diff --git a/src/racket/src/hash.c b/src/racket/src/hash.c
index 1dc23f6e64..70f9c8e16c 100644
--- a/src/racket/src/hash.c
+++ b/src/racket/src/hash.c
@@ -930,6 +930,7 @@ END_XFORM_SKIP;
 typedef struct Hash_Info {
   intptr_t depth; /* always odd */
   Scheme_Object *recur;
+  Scheme_Object *insp; /* obtained lazily */
 } Hash_Info;
 
 static uintptr_t equal_hash_key(Scheme_Object *o, uintptr_t k, Hash_Info *hi);
@@ -942,6 +943,7 @@ static Scheme_Object *hash_recur(int argc, Scheme_Object **argv, Scheme_Object *
 
   hi = (Hash_Info *)SCHEME_PRIM_CLOSURE_ELS(prim)[0];
   hi->depth += 2;
+  hi->insp = NULL; /* in case recursive call is `parameterize'd */
 
   v = to_signed_hash(equal_hash_key(argv[0], 0, hi));
   
@@ -1297,8 +1299,16 @@ static uintptr_t equal_hash_key(Scheme_Object *o, uintptr_t k, Hash_Info *hi)
         }
       } else {
         Scheme_Object *insp;
-        insp = scheme_get_param(scheme_current_config(), MZCONFIG_INSPECTOR);
-        if (scheme_inspector_sees_part(o, insp, -2)) {
+        if (scheme_struct_is_transparent(o))
+          insp = NULL;
+        else {
+          insp = hi->insp;
+          if (!insp) {
+            insp = scheme_get_param(scheme_current_config(), MZCONFIG_INSPECTOR);
+            hi->insp = insp;
+          }
+        }
+        if (!insp || scheme_inspector_sees_part(o, insp, -2)) {
           int i;
           Scheme_Structure *s1 = (Scheme_Structure *)o;
 	
@@ -1476,6 +1486,7 @@ intptr_t scheme_equal_hash_key(Scheme_Object *o)
 
   hi.depth = 1;
   hi.recur = NULL;
+  hi.insp = NULL;
 
   return to_signed_hash(equal_hash_key(o, 0, &hi));
 }
@@ -1486,6 +1497,7 @@ intptr_t scheme_equal_hash_key2(Scheme_Object *o)
 
   hi.depth = 1;
   hi.recur = NULL;
+  hi.insp = NULL;
 
   return to_signed_hash(equal_hash_key2(o, &hi));
 }
@@ -1753,8 +1765,15 @@ static uintptr_t equal_hash_key2(Scheme_Object *o, Hash_Info *hi)
         }
       } else {
         Scheme_Object *insp;
-        insp = scheme_get_param(scheme_current_config(), MZCONFIG_INSPECTOR);
-        if (scheme_inspector_sees_part(o, insp, -2)) {
+        if (scheme_struct_is_transparent(o))
+          insp = NULL;
+        else {
+          if (!insp) {
+            insp = scheme_get_param(scheme_current_config(), MZCONFIG_INSPECTOR);
+            hi->insp = insp;
+          }
+        }
+        if (!insp || scheme_inspector_sees_part(o, insp, -2)) {
           int i;
           uintptr_t k = 0;
           Scheme_Structure *s1 = (Scheme_Structure *)o;
diff --git a/src/racket/src/schpriv.h b/src/racket/src/schpriv.h
index 7367a4819b..dc2eb7e9a0 100644
--- a/src/racket/src/schpriv.h
+++ b/src/racket/src/schpriv.h
@@ -817,6 +817,7 @@ typedef struct Scheme_Struct_Property {
 } Scheme_Struct_Property;
 
 int scheme_inspector_sees_part(Scheme_Object *s, Scheme_Object *insp, int pos);
+int scheme_struct_is_transparent(Scheme_Object *s);
 
 typedef struct Scheme_Struct_Type {
   Scheme_Inclhash_Object iso; /* scheme_struct_type_type */
diff --git a/src/racket/src/struct.c b/src/racket/src/struct.c
index 55e00f2076..b085de8a1d 100644
--- a/src/racket/src/struct.c
+++ b/src/racket/src/struct.c
@@ -3051,6 +3051,23 @@ int scheme_inspector_sees_part(Scheme_Object *s, Scheme_Object *insp, int pos)
   }
 }
 
+int scheme_struct_is_transparent(Scheme_Object *s)
+{
+  Scheme_Struct_Type *stype;
+  int p;
+
+  if (SCHEME_CHAPERONEP(s))
+    s = SCHEME_CHAPERONE_VAL(s);
+
+  stype = ((Scheme_Structure *)s)->stype;
+
+  for (p = stype->name_pos; p--; ) {
+    if (SCHEME_TRUEP(stype->parent_types[p]->inspector))
+      return 0;
+  }
+
+  return 1;
+}
 
 #define STRUCT_mPROCP(o, v)						\
   (SCHEME_PRIMP(o) && ((((Scheme_Primitive_Proc *)o)->pp.flags & SCHEME_PRIM_OTHER_TYPE_MASK) == (v)))