1 files changed, 14 insertions, 0 deletions
diff --git a/proc.c b/proc.c
index e7e011a415..0436a9aaf8 100644
--- a/proc.c
+++ b/proc.c
@@ -499,6 +499,12 @@ bind_local_variables(VALUE bindval)
     return rb_vm_env_local_variables(env);
 }
 
+int
+rb_numparam_id_p(ID id)
+{
+    return (tNUMPARAM_1 << ID_SCOPE_SHIFT) <= id && id < ((tNUMPARAM_1 + 10) << ID_SCOPE_SHIFT);
+}
+
 /*
  *  call-seq:
  *     binding.local_variable_get(symbol) -> obj
@@ -525,6 +531,10 @@ bind_local_variable_get(VALUE bindval, VALUE sym)
     const rb_env_t *env;
 
     if (!lid) goto undefined;
+    if (rb_numparam_id_p(lid)) {
+        rb_name_err_raise("numbered parameter '%1$s' is not a local variable",
+                          bindval, ID2SYM(lid));
+    }
 
     GetBindingPtr(bindval, bind);
 
@@ -574,6 +584,10 @@ bind_local_variable_set(VALUE bindval, VALUE sym, VALUE val)
     const rb_env_t *env;
 
     if (!lid) lid = rb_intern_str(sym);
+    if (rb_numparam_id_p(lid)) {
+        rb_name_err_raise("numbered parameter '%1$s' is not a local variable",
+                          bindval, ID2SYM(lid));
+    }
 
     GetBindingPtr(bindval, bind);
     env = VM_ENV_ENVVAL_PTR(vm_block_ep(&bind->block));