Bugfix in expansion-time progn reduction.

This was exposed by causing an issue in the multi-pass
expansion strategy used in tagbody which shields macro forms
from a global macro using a local macro.

* eval.c (expand_progn): When calling constantp,
pass the macro environment, as required, rather than nil.
This was causing (go ...) forms in tagbody to be expanded
in the global environment using the global go macro
which unconditionally throws an error about an undefined
label, rather than using the harmless local go macrolet.

1 files changed, 1 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index 2bf3d694..b34b364f 100644
--- a/eval.c
+++ b/eval.c
@@ -2576,7 +2576,7 @@ static val expand_progn(val form, val menv)
       return rlcp(cdr(ex_f), form);
     }
 
-    if ((symbolp(ex_f) || constantp(ex_f, nil)) && ex_r)
+    if ((symbolp(ex_f) || constantp(ex_f, menv)) && ex_r)
       return rlcp(ex_r, form);
 
     if (ex_f == f && ex_r == r)