_immed_prim(list_prim,
 						     "list",
 						     0, -1),
 			      env);
   scheme_add_global_constant ("list*",
-			      scheme_make_noncm_prim(list_star_prim,
+			      scheme_make_immed_prim(list_star_prim,
 						     "list*",
 						     1, -1),
 			      env);
@@ -196,57 +196,57 @@ scheme_init_list (Scheme_Env *env)
 						      1, 1, 1),
 			     env);
   scheme_add_global_constant ("length",
-			      scheme_make_noncm_prim(length_prim,
+			      scheme_make_immed_prim(length_prim,
 						     "length",
 						     1, 1),
 			      env);
   scheme_add_global_constant ("append",
-			      scheme_make_noncm_prim(append_prim,
+			      scheme_make_immed_prim(append_prim,
 						     "append",
 						     0, -1),
 			      env);
   scheme_add_global_constant ("reverse",
-			      scheme_make_noncm_prim(reverse_prim,
+			      scheme_make_immed_prim(reverse_prim,
 						     "reverse",
 						     1, 1),
 			      env);
   scheme_add_global_constant ("list-tail",
-			      scheme_make_noncm_prim(list_tail_prim,
+			      scheme_make_immed_prim(list_tail_prim,
 						     "list-tail",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("list-ref",
-			      scheme_make_noncm_prim(list_ref_prim,
+			      scheme_make_immed_prim(list_ref_prim,
 						     "list-ref",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("memq",
-			      scheme_make_noncm_prim(memq,
+			      scheme_make_immed_prim(memq,
 						     "memq",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("memv",
-			      scheme_make_noncm_prim(memv,
+			      scheme_make_immed_prim(memv,
 						     "memv",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("member",
-			      scheme_make_noncm_prim(member,
+			      scheme_make_immed_prim(member,
 						     "member",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("assq",
-			      scheme_make_noncm_prim(assq,
+			      scheme_make_immed_prim(assq,
 						     "assq",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("assv",
-			      scheme_make_noncm_prim(assv,
+			      scheme_make_immed_prim(assv,
 						     "assv",
 						     2, 2),
 			      env);
   scheme_add_global_constant ("assoc",
-			      scheme_make_noncm_prim(assoc,
+			      scheme_make_immed_prim(assoc,
 						     "assoc",
 						     2, 2),
 			      env);
@@ -390,12 +390,12 @@ scheme_init_list (Scheme_Env *env)
 			      env);
 
   scheme_add_global_constant(BOX,
-			     scheme_make_noncm_prim(box,
+			     scheme_make_immed_prim(box,
 						    BOX,
 						    1, 1),
 			     env);
   scheme_add_global_constant("box-immutable",
-			     scheme_make_noncm_prim(immutable_box,
+			     scheme_make_immed_prim(immutable_box,
 						    "box-immutable",
 						    1, 1),
 			     env);
@@ -404,23 +404,23 @@ scheme_init_list (Scheme_Env *env)
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;  
   scheme_add_global_constant(BOXP, p, env);
 
-  p = scheme_make_noncm_prim(unbox, UNBOX, 1, 1);
+  p = scheme_make_immed_prim(unbox, UNBOX, 1, 1);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;  
   scheme_add_global_constant(UNBOX, p, env);
 
   scheme_add_global_constant(SETBOX,
-			     scheme_make_noncm_prim(set_box,
+			     scheme_make_immed_prim(set_box,
 						    SETBOX,
 						    2, 2),
 			     env);
 
   scheme_add_global_constant("make-hash-table",
-			     scheme_make_noncm_prim(make_hash_table,
+			     scheme_make_immed_prim(make_hash_table,
 						    "make-hash-table",
 						    0, 2),
 			     env);
   scheme_add_global_constant("make-immutable-hash-table",
-			     scheme_make_noncm_prim(make_immutable_hash_table,
+			     scheme_make_immed_prim(make_immutable_hash_table,
 						    "make-immutable-hash-table",
 						    1, 2),
 			     env);
@@ -430,7 +430,7 @@ scheme_init_list (Scheme_Env *env)
 						      1, 3, 1),
 			     env);
   scheme_add_global_constant("hash-table-count",
-			     scheme_make_noncm_prim(hash_table_count,
+			     scheme_make_immed_prim(hash_table_count,
 						    "hash-table-count",
 						    1, 1),
 			     env);
@@ -466,28 +466,28 @@ scheme_init_list (Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("hash-table-iterate-first",
-			     scheme_make_noncm_prim(hash_table_iterate_start,
+			     scheme_make_immed_prim(hash_table_iterate_start,
 						    "hash-table-iterate-first",
                                                     1, 1),
 			     env);
   scheme_add_global_constant("hash-table-iterate-next",
-			     scheme_make_noncm_prim(hash_table_iterate_next,
+			     scheme_make_immed_prim(hash_table_iterate_next,
 						    "hash-table-iterate-next",
                                                     2, 2),
 			     env);
   scheme_add_global_constant("hash-table-iterate-value",
-			     scheme_make_noncm_prim(hash_table_iterate_value,
+			     scheme_make_immed_prim(hash_table_iterate_value,
 						    "hash-table-iterate-value",
                                                     2, 2),
 			     env);
   scheme_add_global_constant("hash-table-iterate-key",
-			     scheme_make_noncm_prim(hash_table_iterate_key,
+			     scheme_make_immed_prim(hash_table_iterate_key,
 						    "hash-table-iterate-key",
                                                     2, 2),
 			     env);
 
   scheme_add_global_constant("eq-hash-code",
-			     scheme_make_noncm_prim(eq_hash_code,
+			     scheme_make_immed_prim(eq_hash_code,
 						    "eq-hash-code",
 						    1, 1),
 			     env);
@@ -503,12 +503,12 @@ scheme_init_list (Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("make-weak-box",
-			     scheme_make_noncm_prim(make_weak_box,
+			     scheme_make_immed_prim(make_weak_box,
 						    "make-weak-box",
 						    1, 1),
 			     env);
   scheme_add_global_constant("weak-box-value",
-			     scheme_make_noncm_prim(weak_box_value,
+			     scheme_make_immed_prim(weak_box_value,
 						    "weak-box-value",
 						    1, 1),
 			     env);
@@ -519,12 +519,12 @@ scheme_init_list (Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("make-ephemeron",
-			     scheme_make_noncm_prim(make_ephemeron,
+			     scheme_make_immed_prim(make_ephemeron,
 						    "make-ephemeron",
 						    2, 2),
 			     env);
   scheme_add_global_constant("ephemeron-value",
-			     scheme_make_noncm_prim(ephemeron_value,
+			     scheme_make_immed_prim(ephemeron_value,
 						    "ephemeron-value",
 						    1, 1),
 			     env);
diff --git a/src/mzscheme/src/module.c b/src/mzscheme/src/module.c
index 3f9b092f8c..4bc382f0a5 100644
--- a/src/mzscheme/src/module.c
+++ b/src/mzscheme/src/module.c
@@ -79,17 +79,21 @@ static Scheme_Object *top_level_require_jit(Scheme_Object *data);
 
 static Scheme_Object *module_optimize(Scheme_Object *data, Optimize_Info *info);
 static Scheme_Object *module_resolve(Scheme_Object *data, Resolve_Info *info);
+static Scheme_Object *module_sfs(Scheme_Object *data, SFS_Info *info);
 static Scheme_Object *top_level_require_optimize(Scheme_Object *data, Optimize_Info *info);
 static Scheme_Object *top_level_require_resolve(Scheme_Object *data, Resolve_Info *info);
+static Scheme_Object *top_level_require_sfs(Scheme_Object *data, SFS_Info *info);
 
 static void module_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
                             int depth, int letlimit, int delta, 
-			    int num_toplevels, int num_stxes, int num_lifts);
+			    int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos);
 static void top_level_require_validate(Scheme_Object *data, Mz_CPort *port, 
                                        char *stack, Validate_TLS tls,
                                        int depth, int letlimit, int delta, 
-				       int num_toplevels, int num_stxes, int num_lifts);
+				       int num_toplevels, int num_stxes, int num_lifts,
+                                       struct Validate_Clearing *vc, int tailpos);
 
 static Scheme_Object *write_module(Scheme_Object *obj);
 static Scheme_Object *read_module(Scheme_Object *obj);
@@ -256,12 +260,12 @@ void scheme_init_module(Scheme_Env *env)
 
   scheme_register_syntax(MODULE_EXPD, 
 			 module_optimize,
-			 module_resolve, module_validate, 
+			 module_resolve, module_sfs, module_validate, 
 			 module_execute, module_jit, 
 			 NULL, NULL, -1);
   scheme_register_syntax(REQUIRE_EXPD, 
 			 top_level_require_optimize,
-			 top_level_require_resolve, top_level_require_validate, 
+			 top_level_require_resolve, top_level_require_sfs, top_level_require_validate, 
 			 top_level_require_execute, top_level_require_jit, 
 			 NULL, NULL, 2);
 
@@ -4232,7 +4236,8 @@ static Scheme_Object *module_jit(Scheme_Object *data)
 static void module_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
 			    int depth, int letlimit, int delta, 
-			    int num_toplevels, int num_stxes, int num_lifts)
+			    int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Module *m;
   int i, cnt, let_depth;
@@ -4618,6 +4623,51 @@ module_resolve(Scheme_Object *data, Resolve_Info *old_rslv)
   return scheme_make_syntax_resolved(MODULE_EXPD, data);
 }
 
+static Scheme_Object *
+module_sfs(Scheme_Object *data, SFS_Info *old_info)
+{
+  Scheme_Module *m = (Scheme_Module *)data;
+  Scheme_Object *e, *ex;
+  SFS_Info *info;
+  int i, cnt, let_depth;
+
+  if (!old_info->for_mod) {
+    if (old_info->pass)
+      return data;
+
+    info = scheme_new_sfs_info(m->max_let_depth);
+    info->for_mod = 1;
+    scheme_sfs(data, info, m->max_let_depth);
+    return data;
+  }
+
+  info = old_info;
+
+  cnt = SCHEME_VEC_SIZE(m->body);
+  scheme_sfs_start_sequence(info, cnt, 0);
+
+  for (i = 0; i < cnt; i++) {
+    e = scheme_sfs_expr(SCHEME_VEC_ELS(m->body)[i], info, -1);
+    SCHEME_VEC_ELS(m->body)[i] = e;
+  }
+
+  if (!info->pass) {
+    cnt = SCHEME_VEC_SIZE(m->et_body);
+    for (i = 0; i < cnt; i++) {
+      e = SCHEME_VEC_ELS(m->et_body)[i];
+      
+      let_depth = SCHEME_INT_VAL(SCHEME_VEC_ELS(e)[2]);
+      ex = SCHEME_VEC_ELS(e)[1];
+      
+      info = scheme_new_sfs_info(let_depth);
+      ex = scheme_sfs(ex, info, let_depth);
+      SCHEME_VEC_ELS(e)[1] = ex;
+    }
+  }
+
+  return data;
+}
+
 static Scheme_Object *do_module(Scheme_Object *form, Scheme_Comp_Env *env, 
 				Scheme_Compile_Expand_Info *rec, int drec)
 {
@@ -5561,6 +5611,7 @@ static Scheme_Object *do_module_begin(Scheme_Object *form, Scheme_Comp_Env *env,
 	  SCHEME_VEC_ELS(vec)[4] = (for_stx ? scheme_true : scheme_false);
 	  exp_body = scheme_make_pair(vec, exp_body);
 
+          m = scheme_sfs(m, NULL, ri->max_let_depth);
 	  if (ri->use_jit)
 	    m = scheme_jit_expr(m);
 	
@@ -8159,7 +8210,8 @@ top_level_require_jit(Scheme_Object *data)
 static void top_level_require_validate(Scheme_Object *data, Mz_CPort *port, 
                                        char *stack, Validate_TLS tls,
 				       int depth, int letlimit, int delta, 
-				       int num_toplevels, int num_stxes, int num_lifts)
+				       int num_toplevels, int num_stxes, int num_lifts,
+                                       struct Validate_Clearing *vc, int tailpos)
 {
 }
 
