Merge branch 'master' into strip

original commit: 185e989fcba29be4114c0ea3d8e9e680140d1d4a
2017-05-29 20:24:56 -04:00 · 2017-05-29 20:24:56 -04:00 · 2f58873a96
commit 2f58873a96
parent bd922055d8 2bc65b5d6d
31 changed files with 822 additions and 219 deletions
--- a/18
+++ b/18
@ -456,6 +456,24 @@
 - fix overflow detection for fxsll, fxarithmetic-shift-left, and
  fxarithmetic-shift
    library.ss, fx.ms, release_notes.stex
+- added ephemeron pairs and changed weak hashtables to use
+  ephemeron pairs for key--value mapping to avoid the key-in-value
+  problem
+    prims.ss, primdata.ss, newhash.ss, fasl.ss, mkheader.ss
+    cmacro.ss, prim5.c, fasl.c, gc.c, gcwrapper.c, types.h,
+    4.ms, hash.ms, objects.stex, smgmt.stex, csug.bib
+- check_dirty_ephemeron now puts ephemerons whose keys haven't yet
+  been seen on the pending list rather than the trigger lists.
+    gc.c
+- removed scan of space_ephemeron from check_heap because check_heap
+  as written can't handle the two link fields properly.
+    gcwrapper.c
+- in the ephemerons mat that checks interaction between mutation and
+  collection, added generation arguments to the first two collect
+  calls so they always collect into the intended generation.
+    4.ms
+- updated allx and bullyx patches
+    patch*
 - fix strip-fasl-file for immutable strings and vectors,
  fix an $oops call, and fix a vector-index increment in hashing
    strip.ss, 7.ss, newhash.ss, misc.ms
--- a/c/fasl.c
+++ b/c/fasl.c
@ -860,6 +860,11 @@ static void faslin(ptr tc, ptr *x, ptr t, ptr *pstrbuf, faslFile f) {
            faslin(tc, &INITCAR(*x), t, pstrbuf, f);
            faslin(tc, &INITCDR(*x), t, pstrbuf, f);
            return;
+        case fasl_type_ephemeron:
+            *x = S_cons_in(space_ephemeron, 0, FIX(0), FIX(0));
+            faslin(tc, &INITCAR(*x), t, pstrbuf, f);
+            faslin(tc, &INITCDR(*x), t, pstrbuf, f);
+            return;
        case fasl_type_code: {
            iptr n, m, a; INT flags; iptr free;
            ptr co, reloc, name;
--- a/c/gc.c
+++ b/c/gc.c
@ -29,7 +29,7 @@ static uptr list_length PROTO((ptr ls));
 static ptr dosort PROTO((ptr ls, uptr n));
 static ptr domerge PROTO((ptr l1, ptr l2));
 static IBOOL search_locked PROTO((ptr p));
-static ptr copy PROTO((ptr pp, ISPC pps));
+static ptr copy PROTO((ptr pp, seginfo *si));
 static void sweep_ptrs PROTO((ptr *p, iptr n));
 static void sweep PROTO((ptr tc, ptr p, IBOOL sweep_pure));
 static ptr copy_stack PROTO((ptr old, iptr *length, iptr clength));
@ -49,6 +49,13 @@ static void sweep_code_object PROTO((ptr tc, ptr co));
 static void record_dirty_segment PROTO((IGEN from_g, IGEN to_g, seginfo *si));
 static void sweep_dirty PROTO((void));
 static void resweep_dirty_weak_pairs PROTO((void));
+static void add_ephemeron_to_pending PROTO((ptr p));
+static void add_trigger_ephemerons_to_repending PROTO((ptr p));
+static void check_trigger_ephemerons PROTO((seginfo *si));
+static void check_ephemeron PROTO((ptr pe, int add_to_trigger));
+static void check_pending_ephemerons PROTO(());
+static int check_dirty_ephemeron PROTO((ptr pe, int tg, int youngest));
+static void clear_trigger_ephemerons PROTO(());

 /* MAXPTR is used to pad the sorted_locked_object vector.  The pad value must be greater than any heap address */
 #define MAXPTR ((ptr)-1)
@ -111,10 +118,10 @@ uptr list_length(ptr ls) {
 *   youngest = GENERATION(*ppp);
 */
 #define relocate_dirty(ppp,tg,youngest) {\
-  ptr PP = *ppp; seginfo *SI; ISPC S;\
+  ptr PP = *ppp; seginfo *SI;\
  if (!IMMEDIATE(PP) && (SI = MaybeSegInfo(ptr_get_segment(PP))) != NULL) {\
-    if ((S = SI->space) & space_old) {\
-      relocate_help_help(ppp, PP, S)\
+    if (SI->space & space_old) {\
+      relocate_help_help(ppp, PP, SI)\
      youngest = tg;\
    } else {\
      IGEN pg;\
@ -126,38 +133,38 @@ uptr list_length(ptr ls) {
 }

 #define relocate_help(ppp, pp) {\
-  seginfo *SI; ISPC S;\
-  if (!IMMEDIATE(pp) && (SI = MaybeSegInfo(ptr_get_segment(pp))) != NULL && (S = SI->space) & space_old)\
-    relocate_help_help(ppp, pp, S)\
+  seginfo *SI; \
+  if (!IMMEDIATE(pp) && (SI = MaybeSegInfo(ptr_get_segment(pp))) != NULL && SI->space & space_old)\
+    relocate_help_help(ppp, pp, SI)\
 }

-#define relocate_help_help(ppp, pp, s) {\
+#define relocate_help_help(ppp, pp, si) {\
  if (FWDMARKER(pp) == forward_marker && TYPEBITS(pp) != type_flonum)\
    *ppp = FWDADDRESS(pp);\
  else\
-    *ppp = copy(pp, s);\
+    *ppp = copy(pp, si);\
 }

 #define relocate_return_addr(pcp) {\
-    ISPC S;\
+    seginfo *SI;\
    ptr XCP;\
    XCP = *(pcp);\
-    if ((S = SPACE(XCP)) & space_old) {\
+    if ((SI = SegInfo(ptr_get_segment(XCP)))->space & space_old) {      \
        iptr CO;\
        CO = ENTRYOFFSET(XCP) + ((uptr)XCP - (uptr)&ENTRYOFFSET(XCP));\
-        relocate_code(pcp,XCP,CO,S)\
+        relocate_code(pcp,XCP,CO,SI)\
    }\
 }

 /* in the call to copy below, assuming SPACE(PP) == SPACE(XCP) since
   PP and XCP point to/into the same object */
-#define relocate_code(pcp,XCP,CO,S) {\
+#define relocate_code(pcp,XCP,CO,SI) {\
    ptr PP;\
    PP = (ptr)((uptr)XCP - CO);\
    if (FWDMARKER(PP) == forward_marker)\
        PP = FWDADDRESS(PP);\
    else\
-        PP = copy(PP, S);\
+        PP = copy(PP, SI);\
    *pcp = (ptr)((uptr)PP + CO);\
 }

@ -185,7 +192,19 @@ static IBOOL search_locked(ptr p) {

 #define locked(p) (sorted_locked_objects != FIX(0) && search_locked(p))

-static ptr copy(pp, pps) ptr pp; ISPC pps; {
+FORCEINLINE void check_trigger_ephemerons(seginfo *si) {
+  /* Registering ephemerons to recheck at the granularity of a segment
+     means that the worst-case complexity of GC is quadratic in the
+     number of objects that fit into a segment (but that only happens
+     if the objects are ephemeron keys that are reachable just through
+     a chain via the value field of the same ephemerons). */
+  if (si->trigger_ephemerons) {
+    add_trigger_ephemerons_to_repending(si->trigger_ephemerons);
+    si->trigger_ephemerons = NULL;
+  }
+}
+
+static ptr copy(pp, si) ptr pp; seginfo *si; {
    ptr p, tf; ITYPE t; IGEN tg;

    if (locked(pp)) return pp;
@ -194,6 +213,8 @@ static ptr copy(pp, pps) ptr pp; ISPC pps; {

    change = 1;

+    check_trigger_ephemerons(si);
+
    if ((t = TYPEBITS(pp)) == type_typed_object) {
      tf = TYPEFIELD(pp);
      if (TYPEP(tf, mask_record, type_record)) {
@ -418,9 +439,18 @@ static ptr copy(pp, pps) ptr pp; ISPC pps; {
          return (ptr)0 /* not reached */;
      }
    } else if (t == type_pair) {
-        ptr qq = Scdr(pp); ptr q; seginfo *si;
-        if (qq != pp && TYPEBITS(qq) == type_pair && (si = MaybeSegInfo(ptr_get_segment(qq))) != NULL && si->space == pps && FWDMARKER(qq) != forward_marker && !locked(qq)) {
-          if (pps == (space_weakpair | space_old)) {
+      if (si->space == (space_ephemeron | space_old)) {
+#ifdef ENABLE_OBJECT_COUNTS
+        S_G.countof[tg][countof_ephemeron] += 1;
+#endif /* ENABLE_OBJECT_COUNTS */
+        find_room(space_ephemeron, tg, type_pair, size_ephemeron, p);
+        INITCAR(p) = Scar(pp);
+        INITCDR(p) = Scdr(pp);
+      } else {
+        ptr qq = Scdr(pp); ptr q; seginfo *qsi;
+        if (qq != pp && TYPEBITS(qq) == type_pair && (qsi = MaybeSegInfo(ptr_get_segment(qq))) != NULL && qsi->space == si->space && FWDMARKER(qq) != forward_marker && !locked(qq)) {
+          check_trigger_ephemerons(qsi);
+          if (si->space == (space_weakpair | space_old)) {
 #ifdef ENABLE_OBJECT_COUNTS
            S_G.countof[tg][countof_weakpair] += 2;
 #endif /* ENABLE_OBJECT_COUNTS */
@ -439,7 +469,7 @@ static ptr copy(pp, pps) ptr pp; ISPC pps; {
          FWDMARKER(qq) = forward_marker;
          FWDADDRESS(qq) = q;
        } else {
-          if (pps == (space_weakpair | space_old)) {
+          if (si->space == (space_weakpair | space_old)) {
 #ifdef ENABLE_OBJECT_COUNTS
            S_G.countof[tg][countof_weakpair] += 1;
 #endif /* ENABLE_OBJECT_COUNTS */
@ -453,6 +483,7 @@ static ptr copy(pp, pps) ptr pp; ISPC pps; {
          INITCAR(p) = Scar(pp);
          INITCDR(p) = qq;
        }
+      }
    } else if (t == type_closure) {
        ptr code;

@ -533,10 +564,15 @@ static void sweep(ptr tc, ptr p, IBOOL sweep_pure) {
  ptr tf; ITYPE t;

  if ((t = TYPEBITS(p)) == type_pair) {
-    if ((SPACE(p) & ~(space_locked | space_old)) != space_weakpair) {
-      relocate(&INITCAR(p))
+    ISPC s = SPACE(p) & ~(space_locked | space_old);
+    if (s == space_ephemeron)
+      add_ephemeron_to_pending(p);
+    else {
+      if (s != space_weakpair) {
+        relocate(&INITCAR(p))
+      }
+      relocate(&INITCDR(p))
    }
-    relocate(&INITCDR(p))
  } else if (t == type_closure) {
    if (sweep_pure) {
      ptr code;
@ -827,7 +863,7 @@ void GCENTRY(ptr tc, IGEN mcg, IGEN tg) {
        if (FWDMARKER(sym) != forward_marker &&
            /* coordinate with alloc.c */
            (SYMVAL(sym) != sunbound || SYMPLIST(sym) != Snil || SYMSPLIST(sym) != Snil))
-          (void)copy(sym, SPACE(sym));
+          (void)copy(sym, SegInfo(ptr_get_segment(sym)));
      }
      S_G.buckets_of_generation[g] = NULL;
    }
@ -959,6 +995,9 @@ void GCENTRY(ptr tc, IGEN mcg, IGEN tg) {
    resweep_dirty_weak_pairs();
    resweep_weak_pairs(tg);

+   /* still-pending ephemerons all go to bwp */
+    clear_trigger_ephemerons();
+
   /* forward car fields of locked and unlocked older weak pairs */
    for (g = mcg + 1; g <= static_generation; INCRGEN(g)) {
      for (ls = S_G.locked_objects[g]; ls != Snil; ls = Scdr(ls)) {
@ -1262,6 +1301,12 @@ static void sweep_generation(tc, g) ptr tc; IGEN g; {
        pp += 1;
    })

+    sweep_space(space_ephemeron, {
+        p = TYPE((ptr)pp, type_pair);
+        add_ephemeron_to_pending(p);
+        pp += size_ephemeron / sizeof(ptr);
+    })
+      
    sweep_space(space_pure, {
        relocate_help(pp, p)
        p = *(pp += 1);
@ -1292,6 +1337,13 @@ static void sweep_generation(tc, g) ptr tc; IGEN g; {
        pp = (ptr *)((iptr)pp +
               size_record_inst(UNFIX(RECORDDESCSIZE(RECORDINSTTYPE(p)))));
    })
+
+    /* Waiting until sweeping doesn't trigger a change reduces the
+       chance that an ephemeron must be reigistered as a
+       segment-specific trigger or gets triggered for recheck, but
+       it doesn't change the worst-case complexity. */
+    if (!change)
+      check_pending_ephemerons();
  } while (change);
 }

