debug_check calls are the culprit triggering lookahead

in lazy lists. Changing the semantics of the data argument
so that it can just be the list.

* debug.c (debug): If data is a cons, then replace it with
the first item.

* match.c (match_files): Pass c.data to debug_check, rather
than the value of if2(consp(c.data), car(c.data)) which accesses
car(c.data) whether or not we are debugging.
(match_fun): Likewise.

1 files changed, 2 insertions, 4 deletions

diff --git a/match.c b/match.c
index 746a622c..81107598 100644
--- a/match.c
+++ b/match.c
@@ -3700,8 +3700,7 @@ repeat_spec_same_data:
   {
     spec_bind (specline, first_spec, c.spec);
 
-    debug_check(first_spec, c.bindings, if2(consp(c.data), car(c.data)), 
-                c.data_lineno, nil, nil);
+    debug_check(first_spec, c.bindings, c.data, c.data_lineno, nil, nil);
 
     if (consp(first_spec) && !rest(specline)) {
       val sym = first(first_spec);
@@ -3809,8 +3808,7 @@ val match_fun(val name, val args, val input, val files)
 
   debug_enter;
 
-  debug_check(call, c.bindings, if2(consp(c.data), car(c.data)), 
-              c.data_lineno, nil, nil);
+  debug_check(call, c.bindings, c.data, c.data_lineno, nil, nil);
 
   ret = v_fun(&c);