@@ -8179,6 +8231,12 @@ top_level_require_resolve(Scheme_Object *data, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(REQUIRE_EXPD, cons(dummy, SCHEME_CDR(data)));
 }
 
+static Scheme_Object *
+top_level_require_sfs(Scheme_Object *data, SFS_Info *rslv)
+{
+  return data;
+}
+
 static Scheme_Object *do_require(Scheme_Object *form, Scheme_Comp_Env *env, 
 				 Scheme_Compile_Expand_Info *rec, int drec)
 {
diff --git a/src/mzscheme/src/mzmark.c b/src/mzscheme/src/mzmark.c
index 36f1d424f9..192b872eb3 100644
--- a/src/mzscheme/src/mzmark.c
+++ b/src/mzscheme/src/mzmark.c
@@ -2788,6 +2788,36 @@ static int mark_optimize_info_FIXUP(void *p) {
 #define mark_optimize_info_IS_CONST_SIZE 1
 
 
+static int mark_sfs_info_SIZE(void *p) {
+  return
+  gcBYTES_TO_WORDS(sizeof(SFS_Info));
+}
+
+static int mark_sfs_info_MARK(void *p) {
+  SFS_Info *i = (SFS_Info *)p;
+  
+  gcMARK(i->max_used);
+  gcMARK(i->max_calls);
+  gcMARK(i->saved);
+
+  return
+  gcBYTES_TO_WORDS(sizeof(SFS_Info));
+}
+
+static int mark_sfs_info_FIXUP(void *p) {
+  SFS_Info *i = (SFS_Info *)p;
+  
+  gcFIXUP(i->max_used);
+  gcFIXUP(i->max_calls);
+  gcFIXUP(i->saved);
+
+  return
+  gcBYTES_TO_WORDS(sizeof(SFS_Info));
+}
+
+#define mark_sfs_info_IS_ATOMIC 0
+#define mark_sfs_info_IS_CONST_SIZE 1
+
 
 #endif  /* ENV */
 
@@ -2855,6 +2885,35 @@ static int mark_saved_stack_FIXUP(void *p) {
 #define mark_saved_stack_IS_CONST_SIZE 1
 
 
+static int mark_validate_clearing_SIZE(void *p) {
+  return
+  gcBYTES_TO_WORDS(sizeof(Validate_Clearing));
+}
+
+static int mark_validate_clearing_MARK(void *p) {
+  Validate_Clearing *vc = (Validate_Clearing *)p;
+  
+  gcMARK(vc->stack);
+  gcMARK(vc->ncstack);
+
+  return
+  gcBYTES_TO_WORDS(sizeof(Validate_Clearing));
+}
+
+static int mark_validate_clearing_FIXUP(void *p) {
+  Validate_Clearing *vc = (Validate_Clearing *)p;
+  
+  gcFIXUP(vc->stack);
+  gcFIXUP(vc->ncstack);
+
+  return
+  gcBYTES_TO_WORDS(sizeof(Validate_Clearing));
+}
+
+#define mark_validate_clearing_IS_ATOMIC 0
+#define mark_validate_clearing_IS_CONST_SIZE 1
+
+
 #endif  /* EVAL */
 
 /**********************************************************************/
diff --git a/src/mzscheme/src/mzmarksrc.c b/src/mzscheme/src/mzmarksrc.c
index 7ae9bac768..82cbf9a08a 100644
--- a/src/mzscheme/src/mzmarksrc.c
+++ b/src/mzscheme/src/mzmarksrc.c
@@ -1115,6 +1115,17 @@ mark_optimize_info {
   gcBYTES_TO_WORDS(sizeof(Optimize_Info));
 }
 
+mark_sfs_info {
+ mark:
+  SFS_Info *i = (SFS_Info *)p;
+  
+  gcMARK(i->max_used);
+  gcMARK(i->max_calls);
+  gcMARK(i->saved);
+
+ size:
+  gcBYTES_TO_WORDS(sizeof(SFS_Info));
+}
 
 END env;
 
@@ -1145,6 +1156,17 @@ mark_saved_stack {
   gcBYTES_TO_WORDS(sizeof(Scheme_Saved_Stack));
 }
 
+mark_validate_clearing {
+ mark:
+  Validate_Clearing *vc = (Validate_Clearing *)p;
+  
+  gcMARK(vc->stack);
+  gcMARK(vc->ncstack);
+
+ size:
+  gcBYTES_TO_WORDS(sizeof(Validate_Clearing));
+}
+
 END eval;
 
 /**********************************************************************/
diff --git a/src/mzscheme/src/portfun.c b/src/mzscheme/src/portfun.c
index cc3cb264e6..87a16cbe20 100644
--- a/src/mzscheme/src/portfun.c
+++ b/src/mzscheme/src/portfun.c
@@ -711,7 +711,7 @@ scheme_init_port_fun(Scheme_Env *env)
 						       2, 2),
 			     env);
   scheme_add_global_constant("pipe-content-length", 
-			     scheme_make_noncm_prim(pipe_length, 
+			     scheme_make_immed_prim(pipe_length, 
 						    "pipe-content-length", 
 						    1, 1), 
 			     env);
diff --git a/src/mzscheme/src/print.c b/src/mzscheme/src/print.c
index 9448b7008d..4f6fbc8b1d 100644
--- a/src/mzscheme/src/print.c
+++ b/src/mzscheme/src/print.c
@@ -2272,15 +2272,22 @@ print(Scheme_Object *obj, int notdisplay, int compact, Scheme_Hash_Table *ht,
     {
       int unbox = SAME_TYPE(SCHEME_TYPE(obj), scheme_local_unbox_type);
       Scheme_Local *loc = (Scheme_Local *)obj;
-      if (loc->position < CPT_RANGE(SMALL_LOCAL)) {
+      if ((loc->position < CPT_RANGE(SMALL_LOCAL))
+          && !(SCHEME_LOCAL_FLAGS(loc) & SCHEME_LOCAL_CLEARING_MASK)) {
 	unsigned char s[1];
 	s[0] = loc->position + (unbox 
 				? CPT_SMALL_LOCAL_UNBOX_START 
 				: CPT_SMALL_LOCAL_START);
 	print_this_string(pp, (char *)s, 0, 1);
       } else {
+        int flags;
 	print_compact(pp, unbox ? CPT_LOCAL_UNBOX : CPT_LOCAL);
-	print_compact_number(pp, loc->position);
+        flags = SCHEME_LOCAL_FLAGS(loc) & SCHEME_LOCAL_CLEARING_MASK;
+        if (flags) {
+          print_compact_number(pp, -(loc->position + 1));
+          print_compact_number(pp, flags);
+        } else
+          print_compact_number(pp, loc->position);
       }
     }
   else if (compact && SAME_TYPE(SCHEME_TYPE(obj), scheme_application_type))
diff --git a/src/mzscheme/src/read.c b/src/mzscheme/src/read.c
index 73a9de268d..6707dc37b2 100644
--- a/src/mzscheme/src/read.c
+++ b/src/mzscheme/src/read.c
@@ -4593,20 +4593,26 @@ static Scheme_Object *read_compact(CPort *port, int use_stack)
       break;
     case CPT_LOCAL:
       {
-	int p;
+	int p, flags;
 	p = read_compact_number(port);
-	if (p < 0)
-	  scheme_ill_formed_code(port);
-	v = scheme_make_local(scheme_local_type, p);
+        if (p < 0) {
+          p = -(p + 1);
+          flags = read_compact_number(port);
+        } else
+          flags = 0;
+	v = scheme_make_local(scheme_local_type, p, flags);
       }
       break;
     case CPT_LOCAL_UNBOX:
       {
-	int p;
+	int p, flags;
 	p = read_compact_number(port);
-	if (p < 0)
-	  scheme_ill_formed_code(port);
-	v = scheme_make_local(scheme_local_unbox_type, p);
+        if (p < 0) {
+          p = -(p + 1);
+          flags = read_compact_number(port);
+        } else
+          flags = 0;
+	v = scheme_make_local(scheme_local_unbox_type, p, flags);
       }
       break;
     case CPT_SVECTOR:
@@ -4764,9 +4770,9 @@ static Scheme_Object *read_compact(CPort *port, int use_stack)
 	  ch -= CPT_SMALL_LOCAL_START;
 	}
 	if (ch < MAX_CONST_LOCAL_POS)
-	  v = scheme_local[ch][k];
+	  v = scheme_local[ch][k][0];
 	else
-	  v = scheme_make_local(type, ch);
+	  v = scheme_make_local(type, ch, 0);
       }
       break;
     case CPT_SMALL_MARSHALLED_START:
diff --git a/src/mzscheme/src/schemef.h b/src/mzscheme/src/schemef.h
index 34869703d3..3bbb4138db 100644
--- a/src/mzscheme/src/schemef.h
+++ b/src/mzscheme/src/schemef.h
@@ -425,6 +425,9 @@ MZ_EXTERN Scheme_Object *scheme_make_folding_prim(Scheme_Prim *prim,
 					const char *name,
 					mzshort mina, mzshort maxa,
 					short functional);
+MZ_EXTERN Scheme_Object *scheme_make_immed_prim(Scheme_Prim *prim,
+					        const char *name,
+					        mzshort mina, mzshort maxa);
 MZ_EXTERN Scheme_Object *scheme_make_noncm_prim(Scheme_Prim *prim,
 						const char *name,
 						mzshort mina, mzshort maxa);
diff --git a/src/mzscheme/src/schemex.h b/src/mzscheme/src/schemex.h
index cf21f76e38..98902cd301 100644
--- a/src/mzscheme/src/schemex.h
+++ b/src/mzscheme/src/schemex.h
@@ -346,6 +346,9 @@ Scheme_Object *(*scheme_make_folding_prim)(Scheme_Prim *prim,
 					const char *name,
 					mzshort mina, mzshort maxa,
 					short functional);
+Scheme_Object *(*scheme_make_immed_prim)(Scheme_Prim *prim,
+					        const char *name,
+					        mzshort mina, mzshort maxa);
 Scheme_Object *(*scheme_make_noncm_prim)(Scheme_Prim *prim,
 						const char *name,
 						mzshort mina, mzshort maxa);
diff --git a/src/mzscheme/src/schemex.inc b/src/mzscheme/src/schemex.inc
index 000cd4e34c..18d973d7ad 100644
--- a/src/mzscheme/src/schemex.inc
+++ b/src/mzscheme/src/schemex.inc
@@ -236,6 +236,7 @@
   scheme_extension_table->scheme_make_noneternal_prim = scheme_make_noneternal_prim;
   scheme_extension_table->scheme_make_prim_w_arity = scheme_make_prim_w_arity;
   scheme_extension_table->scheme_make_folding_prim = scheme_make_folding_prim;
+  scheme_extension_table->scheme_make_immed_prim = scheme_make_immed_prim;
   scheme_extension_table->scheme_make_noncm_prim = scheme_make_noncm_prim;
   scheme_extension_table->scheme_make_noneternal_prim_w_arity = scheme_make_noneternal_prim_w_arity;
   scheme_extension_table->scheme_make_prim_w_everything = scheme_make_prim_w_everything;
diff --git a/src/mzscheme/src/schemexm.h b/src/mzscheme/src/schemexm.h
index 352cc4deea..3f618c0b4f 100644
--- a/src/mzscheme/src/schemexm.h
+++ b/src/mzscheme/src/schemexm.h
@@ -236,6 +236,7 @@
 #define scheme_make_noneternal_prim (scheme_extension_table->scheme_make_noneternal_prim)
 #define scheme_make_prim_w_arity (scheme_extension_table->scheme_make_prim_w_arity)
 #define scheme_make_folding_prim (scheme_extension_table->scheme_make_folding_prim)
+#define scheme_make_immed_prim (scheme_extension_table->scheme_make_immed_prim)
 #define scheme_make_noncm_prim (scheme_extension_table->scheme_make_noncm_prim)
 #define scheme_make_noneternal_prim_w_arity (scheme_extension_table->scheme_make_noneternal_prim_w_arity)
 #define scheme_make_prim_w_everything (scheme_extension_table->scheme_make_prim_w_everything)
diff --git a/src/mzscheme/src/schminc.h b/src/mzscheme/src/schminc.h
index 75ec506e73..07a6c63afd 100644
--- a/src/mzscheme/src/schminc.h
+++ b/src/mzscheme/src/schminc.h
@@ -13,7 +13,7 @@
 