@ -1299,7 +1351,11 @@ static iptr size_object(p) ptr p; {
    ITYPE t; ptr tf;

    if ((t = TYPEBITS(p)) == type_pair) {
-        return size_pair;
+        seginfo *si;
+        if ((si = MaybeSegInfo(ptr_get_segment(p))) != NULL && (si->space & ~(space_locked | space_old)) == space_ephemeron)
+            return size_ephemeron;
+        else
+            return size_pair;
    } else if (t == type_closure) {
        ptr code = CLOSCODE(p);
        if (CODETYPE(code) & (code_flag_continuation << code_flags_offset))
@ -1873,6 +1929,12 @@ static void sweep_dirty(void) {
                    relocate_dirty(pp, tg, youngest)
                    pp += 1;
                  }
+                } else if (s == space_ephemeron) {
+                  while (pp < ppend && *pp != forward_marker) {
+                    ptr p = TYPE((ptr)pp, type_pair);
+                    youngest = check_dirty_ephemeron(p, tg, youngest);
+                    pp += size_ephemeron / sizeof(ptr);
+                  }
                } else {
                  S_error_abort("sweep_dirty(gc): unexpected space");
                }
@ -1965,3 +2027,149 @@ static void resweep_dirty_weak_pairs() {
    record_dirty_segment(from_g, min_youngest, dirty_si);
  }
 }
+
+static ptr pending_ephemerons = NULL;
+/* Ephemerons that we haven't looked at, chained through `next`. */
+
+static ptr trigger_ephemerons = NULL;
+/* Ephemerons that we've checked and added to segment triggers,
+   chained through `next`. Ephemerons attached to a segment are
+   chained through `trigger-next`. A #t in `trigger-next` means that
+   the ephemeron has been processed, so we don't need to remove it
+   from the trigger list in a segment. */
+
+static ptr repending_ephemerons = NULL;
+/* Ephemerons in `trigger_ephemerons` that we need to inspect again,
+   removed from the triggering segment and chained here through
+   `trigger-next`. */
+
+static void add_ephemeron_to_pending(ptr pe) {
+  /* We could call check_ephemeron directly here, but the indirection
+     through `pending_ephemerons` can dramatically decrease the number
+     of times that we have to trigger re-checking, especially since
+     check_pending_pehemerons() is run only after all other sweep
+     opportunities are exhausted. */
+  EPHEMERONNEXT(pe) = pending_ephemerons;
+  pending_ephemerons = pe;
+}
+
+static void add_trigger_ephemerons_to_repending(ptr pe) {
+  ptr last_pe = pe, next_pe = EPHEMERONTRIGGERNEXT(pe);
+  while (next_pe != NULL) {
+    last_pe = next_pe;
+    next_pe = EPHEMERONTRIGGERNEXT(next_pe);
+  }
+  EPHEMERONTRIGGERNEXT(last_pe) = repending_ephemerons;
+  repending_ephemerons = pe;
+}
+
+static void check_ephemeron(ptr pe, int add_to_trigger) {
+  ptr p;
+  seginfo *si;
+
+  p = Scar(pe);
+  if (!IMMEDIATE(p) && (si = MaybeSegInfo(ptr_get_segment(p))) != NULL && si->space & space_old && !locked(p)) {
+    if (FWDMARKER(p) == forward_marker && TYPEBITS(p) != type_flonum) {
+      INITCAR(pe) = FWDADDRESS(p);
+      relocate(&INITCDR(pe))
+      if (!add_to_trigger)
+        EPHEMERONTRIGGERNEXT(pe) = Strue; /* in trigger list, #t means "done" */
+    } else {
+      /* Not reached, so far; install as trigger */
+      EPHEMERONTRIGGERNEXT(pe) = si->trigger_ephemerons;
+      si->trigger_ephemerons = pe;
+      if (add_to_trigger) {
+        EPHEMERONNEXT(pe) = trigger_ephemerons;
+        trigger_ephemerons = pe;
+      }
+    }
+  } else {
+    relocate(&INITCDR(pe))
+  }
+}
+
+static void check_pending_ephemerons() {
+  ptr pe, next_pe;
+
+  pe = pending_ephemerons;
+  pending_ephemerons = NULL;
+  while (pe != NULL) {
+    next_pe = EPHEMERONNEXT(pe);
+    check_ephemeron(pe, 1);
+    pe = next_pe;
+  }
+
+  pe = repending_ephemerons;
+  repending_ephemerons = NULL;
+  while (pe != NULL) {
+    next_pe = EPHEMERONTRIGGERNEXT(pe);
+    check_ephemeron(pe, 0);
+    pe = next_pe;
+  }
+}
+
+/* Like check_ephemeron(), but for a dirty, old-generation
+   ephemeron (that was not yet added to the pending list), so we can
+   be less pessimistic than setting `youngest` to the target
+   generation: */
+static int check_dirty_ephemeron(ptr pe, int tg, int youngest) {
+  ptr p;
+  seginfo *si;
+
+  p = Scar(pe);
+  if (!IMMEDIATE(p) && (si = MaybeSegInfo(ptr_get_segment(p))) != NULL) {
+    if (si->space & space_old && !locked(p)) {
+      if (FWDMARKER(p) == forward_marker && TYPEBITS(p) != type_flonum) {
+        INITCAR(pe) = FWDADDRESS(p);
+        relocate(&INITCDR(pe))
+        youngest = tg;
+      } else {
+        /* Not reached, so far; add to pending list */
+	add_ephemeron_to_pending(pe);
+        /* Make the consistent (but pessimistic w.r.t. to wrong-way
+           pointers) assumption that the key will stay live and move
+           to the target generation. That assumption covers the value
+           part, too, since it can't end up younger than the target
+           generation. */
+        youngest = tg;
+      }
+    } else {
+      int pg;
+      if ((pg = si->generation) < youngest)
+        youngest = pg;
+      relocate_dirty(&INITCDR(pe), tg, youngest)
+    }
+  } else {
+    /* Non-collectable key means that the value determines
+       `youngest`: */
+    relocate_dirty(&INITCDR(pe), tg, youngest)
+  }
+
+  return youngest;
+}
+
+static void clear_trigger_ephemerons() {
+  ptr pe;
+
+  if (pending_ephemerons != NULL)
+    S_error_abort("clear_trigger_ephemerons(gc): non-empty pending list");
+
+  pe = trigger_ephemerons;
+  trigger_ephemerons = NULL;
+  while (pe != NULL) {
+    if (EPHEMERONTRIGGERNEXT(pe) == Strue) {
+      /* The ephemeron was triggered and retains its key and value */
+    } else {
+      seginfo *si;
+      ptr p = Scar(pe);
+      /* Key never became reachable, so clear key and value */
+      INITCAR(pe) = Sbwp_object;
+      INITCDR(pe) = Sbwp_object;
+
+      /* Remove trigger */
+      si = SegInfo(ptr_get_segment(p));
+      si->trigger_ephemerons = NULL;
+    }
+    pe = EPHEMERONNEXT(pe);
+  }
+}
--- a/c/gcwrapper.c
+++ b/c/gcwrapper.c
@ -128,6 +128,8 @@ void S_gc_init() {
    S_G.countof_size[countof_guardian] = size_guardian_entry;
  INITVECTIT(S_G.countof_names, countof_oblist) = S_intern((const unsigned char *)"oblist");
    S_G.countof_size[countof_guardian] = 0;
+  INITVECTIT(S_G.countof_names, countof_ephemeron) = S_intern((const unsigned char *)"ephemron");
+    S_G.countof_size[countof_ephemeron] = 0;
  for (i = 0; i < countof_types; i += 1) {
    if (Svector_ref(S_G.countof_names, i) == FIX(0)) {
      fprintf(stderr, "uninitialized countof_name at index %d\n", i);
@ -505,7 +507,7 @@ void S_check_heap(aftergc) IBOOL aftergc; {
            S_checkheap_errors += 1;
            printf("!!! unexpected generation %d segment %#tx in space_new\n", g, (ptrdiff_t)seg);
          }
-        } else if (s == space_impure || s == space_symbol || s == space_pure || s == space_weakpair) {
+        } else if (s == space_impure || s == space_symbol || s == space_pure || s == space_weakpair /* || s == space_ephemeron */) {
          /* out of date: doesn't handle space_port, space_continuation, space_code, space_pure_typed_object, space_impure_record */
          nl = (ptr *)S_G.next_loc[s][g];

@ -530,7 +532,7 @@ void S_check_heap(aftergc) IBOOL aftergc; {
          /* verify that dirty bits are set appropriately */
          /* out of date: doesn't handle space_impure_record, space_port, and maybe others */
          /* also doesn't check the SYMCODE for symbols */
-          if (s == space_impure || s == space_symbol || s == space_weakpair) {
+          if (s == space_impure || s == space_symbol || s == space_weakpair /* || s == space_ephemeron */) {
            found_eos = 0;
            pp2 = pp1 = build_ptr(seg, 0);
            for (d = 0; d < cards_per_segment; d += 1) {
@ -588,7 +590,7 @@ void S_check_heap(aftergc) IBOOL aftergc; {
            }
          }
        }
-        if (aftergc && s != space_empty && !(s & space_locked) && (g == 0 || (s != space_impure && s != space_symbol && s != space_port && s != space_weakpair && s != space_impure_record))) {
+        if (aftergc && s != space_empty && !(s & space_locked) && (g == 0 || (s != space_impure && s != space_symbol && s != space_port && s != space_weakpair && s != space_ephemeron && s != space_impure_record))) {
          for (d = 0; d < cards_per_segment; d += 1) {
            if (si->dirty_bytes[d] != 0xff) {
              S_checkheap_errors += 1;
@ -669,7 +671,7 @@ static void check_dirty() {
            S_checkheap_errors += 1;
            printf("!!! (check_dirty): dirty byte = %d for segment %#tx in %d -> %d dirty list\n", mingval, (ptrdiff_t)(si->number), from_g, to_g);
          }
-          if (s != space_new && s != space_impure && s != space_symbol && s != space_port && s != space_impure_record && s != space_weakpair) {
+          if (s != space_new && s != space_impure && s != space_symbol && s != space_port && s != space_impure_record && s != space_weakpair && s != space_ephemeron) {
            S_checkheap_errors += 1;
            printf("!!! (check_dirty): unexpected space %d for dirty segment %#tx\n", s, (ptrdiff_t)(si->number));
          }
@ -684,6 +686,7 @@ static void check_dirty() {
  check_dirty_space(space_port);
  check_dirty_space(space_impure_record);
  check_dirty_space(space_weakpair);
+  check_dirty_space(space_ephemeron);

  fflush(stdout);
 }
--- a/c/prim5.c
+++ b/c/prim5.c
@ -34,6 +34,8 @@ static ptr s_trunc_rem PROTO((ptr x, ptr y));
 static ptr s_fltofx PROTO((ptr x));
 static ptr s_weak_cons PROTO((ptr car, ptr cdr));
 static ptr s_weak_pairp PROTO((ptr p));
+static ptr s_ephemeron_cons PROTO((ptr car, ptr cdr));
+static ptr s_ephemeron_pairp PROTO((ptr p));
 static ptr s_oblist PROTO((void));
 static ptr s_bigoddp PROTO((ptr n));
 static ptr s_float PROTO((ptr x));
@ -176,6 +178,20 @@ static ptr s_weak_pairp(p) ptr p; {
  return Spairp(p) && (si = MaybeSegInfo(ptr_get_segment(p))) != NULL && (si->space & ~space_locked) == space_weakpair ? Strue : Sfalse;
 }

+static ptr s_ephemeron_cons(car, cdr) ptr car, cdr; {
+  ptr p;
+
+  tc_mutex_acquire()
+  p = S_cons_in(space_ephemeron, 0, car, cdr);
+  tc_mutex_release()
+  return p;
+}
+
+static ptr s_ephemeron_pairp(p) ptr p; {
+  seginfo *si;
+  return Spairp(p) && (si = MaybeSegInfo(ptr_get_segment(p))) != NULL && (si->space & ~space_locked) == space_ephemeron ? Strue : Sfalse;
+}
+
 static ptr s_oblist() {
  ptr ls = Snil;
  iptr idx = S_G.oblist_length;
@ -1465,6 +1481,8 @@ void S_prim5_init() {
    Sforeign_symbol("(cs)s_fltofx", (void *)s_fltofx);
    Sforeign_symbol("(cs)s_weak_cons", (void *)s_weak_cons);
    Sforeign_symbol("(cs)s_weak_pairp", (void *)s_weak_pairp);
+    Sforeign_symbol("(cs)s_ephemeron_cons", (void *)s_ephemeron_cons);
+    Sforeign_symbol("(cs)s_ephemeron_pairp", (void *)s_ephemeron_pairp);
    Sforeign_symbol("(cs)continuation_depth", (void *)S_continuation_depth);
    Sforeign_symbol("(cs)single_continuation", (void *)S_single_continuation);
    Sforeign_symbol("(cs)c_exit", (void *)c_exit);
--- a/c/types.h
+++ b/c/types.h
@ -125,6 +125,7 @@ typedef struct _seginfo {
  struct _seginfo *next;                    /* pointer to the next seginfo (used in occupied_segments and unused_segs */
  struct _seginfo **dirty_prev;             /* pointer to the next pointer on the previous seginfo in the DirtySegments list */
  struct _seginfo *dirty_next;              /* pointer to the next seginfo on the DirtySegments list */
+  ptr trigger_ephemerons;                   /* ephemerons to re-check if object in segment is copied out */
  octet dirty_bytes[cards_per_segment];     /* one dirty byte per card */
 } seginfo;

--- a/csug/csug.bib
+++ b/csug/csug.bib
@ -555,3 +555,14 @@ year = 2008}
  address = {Indianapolis, IN, USA},
  school = {Indiana University}
 }
+
+@inproceedings{Hayes:ephemerons,
+   author = {Barry Hayes},
+   title = {Ephemerons: a New Finalization Mechanism},
+   booktitle = {\it Proceedings of the 12th ACM SIGPLAN
+        Conference on Object-Oriented Languages, Programming, Systems,
+        and Applications},
+   pages = {176--183},
+   url = {https://doi.org/10.1145/263700.263733},
+   year = {1997}
+}
--- a/csug/objects.stex
+++ b/csug/objects.stex
@ -1820,7 +1820,9 @@ except the keys of the hashtable are held weakly, i.e., they are not
 protected from the garbage collector.
 Keys reclaimed by the garbage collector are removed from the table,
 and their associated values are dropped the next time the table
-is modified, if not sooner.
+is modified, if not sooner. A value in the hashtable can refer to a
+key in the hashtable without preventing the garbage collector from
+reclaiming the key (because keys are paired values using ephemeron pairs).

