diff --git a/src/mzscheme/src/fun.c b/src/mzscheme/src/fun.c
index 6957578f32..7003aa4493 100644
--- a/src/mzscheme/src/fun.c
+++ b/src/mzscheme/src/fun.c
@@ -189,11 +189,12 @@ scheme_init_fun (Scheme_Env *env)
   REGISTER_SO(cached_dv_stx);
   REGISTER_SO(cached_ds_stx);
 
-  scheme_add_global_constant("procedure?",
-			     scheme_make_folding_prim(procedure_p,
-						      "procedure?",
-						      1, 1, 1),
-			     env);
+  o = scheme_make_folding_prim(procedure_p,
+			       "procedure?",
+			       1, 1, 1);
+  SCHEME_PRIM_PROC_FLAGS(o) |= SCHEME_PRIM_IS_UNARY_INLINED;
+  scheme_add_global_constant("procedure?", o, env);
+
   scheme_add_global_constant("apply",
 			     scheme_make_prim_w_arity2(apply,
 						       "apply",
diff --git a/src/mzscheme/src/jit.c b/src/mzscheme/src/jit.c
index fef0ad2d39..0359becdda 100644
--- a/src/mzscheme/src/jit.c
+++ b/src/mzscheme/src/jit.c
@@ -2051,6 +2051,18 @@ static int generate_inlined_unary(mz_jit_state *jitter, Scheme_App2_Rec *app, in
   } else if (IS_NAMED_PRIM(rator, "real?")) {
     generate_inlined_type_test(jitter, app, scheme_integer_type, scheme_complex_izi_type, for_branch, branch_short);
     return 1;
+  } else if (IS_NAMED_PRIM(rator, "procedure?")) {
+    generate_inlined_type_test(jitter, app, scheme_prim_type, scheme_native_closure_type, for_branch, branch_short);
+    return 1;
+  } else if (IS_NAMED_PRIM(rator, "vector?")) {
+    generate_inlined_type_test(jitter, app, scheme_vector_type, scheme_vector_type, for_branch, branch_short);
+    return 1;
+  } else if (IS_NAMED_PRIM(rator, "string?")) {
+    generate_inlined_type_test(jitter, app, scheme_char_string_type, scheme_char_string_type, for_branch, branch_short);
+    return 1;
+  } else if (IS_NAMED_PRIM(rator, "bytes?")) {
+    generate_inlined_type_test(jitter, app, scheme_byte_string_type, scheme_byte_string_type, for_branch, branch_short);
+    return 1;
   } else if (IS_NAMED_PRIM(rator, "eof-object?")) {
     generate_inlined_constant_test(jitter, app, scheme_eof, NULL, for_branch, branch_short);
     return 1;
diff --git a/src/mzscheme/src/string.c b/src/mzscheme/src/string.c
index f9664a86d7..f8932eae31 100644
--- a/src/mzscheme/src/string.c
+++ b/src/mzscheme/src/string.c
@@ -288,6 +288,8 @@ static Scheme_Object *complete_symbol, *continues_symbol, *aborts_symbol, *error
 void
 scheme_init_string (Scheme_Env *env)
 {
+  Scheme_Object *p;
+
   REGISTER_SO(sys_symbol);
   sys_symbol = scheme_intern_symbol(SYSTEM_TYPE_NAME);
 
@@ -327,11 +329,10 @@ scheme_init_string (Scheme_Env *env)
   REGISTER_SO(embedding_banner);
   REGISTER_SO(current_locale_name);
 
-  scheme_add_global_constant("string?",
-			     scheme_make_folding_prim(string_p,
-						      "string?",
-						      1, 1, 1),
-			     env);
+  p = scheme_make_folding_prim(string_p, "string?", 1, 1, 1);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
+  scheme_add_global_constant("string?", p, env);
+
   scheme_add_global_constant("make-string",
 			     scheme_make_noncm_prim(make_string,
 						    "make-string",
@@ -597,11 +598,10 @@ scheme_init_string (Scheme_Env *env)
 						      1, 1, 1),
 			     env);
 
-  scheme_add_global_constant("bytes?",
-			     scheme_make_folding_prim(byte_string_p,
-						      "bytes?",
-						      1, 1, 1),
-			     env);
+  p = scheme_make_folding_prim(byte_string_p, "bytes?", 1, 1, 1);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
+  scheme_add_global_constant("bytes?", p, env);
+
   scheme_add_global_constant("make-bytes",
 			     scheme_make_noncm_prim(make_byte_string,
 						    "make-bytes",
diff --git a/src/mzscheme/src/vector.c b/src/mzscheme/src/vector.c
index 9057e1fe31..0f84fa28a9 100644
--- a/src/mzscheme/src/vector.c
+++ b/src/mzscheme/src/vector.c
@@ -49,11 +49,10 @@ scheme_init_vector (Scheme_Env *env)
   zero_length_vector->type = scheme_vector_type;
   SCHEME_VEC_SIZE(zero_length_vector) = 0;
 
-  scheme_add_global_constant("vector?", 
-			     scheme_make_folding_prim(vector_p, 
-						      "vector?", 
-						      1, 1, 1), 
-			     env);
+  p = scheme_make_folding_prim(vector_p, "vector?", 1, 1, 1);
+  SCHEME_PRIM_PROC_FLAGS(p) |= SCHEME_PRIM_IS_UNARY_INLINED;
+  scheme_add_global_constant("vector?", p, env);
+
   scheme_add_global_constant("make-vector", 
 			     scheme_make_noncm_prim(make_vector, 
 						    "make-vector",