 #define USE_COMPILED_STARTUP 1
 
-#define EXPECTED_PRIM_COUNT 892
+#define EXPECTED_PRIM_COUNT 893
 
 #ifdef MZSCHEME_SOMETHING_OMITTED
 # undef USE_COMPILED_STARTUP
diff --git a/src/mzscheme/src/schpriv.h b/src/mzscheme/src/schpriv.h
index 1d6b5931aa..2b781a5a81 100644
--- a/src/mzscheme/src/schpriv.h
+++ b/src/mzscheme/src/schpriv.h
@@ -228,7 +228,7 @@ Scheme_Object *scheme_make_initial_inspectors(void);
 extern int scheme_builtin_ref_counter;
 
 Scheme_Object **scheme_make_builtin_references_table(void);
-Scheme_Object *scheme_make_local(Scheme_Type type, int pos);
+Scheme_Object *scheme_make_local(Scheme_Type type, int pos, int flags);
 
 void scheme_add_embedded_builtins(Scheme_Env *env);
 void scheme_do_add_global_symbol(Scheme_Env *env, Scheme_Object *sym,
@@ -821,7 +821,7 @@ typedef struct {
 } Scheme_With_Continuation_Mark;
 
 typedef struct Scheme_Local {
-  Scheme_Object so;
+  Scheme_Inclhash_Object iso; /* keyex used for clear-on-read flag */
   mzshort position;
 #ifdef MZ_PRECISE_GC
 # ifdef MZSHORT_IS_SHORT
@@ -832,9 +832,14 @@ typedef struct Scheme_Local {
 } Scheme_Local;
 
 #define SCHEME_LOCAL_POS(obj)    (((Scheme_Local *)(obj))->position)
+#define SCHEME_LOCAL_FLAGS(obj)  MZ_OPT_HASH_KEY(&((Scheme_Local *)(obj))->iso)
+
+#define SCHEME_LOCAL_CLEAR_ON_READ 0x1
+#define SCHEME_LOCAL_OTHER_CLEARS  0x2
+#define SCHEME_LOCAL_CLEARING_MASK 0x3
 
 typedef struct Scheme_Toplevel {
-  Scheme_Inclhash_Object iso; /* keyex used for const flag */
+  Scheme_Inclhash_Object iso; /* keyex used for const & ready flags */
   mzshort depth;
   int position;
 } Scheme_Toplevel;
@@ -1689,7 +1694,7 @@ typedef struct Scheme_Comp_Env
 #define CLOS_HAS_REST 1
 #define CLOS_HAS_REF_ARGS 2
 #define CLOS_PRESERVES_MARKS 4
-#define CLOS_FOLDABLE 8
+#define CLOS_SFS 8
 #define CLOS_IS_METHOD 16
 #define CLOS_SINGLE_RESULT 32
 #define CLOS_RESULT_TENTATIVE 64
@@ -1784,11 +1789,13 @@ typedef struct Scheme_Object *(*Scheme_Syntax_Shifter)(Scheme_Object *data, int
 typedef struct CPort Mz_CPort;
 
 typedef mzshort **Validate_TLS;
+struct Validate_Clearing;
 
 typedef void (*Scheme_Syntax_Validater)(Scheme_Object *data, Mz_CPort *port, 
                                         char *stack, Validate_TLS tls,
 					int depth, int letlimit, int delta,
-					int num_toplevels, int num_stxes, int num_lifts);
+					int num_toplevels, int num_stxes, int num_lifts,
+                                        struct Validate_Clearing *vc, int tailpos);
 
 typedef struct Scheme_Object *(*Scheme_Syntax_Executer)(struct Scheme_Object *data);
 
@@ -1859,7 +1866,7 @@ Scheme_Native_Closure_Data *scheme_generate_lambda(Scheme_Closure_Data *obj, int
 						   Scheme_Native_Closure_Data *case_lam);
 
 #define MAX_CONST_LOCAL_POS 64
-extern Scheme_Object *scheme_local[MAX_CONST_LOCAL_POS][2];
+extern Scheme_Object *scheme_local[MAX_CONST_LOCAL_POS][2][3];
 
 #define scheme_new_frame(n) scheme_new_special_frame(n, 0)
 #define scheme_extend_env(f, e) (f->basic.next = e, f)
@@ -1949,6 +1956,31 @@ void scheme_bind_syntaxes(const char *where, Scheme_Object *names, Scheme_Object
                           int *_pos);
 int scheme_is_sub_env(Scheme_Comp_Env *stx_env, Scheme_Comp_Env *env);
 
+typedef struct SFS_Info {
+  MZTAG_IF_REQUIRED  
+  int for_mod, pass;
+  int tail_pos;
+  int depth, stackpos, tlpos;
+  int selfpos, selfstart, selflen;
+  int ip, seqn, max_nontail;
+  int min_touch, max_touch;
+  int *max_used, *max_calls;
+  Scheme_Object *saved;
+} SFS_Info;
+
+SFS_Info *scheme_new_sfs_info(int depth);
+Scheme_Object *scheme_sfs(Scheme_Object *expr, SFS_Info *info, int max_let_depth);
+Scheme_Object *scheme_sfs_expr(Scheme_Object *expr, SFS_Info *si, int self_pos);
+Scheme_Object *scheme_sfs_closure(Scheme_Object *expr, SFS_Info *si, int self_pos);
+
+void scheme_sfs_used(SFS_Info *info, int pos);
+void scheme_sfs_push(SFS_Info *info, int count, int track);
+void scheme_sfs_start_sequence(SFS_Info *si, int cnt, int last_is_tail);
+
+Scheme_Object *scheme_sfs_add_clears(Scheme_Object *expr, Scheme_Object *clears, int pre);
+
+typedef struct Scheme_Object *(*Scheme_Syntax_SFSer)(Scheme_Object *data, SFS_Info *info);
+
 /* Resolving & linking */
 #define DEFINE_VALUES_EXPD 0
 #define DEFINE_SYNTAX_EXPD 1
@@ -1964,10 +1996,11 @@ int scheme_is_sub_env(Scheme_Comp_Env *stx_env, Scheme_Comp_Env *env);
 #define SPLICE_EXPD        11
 #define _COUNT_EXPD_       12
 
-#define scheme_register_syntax(i, fo, fr, fv, fe, fj, cl, sh, pa)        \
+#define scheme_register_syntax(i, fo, fr, fs, fv, fe, fj, cl, sh, pa)    \
      (scheme_syntax_optimizers[i] = fo, \
       scheme_syntax_resolvers[i] = fr, \
       scheme_syntax_executers[i] = fe, \
+      scheme_syntax_sfsers[i] = fs, \
       scheme_syntax_validaters[i] = fv, \
       scheme_syntax_jitters[i] = fj, \
       scheme_syntax_cloners[i] = cl, \
@@ -1975,6 +2008,7 @@ int scheme_is_sub_env(Scheme_Comp_Env *stx_env, Scheme_Comp_Env *env);
       scheme_syntax_protect_afters[i] = pa)
 extern Scheme_Syntax_Optimizer scheme_syntax_optimizers[_COUNT_EXPD_];
 extern Scheme_Syntax_Resolver scheme_syntax_resolvers[_COUNT_EXPD_];
+extern Scheme_Syntax_SFSer scheme_syntax_sfsers[_COUNT_EXPD_];
 extern Scheme_Syntax_Validater scheme_syntax_validaters[_COUNT_EXPD_];
 extern Scheme_Syntax_Executer scheme_syntax_executers[_COUNT_EXPD_];
 extern Scheme_Syntax_Jitter scheme_syntax_jitters[_COUNT_EXPD_];
@@ -2228,7 +2262,8 @@ void scheme_validate_expr(Mz_CPort *port, Scheme_Object *expr,
 			  char *stack, Validate_TLS tls,
                           int depth, int letlimit, int delta,
 			  int num_toplevels, int num_stxes, int num_lifts,
-                          Scheme_Object *app_rator, int proc_with_refs_ok);
+                          Scheme_Object *app_rator, int proc_with_refs_ok, 
+                          int result_ignored, struct Validate_Clearing *vc, int tailpos);
 void scheme_validate_toplevel(Scheme_Object *expr, Mz_CPort *port,
 			      char *stack, Validate_TLS tls,
                               int depth, int delta,
@@ -2244,7 +2279,8 @@ int scheme_validate_rator_wants_box(Scheme_Object *app_rator, int pos,
 
 void scheme_validate_closure(Mz_CPort *port, Scheme_Object *expr, 
                              char *new_stack, Validate_TLS tls,
-                             int num_toplevels, int num_stxes, int num_lifts);
+                             int num_toplevels, int num_stxes, int num_lifts,
+                             int self_pos_in_closure);
 
 #define TRACK_ILL_FORMED_CATCH_LINES 1
 #if TRACK_ILL_FORMED_CATCH_LINES
@@ -2568,6 +2604,9 @@ long scheme_extract_index(const char *name, int pos, int argc,
 void scheme_get_substring_indices(const char *name, Scheme_Object *str,
 				  int argc, Scheme_Object **argv,
 				  int spos, int fpos, long *_start, long *_finish);
+void scheme_do_get_substring_indices(const char *name, Scheme_Object *str,
+                                     int argc, Scheme_Object **argv,
+                                     int spos, int fpos, long *_start, long *_finish, long len);
 
 void scheme_out_of_string_range(const char *name, const char *which,
 				Scheme_Object *i, Scheme_Object *s,
diff --git a/src/mzscheme/src/schvers.h b/src/mzscheme/src/schvers.h
index e79aa107a0..0b4ebd3eb5 100644
--- a/src/mzscheme/src/schvers.h
+++ b/src/mzscheme/src/schvers.h
@@ -10,12 +10,12 @@
    The string and the separate X/Y/Z/W numbers must
    be updated consistently. */
 
-#define MZSCHEME_VERSION "3.99.0.10"
+#define MZSCHEME_VERSION "3.99.0.11"
 
 #define MZSCHEME_VERSION_X 3
 #define MZSCHEME_VERSION_Y 99
 #define MZSCHEME_VERSION_Z 0
-#define MZSCHEME_VERSION_W 10
+#define MZSCHEME_VERSION_W 11
 
 #define MZSCHEME_VERSION_MAJOR ((MZSCHEME_VERSION_X * 100) + MZSCHEME_VERSION_Y)
 #define MZSCHEME_VERSION_MINOR ((MZSCHEME_VERSION_Z * 1000) + MZSCHEME_VERSION_W)
diff --git a/src/mzscheme/src/string.c b/src/mzscheme/src/string.c
index ee9b64f89a..ba067c5e41 100644
--- a/src/mzscheme/src/string.c
+++ b/src/mzscheme/src/string.c
@@ -387,12 +387,12 @@ scheme_init_string (Scheme_Env *env)
   scheme_add_global_constant("string?", p, env);
 
   scheme_add_global_constant("make-string",
-			     scheme_make_noncm_prim(make_string,
+			     scheme_make_immed_prim(make_string,
 						    "make-string",
 						    1, 2),
 			     env);
   scheme_add_global_constant("string",
-			     scheme_make_noncm_prim(string,
+			     scheme_make_immed_prim(string,
 						    "string",
 						    0, -1),
 			     env);
@@ -402,185 +402,185 @@ scheme_init_string (Scheme_Env *env)
 						      1, 1, 1),
 			     env);
 
-  p = scheme_make_noncm_prim(scheme_checked_string_ref, "string-ref", 2, 2);
+  p = scheme_make_immed_prim(scheme_checked_string_ref, "string-ref", 2, 2);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant("string-ref", p, env);
 