 A copy of a weak eq or eqv hashtable created by \scheme{hashtable-copy} is
 also weak.
--- a/csug/smgmt.stex
+++ b/csug/smgmt.stex
@ -309,7 +309,7 @@ memory footprint, while setting it to a larger value may result in fewer
 calls into the operating system to request and free memory space.


-\section{Weak Pairs and Guardians\label{SECTGUARDWEAKPAIRS}}
+\section{Weak Pairs, Ephemeron Pairs, and Guardians\label{SECTGUARDWEAKPAIRS}}

 \index{weak pairs}\index{weak pointers}\emph{Weak pairs} allow programs
 to maintain \emph{weak pointers} to objects.
@ -317,21 +317,30 @@ A weak pointer to an object does not prevent the object from being
 reclaimed by the storage management system, but it does remain valid as
 long as the object is otherwise accessible in the system.

+\index{ephemeron pairs}\emph{Ephemeron pairs} are like weak pairs, but
+ephemeron pairs combine two pointers where the second is retained only
+as long as the first is retained.
+
 \index{guardians}\emph{Guardians}
 allow programs to protect objects from deallocation
 by the garbage collector and to determine when the objects would
 otherwise have been deallocated.

-Weak pairs and guardians allow programs to retain
+Weak pairs, ephemeron pairs, and guardians allow programs to retain
 information about objects in separate data structures (such as hash
 tables) without concern that maintaining this information will cause
-the objects to remain indefinitely in the system.
+the objects to remain indefinitely in the system. Ephemeron pairs
+allow such data structures to retain key--value combinations
+where a value may refer to its key, but the combination
+can be reclaimed if neither must be saved otherwise.
 In addition, guardians allow objects to be saved from deallocation
 indefinitely so that they can be reused or so that clean-up or other
 actions can be performed using the data stored within the objects.

 The implementation of guardians and weak pairs used by {\ChezScheme}
-is described in~\cite{Dybvig:guardians}.
+is described in~\cite{Dybvig:guardians}. Ephemerons are described
+in~\cite{Hayes:ephemerons}, but the implementation in {\ChezScheme}
+avoids quadratic-time worst-case behavior.

 %----------------------------------------------------------------------------
 \entryheader\label{desc:weak-cons}
@ -417,6 +426,89 @@ dropped, but makes no guarantees about when this will occur.
 \endschemedisplay


+%----------------------------------------------------------------------------
+\entryheader\label{desc:ephemeron-cons}
+\formdef{ephemeron-cons}{\categoryprocedure}{(ephemeron-cons \var{obj_1} \var{obj_2})}
+\returns a new ephemeron pair
+\listlibraries
+\endentryheader
+
+\noindent
+\var{obj_1} becomes the car and \var{obj_2} becomes the cdr of the
+new pair.
+Ephemeron pairs are indistinguishable from ordinary pairs in all but two ways:
+
+\begin{itemize}
+\item ephemeron pairs can be distinguished from pairs using the
+\scheme{ephemeron-pair?} predicate, and
+
+\item ephemeron pairs maintain a weak pointer to the object in the
+car of the pair, and the cdr of the pair is preserved only as long
+as the car of the pair is preserved.
+\end{itemize}
+
+\noindent
+
+An ephemeron pair behaves like a weak pair, but the cdr is treated
+specially in addition to the car: the cdr of an ephemeron is set to
+\scheme{#!bwp} at the same time that the car is set to \scheme{#!bwp}.
+Since the car and cdr fields are set to \scheme{#!bwp} at the same
+time, then the fact that the car object may be referenced through the
+cdr object does not by itself imply that car must be preserved (unlike
+a weak pair); instead, the car must be saved for some reason
+independent of the cdr object.
+
+Like weak pairs and other pairs, ephemeron pairs may be altered using
+\scheme{set-car!} and \scheme{set-cdr!}, and ephemeron pairs are
+printed in the same manner as ordinary pairs; there is no reader
+syntax for ephemeron pairs.
+
+\schemedisplay
+(define x (cons 'a 'b))
+(define p (ephemeron-cons x x))
+(car p) ;=> (a . b)
+(cdr p) ;=> (a . b)
+
+(define x (cons 'a 'b))
+(define p (ephemeron-cons x x))
+(set! x '*)
+(collect)
+(car p) ;=> #!bwp
+(cdr p) ;=> #!bwp
+
+(define x (cons 'a 'b))
+(define p (weak-cons x x)) ; \var{not an ephemeron pair}
+(set! x '*)
+(collect)
+(car p) ;=> (a . b)
+(cdr p) ;=> (a . b)
+\endschemedisplay
+
+\noindent
+As with weak pairs, the last two expressions of the middle example
+above may in fact return \scheme{(a . b)} if a garbage collection
+promoting the pair into an older generation occurs prior to the
+assignment of \scheme{x} to \scheme{*}. In the last example above,
+however, the results of the last two expressions will always be
+\scheme{(a . b)}, because the cdr of a weak pair holds a non-weak
+reference, and that non-weak reference prevents the car field from becoming
+\scheme{#!bwp}.
+
+%----------------------------------------------------------------------------
+\entryheader
+\formdef{ephemeron-pair?}{\categoryprocedure}{(ephemeron-pair? \var{obj})}
+\returns \scheme{#t} if obj is a ephemeron pair, \scheme{#f} otherwise
+\listlibraries
+\endentryheader
+
+\schemedisplay
+(ephemeron-pair? (ephemeron-cons 'a 'b)) ;=> #t
+(ephemeron-pair? (cons 'a 'b)) ;=> #f
+(ephemeron-pair? (weak-cons 'a 'b)) ;=> #f
+(ephemeron-pair? "oops") ;=> #f
+\endschemedisplay
+
+
 %----------------------------------------------------------------------------
 \entryheader
 \formdef{bwp-object?}{\categoryprocedure}{(bwp-object? \var{obj})}
@ -473,7 +565,7 @@ subdivided into two disjoint subgroups: a subgroup referred to
 as ``accessible'' objects, and one referred to ``inaccessible'' objects.
 Inaccessible objects are objects that have been proven to be
 inaccessible (except through the guardian mechanism itself or through
-the car field of a weak pair), and
+the car field of a weak or ephemeron pair), and
 accessible objects are objects that have not been proven so.
 The word ``proven'' is important here: it may be that some objects in
 the accessible group are indeed inaccessible but
@ -516,7 +608,7 @@ migrated into an older generation.)

 Although an object registered without a representative and returned from
 a guardian has been proven otherwise
-inaccessible (except possibly via the car field of a weak pair), it has
+inaccessible (except possibly via the car field of a weak or ephemeron pair), it has
 not yet been reclaimed by the storage management system and will not be
 reclaimed until after the last nonweak pointer to it within or outside
 of the guardian system has been dropped.
@ -550,8 +642,8 @@ themselves can be registered with other guardians.

 An object that has been registered with a guardian without a
 representative and placed in
-the car field of a weak pair remains in the car field of the
-weak pair until after it has been returned from the guardian and
+the car field of a weak or ephemeron pair remains in the car field of the
+weak or ephemeron pair until after it has been returned from the guardian and
 dropped by the program or until the guardian itself is dropped.

 \schemedisplay
@ -577,7 +669,7 @@ This can also be forced by invoking \scheme{collect} several times.)

 On the other hand, if a representative (other than the object itself)
 is specified, the guarded object is dropped from the car field of the
-weak pair at the same time as the representative becomes available
+weak or ephemeron pair at the same time as the representative becomes available
 from the guardian.

 \schemedisplay
@ -592,7 +684,7 @@ from the guardian.
 \endschemedisplay

 The following example illustrates that the object is deallocated and
-the car field of the weak pointer set to \scheme{#!bwp} when the guardian
+the car field of the weak pair set to \scheme{#!bwp} when the guardian
 itself is dropped:

 \schemedisplay
--- a/mats/4.ms
+++ b/mats/4.ms
@ -3107,6 +3107,189 @@
                     (bwp-object? (car x))))))
 )

