Newer gcc silently accepts mixing C Code and Declarations

[Michael Culbertson]

> Date: Wed, 2 Jul 2003 23:25:35 +0200
> From: Christian Stimming <stimming at tuhh.de>
> Subject: Newer gcc silently accepts mixing C Code and Declarations

> So what do we do? First of all, if anybody happens to run a non-gcc3.3 and
> discovers such a syntax error, then please don't start flaming the gcc3.3
> folks but please simply go ahead and fix that. Second, does anyone know some
> secret gcc switch that might enable again the detection of that problem? If
> there is none, then, well, what do people think about making gnucash
> - -pedantic proof... or do we simply live with those errors every now and then?

Below is a gcc 3.3 patch that adds a -Wmixed_declarations switch to spit
out a warning for mixed declarations and code in C89 mode.  I haven't
tested it thoroughly, but it should generate the warning anywhere
-pedantic would, and it works in a simple test case.

Enjoy,
Michael Culbertson

-------------- Begin GCC 3.3 Patch --------------------

--- c-parse.c-orig	Sat Jul  5 18:00:17 2003
+++ c-parse.c	Sat Jul  5 18:01:00 2003
@@ -3991,7 +3991,7 @@
     break;}
 case 431:
 #line 1929 "c-parse.y"
-{ if (pedantic && !flag_isoc99)
+{ if ((pedantic || warn_mixed_declarations) && !flag_isoc99)
 		    pedwarn ("ISO C89 forbids mixed declarations and code"); ;
     break;}
 case 446:
--- c-parse.in-orig	Sat Jul  5 17:59:49 2003
+++ c-parse.in	Sat Jul  5 18:00:11 2003
@@ -2032,7 +2032,7 @@
 lineno_stmt_decl_or_labels_ending_decl:
 	  lineno_decl
 	| lineno_stmt_decl_or_labels_ending_stmt lineno_decl
-		{ if (pedantic && !flag_isoc99)
+		{ if ((pedantic || warn_mixed_declarations) && !flag_isoc99)
 		    pedwarn ("ISO C89 forbids mixed declarations and code"); }
 	| lineno_stmt_decl_or_labels_ending_decl lineno_decl
 	| lineno_stmt_decl_or_labels_ending_error lineno_decl
--- c-parse.y-orig	Sat Jul  5 17:59:08 2003
+++ c-parse.y	Sat Jul  5 17:59:40 2003
@@ -1926,7 +1926,7 @@
 lineno_stmt_decl_or_labels_ending_decl:
 	  lineno_decl
 	| lineno_stmt_decl_or_labels_ending_stmt lineno_decl
-		{ if (pedantic && !flag_isoc99)
+		{ if ((pedantic || warn_mixed_declarations) && !flag_isoc99)
 		    pedwarn ("ISO C89 forbids mixed declarations and code"); }
 	| lineno_stmt_decl_or_labels_ending_decl lineno_decl
 	| lineno_stmt_decl_or_labels_ending_error lineno_decl
--- flags.h-orig	Sat Jul  5 17:58:30 2003
+++ flags.h	Sat Jul  5 17:58:56 2003
@@ -189,6 +189,10 @@

 extern int warn_strict_aliasing;

+/* Nonzero means warn about mixed declarations and code in C89 mode */
+
+extern int warn_mixed_declarations;
+
 /* Nonzero if generating code to do profiling.  */

 extern int profile_flag;
--- toplev.c-orig	Sat Jul  5 17:55:14 2003
+++ toplev.c	Sun Jul  6 02:15:11 2003
@@ -1500,6 +1500,10 @@

 int warn_strict_aliasing;

+/* Nonzero means warn about mixed declarations and code in C89 mode */
+
+int warn_mixed_declarations;
+
 /* Likewise for -W.  */

 static const lang_independent_options W_options[] =
@@ -1547,7 +1551,9 @@
   {"missing-noreturn", &warn_missing_noreturn, 1,
    N_("Warn about functions which might be candidates for attribute noreturn") },
   {"strict-aliasing", &warn_strict_aliasing, 1,
-   N_ ("Warn about code which might break the strict aliasing rules") }
+   N_ ("Warn about code which might break the strict aliasing rules") },
+  {"mixed-declarations", &warn_mixed_declarations, 1,
+   N_("Warn about mixed declarations and code in C89 mode") }
 };

 void