 
-  p = scheme_make_noncm_prim(scheme_checked_string_set, "string-set!", 3, 3);
+  p = scheme_make_immed_prim(scheme_checked_string_set, "string-set!", 3, 3);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("string-set!", p, env);
 
   scheme_add_global_constant("string=?",
-			     scheme_make_noncm_prim(string_eq,
+			     scheme_make_immed_prim(string_eq,
 						    "string=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale=?",
-			     scheme_make_noncm_prim(string_locale_eq,
+			     scheme_make_immed_prim(string_locale_eq,
 						    "string-locale=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-ci=?",
-			     scheme_make_noncm_prim(string_ci_eq,
+			     scheme_make_immed_prim(string_ci_eq,
 						    "string-ci=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale-ci=?",
-			     scheme_make_noncm_prim(string_locale_ci_eq,
+			     scheme_make_immed_prim(string_locale_ci_eq,
 						    "string-locale-ci=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string<?",
-			     scheme_make_noncm_prim(string_lt,
+			     scheme_make_immed_prim(string_lt,
 						    "string<?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale<?",
-			     scheme_make_noncm_prim(string_locale_lt,
+			     scheme_make_immed_prim(string_locale_lt,
 						    "string-locale<?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string>?",
-			     scheme_make_noncm_prim(string_gt,
+			     scheme_make_immed_prim(string_gt,
 						    "string>?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale>?",
-			     scheme_make_noncm_prim(string_locale_gt,
+			     scheme_make_immed_prim(string_locale_gt,
 						    "string-locale>?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string<=?",
-			     scheme_make_noncm_prim(string_lt_eq,
+			     scheme_make_immed_prim(string_lt_eq,
 						    "string<=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string>=?",
-			     scheme_make_noncm_prim(string_gt_eq,
+			     scheme_make_immed_prim(string_gt_eq,
 						    "string>=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-ci<?",
-			     scheme_make_noncm_prim(string_ci_lt,
+			     scheme_make_immed_prim(string_ci_lt,
 						    "string-ci<?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale-ci<?",
-			     scheme_make_noncm_prim(string_locale_ci_lt,
+			     scheme_make_immed_prim(string_locale_ci_lt,
 						    "string-locale-ci<?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-ci>?",
-			     scheme_make_noncm_prim(string_ci_gt,
+			     scheme_make_immed_prim(string_ci_gt,
 						    "string-ci>?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-locale-ci>?",
-			     scheme_make_noncm_prim(string_locale_ci_gt,
+			     scheme_make_immed_prim(string_locale_ci_gt,
 						    "string-locale-ci>?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-ci<=?",
-			     scheme_make_noncm_prim(string_ci_lt_eq,
+			     scheme_make_immed_prim(string_ci_lt_eq,
 						    "string-ci<=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("string-ci>=?",
-			     scheme_make_noncm_prim(string_ci_gt_eq,
+			     scheme_make_immed_prim(string_ci_gt_eq,
 						    "string-ci>=?",
 						    2, -1),
 			     env);
 
   scheme_add_global_constant("substring",
-			     scheme_make_noncm_prim(substring,
+			     scheme_make_immed_prim(substring,
 						    "substring",
 						    2, 3),
 			     env);
   scheme_add_global_constant("string-append",
-			     scheme_make_noncm_prim(string_append,
+			     scheme_make_immed_prim(string_append,
 						    "string-append",
 						    0, -1),
 			     env);
   scheme_add_global_constant("string->list",
-			     scheme_make_noncm_prim(string_to_list,
+			     scheme_make_immed_prim(string_to_list,
 						    "string->list",
 						    1, 1),
 			     env);
   scheme_add_global_constant("list->string",
-			     scheme_make_noncm_prim(list_to_string,
+			     scheme_make_immed_prim(list_to_string,
 						    "list->string",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-copy",
-			     scheme_make_noncm_prim(string_copy,
+			     scheme_make_immed_prim(string_copy,
 						    "string-copy",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-copy!",
-			     scheme_make_noncm_prim(string_copy_bang,
+			     scheme_make_immed_prim(string_copy_bang,
 						    "string-copy!",
 						    3, 5),
 			     env);
   scheme_add_global_constant("string-fill!",
-			     scheme_make_noncm_prim(string_fill,
+			     scheme_make_immed_prim(string_fill,
 						    "string-fill!",
 						    2, 2),
 			     env);
   scheme_add_global_constant("string->immutable-string",
-			     scheme_make_noncm_prim(string_to_immutable,
+			     scheme_make_immed_prim(string_to_immutable,
 						    "string->immutable-string",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-normalize-nfc",
-			     scheme_make_noncm_prim(string_normalize_c,
+			     scheme_make_immed_prim(string_normalize_c,
 						    "string-normalize-nfc",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-normalize-nfkc",
-			     scheme_make_noncm_prim(string_normalize_kc,
+			     scheme_make_immed_prim(string_normalize_kc,
 						    "string-normalize-nfkc",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-normalize-nfd",
-			     scheme_make_noncm_prim(string_normalize_d,
+			     scheme_make_immed_prim(string_normalize_d,
 						    "string-normalize-nfd",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-normalize-nfkd",
-			     scheme_make_noncm_prim(string_normalize_kd,
+			     scheme_make_immed_prim(string_normalize_kd,
 						    "string-normalize-nfkd",
 						    1, 1),
 			     env);
 
   scheme_add_global_constant("string-upcase",
-			     scheme_make_noncm_prim(string_upcase,
+			     scheme_make_immed_prim(string_upcase,
 						    "string-upcase",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-downcase",
-			     scheme_make_noncm_prim(string_downcase,
+			     scheme_make_immed_prim(string_downcase,
 						    "string-downcase",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-titlecase",
-			     scheme_make_noncm_prim(string_titlecase,
+			     scheme_make_immed_prim(string_titlecase,
 						    "string-titlecase",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-foldcase",
-			     scheme_make_noncm_prim(string_foldcase,
+			     scheme_make_immed_prim(string_foldcase,
 						    "string-foldcase",
 						    1, 1),
 			     env);
 
   scheme_add_global_constant("string-locale-upcase",
-			     scheme_make_noncm_prim(string_locale_upcase,
+			     scheme_make_immed_prim(string_locale_upcase,
 						    "string-locale-upcase",
 						    1, 1),
 			     env);
   scheme_add_global_constant("string-locale-downcase",
-			     scheme_make_noncm_prim(string_locale_downcase,
+			     scheme_make_immed_prim(string_locale_downcase,
 						    "string-locale-downcase",
 						    1, 1),
 			     env);
@@ -591,18 +591,18 @@ scheme_init_string (Scheme_Env *env)
 						       MZCONFIG_LOCALE),
 			     env);
   scheme_add_global_constant("locale-string-encoding",
-			     scheme_make_noncm_prim(locale_string_encoding,
+			     scheme_make_immed_prim(locale_string_encoding,
 						    "locale-string-encoding",
 						    0, 0),
 			     env);
   scheme_add_global_constant("system-language+country",
-			     scheme_make_noncm_prim(system_language_country,
+			     scheme_make_immed_prim(system_language_country,
 						    "system-language+country",
 						    0, 0),
 			     env);
 
   scheme_add_global_constant("bytes-converter?",
-			     scheme_make_noncm_prim(byte_converter_p,
+			     scheme_make_immed_prim(byte_converter_p,
 						    "bytes-converter?",
 						    1, 1),
 			     env);
@@ -619,12 +619,12 @@ scheme_init_string (Scheme_Env *env)
 						       2, 2),
 			     env);
   scheme_add_global_constant("bytes-open-converter",
-			     scheme_make_noncm_prim(byte_string_open_converter,
+			     scheme_make_immed_prim(byte_string_open_converter,
 						    "bytes-open-converter",
 						    2, 2),
 			     env);
   scheme_add_global_constant("bytes-close-converter",
-			     scheme_make_noncm_prim(byte_string_close_converter,
+			     scheme_make_immed_prim(byte_string_close_converter,
 						    "bytes-close-converter",
 						    1, 1),
 			     env);
@@ -656,12 +656,12 @@ scheme_init_string (Scheme_Env *env)
   scheme_add_global_constant("bytes?", p, env);
 
   scheme_add_global_constant("make-bytes",
-			     scheme_make_noncm_prim(make_byte_string,
+			     scheme_make_immed_prim(make_byte_string,
 						    "make-bytes",
 						    1, 2),
 			     env);
   scheme_add_global_constant("bytes",
-			     scheme_make_noncm_prim(byte_string,
+			     scheme_make_immed_prim(byte_string,
 						    "bytes",
 						    0, -1),
 			     env);
@@ -671,121 +671,121 @@ scheme_init_string (Scheme_Env *env)
 						      1, 1, 1),
 			     env);
 
-  p = scheme_make_noncm_prim(scheme_checked_byte_string_ref, "bytes-ref", 2, 2);
+  p = scheme_make_immed_prim(scheme_checked_byte_string_ref, "bytes-ref", 2, 2);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant("bytes-ref", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_byte_string_set, "bytes-set!", 3, 3);
+  p = scheme_make_immed_prim(scheme_checked_byte_string_set, "bytes-set!", 3, 3);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("bytes-set!", p, env);
 
   scheme_add_global_constant("bytes=?",
-			     scheme_make_noncm_prim(byte_string_eq,
+			     scheme_make_immed_prim(byte_string_eq,
 						    "bytes=?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("bytes<?",
-			     scheme_make_noncm_prim(byte_string_lt,
+			     scheme_make_immed_prim(byte_string_lt,
 						    "bytes<?",
 						    2, -1),
 			     env);
   scheme_add_global_constant("bytes>?",
-			     scheme_make_noncm_prim(byte_string_gt,
+			     scheme_make_immed_prim(byte_string_gt,
 						    "bytes>?",
 						    2, -1),
 			     env);
 
   scheme_add_global_constant("subbytes",
-			     scheme_make_noncm_prim(byte_substring,
+			     scheme_make_immed_prim(byte_substring,
 						    "subbytes",
 						    2, 3),
 			     env);
   scheme_add_global_constant("bytes-append",
-			     scheme_make_noncm_prim(byte_string_append,
+			     scheme_make_immed_prim(byte_string_append,
 						    "bytes-append",
 						    0, -1),
 			     env);
   scheme_add_global_constant("bytes->list",
-			     scheme_make_noncm_prim(byte_string_to_list,
+			     scheme_make_immed_prim(byte_string_to_list,
 						    "bytes->list",
 						    1, 1),
 			     env);
   scheme_add_global_constant("list->bytes",
-			     scheme_make_noncm_prim(list_to_byte_string,
+			     scheme_make_immed_prim(list_to_byte_string,
 						    "list->bytes",
 						    1, 1),
 			     env);
   scheme_add_global_constant("bytes-copy",
-			     scheme_make_noncm_prim(byte_string_copy,
+			     scheme_make_immed_prim(byte_string_copy,
 						    "bytes-copy",
 						    1, 1),
 			     env);
   scheme_add_global_constant("bytes-copy!",
-			     scheme_make_noncm_prim(byte_string_copy_bang,
+			     scheme_make_immed_prim(byte_string_copy_bang,
 						    "bytes-copy!",
 						    3, 5),
 			     env);
   scheme_add_global_constant("bytes-fill!",
-			     scheme_make_noncm_prim(byte_string_fill,
+			     scheme_make_immed_prim(byte_string_fill,
 						    "bytes-fill!",
 						    2, 2),
 			     env);
   scheme_add_global_constant("bytes->immutable-bytes",
-			     scheme_make_noncm_prim(byte_string_to_immutable,
+			     scheme_make_immed_prim(byte_string_to_immutable,
 						    "bytes->immutable-bytes",
 						    1, 1),
 			     env);
 