+(mat ephemeron
+   (begin
+     (define ephemeron-key car)
+     (define ephemeron-value cdr)
+     
+     (define gdn (make-guardian))
+     #t)
+
+   (ephemeron-pair? (ephemeron-cons 1 2))
+
+   (begin
+     ;; ----------------------------------------
+     ;; Check that the ephemeron value doesn't retain
+     ;; itself as an epehemeron key
+     (define-values (es wps saved)
+       (let loop ([n 1000] [es '()] [wps '()] [saved '()])
+         (cond
+          [(zero? n)
+           (values es wps saved)]
+          [else
+           (let ([k1 (gensym)]
+                 [k2 (gensym)])
+             (gdn k2)
+             (loop (sub1 n)
+                   (cons (ephemeron-cons k1 (box k1))
+                         (cons (ephemeron-cons k2 (box k2))
+                               es))
+                   (weak-cons k1 (weak-cons k2 wps))
+                   (cons k1 saved)))])))
+     
+     (collect (collect-maximum-generation))
+
+     ;; All now waiting to be reported by the guardian
+     (let loop ([es es] [wps wps] [saved saved])
+       (cond
+        [(null? saved) #t]
+        [else
+         (and
+          (eq? (car saved) (car wps))
+          (eq? (car saved) (ephemeron-key (car es)))
+          (eq? (car saved) (unbox (ephemeron-value (car es))))
+          (eq? (cadr wps) (ephemeron-key (cadr es)))
+          (eq? (cadr wps) (unbox (ephemeron-value (cadr es))))
+          (loop (cddr es) (cddr wps) (cdr saved)))])))
+
+   (begin
+     ;; Report each from the guardian:
+     (let loop ([saved saved])
+       (unless (null? saved)
+         (gdn)
+         (loop (cdr saved))))
+
+     (collect (collect-maximum-generation))
+
+     (let loop ([es es] [wps wps] [saved saved])
+       (cond
+        [(null? saved) #t]
+        [else
+         (and
+          (eq? (car saved) (car wps))
+          (eq? (car saved) (ephemeron-key (car es)))
+          (eq? (car saved) (unbox (ephemeron-value (car es))))
+          (eq? #!bwp (cadr wps))
+          (eq? #!bwp (ephemeron-key (cadr es)))
+          (eq? #!bwp (ephemeron-value (cadr es)))
+          (loop (cddr es) (cddr wps) (cdr saved)))])))
+
+   ;; ----------------------------------------
+   ;; Stress test to check that the GC doesn't suffer from quadratic
+   ;; behavior
+   (begin
+     (define (wrapper v) (list 1 2 3 4 5 v))
+     
+     ;; Create a chain of ephemerons where we have all
+     ;; the the ephemerons immediately in a list,
+     ;; but we discover the keys one at a time
+     (define (mk n prev-key es)
+       (cond
+        [(zero? n)
+         (values prev-key es)]
+        [else
+         (let ([key (gensym)])
+           (mk (sub1 n)
+               key
+               (cons (ephemeron-cons key (wrapper prev-key))
+                     es)))]))
+
+     ;; Create a chain of ephemerons where we have all
+     ;; of the keys immediately in a list,
+     ;; but we discover the ephemerons one at a time
+     (define (mk* n prev-e keys)
+       (cond
+        [(zero? n)
+         (values prev-e keys)]
+        [else
+         (let ([key (gensym)])
+           (mk* (sub1 n)
+                (ephemeron-cons key (wrapper prev-e))
+                (cons key
+                      keys)))]))
+
+     (define (measure-time n keep-alive)
+       ;; Hang the discover-keys-one-at-a-time chain
+       ;; off the end of the discover-ephemerons-one-at-a-time
+       ;; chain, which is the most complex case for avoiding
+       ;; quadratic GC times
+       (define-values (key es) (mk n (gensym) '()))
+       (define-values (root holds) (mk* n key es))
+
+       (define start (current-time))
+       (collect (collect-maximum-generation))
+       (let ([delta (time-difference (current-time) start)])
+         ;; Sanity check on ephemerons
+         (for-each (lambda (e)
+                     (when (eq? #!bwp (ephemeron-key e))
+                       (error 'check "oops")))
+                   es)
+         ;; Keep `root` and `holds` live:
+         (keep-alive (cons root holds))
+         ;; Return duration:
+         delta))
+
+     (define N 10000)
+
+     ;; The first time should be roughy x10 the second (not x100)
+     (let loop ([tries 3])
+       (define dummy #f)
+       (define (keep-alive v) (set! dummy (cons dummy v)))
+       (define t1 (measure-time (* 10 N) keep-alive))
+       (define dummy2 (set! dummy #f))
+       (define t2 (measure-time N keep-alive))
+       (define (duration->inexact t) (+ (* (time-second t) 1e9)
+                                        (time-nanosecond t)))
+       (set! dummy #f)
+       (or (< (/ (duration->inexact t1) (duration->inexact t2)) 20)
+           (and (positive? tries)
+                (loop (sub1 tries))))))
+
+   ;; ----------------------------------------
+   ;; Check interaction of mutation and generations
+   
+   ;; This check disables interrups so that a garbage collection
+   ;; happens only for the explicit `collect` request.
+   (with-interrupts-disabled
+     (let ([e (ephemeron-cons (gensym) 'ok)])
+       (collect 0) ; => `e` is moved to generation 1
+       (and
+         (eq? #!bwp (ephemeron-key e))
+         (eq? #!bwp (ephemeron-value e))
+         (let ([s (gensym)])
+           (set-car! e s)
+           (set-cdr! e 'ok-again)
+           (collect 0) ; => `s` is moved to generation 1
+           (and
+             (eq? s (ephemeron-key e))
+             (eq? 'ok-again (ephemeron-value e))
+             (begin
+               (set! s #f)
+               (collect 1) ; collect former `s`
+               (and
+                 (eq? #!bwp (ephemeron-key e))
+                 (eq? #!bwp (ephemeron-value e)))))))))
+
+   ;; ----------------------------------------
+   ;; Check fasl:
+   (let ([s (gensym)])
+     (define-values (o get) (open-bytevector-output-port))
+     (fasl-write (list s
+                       (ephemeron-cons s 'ok))
+                 o)
+     (let* ([l (fasl-read (open-bytevector-input-port (get)))]
+            [e (cadr l)])
+       (and
+        (eq? (car l) (ephemeron-key e))
+        (eq? 'ok (ephemeron-value e))
+        (begin
+          (set! s #f)
+          (set! l #f)
+          (collect (collect-maximum-generation))
+          (and
+           (eq? #!bwp (ephemeron-key e))
+           (eq? #!bwp (ephemeron-value e))))))))
+
 (mat $primitive
   (procedure? #%car)
   (procedure? #2%car)
--- a/mats/hash.ms
+++ b/mats/hash.ms
@ -1173,6 +1173,37 @@
      (hashtable-delete! ht 'a)
      (list (hashtable-size ht) (= (#%$hashtable-veclen ht) len)))
    '(0 #t))
+
+  ; test that weak-hashtable values do not imply that values
+  ; are reachable
+  (let ([wk1 (list 1)]
+        [wk2 (list 2)]
+        [wk3 (list 3)]
+        [wk4 (list 4)]
+        [ht (make-weak-eq-hashtable)])
+    (hashtable-set! ht wk1 wk1)
+    (hashtable-set! ht wk2 wk1)
+    (hashtable-set! ht wk3 wk3)
+    (hashtable-set! ht wk4 wk2)
+    (collect (collect-maximum-generation))
+    (and
+     (same-elements? (hashtable-keys ht) '#((1) (2) (3) (4)))
+     (equal? (hashtable-ref ht wk1 #f) wk1)
+     (equal? (hashtable-ref ht wk2 #f) wk1)
+     (equal? (hashtable-ref ht wk3 #f) wk3)
+     (equal? (hashtable-ref ht wk4 #f) wk2)
+     (begin
+       (set! wk1 #f)
+       (set! wk2 #f)
+       (set! wk3 #f)
+       (collect (collect-maximum-generation))
+       (and
+        (same-elements? (hashtable-keys ht) '#((1) (2) (4)))
+        (equal? (hashtable-ref ht wk4 #f) '(2))
+        (begin
+          (set! wk4 #f)
+          (collect (collect-maximum-generation))
+          (same-elements? (hashtable-keys ht) '#()))))))
 )

