From: Matt Birkholz <matt@birchwood-abbey.net>
Date: Tue, 23 Oct 2018 18:39:51 +0000 (-0700)
Subject: find_binding_cell: no bindings in a null environment
X-Git-Tag: mit-scheme-pucked-10.1.2~16^2~185^2
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=3fab110bc5d8e5d050889c1eb301440d27b186b6;p=mit-scheme.git

find_binding_cell: no bindings in a null environment

No need to fail an assert during test-library-loader neither.
---

diff --git a/src/microcode/lookup.c b/src/microcode/lookup.c
index 78fb18345..d4f2b6448 100644
--- a/src/microcode/lookup.c
+++ b/src/microcode/lookup.c
@@ -1204,6 +1204,8 @@ static SCHEME_OBJECT *
 find_binding_cell (SCHEME_OBJECT environment, SCHEME_OBJECT symbol,
 		   SCHEME_OBJECT * frame_ret)
 {
+  if (NULL_FRAME_P (environment))
+    return (0);
   assert (ENVIRONMENT_P (environment));
   SCHEME_OBJECT frame = environment;
   while (1)