 
   scheme_add_global_constant("bytes-utf-8-index",
-			     scheme_make_noncm_prim(byte_string_utf8_index,
+			     scheme_make_immed_prim(byte_string_utf8_index,
 						    "bytes-utf-8-index",
 						    2, 4),
 			     env);
   scheme_add_global_constant("bytes-utf-8-length",
-			     scheme_make_noncm_prim(byte_string_utf8_length,
+			     scheme_make_immed_prim(byte_string_utf8_length,
 						    "bytes-utf-8-length",
 						    1, 4),
 			     env);
   scheme_add_global_constant("bytes-utf-8-ref",
-			     scheme_make_noncm_prim(byte_string_utf8_ref,
+			     scheme_make_immed_prim(byte_string_utf8_ref,
 						    "bytes-utf-8-ref",
 						    2, 4),
 			     env);
 
   scheme_add_global_constant("bytes->string/utf-8",
-			     scheme_make_noncm_prim(byte_string_to_char_string,
+			     scheme_make_immed_prim(byte_string_to_char_string,
 						    "bytes->string/utf-8",
 						    1, 4),
 			     env);
   scheme_add_global_constant("bytes->string/locale",
-			     scheme_make_noncm_prim(byte_string_to_char_string_locale,
+			     scheme_make_immed_prim(byte_string_to_char_string_locale,
 						    "bytes->string/locale",
 						    1, 4),
 			     env);
   scheme_add_global_constant("bytes->string/latin-1",
-			     scheme_make_noncm_prim(byte_string_to_char_string_latin1,
+			     scheme_make_immed_prim(byte_string_to_char_string_latin1,
 						    "bytes->string/latin-1",
 						    1, 4),
 			     env);
   scheme_add_global_constant("string->bytes/utf-8",
-			     scheme_make_noncm_prim(char_string_to_byte_string,
+			     scheme_make_immed_prim(char_string_to_byte_string,
 						    "string->bytes/utf-8",
 						    1, 4),
 			     env);
   scheme_add_global_constant("string->bytes/locale",
-			     scheme_make_noncm_prim(char_string_to_byte_string_locale,
+			     scheme_make_immed_prim(char_string_to_byte_string_locale,
 						    "string->bytes/locale",
 						    1, 4),
 			     env);
   scheme_add_global_constant("string->bytes/latin-1",
-			     scheme_make_noncm_prim(char_string_to_byte_string_latin1,
+			     scheme_make_immed_prim(char_string_to_byte_string_latin1,
 						    "string->bytes/latin-1",
 						    1, 4),
 			     env);
 
   scheme_add_global_constant("string-utf-8-length",
-			     scheme_make_noncm_prim(char_string_utf8_length,
+			     scheme_make_immed_prim(char_string_utf8_length,
 						    "string-utf-8-length",
 						    1, 3),
 			     env);
@@ -795,23 +795,23 @@ scheme_init_string (Scheme_Env *env)
      more problems than it solves... */
 
   scheme_add_global_constant("version",
-			     scheme_make_noncm_prim(version,
+			     scheme_make_immed_prim(version,
 						    "version",
 						    0, 0),
 			     env);
   scheme_add_global_constant("banner",
-			     scheme_make_noncm_prim(banner,
+			     scheme_make_immed_prim(banner,
 						    "banner",
 						    0, 0),
 			     env);
 
   scheme_add_global_constant("getenv",
-			     scheme_make_noncm_prim(sch_getenv,
+			     scheme_make_immed_prim(sch_getenv,
 						    "getenv",
 						    1, 1),
 			     env);
   scheme_add_global_constant("putenv",
-			     scheme_make_noncm_prim(sch_putenv,
+			     scheme_make_immed_prim(sch_putenv,
 						    "putenv",
 						    2, 2),
 			     env);
@@ -819,12 +819,12 @@ scheme_init_string (Scheme_Env *env)
   /* Don't make these folding, since they're platform-specific: */
 
   scheme_add_global_constant("system-type",
-			     scheme_make_noncm_prim(system_type,
+			     scheme_make_immed_prim(system_type,
 						    "system-type",
 						    0, 1),
 			     env);
   scheme_add_global_constant("system-library-subpath",
-			     scheme_make_noncm_prim(system_library_subpath,
+			     scheme_make_immed_prim(system_library_subpath,
 						    "system-library-subpath",
 						    0, 1),
 			     env);
@@ -908,24 +908,26 @@ void scheme_out_of_string_range(const char *name, const char *which,
 
   is_byte = SCHEME_BYTE_STRINGP(s);
 
-  if ((is_byte ? SCHEME_BYTE_STRTAG_VAL(s) : SCHEME_CHAR_STRTAG_VAL(s))) {
+  if (len) {
     char *sstr;
     int slen;
 
     sstr = scheme_make_provided_string(s, 2, &slen);
     scheme_raise_exn(MZEXN_FAIL_CONTRACT,
-		     "%s: %sindex %s out of range [%d, %d] for %sstring: %t",
+		     "%s: %sindex %s out of range [%d, %d] for %s%s: %t",
 		     name, which,
 		     scheme_make_provided_string(i, 2, NULL),
 		     start, len,
 		     is_byte ? "byte-" : "",
+                     SCHEME_VECTORP(s) ? "vector" : "string",
 		     sstr, slen);
   } else {
     scheme_raise_exn(MZEXN_FAIL_CONTRACT,
-		     "%s: %sindex %s out of range for empty %sstring",
+		     "%s: %sindex %s out of range for empty %s%s",
 		     name, which,
 		     scheme_make_provided_string(i, 0, NULL),
-		     is_byte ? "byte-" : "");
+		     is_byte ? "byte-" : "",
+                     SCHEME_VECTORP(s) ? "vector" : "string");
   }
 }
 
@@ -960,6 +962,8 @@ void scheme_get_substring_indices(const char *name, Scheme_Object *str,
   long len;
   long start, finish;
 
+  if (SCHEME_VECTORP(str))
+    len = SCHEME_VEC_SIZE(str);
   if (SCHEME_CHAR_STRINGP(str))
     len = SCHEME_CHAR_STRTAG_VAL(str);
   else
@@ -985,9 +989,9 @@ void scheme_get_substring_indices(const char *name, Scheme_Object *str,
   *_finish = finish;
 }
 
-static void get_substring_indices(const char *name, Scheme_Object *str,
-                                  int argc, Scheme_Object **argv,
-                                  int spos, int fpos, long *_start, long *_finish, long len)
+void scheme_do_get_substring_indices(const char *name, Scheme_Object *str,
+                                     int argc, Scheme_Object **argv,
+                                     int spos, int fpos, long *_start, long *_finish, long len)
 {
   if (argc > spos) {
     if (SCHEME_INTP(argv[spos])) {
diff --git a/src/mzscheme/src/strops.inc b/src/mzscheme/src/strops.inc
index fa17e80a83..74c668f7bb 100644
--- a/src/mzscheme/src/strops.inc
+++ b/src/mzscheme/src/strops.inc
@@ -208,8 +208,8 @@ X__(substring) (int argc, Scheme_Object *argv[])
 
   chars = SCHEME_X_STR_VAL(argv[0]);
 
-  get_substring_indices(SUBXSTR, argv[0], argc, argv, 1, 2,
-                        &start, &finish, SCHEME_X_STRTAG_VAL(argv[0]));
+  scheme_do_get_substring_indices(SUBXSTR, argv[0], argc, argv, 1, 2,
+                                  &start, &finish, SCHEME_X_STRTAG_VAL(argv[0]));
 
   str = X(scheme_alloc, _string)(finish-start, 0);
   memcpy(SCHEME_X_STR_VAL(str), chars + start, (finish - start) * sizeof(Xchar));
@@ -349,18 +349,18 @@ X__(string_copy_bang)(int argc, Scheme_Object *argv[])
   if (!SCHEME_MUTABLE_X_STRINGP(s1))
     scheme_wrong_type(XSTRINGSTR "-copy!", "mutable " XSTR "string", 0, argc, argv);
 
-  get_substring_indices(XSTRINGSTR "-copy!", s1, 
-                        argc, argv, 1, 5, 
-                        &ostart, &ofinish, SCHEME_X_STRTAG_VAL(s1));
+  scheme_do_get_substring_indices(XSTRINGSTR "-copy!", s1, 
+                                  argc, argv, 1, 5, 
+                                  &ostart, &ofinish, SCHEME_X_STRTAG_VAL(s1));
 
   s2 = argv[2];
   if (!SCHEME_X_STRINGP(s2))
     scheme_wrong_type(XSTRINGSTR "-copy!", XSTR "string", 2, argc, argv);
 
-  get_substring_indices(XSTRINGSTR "-copy!", s2, 
-                        argc, argv, 3, 4, 
-                        &istart, &ifinish, SCHEME_X_STRTAG_VAL(s2));
-
+  scheme_do_get_substring_indices(XSTRINGSTR "-copy!", s2, 
+                                  argc, argv, 3, 4, 
+                                  &istart, &ifinish, SCHEME_X_STRTAG_VAL(s2));
+  
   if ((ofinish - ostart) < (ifinish - istart)) {
     scheme_arg_mismatch(XSTRINGSTR "-copy!",
 			"not enough room in target " XSTR "string: ",
diff --git a/src/mzscheme/src/struct.c b/src/mzscheme/src/struct.c
index e081589aae..2d7bcd89e7 100644
--- a/src/mzscheme/src/struct.c
+++ b/src/mzscheme/src/struct.c
@@ -2300,7 +2300,7 @@ make_struct_proc(Scheme_Struct_Type *struct_type,
       p = scheme_make_folding_prim_closure(struct_getter,
 					   1, a,
 					   func_name,
-					   1 + need_pos, 1 + need_pos, 1);
+					   1 + need_pos, 1 + need_pos, 0);
       if (need_pos)
 	flags |= SCHEME_PRIM_STRUCT_TYPE_INDEXLESS_GETTER | SCHEME_PRIM_IS_STRUCT_OTHER;
       else
diff --git a/src/mzscheme/src/stxobj.c b/src/mzscheme/src/stxobj.c
index 37e66ffa05..c315eea4c5 100644
--- a/src/mzscheme/src/stxobj.c
+++ b/src/mzscheme/src/stxobj.c
@@ -400,70 +400,70 @@ void scheme_init_stx(Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("syntax-original?", 
-			     scheme_make_noncm_prim(syntax_original_p,
+			     scheme_make_immed_prim(syntax_original_p,
 						    "syntax-original?",
 						    1, 1),
 			     env);
   scheme_add_global_constant("syntax-property", 
-			     scheme_make_noncm_prim(syntax_property,
+			     scheme_make_immed_prim(syntax_property,
 						    "syntax-property",
 						    2, 3),
 			     env);
   scheme_add_global_constant("syntax-property-symbol-keys", 
-			     scheme_make_noncm_prim(syntax_property_keys,
+			     scheme_make_immed_prim(syntax_property_keys,
 						    "syntax-property-symbol-keys",
 						    1, 1),
 			     env);
 
   scheme_add_global_constant("syntax-track-origin", 
-			     scheme_make_noncm_prim(syntax_track_origin,
+			     scheme_make_immed_prim(syntax_track_origin,
 						    "syntax-track-origin",
 						    3, 3),
 			     env);
 
   scheme_add_global_constant("bound-identifier=?", 
-			     scheme_make_noncm_prim(bound_eq,
+			     scheme_make_immed_prim(bound_eq,
 						    "bound-identifier=?",
 						    2, 2),
 			     env);
   scheme_add_global_constant("free-identifier=?", 
-			     scheme_make_noncm_prim(module_eq,
+			     scheme_make_immed_prim(module_eq,
 						    "free-identifier=?",
 						    2, 2),
 			     env);
   scheme_add_global_constant("free-transformer-identifier=?", 
-			     scheme_make_noncm_prim(module_trans_eq,
+			     scheme_make_immed_prim(module_trans_eq,
 						    "free-transformer-identifier=?",
 						    2, 2),
 			     env);
   scheme_add_global_constant("free-template-identifier=?", 
-			     scheme_make_noncm_prim(module_templ_eq,
+			     scheme_make_immed_prim(module_templ_eq,
 						    "free-template-identifier=?",
 						    2, 2),
 			     env);
   scheme_add_global_constant("free-label-identifier=?", 
-			     scheme_make_noncm_prim(module_label_eq,
+			     scheme_make_immed_prim(module_label_eq,
 						    "free-label-identifier=?",
 						    2, 2),
 			     env);
 