 (mat eq-hashtable-cell
--- a/mats/patch-compile-0-f-f-t
+++ b/mats/patch-compile-0-f-f-t
@ -1,5 +1,5 @@
-*** errors-compile-0-f-f-f	2017-03-15 13:19:08.859800901 -0400
--- errors-compile-0-f-f-t	2017-03-15 13:25:14.618006463 -0400
+*** errors-compile-0-f-f-f	2017-05-28 20:37:09.000000000 -0400
+--- errors-compile-0-f-f-t	2017-05-28 20:47:43.000000000 -0400
 ***************
 *** 3603,3609 ****
  misc.mo:Expected error in mat compute-composition: "compute-composition: invalid generation -1".
@ -43,7 +43,7 @@
  7.mo:Expected error in mat bytes-allocated: "bytes-allocated: invalid space gnu".
  7.mo:Expected error in mat bytes-allocated: "bytes-allocated: invalid space gnu".
 ***************
-*** 8451,8463 ****
+*** 8461,8473 ****
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -57,7 +57,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
--- 8451,8463 ----
+--- 8461,8473 ----
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
--- a/mats/patch-compile-0-f-t-f
+++ b/mats/patch-compile-0-f-t-f
@ -1,5 +1,5 @@
-*** errors-compile-0-f-f-f	2017-03-15 13:19:08.859800901 -0400
--- errors-compile-0-f-t-f	2017-03-15 13:34:41.791223868 -0400
+*** errors-compile-0-f-f-f	2017-05-29 03:04:27.000000000 -0400
+--- errors-compile-0-f-t-f	2017-05-29 02:30:33.000000000 -0400
 ***************
 *** 125,131 ****
  3.mo:Expected error in mat dipa-letrec: "attempt to reference undefined variable a".
@ -182,7 +182,7 @@
  record.mo:Expected error in mat foreign-data: "foreign-alloc: <int> is not a positive fixnum".
  record.mo:Expected error in mat foreign-data: "foreign-alloc: -5 is not a positive fixnum".
 ***************
-*** 7266,7304 ****
+*** 7275,7313 ****
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -222,7 +222,7 @@
  record.mo:Expected error in mat record?: "record?: 4 is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
--- 7266,7304 ----
+--- 7275,7313 ----
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -263,7 +263,7 @@
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
 ***************
-*** 7313,7369 ****
+*** 7322,7378 ****
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: invalid protocol flimflam".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure not-a-procedure".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure spam".
@ -321,7 +321,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "define-record-type: incompatible record type cpoint - different parent".
  record.mo:Expected error in mat r6rs-records-syntactic: "define-record-type: incompatible record type cpoint - different parent".
  record.mo:Expected error in mat r6rs-records-syntactic: "cannot extend define-record-type parent fratrat".
--- 7313,7369 ----
+--- 7322,7378 ----
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: invalid protocol flimflam".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure not-a-procedure".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure spam".
--- a/mats/patch-compile-0-t-f-f
+++ b/mats/patch-compile-0-t-f-f
@ -1,5 +1,5 @@
-*** errors-compile-0-f-f-f	2017-03-15 13:19:08.859800901 -0400
--- errors-compile-0-t-f-f	2017-03-15 13:31:20.355212128 -0400
+*** errors-compile-0-f-f-f	2017-05-29 03:04:27.000000000 -0400
+--- errors-compile-0-t-f-f	2017-05-29 02:38:26.000000000 -0400
 ***************
 *** 93,99 ****
  3.mo:Expected error in mat case-lambda: "incorrect number of arguments to #<procedure foo>".
@ -4261,7 +4261,7 @@
  7.mo:Expected error in mat top-level-value-functions: "define-top-level-value: #<environment *scheme*> is not a symbol".
  7.mo:Expected error in mat top-level-value-functions: "variable i-am-not-bound-i-hope is not bound".
 ***************
-*** 7401,7491 ****
+*** 7410,7500 ****
  hash.mo:Expected error in mat old-hash-table: "hash-table-for-each: ((a . b)) is not an eq hashtable".
  hash.mo:Expected error in mat old-hash-table: "incorrect number of arguments to #<procedure>".
  hash.mo:Expected error in mat old-hash-table: "incorrect number of arguments to #<procedure>".
@ -4353,7 +4353,7 @@
  hash.mo:Expected error in mat hashtable-arguments: "hashtable-weak?: (hash . table) is not a hashtable".
  hash.mo:Expected error in mat hash-return-value: "hashtable-ref: invalid hash-function #<procedure> return value "oops" for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-ref: invalid hash-function #<procedure> return value 3.5 for any".
--- 7401,7491 ----
+--- 7410,7500 ----
  hash.mo:Expected error in mat old-hash-table: "hash-table-for-each: ((a . b)) is not an eq hashtable".
  hash.mo:Expected error in mat old-hash-table: "incorrect number of arguments to #<procedure>".
  hash.mo:Expected error in mat old-hash-table: "incorrect number of arguments to #<procedure>".
@ -4446,7 +4446,7 @@
  hash.mo:Expected error in mat hash-return-value: "hashtable-ref: invalid hash-function #<procedure> return value "oops" for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-ref: invalid hash-function #<procedure> return value 3.5 for any".
 ***************
-*** 7505,7600 ****
+*** 7514,7609 ****
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value "oops" for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value 3.5 for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value 1+2i for any".
@ -4543,7 +4543,7 @@
  hash.mo:Expected error in mat eqv-hashtable-arguments: "make-weak-eqv-hashtable: invalid size argument -1".
  hash.mo:Expected error in mat eqv-hashtable-arguments: "make-weak-eqv-hashtable: invalid size argument #t".
  hash.mo:Expected error in mat eqv-hashtable-arguments: "make-weak-eqv-hashtable: invalid size argument #f".
--- 7505,7600 ----
+--- 7514,7609 ----
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value "oops" for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value 3.5 for any".
  hash.mo:Expected error in mat hash-return-value: "hashtable-delete!: invalid hash-function #<procedure> return value 1+2i for any".
@ -4641,7 +4641,7 @@
  hash.mo:Expected error in mat eqv-hashtable-arguments: "make-weak-eqv-hashtable: invalid size argument #t".
  hash.mo:Expected error in mat eqv-hashtable-arguments: "make-weak-eqv-hashtable: invalid size argument #f".
 ***************
-*** 7602,7617 ****
+*** 7611,7626 ****
  hash.mo:Expected error in mat generic-hashtable: "hashtable-delete!: #<hashtable> is not mutable".
  hash.mo:Expected error in mat generic-hashtable: "hashtable-update!: #<hashtable> is not mutable".
  hash.mo:Expected error in mat generic-hashtable: "hashtable-update!: #<hashtable> is not mutable".
@ -4658,7 +4658,7 @@
  hash.mo:Expected error in mat hash-functions: "string-ci-hash: hello is not a string".
  hash.mo:Expected error in mat fasl-other-hashtable: "fasl-write: invalid fasl object #<eqv hashtable>".
  hash.mo:Expected error in mat fasl-other-hashtable: "fasl-write: invalid fasl object #<hashtable>".
--- 7602,7617 ----
+--- 7611,7626 ----
  hash.mo:Expected error in mat generic-hashtable: "hashtable-delete!: #<hashtable> is not mutable".
  hash.mo:Expected error in mat generic-hashtable: "hashtable-update!: #<hashtable> is not mutable".
  hash.mo:Expected error in mat generic-hashtable: "hashtable-update!: #<hashtable> is not mutable".
@ -4676,7 +4676,7 @@
  hash.mo:Expected error in mat fasl-other-hashtable: "fasl-write: invalid fasl object #<eqv hashtable>".
  hash.mo:Expected error in mat fasl-other-hashtable: "fasl-write: invalid fasl object #<hashtable>".
 ***************
-*** 7726,7733 ****
+*** 7736,7743 ****
  8.mo:Expected error in mat with-syntax: "invalid syntax a".
  8.mo:Expected error in mat with-syntax: "duplicate pattern variable x in (x x)".
  8.mo:Expected error in mat with-syntax: "duplicate pattern variable x in (x x)".
@ -4685,7 +4685,7 @@
  8.mo:Expected error in mat generate-temporaries: "generate-temporaries: improper list structure (a b . c)".
  8.mo:Expected error in mat generate-temporaries: "generate-temporaries: cyclic list structure (a b c b c b ...)".
  8.mo:Expected error in mat syntax->list: "syntax->list: invalid argument #<syntax a>".
--- 7726,7733 ----
+--- 7736,7743 ----
  8.mo:Expected error in mat with-syntax: "invalid syntax a".
  8.mo:Expected error in mat with-syntax: "duplicate pattern variable x in (x x)".
  8.mo:Expected error in mat with-syntax: "duplicate pattern variable x in (x x)".
@ -4695,7 +4695,7 @@
  8.mo:Expected error in mat generate-temporaries: "generate-temporaries: cyclic list structure (a b c b c b ...)".
  8.mo:Expected error in mat syntax->list: "syntax->list: invalid argument #<syntax a>".
 ***************
-*** 8315,8330 ****
+*** 8325,8340 ****
  8.mo:Expected error in mat rnrs-eval: "attempt to assign unbound identifier foo".
  8.mo:Expected error in mat rnrs-eval: "invalid definition in immutable environment (define cons (quote #<procedure vector>))".
  8.mo:Expected error in mat top-level-syntax-functions: "top-level-syntax: "hello" is not a symbol".
@ -4712,7 +4712,7 @@
  8.mo:Expected error in mat top-level-syntax-functions: "define-top-level-syntax: hello is not an environment".
  8.mo:Expected error in mat top-level-syntax-functions: "define-top-level-syntax: #<environment *scheme*> is not a symbol".
  8.mo:Expected error in mat top-level-syntax-functions: "define-top-level-syntax: cannot modify immutable environment #<environment *scheme*>".
--- 8315,8330 ----
+--- 8325,8340 ----
  8.mo:Expected error in mat rnrs-eval: "attempt to assign unbound identifier foo".
  8.mo:Expected error in mat rnrs-eval: "invalid definition in immutable environment (define cons (quote #<procedure vector>))".
  8.mo:Expected error in mat top-level-syntax-functions: "top-level-syntax: "hello" is not a symbol".
@ -4730,7 +4730,7 @@
  8.mo:Expected error in mat top-level-syntax-functions: "define-top-level-syntax: #<environment *scheme*> is not a symbol".
  8.mo:Expected error in mat top-level-syntax-functions: "define-top-level-syntax: cannot modify immutable environment #<environment *scheme*>".
 ***************
-*** 8403,8425 ****
+*** 8413,8435 ****
  fx.mo:Expected error in mat fx=?: "fx=?: (a) is not a fixnum".
  fx.mo:Expected error in mat fx=?: "fx=?: <int> is not a fixnum".
  fx.mo:Expected error in mat fx=?: "fx=?: <-int> is not a fixnum".
@ -4754,7 +4754,7 @@
  fx.mo:Expected error in mat $fxu<: "incorrect number of arguments to #<procedure $fxu<>".
  fx.mo:Expected error in mat $fxu<: "incorrect number of arguments to #<procedure $fxu<>".
  fx.mo:Expected error in mat $fxu<: "$fxu<: <-int> is not a fixnum".
--- 8403,8425 ----
+--- 8413,8435 ----
  fx.mo:Expected error in mat fx=?: "fx=?: (a) is not a fixnum".
  fx.mo:Expected error in mat fx=?: "fx=?: <int> is not a fixnum".
  fx.mo:Expected error in mat fx=?: "fx=?: <-int> is not a fixnum".
@ -4779,7 +4779,7 @@
  fx.mo:Expected error in mat $fxu<: "incorrect number of arguments to #<procedure $fxu<>".
  fx.mo:Expected error in mat $fxu<: "$fxu<: <-int> is not a fixnum".
 ***************
-*** 8451,8463 ****
+*** 8461,8473 ****
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -4793,7 +4793,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
--- 8451,8463 ----
+--- 8461,8473 ----
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -4808,7 +4808,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
 ***************
-*** 8507,8519 ****
+*** 8517,8529 ****
  fx.mo:Expected error in mat fx1+: "fx1+: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx1+: "fx1+: <int> is not a fixnum".
  fx.mo:Expected error in mat fx1+: "fx1+: a is not a fixnum".
@ -4822,7 +4822,7 @@
  fx.mo:Expected error in mat fxmax: "fxmax: a is not a fixnum".
  fx.mo:Expected error in mat fxmax: "fxmax: <int> is not a fixnum".
  fx.mo:Expected error in mat fxmax: "fxmax: <-int> is not a fixnum".
--- 8507,8519 ----
+--- 8517,8529 ----
  fx.mo:Expected error in mat fx1+: "fx1+: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx1+: "fx1+: <int> is not a fixnum".
  fx.mo:Expected error in mat fx1+: "fx1+: a is not a fixnum".
@ -4837,9 +4837,9 @@
  fx.mo:Expected error in mat fxmax: "fxmax: <int> is not a fixnum".
  fx.mo:Expected error in mat fxmax: "fxmax: <-int> is not a fixnum".
 ***************
-*** 8610,8619 ****
+*** 8621,8630 ****
  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments <int> and 10".
-  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments 4096 and <int>".
+  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments -4097 and <int>".
  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments <-int> and 1".
 ! fx.mo:Expected error in mat fxbit-field: "incorrect argument count in call (fxbit-field)".
 ! fx.mo:Expected error in mat fxbit-field: "incorrect argument count in call (fxbit-field 35)".
@ -4848,9 +4848,9 @@
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: 35.0 is not a fixnum".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: 5.0 is not a valid start index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: 8.0 is not a valid end index".
--- 8610,8619 ----
+--- 8621,8630 ----
  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments <int> and 10".
-  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments 4096 and <int>".
+  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments -4097 and <int>".
  fx.mo:Expected error in mat fxarithmetic-shift: "fxarithmetic-shift: fixnum overflow with arguments <-int> and 1".
 ! fx.mo:Expected error in mat fxbit-field: "incorrect number of arguments to #<procedure fxbit-field>".
 ! fx.mo:Expected error in mat fxbit-field: "incorrect number of arguments to #<procedure fxbit-field>".
@ -4860,7 +4860,7 @@
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: 5.0 is not a valid start index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: 8.0 is not a valid end index".
 ***************
-*** 8627,8660 ****
+*** 8638,8671 ****
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid end index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid start index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid end index".
@ -4895,7 +4895,7 @@
  fx.mo:Expected error in mat fxif: "fxif: a is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: 3.4 is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: (a) is not a fixnum".
--- 8627,8660 ----
+--- 8638,8671 ----
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid end index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid start index".
  fx.mo:Expected error in mat fxbit-field: "fxbit-field: <int> is not a valid end index".
@ -4931,7 +4931,7 @@
  fx.mo:Expected error in mat fxif: "fxif: 3.4 is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: (a) is not a fixnum".
 ***************
-*** 8664,8707 ****
+*** 8675,8718 ****
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
@ -4976,7 +4976,7 @@
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: 3.4 is not a fixnum".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: "3" is not a fixnum".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: <int> is not a fixnum".
--- 8664,8707 ----
+--- 8675,8718 ----
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
  fx.mo:Expected error in mat fxif: "fxif: <-int> is not a fixnum".
@ -5022,7 +5022,7 @@
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: "3" is not a fixnum".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: <int> is not a fixnum".
 ***************
-*** 8710,8720 ****
+*** 8721,8731 ****
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index -1".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index <int>".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index <int>".
@ -5034,7 +5034,7 @@
  fx.mo:Expected error in mat fxcopy-bit-field: "fxcopy-bit-field: "3" is not a fixnum".
  fx.mo:Expected error in mat fxcopy-bit-field: "fxcopy-bit-field: 3.4 is not a valid start index".
  fx.mo:Expected error in mat fxcopy-bit-field: "fxcopy-bit-field: 3/4 is not a valid end index".
--- 8710,8720 ----
+--- 8721,8731 ----
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index -1".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index <int>".
  fx.mo:Expected error in mat fxcopy-bit: "fxcopy-bit: invalid bit index <int>".
@ -5047,7 +5047,7 @@
  fx.mo:Expected error in mat fxcopy-bit-field: "fxcopy-bit-field: 3.4 is not a valid start index".
  fx.mo:Expected error in mat fxcopy-bit-field: "fxcopy-bit-field: 3/4 is not a valid end index".
 ***************
-*** 8774,8783 ****
+*** 8785,8794 ****
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: (a) is not a fixnum".
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: undefined for 0".
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: undefined for 0".
@ -5058,7 +5058,7 @@
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: 1.0 is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: 3.0 is not a fixnum".
--- 8774,8783 ----
+--- 8785,8794 ----
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: (a) is not a fixnum".
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: undefined for 0".
  fx.mo:Expected error in mat fxdiv0-and-mod0: "fxmod0: undefined for 0".
@ -5070,7 +5070,7 @@
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: 3.0 is not a fixnum".
 ***************
-*** 8793,8802 ****
+*** 8804,8813 ****
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
@ -5081,7 +5081,7 @@
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: 1.0 is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: 3.0 is not a fixnum".
--- 8793,8802 ----
+--- 8804,8813 ----
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx+/carry: "fx+/carry: <-int> is not a fixnum".
@ -5093,7 +5093,7 @@
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: 3.0 is not a fixnum".
 ***************
-*** 8812,8821 ****
+*** 8823,8832 ****
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
@ -5104,7 +5104,7 @@
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: 1.0 is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: 3.0 is not a fixnum".
--- 8812,8821 ----
+--- 8823,8832 ----
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx-/carry: "fx-/carry: <-int> is not a fixnum".
@ -5116,7 +5116,7 @@
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: 2.0 is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: 3.0 is not a fixnum".
 ***************
-*** 8831,8841 ****
+*** 8842,8852 ****
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
@ -5128,7 +5128,7 @@
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: a is not a fixnum".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid start index 0.0".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index 2.0".
--- 8831,8841 ----
+--- 8842,8852 ----
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
  fx.mo:Expected error in mat fx*/carry: "fx*/carry: <-int> is not a fixnum".
@ -5141,7 +5141,7 @@
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid start index 0.0".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index 2.0".
