diff --git a/include/mruby/internal.h b/include/mruby/internal.h
index 4b06dd522..0b5a88af8 100644
--- a/include/mruby/internal.h
+++ b/include/mruby/internal.h
@@ -279,4 +279,7 @@ mrb_value mrb_bint_abs(mrb_state *mrb, mrb_value x);
 void mrb_task_mark_all(mrb_state *mrb);
 #endif
 
+/* Internal object allocation without type validation (gc.c) */
+struct RBasic* mrb_obj_alloc_core(mrb_state*, enum mrb_vtype, struct RClass*);
+
 #endif  /* MRUBY_INTERNAL_H */
diff --git a/src/gc.c b/src/gc.c
index 283d1dcdb..4f203b92b 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -563,38 +563,14 @@ mrb_gc_unregister(mrb_state *mrb, mrb_value obj)
   ARY_SET_LEN(a, w);
 }
 
-MRB_API struct RBasic*
-mrb_obj_alloc(mrb_state *mrb, enum mrb_vtype ttype, struct RClass *cls)
+/* Core allocation without type validation.
+   Used internally by mrb_proc_new, mrb_env_new, etc. */
+struct RBasic*
+mrb_obj_alloc_core(mrb_state *mrb, enum mrb_vtype ttype, struct RClass *cls)
 {
   static const RVALUE RVALUE_zero = { { { NULL, MRB_TT_FALSE } } };
   mrb_gc *gc = &mrb->gc;
 
-  if (cls) {
-    enum mrb_vtype tt;
-
-    switch (cls->tt) {
-    case MRB_TT_CLASS:
-    case MRB_TT_SCLASS:
-    case MRB_TT_MODULE:
-    case MRB_TT_ENV:
-      break;
-    default:
-      mrb_raise(mrb, E_TYPE_ERROR, "allocation failure");
-    }
-    tt = MRB_INSTANCE_TT(cls);
-    if (ttype != MRB_TT_SCLASS &&
-        ttype != MRB_TT_ICLASS &&
-        ttype != MRB_TT_ENV &&
-        ttype != MRB_TT_BIGINT &&
-        ttype != tt &&
-        !(cls == mrb->object_class && (ttype == MRB_TT_CPTR || ttype == MRB_TT_CDATA || ttype == MRB_TT_ISTRUCT))) {
-      mrb_raisef(mrb, E_TYPE_ERROR, "allocation failure of %C", cls);
-    }
-  }
-  if (ttype <= MRB_TT_FREE) {
-    mrb_raisef(mrb, E_TYPE_ERROR, "allocation failure of %C (type %d)", cls, (int)ttype);
-  }
-
 #ifdef MRB_GC_STRESS
   mrb_full_gc(mrb);
 #endif
@@ -625,6 +601,37 @@ mrb_obj_alloc(mrb_state *mrb, enum mrb_vtype ttype, struct RClass *cls)
   return &p->as.basic;
 }
 
+MRB_API struct RBasic*
+mrb_obj_alloc(mrb_state *mrb, enum mrb_vtype ttype, struct RClass *cls)
+{
+  if (cls) {
+    enum mrb_vtype tt;
+
+    switch (cls->tt) {
+    case MRB_TT_CLASS:
+    case MRB_TT_SCLASS:
+    case MRB_TT_MODULE:
+    case MRB_TT_ENV:
+      break;
+    default:
+      mrb_raise(mrb, E_TYPE_ERROR, "allocation failure");
+    }
+    tt = MRB_INSTANCE_TT(cls);
+    if (ttype != MRB_TT_SCLASS &&
+        ttype != MRB_TT_ICLASS &&
+        ttype != MRB_TT_ENV &&
+        ttype != MRB_TT_BIGINT &&
+        ttype != tt &&
+        !(cls == mrb->object_class && (ttype == MRB_TT_CPTR || ttype == MRB_TT_CDATA || ttype == MRB_TT_ISTRUCT))) {
+      mrb_raisef(mrb, E_TYPE_ERROR, "allocation failure of %C", cls);
+    }
+  }
+  if (ttype <= MRB_TT_FREE) {
+    mrb_raisef(mrb, E_TYPE_ERROR, "allocation failure of %C (type %d)", cls, (int)ttype);
+  }
+  return mrb_obj_alloc_core(mrb, ttype, cls);
+}
+
 static inline void
 add_gray_list(mrb_gc *gc, struct RBasic *obj)
 {
diff --git a/src/proc.c b/src/proc.c
index 4864cadd1..963841689 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -47,7 +47,7 @@ mrb_proc_new(mrb_state *mrb, const mrb_irep *irep)
   struct RProc *p;
   mrb_callinfo *ci = mrb->c->ci;
 
-  p = MRB_OBJ_ALLOC(mrb, MRB_TT_PROC, mrb->proc_class);
+  p = (struct RProc*)mrb_obj_alloc_core(mrb, MRB_TT_PROC, mrb->proc_class);
   if (ci) {
     struct RClass *tc = NULL;
 
@@ -76,7 +76,7 @@ mrb_env_new(mrb_state *mrb, struct mrb_context *c, mrb_callinfo *ci, int nstacks
   int n = ci->n;
   int nk = ci->nk;
 
-  e = MRB_OBJ_ALLOC(mrb, MRB_TT_ENV, NULL);
+  e = (struct REnv*)mrb_obj_alloc_core(mrb, MRB_TT_ENV, NULL);
   e->c = tc;
   MRB_ENV_SET_LEN(e, nstacks);
   bidx += (n == 15) ? 1 : n;