   scheme_add_global_constant("identifier-binding", 
-			     scheme_make_noncm_prim(module_binding,
+			     scheme_make_immed_prim(module_binding,
 						    "identifier-binding",
 						    1, 1),
 			     env);
   scheme_add_global_constant("identifier-transformer-binding", 
-			     scheme_make_noncm_prim(module_trans_binding,
+			     scheme_make_immed_prim(module_trans_binding,
 						    "identifier-transformer-binding",
 						    1, 2),
 			     env);
   scheme_add_global_constant("identifier-template-binding", 
-			     scheme_make_noncm_prim(module_templ_binding,
+			     scheme_make_immed_prim(module_templ_binding,
 						    "identifier-template-binding",
 						    1, 1),
 			     env);
   scheme_add_global_constant("identifier-label-binding", 
-			     scheme_make_noncm_prim(module_label_binding,
+			     scheme_make_immed_prim(module_label_binding,
 						    "identifier-label-binding",
 						    1, 1),
 			     env);
@@ -476,7 +476,7 @@ void scheme_init_stx(Scheme_Env *env)
 			     env);
 
   scheme_add_global_constant("syntax-recertify", 
-			     scheme_make_noncm_prim(syntax_recertify,
+			     scheme_make_immed_prim(syntax_recertify,
 						    "syntax-recertify",
 						    4, 4),
 			     env);
diff --git a/src/mzscheme/src/stypes.h b/src/mzscheme/src/stypes.h
index 87d97edb7c..8008657cba 100644
--- a/src/mzscheme/src/stypes.h
+++ b/src/mzscheme/src/stypes.h
@@ -235,6 +235,8 @@ enum {
   scheme_rt_marshal_info,               /* 213 */
   scheme_rt_unmarshal_info,             /* 214 */
   scheme_rt_runstack,                   /* 215 */
+  scheme_rt_sfs_info,                   /* 216 */
+  scheme_rt_validate_clearing,          /* 217 */
 #endif
 
   _scheme_last_type_
diff --git a/src/mzscheme/src/symbol.c b/src/mzscheme/src/symbol.c
index 8446dce184..2b9217e0bd 100644
--- a/src/mzscheme/src/symbol.c
+++ b/src/mzscheme/src/symbol.c
@@ -302,16 +302,16 @@ scheme_init_symbol (Scheme_Env *env)
   scheme_add_global_constant("symbol?", p, env);
 
   scheme_add_global_constant("string->symbol",
-			     scheme_make_noncm_prim(string_to_symbol_prim,
+			     scheme_make_immed_prim(string_to_symbol_prim,
 						    "string->symbol",
 						    1, 1), env);
   scheme_add_global_constant("string->uninterned-symbol",
-			     scheme_make_noncm_prim(string_to_uninterned_symbol_prim,
+			     scheme_make_immed_prim(string_to_uninterned_symbol_prim,
 						    "string->uninterned-symbol",
 						    1, 1),
 			     env);
   scheme_add_global_constant("symbol->string",
-			     scheme_make_noncm_prim(symbol_to_string_prim,
+			     scheme_make_immed_prim(symbol_to_string_prim,
 						    "symbol->string",
 						    1, 1),
 			     env);
@@ -327,17 +327,17 @@ scheme_init_symbol (Scheme_Env *env)
 						      2, -1, 1),
 			     env);
   scheme_add_global_constant("string->keyword",
-			     scheme_make_noncm_prim(string_to_keyword_prim,
+			     scheme_make_immed_prim(string_to_keyword_prim,
 						    "string->keyword",
 						    1, 1), env);
   scheme_add_global_constant("keyword->string",
-			     scheme_make_noncm_prim(keyword_to_string_prim,
+			     scheme_make_immed_prim(keyword_to_string_prim,
 						    "keyword->string",
 						    1, 1),
 			     env);
 
   scheme_add_global_constant("gensym",
-			     scheme_make_noncm_prim(gensym,
+			     scheme_make_immed_prim(gensym,
 						    "gensym",
 						    0, 1),
 			     env);
diff --git a/src/mzscheme/src/syntax.c b/src/mzscheme/src/syntax.c
index c74c01b6f5..98f80086c3 100644
--- a/src/mzscheme/src/syntax.c
+++ b/src/mzscheme/src/syntax.c
@@ -43,6 +43,7 @@ Scheme_Object scheme_undefined[1];
 
 Scheme_Syntax_Optimizer scheme_syntax_optimizers[_COUNT_EXPD_];
 Scheme_Syntax_Resolver scheme_syntax_resolvers[_COUNT_EXPD_];
+Scheme_Syntax_SFSer scheme_syntax_sfsers[_COUNT_EXPD_];
 Scheme_Syntax_Validater scheme_syntax_validaters[_COUNT_EXPD_];
 Scheme_Syntax_Executer scheme_syntax_executers[_COUNT_EXPD_];
 Scheme_Syntax_Jitter scheme_syntax_jitters[_COUNT_EXPD_];
@@ -137,46 +138,67 @@ static Scheme_Object *begin0_resolve(Scheme_Object *data, Resolve_Info *info);
 static Scheme_Object *apply_values_resolve(Scheme_Object *data, Resolve_Info *info);
 static Scheme_Object *splice_resolve(Scheme_Object *data, Resolve_Info *info);
 
+static Scheme_Object *define_values_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *ref_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *set_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *define_syntaxes_sfs(Scheme_Object *expr, SFS_Info *info);
+static Scheme_Object *define_for_syntaxes_sfs(Scheme_Object *expr, SFS_Info *info);
+static Scheme_Object *case_lambda_sfs(Scheme_Object *expr, SFS_Info *info);
+static Scheme_Object *begin0_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *apply_values_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *splice_sfs(Scheme_Object *data, SFS_Info *info);
+static Scheme_Object *bangboxenv_sfs(Scheme_Object *data, SFS_Info *info);
+
 static void define_values_validate(Scheme_Object *data, Mz_CPort *port, 
                                    char *stack, Validate_TLS tls,
                                    int depth, int letlimit, int delta, 
-				   int num_toplevels, int num_stxes, int num_lifts);
+				   int num_toplevels, int num_stxes, int num_lifts,
+                                   struct Validate_Clearing *vc, int tailpos);
 static void ref_validate(Scheme_Object *data, Mz_CPort *port, 
                          char *stack, Validate_TLS tls,
                          int depth, int letlimit, int delta, 
-			 int num_toplevels, int num_stxes, int num_lifts);
+			 int num_toplevels, int num_stxes, int num_lifts,
+                         struct Validate_Clearing *vc, int tailpos);
 static void set_validate(Scheme_Object *data, Mz_CPort *port, 
                          char *stack, Validate_TLS tls,
                          int depth, int letlimit, int delta, 
-			 int num_toplevels, int num_stxes, int num_lifts);
+			 int num_toplevels, int num_stxes, int num_lifts,
+                         struct Validate_Clearing *vc, int tailpos);
 static void define_syntaxes_validate(Scheme_Object *data, Mz_CPort *port, 
                                      char *stack, Validate_TLS tls,
                                      int depth, int letlimit, int delta, 
-				     int num_toplevels, int num_stxes, int num_lifts);
+				     int num_toplevels, int num_stxes, int num_lifts,
+                                     struct Validate_Clearing *vc, int tailpos);
 static void define_for_syntaxes_validate(Scheme_Object *data, Mz_CPort *port, 
                                          char *stack, Validate_TLS tls,
                                          int depth, int letlimit, int delta, 
-					 int num_toplevels, int num_stxes, int num_lifts);
+					 int num_toplevels, int num_stxes, int num_lifts,
+                                         struct Validate_Clearing *vc, int tailpos);
 static void case_lambda_validate(Scheme_Object *data, Mz_CPort *port, 
                                  char *stack, Validate_TLS tls,
                                  int depth, int letlimit, int delta, 
-				 int num_toplevels, int num_stxes, int num_lifts);
+				 int num_toplevels, int num_stxes, int num_lifts,
+                                 struct Validate_Clearing *vc, int tailpos);
 static void begin0_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
                             int depth, int letlimit, int delta,
-			    int num_toplevels, int num_stxes, int num_lifts);
+			    int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos);
 static void apply_values_validate(Scheme_Object *data, Mz_CPort *port, 
                                   char *stack, Validate_TLS tls,
                                   int depth, int letlimit, int delta,
-                                  int num_toplevels, int num_stxes, int num_lifts);
+                                  int num_toplevels, int num_stxes, int num_lifts,
+                                  struct Validate_Clearing *vc, int tailpos);
 static void splice_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
                             int depth, int letlimit, int delta,
-                            int num_toplevels, int num_stxes, int num_lifts);
+                            int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos);
 static void bangboxenv_validate(Scheme_Object *data, Mz_CPort *port, 
                                 char *stack, Validate_TLS tls,
                                 int depth, int letlimit, int delta,
-				int num_toplevels, int num_stxes, int num_lifts);
+				int num_toplevels, int num_stxes, int num_lifts,
+                                struct Validate_Clearing *vc, int tailpos);
 
 static Scheme_Object *define_values_jit(Scheme_Object *data);
 static Scheme_Object *ref_jit(Scheme_Object *data);
@@ -260,54 +282,54 @@ scheme_init_syntax (Scheme_Env *env)
 
   scheme_register_syntax(DEFINE_VALUES_EXPD, 
 			 define_values_optimize, 
-			 define_values_resolve, define_values_validate, 
+			 define_values_resolve, define_values_sfs, define_values_validate, 
 			 define_values_execute, define_values_jit, 
 			 NULL, NULL, -2);
   scheme_register_syntax(SET_EXPD,
 			 set_optimize,
-			 set_resolve, set_validate,
+			 set_resolve, set_sfs, set_validate,
 			 set_execute, set_jit, 
 			 set_clone, set_shift, 2);
   scheme_register_syntax(REF_EXPD, 
 			 ref_optimize,
-			 ref_resolve, ref_validate, 
+			 ref_resolve, ref_sfs, ref_validate, 
 			 ref_execute, ref_jit, 
 			 NULL, ref_shift, 0);
   scheme_register_syntax(DEFINE_SYNTAX_EXPD, 
 			 define_syntaxes_optimize,
-			 define_syntaxes_resolve, define_syntaxes_validate,
+			 define_syntaxes_resolve, define_syntaxes_sfs, define_syntaxes_validate,
 			 define_syntaxes_execute, define_syntaxes_jit, 
 			 NULL, NULL, -2);
   scheme_register_syntax(DEFINE_FOR_SYNTAX_EXPD, 
 			 define_for_syntaxes_optimize, 
-			 define_for_syntaxes_resolve, define_for_syntaxes_validate,
+			 define_for_syntaxes_resolve, define_for_syntaxes_sfs, define_for_syntaxes_validate,
 			 define_for_syntaxes_execute, define_for_syntaxes_jit, 
 			 NULL, NULL, -2);
   scheme_register_syntax(CASE_LAMBDA_EXPD, 
 			 case_lambda_optimize,
-			 case_lambda_resolve, case_lambda_validate,
+			 case_lambda_resolve, case_lambda_sfs, case_lambda_validate,
 			 case_lambda_execute, case_lambda_jit, 
 			 NULL, case_lambda_shift, -1);
   scheme_register_syntax(BEGIN0_EXPD, 
 			 begin0_optimize,
-			 begin0_resolve, begin0_validate,
+			 begin0_resolve, begin0_sfs, begin0_validate,
 			 begin0_execute, begin0_jit, 
 			 begin0_clone, begin0_shift, -1);
 
   scheme_register_syntax(APPVALS_EXPD,
 			 apply_values_optimize,
-			 apply_values_resolve, apply_values_validate,
+			 apply_values_resolve, apply_values_sfs, apply_values_validate,
 			 apply_values_execute, apply_values_jit, 
 			 apply_values_clone, apply_values_shift, 1);
 
   scheme_register_syntax(SPLICE_EXPD,
 			 splice_optimize,
-			 splice_resolve, splice_validate,
+			 splice_resolve, splice_sfs, splice_validate,
 			 splice_execute, splice_jit, 
 			 splice_clone, splice_shift, 0);
 
   scheme_register_syntax(BOXENV_EXPD, 
-			 NULL, NULL, bangboxenv_validate,
+			 NULL, NULL, bangboxenv_sfs, bangboxenv_validate,
 			 bangboxenv_execute, bangboxenv_jit, 
 			 NULL, NULL, 1);
 