 ***************
-*** 8858,8867 ****
+*** 8869,8878 ****
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: count 1 is greater than difference between end index 5 and start index 5".
@ -5152,7 +5152,7 @@
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: a is not a fixnum".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid start index 0.0".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index 2.0".
--- 8858,8867 ----
+--- 8869,8878 ----
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxrotate-bit-field: "fxrotate-bit-field: count 1 is greater than difference between end index 5 and start index 5".
@ -5164,7 +5164,7 @@
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid start index 0.0".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index 2.0".
 ***************
-*** 8877,8894 ****
+*** 8888,8905 ****
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index <-int>".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: start index 7 is greater than end index 5".
@ -5183,7 +5183,7 @@
  fl.mo:Expected error in mat fl=: "fl=: (a) is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: a is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: a is not a flonum".
--- 8877,8894 ----
+--- 8888,8905 ----
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index <int>".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: invalid end index <-int>".
  fx.mo:Expected error in mat fxreverse-bit-field: "fxreverse-bit-field: start index 7 is greater than end index 5".
@ -5203,7 +5203,7 @@
  fl.mo:Expected error in mat fl=: "fl=: a is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: a is not a flonum".
 ***************
-*** 8896,8902 ****
+*** 8907,8913 ****
  fl.mo:Expected error in mat fl=: "fl=: 3 is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: 7/2 is not a flonum".
@ -5211,7 +5211,7 @@
  fl.mo:Expected error in mat fl<: "fl<: (a) is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: a is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: a is not a flonum".
--- 8896,8902 ----
+--- 8907,8913 ----
  fl.mo:Expected error in mat fl=: "fl=: 3 is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl=: "fl=: 7/2 is not a flonum".
@ -5220,7 +5220,7 @@
  fl.mo:Expected error in mat fl<: "fl<: a is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: a is not a flonum".
 ***************
-*** 8904,8910 ****
+*** 8915,8921 ****
  fl.mo:Expected error in mat fl<: "fl<: 3 is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: 7/2 is not a flonum".
@ -5228,7 +5228,7 @@
  fl.mo:Expected error in mat fl>: "fl>: (a) is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: a is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: a is not a flonum".
--- 8904,8910 ----
+--- 8915,8921 ----
  fl.mo:Expected error in mat fl<: "fl<: 3 is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl<: "fl<: 7/2 is not a flonum".
@ -5237,7 +5237,7 @@
  fl.mo:Expected error in mat fl>: "fl>: a is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: a is not a flonum".
 ***************
-*** 8912,8918 ****
+*** 8923,8929 ****
  fl.mo:Expected error in mat fl>: "fl>: 3 is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: 7/2 is not a flonum".
@ -5245,7 +5245,7 @@
  fl.mo:Expected error in mat fl<=: "fl<=: (a) is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: a is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: a is not a flonum".
--- 8912,8918 ----
+--- 8923,8929 ----
  fl.mo:Expected error in mat fl>: "fl>: 3 is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl>: "fl>: 7/2 is not a flonum".
@ -5254,7 +5254,7 @@
  fl.mo:Expected error in mat fl<=: "fl<=: a is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: a is not a flonum".
 ***************
-*** 8920,8926 ****
+*** 8931,8937 ****
  fl.mo:Expected error in mat fl<=: "fl<=: 3 is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: 7/2 is not a flonum".
@ -5262,7 +5262,7 @@
  fl.mo:Expected error in mat fl>=: "fl>=: (a) is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: a is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: a is not a flonum".
--- 8920,8926 ----
+--- 8931,8937 ----
  fl.mo:Expected error in mat fl<=: "fl<=: 3 is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl<=: "fl<=: 7/2 is not a flonum".
@ -5271,7 +5271,7 @@
  fl.mo:Expected error in mat fl>=: "fl>=: a is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: a is not a flonum".
 ***************
-*** 8928,8967 ****
+*** 8939,8978 ****
  fl.mo:Expected error in mat fl>=: "fl>=: 3 is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: 7/2 is not a flonum".
@ -5312,7 +5312,7 @@
  fl.mo:Expected error in mat fl>=?: "fl>=?: a is not a flonum".
  fl.mo:Expected error in mat fl>=?: "fl>=?: a is not a flonum".
  fl.mo:Expected error in mat fl>=?: "fl>=?: 3 is not a flonum".
--- 8928,8967 ----
+--- 8939,8978 ----
  fl.mo:Expected error in mat fl>=: "fl>=: 3 is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: 7/2 is not a flonum".
  fl.mo:Expected error in mat fl>=: "fl>=: 7/2 is not a flonum".
@ -5354,7 +5354,7 @@
  fl.mo:Expected error in mat fl>=?: "fl>=?: a is not a flonum".
  fl.mo:Expected error in mat fl>=?: "fl>=?: 3 is not a flonum".
 ***************
-*** 8971,8977 ****
+*** 8982,8988 ****
  fl.mo:Expected error in mat fl+: "fl+: (a . b) is not a flonum".
  fl.mo:Expected error in mat fl+: "fl+: 1 is not a flonum".
  fl.mo:Expected error in mat fl+: "fl+: 2/3 is not a flonum".
@ -5362,7 +5362,7 @@
  fl.mo:Expected error in mat fl-: "fl-: (a . b) is not a flonum".
  fl.mo:Expected error in mat fl-: "fl-: 1 is not a flonum".
  fl.mo:Expected error in mat fl-: "fl-: a is not a flonum".
--- 8971,8977 ----
+--- 8982,8988 ----
  fl.mo:Expected error in mat fl+: "fl+: (a . b) is not a flonum".
  fl.mo:Expected error in mat fl+: "fl+: 1 is not a flonum".
  fl.mo:Expected error in mat fl+: "fl+: 2/3 is not a flonum".
@ -5371,7 +5371,7 @@
  fl.mo:Expected error in mat fl-: "fl-: 1 is not a flonum".
  fl.mo:Expected error in mat fl-: "fl-: a is not a flonum".
 ***************
-*** 8981,9063 ****
+*** 8992,9074 ****
  fl.mo:Expected error in mat fl*: "fl*: (a . b) is not a flonum".
  fl.mo:Expected error in mat fl*: "fl*: 1 is not a flonum".
  fl.mo:Expected error in mat fl*: "fl*: 2/3 is not a flonum".
@ -5455,7 +5455,7 @@
  fl.mo:Expected error in mat flround: "flround: a is not a flonum".
  fl.mo:Expected error in mat flround: "flround: 2.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flround: "flround: 2+1i is not a flonum".
--- 8981,9063 ----
+--- 8992,9074 ----
  fl.mo:Expected error in mat fl*: "fl*: (a . b) is not a flonum".
  fl.mo:Expected error in mat fl*: "fl*: 1 is not a flonum".
  fl.mo:Expected error in mat fl*: "fl*: 2/3 is not a flonum".
@ -5540,7 +5540,7 @@
  fl.mo:Expected error in mat flround: "flround: 2.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flround: "flround: 2+1i is not a flonum".
 ***************
-*** 9077,9125 ****
+*** 9088,9136 ****
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: 3 is not a flonum".
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: 3/4 is not a flonum".
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: hi is not a flonum".
@ -5590,7 +5590,7 @@
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
--- 9077,9125 ----
+--- 9088,9136 ----
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: 3 is not a flonum".
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: 3/4 is not a flonum".
  fl.mo:Expected error in mat flinfinite?: "flinfinite?: hi is not a flonum".
@ -5641,7 +5641,7 @@
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
 ***************
-*** 9127,9133 ****
+*** 9138,9144 ****
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: 0.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: 0+1i is not a flonum".
@ -5649,7 +5649,7 @@
  fl.mo:Expected error in mat flmax: "flmax: a is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: a is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 3 is not a flonum".
--- 9127,9133 ----
+--- 9138,9144 ----
  fl.mo:Expected error in mat flmin: "flmin: a is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: 0.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flmin: "flmin: 0+1i is not a flonum".
@ -5658,7 +5658,7 @@
  fl.mo:Expected error in mat flmax: "flmax: a is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 3 is not a flonum".
 ***************
-*** 9135,9148 ****
+*** 9146,9159 ****
  fl.mo:Expected error in mat flmax: "flmax: a is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 0.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 0+1i is not a flonum".
@ -5673,7 +5673,7 @@
  fl.mo:Expected error in mat fldenominator: "fldenominator: a is not a flonum".
  fl.mo:Expected error in mat fldenominator: "fldenominator: 3 is not a flonum".
  fl.mo:Expected error in mat fldenominator: "fldenominator: 0+1i is not a flonum".
--- 9135,9148 ----
+--- 9146,9159 ----
  fl.mo:Expected error in mat flmax: "flmax: a is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 0.0+1.0i is not a flonum".
  fl.mo:Expected error in mat flmax: "flmax: 0+1i is not a flonum".
@ -5689,7 +5689,7 @@
  fl.mo:Expected error in mat fldenominator: "fldenominator: 3 is not a flonum".
  fl.mo:Expected error in mat fldenominator: "fldenominator: 0+1i is not a flonum".
 ***************
-*** 9188,9194 ****
+*** 9199,9205 ****
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
@ -5697,7 +5697,7 @@
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
--- 9188,9194 ----
+--- 9199,9205 ----
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
@ -5706,7 +5706,7 @@
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
  cfl.mo:Expected error in mat cfl-: "cfl-: a is not a cflonum".
 ***************
-*** 9198,9211 ****
+*** 9209,9222 ****
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
@ -5721,7 +5721,7 @@
  foreign.mo:Expected error in mat load-shared-object: "load-shared-object: invalid path 3".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: no entry for "i do not exist"".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: no entry for "i do not exist"".
--- 9198,9211 ----
+--- 9209,9222 ----
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
  cfl.mo:Expected error in mat cfl/: "cfl/: a is not a cflonum".
@ -5737,7 +5737,7 @@
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: no entry for "i do not exist"".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: no entry for "i do not exist"".
 ***************
-*** 9240,9247 ****
+*** 9251,9258 ****
  foreign.mo:Expected error in mat foreign-procedure: "id: invalid foreign-procedure argument foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle abcde".
  foreign.mo:Expected error in mat foreign-procedure: "float_id: invalid foreign-procedure argument 0".
@ -5746,7 +5746,7 @@
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier i-am-not-a-type".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
  foreign.mo:Expected error in mat foreign-bytevectors: "u8*->u8*: invalid foreign-procedure argument "hello"".
--- 9240,9247 ----
+--- 9251,9258 ----
  foreign.mo:Expected error in mat foreign-procedure: "id: invalid foreign-procedure argument foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle abcde".
  foreign.mo:Expected error in mat foreign-procedure: "float_id: invalid foreign-procedure argument 0".
@ -5756,7 +5756,7 @@
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
  foreign.mo:Expected error in mat foreign-bytevectors: "u8*->u8*: invalid foreign-procedure argument "hello"".
 ***************
-*** 9725,9737 ****
+*** 9736,9748 ****
  unix.mo:Expected error in mat file-operations: "file-access-time: failed for "testlink": no such file or directory".
  unix.mo:Expected error in mat file-operations: "file-change-time: failed for "testlink": no such file or directory".
  unix.mo:Expected error in mat file-operations: "file-modification-time: failed for "testlink": no such file or directory".
@ -5770,7 +5770,7 @@
  windows.mo:Expected error in mat registry: "get-registry: pooh is not a string".
  windows.mo:Expected error in mat registry: "put-registry!: 3 is not a string".
  windows.mo:Expected error in mat registry: "put-registry!: 3 is not a string".
--- 9725,9737 ----
+--- 9736,9748 ----
  unix.mo:Expected error in mat file-operations: "file-access-time: failed for "testlink": no such file or directory".
  unix.mo:Expected error in mat file-operations: "file-change-time: failed for "testlink": no such file or directory".
  unix.mo:Expected error in mat file-operations: "file-modification-time: failed for "testlink": no such file or directory".
@ -5785,7 +5785,7 @@
  windows.mo:Expected error in mat registry: "put-registry!: 3 is not a string".
  windows.mo:Expected error in mat registry: "put-registry!: 3 is not a string".
 ***************
-*** 9759,9830 ****
+*** 9770,9841 ****
  ieee.mo:Expected error in mat flonum->fixnum: "flonum->fixnum: result for -inf.0 would be outside of fixnum range".
  ieee.mo:Expected error in mat flonum->fixnum: "flonum->fixnum: result for +nan.0 would be outside of fixnum range".
  ieee.mo:Expected error in mat fllp: "fllp: 3 is not a flonum".
@ -5858,7 +5858,7 @@
  date.mo:Expected error in mat time: "time>=?: 3 is not a time record".
  date.mo:Expected error in mat time: "time>=?: #<procedure car> is not a time record".
  date.mo:Expected error in mat time: "time>=?: types of <time> and <time> differ".
--- 9759,9830 ----
+--- 9770,9841 ----
  ieee.mo:Expected error in mat flonum->fixnum: "flonum->fixnum: result for -inf.0 would be outside of fixnum range".
  ieee.mo:Expected error in mat flonum->fixnum: "flonum->fixnum: result for +nan.0 would be outside of fixnum range".
  ieee.mo:Expected error in mat fllp: "fllp: 3 is not a flonum".
@ -5932,7 +5932,7 @@
  date.mo:Expected error in mat time: "time>=?: #<procedure car> is not a time record".
  date.mo:Expected error in mat time: "time>=?: types of <time> and <time> differ".
 ***************
-*** 9832,9846 ****
+*** 9843,9857 ****
  date.mo:Expected error in mat time: "add-duration: <time> does not have type time-duration".
  date.mo:Expected error in mat time: "subtract-duration: <time> does not have type time-duration".
  date.mo:Expected error in mat time: "copy-time: <date> is not a time record".
@ -5948,7 +5948,7 @@
  date.mo:Expected error in mat date: "make-date: invalid nanosecond -1".
  date.mo:Expected error in mat date: "make-date: invalid nanosecond <int>".
  date.mo:Expected error in mat date: "make-date: invalid nanosecond zero".
--- 9832,9846 ----
+--- 9843,9857 ----
  date.mo:Expected error in mat time: "add-duration: <time> does not have type time-duration".
  date.mo:Expected error in mat time: "subtract-duration: <time> does not have type time-duration".
  date.mo:Expected error in mat time: "copy-time: <date> is not a time record".
@ -5965,7 +5965,7 @@
  date.mo:Expected error in mat date: "make-date: invalid nanosecond <int>".
  date.mo:Expected error in mat date: "make-date: invalid nanosecond zero".
 ***************
-*** 9866,9918 ****
+*** 9877,9929 ****
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset 90000".
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset est".
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset "est"".
@ -6019,7 +6019,7 @@
  date.mo:Expected error in mat date: "current-date: invalid time-zone offset -90000".
  date.mo:Expected error in mat date: "current-date: invalid time-zone offset 90000".
  date.mo:Expected error in mat conversions/sleep: "date->time-utc: <time> is not a date record".
--- 9866,9918 ----
+--- 9877,9929 ----
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset 90000".
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset est".
  date.mo:Expected error in mat date: "make-date: invalid time-zone offset "est"".
--- a/mats/patch-compile-0-t-f-t
+++ b/mats/patch-compile-0-t-f-t
@ -1,5 +1,5 @@
-*** errors-compile-0-t-f-f	2017-03-15 13:31:20.355212128 -0400
--- errors-compile-0-t-f-t	2017-03-15 13:21:31.790099674 -0400
+*** errors-compile-0-t-f-f	2017-05-28 20:58:24.000000000 -0400
+--- errors-compile-0-t-f-t	2017-05-28 20:41:04.000000000 -0400
 ***************
 *** 3603,3609 ****
  misc.mo:Expected error in mat compute-composition: "compute-composition: invalid generation -1".
--- a/mats/patch-compile-0-t-t-f
+++ b/mats/patch-compile-0-t-t-f
@ -1,5 +1,5 @@
-*** errors-compile-0-t-f-f	2017-03-15 13:31:20.355212128 -0400
--- errors-compile-0-t-t-f	2017-03-15 13:27:50.847239990 -0400
+*** errors-compile-0-t-f-f	2017-05-28 20:58:24.000000000 -0400
+--- errors-compile-0-t-t-f	2017-05-28 20:52:16.000000000 -0400
 ***************
 *** 144,150 ****
  3.mo:Expected error in mat cpvalid: "attempt to reference undefined variable b".
@ -142,7 +142,7 @@
  record.mo:Expected error in mat foreign-data: "foreign-alloc: <int> is not a positive fixnum".
  record.mo:Expected error in mat foreign-data: "foreign-alloc: -5 is not a positive fixnum".
 ***************
-*** 7266,7304 ****
+*** 7275,7313 ****
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -182,7 +182,7 @@
  record.mo:Expected error in mat record?: "record?: 4 is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
--- 7266,7304 ----
+--- 7275,7313 ----
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -223,7 +223,7 @@
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
 ***************
-*** 7324,7359 ****
+*** 7333,7368 ****
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: record constructor descriptor #<record constructor descriptor> is not for parent of record type #<record type grand-child>".
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-type-descriptor: cannot extend sealed record type #<record type bar>".
  record.mo:Expected error in mat r6rs-records-syntactic: "invalid syntax point".
@ -260,7 +260,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "record-rtd: #<ex3> is not a record".
  record.mo:Expected error in mat r6rs-records-syntactic: "record-rtd: #<ex3> is not a record".
  record.mo:Expected error in mat r6rs-records-syntactic: "parent record type is sealed ex3".
--- 7324,7359 ----
+--- 7333,7368 ----
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: record constructor descriptor #<record constructor descriptor> is not for parent of record type #<record type grand-child>".
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-type-descriptor: cannot extend sealed record type #<record type bar>".
  record.mo:Expected error in mat r6rs-records-syntactic: "invalid syntax point".
--- a/mats/patch-interpret-0-f-f-f
+++ b/mats/patch-interpret-0-f-f-f
@ -1,5 +1,5 @@
-*** errors-compile-0-f-f-f	2017-03-15 13:19:08.859800901 -0400
--- errors-interpret-0-f-f-f	2017-03-15 13:37:17.060462746 -0400
