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Re: [PATCH] [COMMITTED] Add warning about false being implicitly converted to NULL in parameter passing
On Monday, 12. March 2007, Manuel López-Ibáñez wrote:
> Since yours is approved and mine hasn't been reviewed yet. Would you
> mind posting the final patch once you commit it?
Sure. Here is the factored out version, committed to mainline as r122934.
2007-03-15 Dirk Mueller <dmueller@suse.de>
PR c++/30860
* call.c (convert_conversion_warnings): New..
(convert_like_real): .. factored out from here.
(convert_conversion_warnings): Add warning about
false being converted to NULL in argument passing.
* g++.dg/warn/Wconversion2.C: New.
--- cp/call.c
+++ cp/call.c
@@ -4245,6 +4245,41 @@ build_temp (tree expr, tree type, int fl
return expr;
}
+/* Perform warnings about conversion of EXPR to type TOTYPE.
+ FN and ARGNUM are used for diagnostics. */
+
+static void
+convert_conversion_warnings (tree totype, tree expr, tree fn, int argnum)
+{
+ tree t = non_reference (totype);
+
+ /* Issue warnings about peculiar, but valid, uses of NULL. */
+ if (expr == null_node && TREE_CODE (t) != BOOLEAN_TYPE && ARITHMETIC_TYPE_P
(t))
+ {
+ if (fn)
+ warning (OPT_Wconversion, "passing NULL to non-pointer argument %P of %qD",
+ argnum, fn);
+ else
+ warning (OPT_Wconversion, "converting to non-pointer type %qT from NULL",
t);
+ }
+
+ /* Warn about assigning a floating-point type to an integer type. */
+ if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
+ && TREE_CODE (t) == INTEGER_TYPE)
+ {
+ if (fn)
+ warning (OPT_Wconversion, "passing %qT for argument %P to %qD",
+ TREE_TYPE (expr), argnum, fn);
+ else
+ warning (OPT_Wconversion, "converting to %qT from %qT", t, TREE_TYPE
(expr));
+ }
+
+ /* Issue warnings if "false" is converted to a NULL pointer */
+ if (expr == boolean_false_node && fn && POINTER_TYPE_P (t))
+ warning (OPT_Wconversion,
+ "converting %<false%> to pointer type for argument %P of %qD",
+ argnum, fn);
+}
/* Perform the conversions in CONVS on the expression EXPR. FN and
ARGNUM are used for diagnostics. ARGNUM is zero based, -1
@@ -4293,30 +4328,7 @@ convert_like_real (conversion *convs, tr
}
if (issue_conversion_warnings)
- {
- tree t = non_reference (totype);
-
- /* Issue warnings about peculiar, but valid, uses of NULL. */
- if (expr == null_node && TREE_CODE (t) != BOOLEAN_TYPE &&
ARITHMETIC_TYPE_P (t))
- {
- if (fn)
- warning (OPT_Wconversion, "passing NULL to non-pointer argument %P
of %qD",
- argnum, fn);
- else
- warning (OPT_Wconversion, "converting to non-pointer type %qT from
NULL", t);
- }
-
- /* Warn about assigning a floating-point type to an integer type. */
- if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
- && TREE_CODE (t) == INTEGER_TYPE)
- {
- if (fn)
- warning (OPT_Wconversion, "passing %qT for argument %P to %qD",
- TREE_TYPE (expr), argnum, fn);
- else
- warning (OPT_Wconversion, "converting to %qT from %qT", t, TREE_TYPE
(expr));
- }
- }
+ convert_conversion_warnings (totype, expr, fn, argnum);
switch (convs->kind)
{
--- testsuite/g++.dg/warn/Wconversion2.C
+++ testsuite/g++.dg/warn/Wconversion2.C
@@ -0,0 +1,4 @@
+// { dg-options "-Wconversion" }
+
+void foo(const char *);
+void bar() { foo(false); } // { dg-warning "pointer type argument" }