@@ -846,7 +868,8 @@ static Scheme_Object *define_values_jit(Scheme_Object *data)
 static void define_values_validate(Scheme_Object *data, Mz_CPort *port, 
 				   char *stack,  Validate_TLS tls,
                                    int depth, int letlimit, int delta, 
-                                   int num_toplevels, int num_stxes, int num_lifts)
+                                   int num_toplevels, int num_stxes, int num_lifts,
+                                   struct Validate_Clearing *vc, int tailpos)
 {
   int i, size;
   Scheme_Object *val, *only_var;
@@ -954,7 +977,7 @@ static void define_values_validate(Scheme_Object *data, Mz_CPort *port,
   scheme_validate_expr(port, val, stack, tls, 
                        depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, !!only_var);
+                       NULL, !!only_var, 0, vc, 0);
 }
 
 static Scheme_Object *
@@ -1004,6 +1027,16 @@ define_values_resolve(Scheme_Object *data, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(DEFINE_VALUES_EXPD, vec);
 }
 
+static Scheme_Object *
+define_values_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  Scheme_Object *e;
+  scheme_sfs_start_sequence(info, 1, 0);
+  e = scheme_sfs_expr(SCHEME_VEC_ELS(data)[0], info, -1);
+  SCHEME_VEC_ELS(data)[0] = e;
+  return data;
+}
+
 void scheme_resolve_lift_definition(Resolve_Info *info, Scheme_Object *var, Scheme_Object *rhs)
 {
   Scheme_Object *decl, *vec, *pr;
@@ -1474,7 +1507,8 @@ static Scheme_Object *set_jit(Scheme_Object *data)
 static void set_validate(Scheme_Object *data, Mz_CPort *port, 
 			 char *stack, Validate_TLS tls,
                          int depth, int letlimit, int delta, 
-                         int num_toplevels, int num_stxes, int num_lifts)
+                         int num_toplevels, int num_stxes, int num_lifts,
+                         struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Object *val, *tl;
 
@@ -1488,7 +1522,7 @@ static void set_validate(Scheme_Object *data, Mz_CPort *port,
 
   scheme_validate_expr(port, val, stack, tls, depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, 0);
   scheme_validate_toplevel(tl, port, stack, tls, depth, delta, 
                            num_toplevels, num_stxes, num_lifts,
                            0);
@@ -1520,7 +1554,7 @@ set_optimize(Scheme_Object *data, Optimize_Info *info)
     /* Offset: */
     delta = scheme_optimize_info_get_shift(info, pos);
     if (delta)
-      var = scheme_make_local(scheme_local_type, pos + delta);
+      var = scheme_make_local(scheme_local_type, pos + delta, 0);
   } else {
     scheme_optimize_info_used_top(info);
   }
@@ -1602,6 +1636,26 @@ set_resolve(Scheme_Object *data, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(SET_EXPD, cons(set_undef, cons(var, val)));
 }
 
+static Scheme_Object *
+set_sfs(Scheme_Object *orig_data, SFS_Info *info)
+{
+  Scheme_Object *data, *var, *val;
+
+  data = SCHEME_CDR(orig_data);
+  var = SCHEME_CAR(data);
+  val = SCHEME_CDR(data);
+  
+  scheme_sfs_start_sequence(info, 2, 0);
+
+  val = scheme_sfs_expr(val, info, -1);
+  var = scheme_sfs_expr(var, info, -1);
+
+  SCHEME_CAR(data) = var;
+  SCHEME_CDR(data) = val;
+
+  return orig_data;
+}
+
 static Scheme_Object *
 set_syntax (Scheme_Object *form, Scheme_Comp_Env *env, Scheme_Compile_Info *rec, int drec)
 {
@@ -1813,7 +1867,8 @@ static Scheme_Object *ref_jit(Scheme_Object *data)
 static void ref_validate(Scheme_Object *tl, Mz_CPort *port, 
 			 char *stack, Validate_TLS tls,
                          int depth, int letlimit, int delta, 
-                         int num_toplevels, int num_stxes, int num_lifts)
+                         int num_toplevels, int num_stxes, int num_lifts,
+                         struct Validate_Clearing *vc, int tailpos)
 {
   scheme_validate_toplevel(tl,  port, stack, tls, depth, delta, 
                            num_toplevels, num_stxes, num_lifts,
@@ -1841,6 +1896,18 @@ ref_resolve(Scheme_Object *tl, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(REF_EXPD, scheme_resolve_expr(tl, rslv));
 }
 
+static Scheme_Object *
+ref_sfs(Scheme_Object *tl, SFS_Info *info)
+{
+  Scheme_Object *naya;
+  scheme_sfs_start_sequence(info, 1, 0);
+  naya = scheme_sfs_expr(tl, info, -1);
+  if (SAME_OBJ(naya, tl))
+    return tl;
+  else
+    return scheme_make_syntax_resolved(REF_EXPD, naya);
+}
+
 static Scheme_Object *
 ref_syntax (Scheme_Object *form, Scheme_Comp_Env *env, Scheme_Compile_Info *rec, int drec)
 {
@@ -2019,6 +2086,22 @@ apply_values_resolve(Scheme_Object *data, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(APPVALS_EXPD, cons(f, e));
 }
 
+static Scheme_Object *
+apply_values_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  Scheme_Object *f, *e;
+
+  f = SCHEME_CAR(data);
+  e = SCHEME_CDR(data);
+
+  scheme_sfs_start_sequence(info, 2, 0);
+
+  f = scheme_sfs_expr(f, info, -1);
+  e = scheme_sfs_expr(e, info, -1);
+
+  return data;
+}
+
 static Scheme_Object *
 apply_values_shift(Scheme_Object *data, int delta, int after_depth)
 {
@@ -2052,7 +2135,8 @@ apply_values_clone(int dup_ok, Scheme_Object *data, Optimize_Info *info, int del
 static void apply_values_validate(Scheme_Object *data, Mz_CPort *port, 
                                   char *stack, Validate_TLS tls,
                                   int depth, int letlimit, int delta, 
-                                  int num_toplevels, int num_stxes, int num_lifts)
+                                  int num_toplevels, int num_stxes, int num_lifts,
+                                  struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Object *f, *e;
 
@@ -2062,11 +2146,11 @@ static void apply_values_validate(Scheme_Object *data, Mz_CPort *port,
   scheme_validate_expr(port, f, stack, tls,
                        depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, 0);
   scheme_validate_expr(port, e, stack, tls,
                        depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, 0);
 }
 
 /**********************************************************************/
@@ -2215,15 +2299,21 @@ static Scheme_Object *case_lambda_jit(Scheme_Object *expr)
 
 static void case_lambda_validate(Scheme_Object *data, Mz_CPort *port, char *stack, Validate_TLS tls,
 				 int depth, int letlimit, int delta, 
-                                 int num_toplevels, int num_stxes, int num_lifts)
+                                 int num_toplevels, int num_stxes, int num_lifts,
+                                 struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Case_Lambda *seq = (Scheme_Case_Lambda *)data;
+  Scheme_Object *e;
   int i;
 
   for (i = 0; i < seq->count; i++) { 
-    scheme_validate_expr(port, seq->array[i], stack, tls, depth, letlimit, delta, 
+    e = seq->array[i];
+    if (!SAME_TYPE(SCHEME_TYPE(e), scheme_unclosed_procedure_type)
+        && !SAME_TYPE(SCHEME_TYPE(e), scheme_closure_type))
+      scheme_ill_formed_code(port);
+    scheme_validate_expr(port, e, stack, tls, depth, letlimit, delta, 
                          num_toplevels, num_stxes, num_lifts,
-                         NULL, 0);
+                         NULL, 0, 0, vc, 0);
   }
 }
 
@@ -2250,6 +2340,48 @@ case_lambda_resolve(Scheme_Object *expr, Resolve_Info *rslv)
   return scheme_make_syntax_resolved(CASE_LAMBDA_EXPD, expr);
 }
 
+static Scheme_Object *
+case_lambda_sfs(Scheme_Object *expr, SFS_Info *info)
+{
+  Scheme_Case_Lambda *seq = (Scheme_Case_Lambda *)expr;
+  Scheme_Object *le, *clears = scheme_null;
+  int i;
+
+  scheme_sfs_start_sequence(info, seq->count, 0);
+
+  for (i = 0; i < seq->count; i++) {
+    le = seq->array[i];
+    le = scheme_sfs_expr(le, info, -1);
+    if (SAME_TYPE(SCHEME_TYPE(le), scheme_syntax_type)
+        && (SCHEME_PINT_VAL(le) == BEGIN0_EXPD)) {
+      /* Some clearing actions were added to the closure.
+         Lift them out. */
+      int j;
+      Scheme_Sequence *cseq = (Scheme_Sequence *)SCHEME_IPTR_VAL(le);
+      if (!cseq->count)
+        scheme_signal_error("internal error: empty sequence");
+      for (j = 1; j < cseq->count; j++) {
+        int pos;
+        pos = SCHEME_LOCAL_POS(cseq->array[j]);
+        clears = scheme_make_pair(scheme_make_integer(pos), clears);
+      }
+      le = cseq->array[0];
+    }
+    if (!SAME_TYPE(SCHEME_TYPE(le), scheme_unclosed_procedure_type)
+        && !SAME_TYPE(SCHEME_TYPE(le), scheme_closure_type)) {
+      scheme_signal_error("internal error: not a lambda for case-lambda: %d",
+                          SCHEME_TYPE(le));
+    }
+    seq->array[i] = le;
+  }
+
+  if (!SCHEME_NULLP(clears)) {
+    expr = scheme_make_syntax_resolved(CASE_LAMBDA_EXPD, expr);
+    return scheme_sfs_add_clears(expr, clears, 0);
+  } else
+    return expr;
+}
+
 static Scheme_Object *
 case_lambda_optimize(Scheme_Object *expr, Optimize_Info *info)
 {
@@ -2285,7 +2417,7 @@ case_lambda_shift(Scheme_Object *data, int delta, int after_depth)
   return data;
 }
 
-Scheme_Object *scheme_unclose_case_lambda(Scheme_Object *expr, int jit)
+Scheme_Object *scheme_unclose_case_lambda(Scheme_Object *expr, int mode)
 {
   Scheme_Case_Lambda *cl = (Scheme_Case_Lambda *)expr;
   Scheme_Closure *c;
@@ -2314,9 +2446,13 @@ Scheme_Object *scheme_unclose_case_lambda(Scheme_Object *expr, int jit)
       cl2->array[i] = (Scheme_Object *)c->code;
     }
 
-    if (jit)
+    if (mode == 2) {
+      /* sfs */
+      return scheme_make_syntax_resolved(CASE_LAMBDA_EXPD, expr);
+    } else if (mode == 1) {
+      /* JIT */
       return case_lambda_jit((Scheme_Object *)cl2);
-    else
+    } else
       return (Scheme_Object *)cl2;
   }
   
@@ -2535,6 +2671,14 @@ Scheme_Object *bangboxenv_execute(Scheme_Object *data)
   return _scheme_tail_eval(data);
 }
 