+*** errors-compile-0-f-f-f	2017-05-29 03:04:27.000000000 -0400
+--- errors-interpret-0-f-f-f	2017-05-29 02:47:10.000000000 -0400
 ***************
 *** 1,7 ****
  primvars.mo:Expected error in mat make-parameter: "make-parameter: 2 is not a procedure".
@ -232,7 +232,7 @@
  7.mo:Expected error in mat eval: "compile: 7 is not an environment".
  7.mo:Expected error in mat expand: "sc-expand: 7 is not an environment".
 ***************
-*** 7277,7283 ****
+*** 7286,7292 ****
  record.mo:Expected error in mat record25: "invalid value #\9 for foreign type uptr".
  record.mo:Expected error in mat record25: "invalid value 10 for foreign type float".
  record.mo:Expected error in mat record25: "invalid value 11.0+0.0i for foreign type double".
@ -240,7 +240,7 @@
  record.mo:Expected error in mat record25: "invalid value 12.0 for foreign type long-long".
  record.mo:Expected error in mat record25: "invalid value 13.0 for foreign type unsigned-long-long".
  record.mo:Expected error in mat record25: "invalid value 3.0 for foreign type int".
--- 7277,7283 ----
+--- 7286,7292 ----
  record.mo:Expected error in mat record25: "invalid value #\9 for foreign type uptr".
  record.mo:Expected error in mat record25: "invalid value 10 for foreign type float".
  record.mo:Expected error in mat record25: "invalid value 11.0+0.0i for foreign type double".
@ -249,7 +249,7 @@
  record.mo:Expected error in mat record25: "invalid value 13.0 for foreign type unsigned-long-long".
  record.mo:Expected error in mat record25: "invalid value 3.0 for foreign type int".
 ***************
-*** 8451,8463 ****
+*** 8461,8473 ****
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -263,7 +263,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
--- 8451,8463 ----
+--- 8461,8473 ----
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -278,7 +278,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
 ***************
-*** 9213,9237 ****
+*** 9224,9248 ****
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
@ -304,7 +304,7 @@
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier booleen".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier integer-34".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure result type specifier chare".
--- 9213,9237 ----
+--- 9224,9248 ----
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
@ -331,7 +331,7 @@
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier integer-34".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure result type specifier chare".
 ***************
-*** 9244,9275 ****
+*** 9255,9286 ****
  foreign.mo:Expected error in mat foreign-sizeof: "incorrect argument count in call (foreign-sizeof (quote int) (quote int))".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier i-am-not-a-type".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
@ -364,7 +364,7 @@
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
--- 9244,9275 ----
+--- 9255,9286 ----
  foreign.mo:Expected error in mat foreign-sizeof: "incorrect argument count in call (foreign-sizeof (quote int) (quote int))".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier i-am-not-a-type".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
@ -398,7 +398,7 @@
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
 ***************
-*** 9277,9302 ****
+*** 9288,9313 ****
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
@ -425,7 +425,7 @@
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
--- 9277,9302 ----
+--- 9288,9313 ----
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
@ -453,7 +453,7 @@
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
 ***************
-*** 9307,9341 ****
+*** 9318,9352 ****
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
@ -489,7 +489,7 @@
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
--- 9307,9341 ----
+--- 9318,9352 ----
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
@ -526,7 +526,7 @@
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
 ***************
-*** 9921,9930 ****
+*** 9932,9941 ****
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
@ -537,7 +537,7 @@
  oop.mo:Expected error in mat oop: "m1: not applicable to 17".
  oop.mo:Expected error in mat oop: "variable <a>-x1 is not bound".
  oop.mo:Expected error in mat oop: "variable <a>-x1-set! is not bound".
--- 9921,9930 ----
+--- 9932,9941 ----
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
--- a/mats/patch-interpret-0-f-t-f
+++ b/mats/patch-interpret-0-f-t-f
@ -1,5 +1,5 @@
-*** errors-compile-0-f-t-f	2017-03-15 13:34:41.791223868 -0400
--- errors-interpret-0-f-t-f	2017-03-15 13:39:51.605705652 -0400
+*** errors-compile-0-f-t-f	2017-05-29 02:30:33.000000000 -0400
+--- errors-interpret-0-f-t-f	2017-05-29 02:54:57.000000000 -0400
 ***************
 *** 1,7 ****
  primvars.mo:Expected error in mat make-parameter: "make-parameter: 2 is not a procedure".
@ -312,7 +312,7 @@
  record.mo:Expected error in mat foreign-data: "foreign-alloc: <int> is not a positive fixnum".
  record.mo:Expected error in mat foreign-data: "foreign-alloc: -5 is not a positive fixnum".
 ***************
-*** 7266,7304 ****
+*** 7275,7313 ****
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -352,7 +352,7 @@
  record.mo:Expected error in mat record?: "record?: 4 is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
--- 7266,7304 ----
+--- 7275,7313 ----
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -393,7 +393,7 @@
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
 ***************
-*** 7313,7369 ****
+*** 7322,7378 ****
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: invalid protocol flimflam".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure not-a-procedure".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure spam".
@ -451,7 +451,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "define-record-type: incompatible record type cpoint - different parent".
  record.mo:Expected error in mat r6rs-records-syntactic: "define-record-type: incompatible record type cpoint - different parent".
  record.mo:Expected error in mat r6rs-records-syntactic: "cannot extend define-record-type parent fratrat".
--- 7313,7369 ----
+--- 7322,7378 ----
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: invalid protocol flimflam".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure not-a-procedure".
  record.mo:Expected error in mat r6rs-records-procedural: "attempt to apply non-procedure spam".
@ -510,7 +510,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "define-record-type: incompatible record type cpoint - different parent".
  record.mo:Expected error in mat r6rs-records-syntactic: "cannot extend define-record-type parent fratrat".
 ***************
-*** 8451,8463 ****
+*** 8461,8473 ****
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -524,7 +524,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
--- 8451,8463 ----
+--- 8461,8473 ----
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx-: "fx-: #f is not a fixnum".
  fx.mo:Expected error in mat fx*: "fx*: (a . b) is not a fixnum".
@ -539,7 +539,7 @@
  fx.mo:Expected error in mat r6rs:fx*: "fx*: <-int> is not a fixnum".
  fx.mo:Expected error in mat r6rs:fx*: "fx*: #f is not a fixnum".
 ***************
-*** 9921,9930 ****
+*** 9932,9941 ****
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
@ -550,7 +550,7 @@
  oop.mo:Expected error in mat oop: "m1: not applicable to 17".
  oop.mo:Expected error in mat oop: "variable <a>-x1 is not bound".
  oop.mo:Expected error in mat oop: "variable <a>-x1-set! is not bound".
--- 9921,9930 ----
+--- 9932,9941 ----
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
--- a/mats/patch-interpret-0-t-f-f
+++ b/mats/patch-interpret-0-t-f-f
@ -1,5 +1,5 @@
-*** errors-compile-0-t-f-f	2017-03-15 13:31:20.355212128 -0400
--- errors-interpret-0-t-f-f	2017-03-15 14:09:36.249053122 -0400
+*** errors-compile-0-t-f-f	2017-05-28 20:58:24.000000000 -0400
+--- errors-interpret-0-t-f-f	2017-05-28 22:10:11.000000000 -0400
 ***************
 *** 1,7 ****
  primvars.mo:Expected error in mat make-parameter: "make-parameter: 2 is not a procedure".
@ -205,7 +205,7 @@
  7.mo:Expected error in mat eval: "compile: 7 is not an environment".
  7.mo:Expected error in mat expand: "sc-expand: 7 is not an environment".
 ***************
-*** 7277,7283 ****
+*** 7286,7292 ****
  record.mo:Expected error in mat record25: "invalid value #\9 for foreign type uptr".
  record.mo:Expected error in mat record25: "invalid value 10 for foreign type float".
  record.mo:Expected error in mat record25: "invalid value 11.0+0.0i for foreign type double".
@ -213,7 +213,7 @@
  record.mo:Expected error in mat record25: "invalid value 12.0 for foreign type long-long".
  record.mo:Expected error in mat record25: "invalid value 13.0 for foreign type unsigned-long-long".
  record.mo:Expected error in mat record25: "invalid value 3.0 for foreign type int".
--- 7277,7283 ----
+--- 7286,7292 ----
  record.mo:Expected error in mat record25: "invalid value #\9 for foreign type uptr".
  record.mo:Expected error in mat record25: "invalid value 10 for foreign type float".
  record.mo:Expected error in mat record25: "invalid value 11.0+0.0i for foreign type double".
@ -222,7 +222,7 @@
  record.mo:Expected error in mat record25: "invalid value 13.0 for foreign type unsigned-long-long".
  record.mo:Expected error in mat record25: "invalid value 3.0 for foreign type int".
 ***************
-*** 9213,9237 ****
+*** 9224,9248 ****
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
@ -248,7 +248,7 @@
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier booleen".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier integer-34".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure result type specifier chare".
--- 9213,9237 ----
+--- 9224,9248 ----
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
  foreign.mo:Expected error in mat foreign-procedure: "foreign-procedure: invalid foreign procedure handle foo".
@ -275,7 +275,7 @@
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure argument type specifier integer-34".
  foreign.mo:Expected error in mat foreign-procedure: "invalid foreign-procedure result type specifier chare".
 ***************
-*** 9244,9275 ****
+*** 9255,9286 ****
  foreign.mo:Expected error in mat foreign-sizeof: "incorrect number of arguments to #<procedure foreign-sizeof>".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier i-am-not-a-type".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
@ -308,7 +308,7 @@
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
--- 9244,9275 ----
+--- 9255,9286 ----
  foreign.mo:Expected error in mat foreign-sizeof: "incorrect number of arguments to #<procedure foreign-sizeof>".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier i-am-not-a-type".
  foreign.mo:Expected error in mat foreign-sizeof: "foreign-sizeof: invalid foreign type specifier 1".
@ -342,7 +342,7 @@
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
 ***************
-*** 9277,9302 ****
+*** 9288,9313 ****
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
@ -369,7 +369,7 @@
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
--- 9277,9302 ----
+--- 9288,9313 ----
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
  foreign.mo:Expected error in mat foreign-strings: "foreign-callable: invalid return value ("ello" 4) from #<procedure>".
@ -397,7 +397,7 @@
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
 ***************
-*** 9307,9341 ****
+*** 9318,9352 ****
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
@ -433,7 +433,7 @@
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
--- 9307,9341 ----
+--- 9318,9352 ----
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
  foreign.mo:Expected error in mat foreign-fixed-types: "foreign-callable: invalid return value (- x 7) from #<procedure>".
@ -470,7 +470,7 @@
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
  foreign.mo:Expected error in mat foreign-C-types: "foreign-callable: invalid return value (73 74) from #<procedure>".
 ***************
-*** 9921,9930 ****
+*** 9932,9941 ****
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
@ -481,7 +481,7 @@
  oop.mo:Expected error in mat oop: "m1: not applicable to 17".
  oop.mo:Expected error in mat oop: "variable <a>-x1 is not bound".
  oop.mo:Expected error in mat oop: "variable <a>-x1-set! is not bound".
--- 9921,9930 ----
+--- 9932,9941 ----
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
--- a/mats/patch-interpret-0-t-t-f
+++ b/mats/patch-interpret-0-t-t-f
@ -1,5 +1,5 @@
-*** errors-compile-0-t-t-f	2017-03-15 13:27:50.847239990 -0400
--- errors-interpret-0-t-t-f	2017-03-15 14:13:06.129081411 -0400
+*** errors-compile-0-t-t-f	2017-05-28 20:52:16.000000000 -0400
+--- errors-interpret-0-t-t-f	2017-05-28 22:15:43.000000000 -0400
 ***************
 *** 1,7 ****
  primvars.mo:Expected error in mat make-parameter: "make-parameter: 2 is not a procedure".
@ -312,7 +312,7 @@
  record.mo:Expected error in mat foreign-data: "foreign-alloc: <int> is not a positive fixnum".
  record.mo:Expected error in mat foreign-data: "foreign-alloc: -5 is not a positive fixnum".
 ***************
-*** 7266,7304 ****
+*** 7275,7313 ****
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -352,7 +352,7 @@
  record.mo:Expected error in mat record?: "record?: 4 is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
--- 7266,7304 ----
+--- 7275,7313 ----
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record22: "invalid field specifier (immutable creepy q)".
  record.mo:Expected error in mat record23: "make-record-type: cannot extend sealed record type #<record type foo>".
@ -393,7 +393,7 @@
  record.mo:Expected error in mat record?: "record?: a is not a record type descriptor".
  record.mo:Expected error in mat record?: "record?: #(1) is not a record type descriptor".
 ***************
-*** 7324,7359 ****
+*** 7333,7368 ****
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: record constructor descriptor #<record constructor descriptor> is not for parent of record type #<record type grand-child>".
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-type-descriptor: cannot extend sealed record type #<record type bar>".
  record.mo:Expected error in mat r6rs-records-syntactic: "invalid syntax point".
@ -430,7 +430,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "record-rtd: #<ex3> is not a record".
  record.mo:Expected error in mat r6rs-records-syntactic: "record-rtd: #<ex3> is not a record".
  record.mo:Expected error in mat r6rs-records-syntactic: "parent record type is sealed ex3".
--- 7324,7359 ----
+--- 7333,7368 ----
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-constructor-descriptor: record constructor descriptor #<record constructor descriptor> is not for parent of record type #<record type grand-child>".
  record.mo:Expected error in mat r6rs-records-procedural: "make-record-type-descriptor: cannot extend sealed record type #<record type bar>".
  record.mo:Expected error in mat r6rs-records-syntactic: "invalid syntax point".
@ -468,7 +468,7 @@
  record.mo:Expected error in mat r6rs-records-syntactic: "record-rtd: #<ex3> is not a record".
  record.mo:Expected error in mat r6rs-records-syntactic: "parent record type is sealed ex3".
 ***************
-*** 9921,9930 ****
+*** 9932,9941 ****
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
@ -479,7 +479,7 @@
  oop.mo:Expected error in mat oop: "m1: not applicable to 17".
  oop.mo:Expected error in mat oop: "variable <a>-x1 is not bound".
  oop.mo:Expected error in mat oop: "variable <a>-x1-set! is not bound".
--- 9921,9930 ----
+--- 9932,9941 ----
  exceptions.mo:Expected error in mat assert: "failed assertion (memq (quote b) (quote (1 2 a 3 4)))".
  exceptions.mo:Expected error in mat assert: "failed assertion (q ...)".
  exceptions.mo:Expected error in mat assert: "failed assertion (andmap symbol? (syntax (x ...)))".
--- a/mats/patch-interpret-3-f-f-f
+++ b/mats/patch-interpret-3-f-f-f
@ -1,5 +1,5 @@
-*** errors-compile-3-f-f-f	2017-03-15 14:40:40.405994677 -0400
--- errors-interpret-3-f-f-f	2017-03-15 14:58:08.035311732 -0400
+*** errors-compile-3-f-f-f	2017-05-29 02:26:29.000000000 -0400
+--- errors-interpret-3-f-f-f	2017-05-29 03:10:12.000000000 -0400
 ***************
 *** 1,3 ****
 --- 1,9 ----
--- a/mats/patch-interpret-3-f-t-f
+++ b/mats/patch-interpret-3-f-t-f
@ -1,5 +1,5 @@
-*** errors-compile-3-f-t-f	2017-03-15 14:55:31.783838227 -0400
--- errors-interpret-3-f-t-f	2017-03-15 15:00:39.238802247 -0400
+*** errors-compile-3-f-t-f	2017-05-29 02:34:27.000000000 -0400
+--- errors-interpret-3-f-t-f	2017-05-29 02:58:45.000000000 -0400
 ***************
 *** 1,3 ****
 --- 1,9 ----
--- a/mats/patch-interpret-3-t-f-f
+++ b/mats/patch-interpret-3-t-f-f
@ -1,5 +1,5 @@
-*** errors-compile-3-t-f-f	2017-03-15 14:52:21.788478423 -0400
--- errors-interpret-3-t-f-f	2017-03-15 15:29:24.979528265 -0400
+*** errors-compile-3-t-f-f	2017-05-28 23:30:31.000000000 -0400
+--- errors-interpret-3-t-f-f	2017-05-29 00:44:38.000000000 -0400
 ***************
 *** 1,3 ****
 --- 1,9 ----
--- a/mats/patch-interpret-3-t-t-f
+++ b/mats/patch-interpret-3-t-t-f
@ -1,5 +1,5 @@
-*** errors-compile-3-t-t-f	2017-03-15 14:49:04.970141609 -0400
--- errors-interpret-3-t-t-f	2017-03-15 15:32:47.443984424 -0400
+*** errors-compile-3-t-t-f	2017-05-28 23:25:02.000000000 -0400
+--- errors-interpret-3-t-t-f	2017-05-29 00:50:59.000000000 -0400
 ***************
 *** 1,3 ****
 --- 1,9 ----
--- a/s/cmacros.ss
+++ b/s/cmacros.ss
@ -440,7 +440,7 @@
 (define-constant fasl-type-small-integer 25)
 (define-constant fasl-type-base-rtd 26)
 (define-constant fasl-type-fxvector 27)
-; 28
+(define-constant fasl-type-ephemeron 28)
 (define-constant fasl-type-bytevector 29)
 (define-constant fasl-type-weak-pair 30)
 (define-constant fasl-type-eq-hashtable 31)
@ -640,15 +640,16 @@
      (symbol "symbol" #\x 2)            ;
      (port "port" #\q 3)                ;
      (weakpair "weakpr" #\w 4)          ;
-      (pure "pure" #\p 5)                ; swept immutable objects allocated here (all ptrs)
-      (continuation "cont" #\k 6)        ;
-      (code "code" #\c 7)                ;
-      (pure-typed-object "p-tobj" #\r 8) ;
-      (impure-record "ip-rec" #\s 9))    ;
+      (ephemeron "emph" #\e 5)           ;
+      (pure "pure" #\p 6)                ; swept immutable objects allocated here (all ptrs)
+      (continuation "cont" #\k 7)        ;
+      (code "code" #\c 8)                ;
+      (pure-typed-object "p-tobj" #\r 9) ;
+      (impure-record "ip-rec" #\s 10))   ;
    (unswept
-      (data "data" #\d 10)))             ; unswept objects allocated here
+      (data "data" #\d 11)))             ; unswept objects allocated here
  (unreal
-    (empty "empty" #\e 11)))             ; available segments
+    (empty "empty" #\e 12)))             ; available segments

