Regression 2.0 related to symbol aliases

[Tim Van Holder]

Revision 1.57 of src/symtab.c removed a symbol_type_set() call
from symbol_make_alias() (without altering that function's
descriptive comment, by the way).  symbol_type_set() calls were
added to symbol_check_alias_consistency(), presumably to make
up for that removal.  However, symbol_check_alias_consistency()
isn't called (via symbols_pack()) until the grammar file has been
completely, and the symbol type info is used during that parse.

As a result, aliases for typed symbols are completely broken in
bison 2.0.  The patch below restores the symbol_make_alias()
behavior, and avoids type redeclaration errors in
symbol_check_alias_consistency().
I also added a simplistic test.

Index: src/symtab.c
===================================================================
RCS file: /cvsroot/bison/bison/src/symtab.c,v
retrieving revision 1.59
diff -u -u -p -d -r1.59 src/symtab.c
--- src/symtab.c        16 Dec 2004 00:08:21 -0000      1.59
+++ src/symtab.c        12 Apr 2005 13:12:03 -0000
@@ -264,6 +264,7 @@ symbol_make_alias (symbol *sym, symbol *
        abort ();
       sym->number = symval->number =
        (symval->number < sym->number) ? symval->number : sym->number;
+      symbol_type_set (symval, sym->type_name, loc);
     }
 }

@@ -285,10 +286,14 @@ symbol_check_alias_consistency (symbol *

   if (orig->type_name || alias->type_name)
     {
-      if (orig->type_name)
-       symbol_type_set (alias, orig->type_name, orig->type_location);
-      else
-       symbol_type_set (orig, alias->type_name, alias->type_location);
+      if (!(orig->type_name && alias->type_name)
+         || orig->type_name != alias->type_name)
+       {
+         if (orig->type_name)
+           symbol_type_set (alias, orig->type_name, orig->type_location);
+         else
+           symbol_type_set (orig, alias->type_name, alias->type_location);
+       }
     }
--- input.at    12 Apr 2005 13:44:39 +0200      1.30
+++ input.at    12 Apr 2005 15:19:47 +0200      
@@ -272,3 +272,28 @@ AT_PARSER_CHECK([./input], 0,
 ]])

 AT_CLEANUP
+
+
+## ---------------------- ##
+## Typed symbol aliases.  ##
+## ---------------------- ##
+
+AT_SETUP([Typed symbol aliases])
+
+# Bison 2.0 broke typed symbol aliases - ensure they work.
+
+AT_DATA_GRAMMAR([input.y],
+[[%union
+{
+  int val;
+};
+%token <val> MY_TOKEN "MY TOKEN"
+%type <val> exp
+%%
+exp: "MY TOKEN";
+%%
+]])
+
+AT_CHECK([bison -o input.c input.y])
+
+AT_CLEANUP