+static Scheme_Object *bangboxenv_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  Scheme_Object *e;
+  e = scheme_sfs_expr(SCHEME_CDR(data), info, -1);
+  SCHEME_CDR(data) = e;
+  return data;
+}
+
 static Scheme_Object *bangboxenv_jit(Scheme_Object *data)
 {
   Scheme_Object *orig, *naya;
@@ -2550,7 +2694,8 @@ static Scheme_Object *bangboxenv_jit(Scheme_Object *data)
 static void bangboxenv_validate(Scheme_Object *data, Mz_CPort *port, 
 				char *stack, Validate_TLS tls,
                                 int depth, int letlimit, int delta, 
-                                int num_toplevels, int num_stxes, int num_lifts)
+                                int num_toplevels, int num_stxes, int num_lifts,
+                                struct Validate_Clearing *vc, int tailpos)
 {
   if (!SCHEME_PAIRP(data))
     scheme_ill_formed_code(port);
@@ -2559,7 +2704,7 @@ static void bangboxenv_validate(Scheme_Object *data, Mz_CPort *port,
 
   scheme_validate_expr(port, SCHEME_CDR(data), stack, tls, depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, tailpos);
 }
 
 /**********************************************************************/
@@ -4365,16 +4510,21 @@ static Scheme_Object *begin0_jit(Scheme_Object *data)
 static void begin0_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
 			    int depth, int letlimit, int delta, 
-                            int num_toplevels, int num_stxes, int num_lifts)
+                            int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos)
 {
   Scheme_Sequence *seq = (Scheme_Sequence *)data;
   int i;
 
+  if (!SAME_TYPE(SCHEME_TYPE(seq), scheme_begin0_sequence_type)
+      && !SAME_TYPE(SCHEME_TYPE(seq), scheme_sequence_type))
+    scheme_ill_formed_code(port);
+
   for (i = 0; i < seq->count; i++) { 
     scheme_validate_expr(port, seq->array[i], stack, tls,
                          depth, letlimit, delta, 
                          num_toplevels, num_stxes, num_lifts,
-                         NULL, 0);
+                         NULL, 0, i > 0, vc, 0);
   }
 }
 
@@ -4436,6 +4586,24 @@ begin0_resolve(Scheme_Object *obj, Resolve_Info *info)
   return scheme_make_syntax_resolved(BEGIN0_EXPD, obj);
 }
 
+static Scheme_Object *
+begin0_sfs(Scheme_Object *obj, SFS_Info *info)
+{
+  int i, cnt;
+  
+  cnt = ((Scheme_Sequence *)obj)->count;
+
+  scheme_sfs_start_sequence(info, cnt, 0);
+
+  for (i = 0; i < cnt; i++) {
+    Scheme_Object *le;
+    le = scheme_sfs_expr(((Scheme_Sequence *)obj)->array[i], info, -1);
+    ((Scheme_Sequence *)obj)->array[i] = le;
+  }
+
+  return obj;
+}
+
 static Scheme_Object *
 do_begin_syntax(char *name,
 		Scheme_Object *form, Scheme_Comp_Env *env, Scheme_Compile_Info *rec, int drec, 
@@ -4659,6 +4827,17 @@ splice_resolve(Scheme_Object *data, Resolve_Info *rslv)
                                      scheme_resolve_expr(data, rslv));
 }
 
+static Scheme_Object *
+splice_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  Scheme_Object *naya;
+  naya = scheme_sfs_expr(data, info, -1);
+  if (SAME_OBJ(naya, data))
+    return data;
+  else
+    return scheme_make_syntax_resolved(SPLICE_EXPD, data);
+}
+
 static Scheme_Object *
 splice_shift(Scheme_Object *data, int delta, int after_depth)
 {
@@ -4677,12 +4856,13 @@ splice_clone(int dup_ok, Scheme_Object *data, Optimize_Info *info, int delta, in
 static void splice_validate(Scheme_Object *data, Mz_CPort *port, 
                             char *stack, Validate_TLS tls,
                             int depth, int letlimit, int delta, 
-                            int num_toplevels, int num_stxes, int num_lifts)
+                            int num_toplevels, int num_stxes, int num_lifts,
+                            struct Validate_Clearing *vc, int tailpos)
 {
   scheme_validate_expr(port, data, stack, tls,
                        depth, letlimit, delta, 
                        num_toplevels, num_stxes, num_lifts,
-                       NULL, 0);
+                       NULL, 0, 0, vc, 0);
 }
 
 /**********************************************************************/
@@ -4965,7 +5145,8 @@ static void do_define_syntaxes_validate(Scheme_Object *data, Mz_CPort *port,
 static void define_syntaxes_validate(Scheme_Object *data, Mz_CPort *port, 
 				     char *stack, Validate_TLS tls,
                                      int depth, int letlimit, int delta, 
-				     int num_toplevels, int num_stxes, int num_lifts)
+				     int num_toplevels, int num_stxes, int num_lifts,
+                                     struct Validate_Clearing *vc, int tailpos)
 {
   do_define_syntaxes_validate(data, port, stack, tls, depth, letlimit, delta, 
                               num_toplevels, num_stxes, num_lifts, 0);
@@ -4974,7 +5155,8 @@ static void define_syntaxes_validate(Scheme_Object *data, Mz_CPort *port,
 static void define_for_syntaxes_validate(Scheme_Object *data, Mz_CPort *port, 
 					 char *stack, Validate_TLS tls,
                                          int depth, int letlimit, int delta, 
-					 int num_toplevels, int num_stxes, int num_lifts)
+					 int num_toplevels, int num_stxes, int num_lifts,
+                                         struct Validate_Clearing *vc, int tailpos)
 {
   do_define_syntaxes_validate(data, port, stack, tls, depth, letlimit, delta, 
                               num_toplevels, num_stxes, num_lifts, 1);
@@ -5071,6 +5253,31 @@ static Scheme_Object *define_for_syntaxes_resolve(Scheme_Object *data, Resolve_I
   return do_define_syntaxes_resolve(data, info, 1);
 }
 
+static Scheme_Object *do_define_syntaxes_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  Scheme_Object *e;
+
+  if (!info->pass) {
+    int depth;
+    depth = SCHEME_INT_VAL(SCHEME_VEC_ELS(data)[2]);
+    info = scheme_new_sfs_info(depth);
+    e = scheme_sfs(SCHEME_VEC_ELS(data)[0], info, depth);
+    SCHEME_VEC_ELS(data)[0] = e;
+  }
+
+  return data;
+}
+
+static Scheme_Object *define_syntaxes_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  return do_define_syntaxes_sfs(data, info);
+}
+
+static Scheme_Object *define_for_syntaxes_sfs(Scheme_Object *data, SFS_Info *info)
+{
+  return do_define_syntaxes_sfs(data, info);
+}
+
 static Scheme_Object *stx_val(Scheme_Object *name, Scheme_Object *_env)
 {
   Scheme_Env *env = (Scheme_Env *)_env;
diff --git a/src/mzscheme/src/vector.c b/src/mzscheme/src/vector.c
index 75e89db5d9..1218f0ff71 100644
--- a/src/mzscheme/src/vector.c
+++ b/src/mzscheme/src/vector.c
@@ -34,6 +34,7 @@ static Scheme_Object *vector_length (int argc, Scheme_Object *argv[]);
 static Scheme_Object *vector_to_list (int argc, Scheme_Object *argv[]);
 static Scheme_Object *list_to_vector (int argc, Scheme_Object *argv[]);
 static Scheme_Object *vector_fill (int argc, Scheme_Object *argv[]);
+static Scheme_Object *vector_copy_bang(int argc, Scheme_Object *argv[]);
 static Scheme_Object *vector_to_immutable (int argc, Scheme_Object *argv[]);
 static Scheme_Object *vector_to_values (int argc, Scheme_Object *argv[]);
 
@@ -55,17 +56,17 @@ scheme_init_vector (Scheme_Env *env)
   scheme_add_global_constant("vector?", p, env);
 
   scheme_add_global_constant("make-vector", 
-			     scheme_make_noncm_prim(make_vector, 
+			     scheme_make_immed_prim(make_vector, 
 						    "make-vector", 
 						    1, 2), 
 			     env);
   scheme_add_global_constant("vector", 
-			     scheme_make_noncm_prim(vector, 
+			     scheme_make_immed_prim(vector, 
 						    "vector", 
 						    0, -1), 
 			     env);
   scheme_add_global_constant("vector-immutable", 
-			     scheme_make_noncm_prim(vector_immutable, 
+			     scheme_make_immed_prim(vector_immutable, 
 						    "vector-immutable", 
 						    0, -1), 
 			     env);
@@ -75,35 +76,40 @@ scheme_init_vector (Scheme_Env *env)
 						      1, 1, 1), 
 			     env);
 
-  p = scheme_make_noncm_prim(scheme_checked_vector_ref, 
+  p = scheme_make_immed_prim(scheme_checked_vector_ref, 
 			     "vector-ref", 
 			     2, 2);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_BINARY_INLINED;
   scheme_add_global_constant("vector-ref", p, env);
 
-  p = scheme_make_noncm_prim(scheme_checked_vector_set,
+  p = scheme_make_immed_prim(scheme_checked_vector_set,
 			     "vector-set!", 
 			     3, 3);
   SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_MIN_NARY_INLINED;
   scheme_add_global_constant("vector-set!", p, env);
 
   scheme_add_global_constant("vector->list", 
-			     scheme_make_noncm_prim(vector_to_list, 
+			     scheme_make_immed_prim(vector_to_list, 
 						    "vector->list", 
 						    1, 1), 
 			     env);
   scheme_add_global_constant("list->vector", 
-			     scheme_make_noncm_prim(list_to_vector, 
+			     scheme_make_immed_prim(list_to_vector, 
 						    "list->vector", 
 						    1, 1), 
 			     env);
   scheme_add_global_constant("vector-fill!", 
-			     scheme_make_noncm_prim(vector_fill, 
+			     scheme_make_immed_prim(vector_fill, 
 						    "vector-fill!", 
 						    2, 2), 
 			     env);
+  scheme_add_global_constant("vector-copy!", 
+			     scheme_make_immed_prim(vector_copy_bang, 
+						    "vector-copy!", 
+						    3, 5), 
+			     env);
   scheme_add_global_constant("vector->immutable-vector", 
-			     scheme_make_noncm_prim(vector_to_immutable, 
+			     scheme_make_immed_prim(vector_to_immutable, 
 						    "vector->immutable-vector", 
 						    1, 1), 
 			     env);
@@ -356,6 +362,42 @@ vector_fill (int argc, Scheme_Object *argv[])
   return argv[0];
 }
 
+static Scheme_Object *vector_copy_bang(int argc, Scheme_Object *argv[])
+{
+  Scheme_Object *s1, *s2;
+  long istart, ifinish;
+  long ostart, ofinish;
+
+  s1 = argv[0];
+  if (!SCHEME_MUTABLE_VECTORP(s1))
+    scheme_wrong_type("vector-copy!", "mutable vector", 0, argc, argv);
+
+  scheme_do_get_substring_indices("vector-copy!", s1, 
+                                  argc, argv, 1, 5, 
+                                  &ostart, &ofinish, SCHEME_VEC_SIZE(s1));
+
+  s2 = argv[2];
+  if (!SCHEME_VECTORP(s2))
+    scheme_wrong_type("vector-copy!", "vector", 2, argc, argv);
+
+  scheme_do_get_substring_indices("vector-copy!", s2, 
+                                  argc, argv, 3, 4, 
+                                  &istart, &ifinish, SCHEME_VEC_SIZE(s2));
+
+  if ((ofinish - ostart) < (ifinish - istart)) {
+    scheme_arg_mismatch("vector-copy!",
+			"not enough room in target vector: ",
+			argv[2]);
+    return NULL;
+  }
+
+  memmove(SCHEME_VEC_ELS(s1) + ostart,
+	  SCHEME_VEC_ELS(s2) + istart,
+	  (ifinish - istart) * sizeof(Scheme_Object*));
+  
+  return scheme_void;
+}
+
 static Scheme_Object *vector_to_immutable (int argc, Scheme_Object *argv[])
 {
   Scheme_Object *vec, *ovec;