 ;;; enumeration of types for which gc tracks object counts
 ;;; also update gc.c
@ -678,7 +679,8 @@
 (define-constant countof-locked 22)
 (define-constant countof-guardian 23)
 (define-constant countof-oblist 24)
-(define-constant countof-types 25)
+(define-constant countof-ephemeron 25)
+(define-constant countof-types 26)

 ;;; type-fixnum is assumed to be all zeros by at least by vector, fxvector,
 ;;; and bytevector index checks
@ -1182,6 +1184,12 @@
  ([iptr type]
   [ptr ref]))

+(define-primitive-structure-disps ephemeron type-pair
+  ([ptr car]
+   [ptr cdr]
+   [ptr next] ; `next` is needed by the GC to keep track of pending ephemerons
+   [ptr trigger-next])) ; `trigger-next` is similar, but for segment-specific lists
+
 (define-primitive-structure-disps tlc type-typed-object
  ([iptr type]
   [ptr keyval]
--- a/s/fasl.ss
+++ b/s/fasl.ss
@ -204,26 +204,32 @@

 (define wrf-pair
  (lambda (x p t a?)
-    (if (weak-pair? x)
-        (begin
-          (put-u8 p (constant fasl-type-weak-pair))
-          (wrf (car x) p t a?)
-          (wrf (cdr x) p t a?))
-        (begin ; more like list*
-          (put-u8 p (constant fasl-type-pair))
-          (let ([n (let wrf-pair-loop0 ([n 1] [x (cdr x)])
-                     ; cut off at end or at shared structure
-                      (if (and (pair? x)
-                               (not (weak-pair? x))
-                               (not (eq-hashtable-ref (table-hash t) x #f)))
-                          (wrf-pair-loop0 (fx+ n 1) (cdr x))
-                          n))])
-             (put-uptr p n)
-             (let wrf-pair-loop1 ([x x] [n n])
-                (wrf (car x) p t a?)
-                (if (fx= n 1)
-                    (wrf (cdr x) p t a?)
-                    (wrf-pair-loop1 (cdr x) (fx- n 1)))))))))
+    (cond
+      [(weak-pair? x)
+       (put-u8 p (constant fasl-type-weak-pair))
+       (wrf (car x) p t a?)
+       (wrf (cdr x) p t a?)]
+      [(ephemeron-pair? x)
+       (put-u8 p (constant fasl-type-ephemeron))
+       (wrf (car x) p t a?)
+       (wrf (cdr x) p t a?)]
+      [else
+       ; more like list*
+       (put-u8 p (constant fasl-type-pair))
+       (let ([n (let wrf-pair-loop0 ([n 1] [x (cdr x)])
+                  ; cut off at end or at shared structure
+                  (if (and (pair? x)
+                           (not (weak-pair? x))
+                           (not (ephemeron-pair? x))
+                           (not (eq-hashtable-ref (table-hash t) x #f)))
+                      (wrf-pair-loop0 (fx+ n 1) (cdr x))
+                      n))])
+         (put-uptr p n)
+         (let wrf-pair-loop1 ([x x] [n n])
+           (wrf (car x) p t a?)
+           (if (fx= n 1)
+               (wrf (cdr x) p t a?)
+               (wrf-pair-loop1 (cdr x) (fx- n 1)))))])))

 (define wrf-symbol
  (lambda (x p t a?)
--- a/s/library.ss
+++ b/s/library.ss
@ -1435,7 +1435,7 @@
             [b (vector-ref vec idx)])
        (lookup-keyval x b
          values
-          (let ([keyval (if (eq-ht-weak? h) (weak-cons x v) (cons x v))])
+          (let ([keyval (if (eq-ht-weak? h) (ephemeron-cons x v) (cons x v))])
            (vector-set! vec idx ($make-tlc h keyval b))
            (incr-size! h vec)
            keyval))))
@ -1451,7 +1451,7 @@
              (begin
                (vector-set! vec idx
                  ($make-tlc h
-                    (if (eq-ht-weak? h) (weak-cons x v) (cons x v))
+                    (if (eq-ht-weak? h) (ephemeron-cons x v) (cons x v))
                    b))
                (incr-size! h vec))))))
  
--- a/s/mkheader.ss
+++ b/s/mkheader.ss
@ -781,6 +781,11 @@
        (definit INITBOXREF box ref)
        (defset SETBOXREF box ref)

+        (defref EPHEMERONNEXT ephemeron next)
+        (definit INITEPHEMERONNEXT ephemeron next)
+        (defref EPHEMERONTRIGGERNEXT ephemeron trigger-next)
+        (definit INITEPHEMERONTRIGGERNEXT ephemeron trigger-next)
+
        (defref TLCTYPE tlc type)
        (defref TLCKEYVAL tlc keyval)
        (defref TLCHT tlc ht)
--- a/s/newhash.ss
+++ b/s/newhash.ss
@ -1019,7 +1019,7 @@ Documentation notes:
                          b
                          ($make-tlc h2
                            (let* ([keyval ($tlc-keyval b)] [key (car keyval)] [val (cdr keyval)])
-                              (if weak?  (weak-cons key val) (cons key val)))
+                              (if weak?  (ephemeron-cons key val) (cons key val)))
                            (inner ($tlc-next b))))))
                  (outer (fx+ i 1)))))
          h2))))
--- a/s/primdata.ss
+++ b/s/primdata.ss
@ -1241,6 +1241,8 @@
  (environment? [sig [(ptr) -> (boolean)]] [flags pure unrestricted mifoldable discard])
  (environment-mutable? [sig [(environment) -> (boolean)]] [flags pure mifoldable discard])
  (environment-symbols [sig [(environment) -> (list)]] [flags true])
+  (ephemeron-cons [sig [(ptr ptr) -> (ptr)]] [flags unrestricted alloc])
+  (ephemeron-pair? [sig [(ptr) -> (boolean)]] [flags pure unrestricted mifoldable discard])
  (errorf [sig [(who string sub-ptr ...) -> (bottom)]] [flags abort-op]) ; second arg is format string
  (eq-hashtable? [sig [(ptr) -> (boolean)]] [flags pure unrestricted mifoldable discard])
  (eq-hashtable-cell [sig [(eq-hashtable ptr ptr) -> ((ptr . ptr))]] [flags true])
--- a/s/prims.ss
+++ b/s/prims.ss
@ -63,6 +63,16 @@
    (scheme-object)
    scheme-object))

+(define ephemeron-cons
+  (foreign-procedure "(cs)s_ephemeron_cons"
+    (scheme-object scheme-object)
+    scheme-object))
+
+(define ephemeron-pair?
+  (foreign-procedure "(cs)s_ephemeron_pairp"
+    (scheme-object)
+    scheme-object))
+
 (define $split-continuation
  (foreign-procedure "(cs)single_continuation"
    (scheme-object iptr)