Hi,
another duplicated diagnostic message. This one happens for snippets
like the below due to the temporary for the const ref:
int g(const int&);
int m2()
{
return g(__null);
}
50660.C:4:18: warning: passing NULL to non-pointer argument 1 of ‘int
g(const int&)’
50660.C:4:18: warning: passing NULL to non-pointer argument 1 of ‘int
g(const int&)’
I'm changing conversion_null_warnings to return true when a warning is
actually produced, which is checked by convert_like_real before calling
again itself recursively. I think it should be safe to shut down in that
case all kinds of further warnings, otherwise, we could even envisage
adding an issue_conversion_null_warnings parameter to convert_like_real,
as a last resort which certainly works.
Patch tested x86_64-linux.
Thanks,
Paolo.
/////////////////////
2011-10-09 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/50660
* call.c (conversion_null_warnings): Return true when a warning
is actually emitted.
(convert_like_real): When conversion_null_warnings returns true
set issue_conversion_warnings to false.
Index: call.c
===================================================================
--- call.c (revision 179720)
+++ call.c (working copy)
@@ -5509,9 +5509,9 @@ build_temp (tree expr, tree type, int flags,
/* Perform warnings about peculiar, but valid, conversions from/to NULL.
EXPR is implicitly converted to type TOTYPE.
- FN and ARGNUM are used for diagnostics. */
+ FN and ARGNUM are used for diagnostics. Returns true if warned. */
-static void
+static bool
conversion_null_warnings (tree totype, tree expr, tree fn, int argnum)
{
tree t = non_reference (totype);
@@ -5526,6 +5526,7 @@ conversion_null_warnings (tree totype, tree expr,
else
warning_at (input_location, OPT_Wconversion_null,
"converting to non-pointer type %qT from NULL", t);
+ return true;
}
/* Issue warnings if "false" is converted to a NULL pointer */
@@ -5538,7 +5539,9 @@ conversion_null_warnings (tree totype, tree expr,
else
warning_at (input_location, OPT_Wconversion_null,
"converting %<false%> to pointer type %qT", t);
+ return true;
}
+ return false;
}
/* Perform the conversions in CONVS on the expression EXPR. FN and
@@ -5624,8 +5627,9 @@ convert_like_real (conversion *convs, tree expr, t
return cp_convert (totype, expr);
}
- if (issue_conversion_warnings && (complain & tf_warning))
- conversion_null_warnings (totype, expr, fn, argnum);
+ if (issue_conversion_warnings && (complain & tf_warning)
+ && conversion_null_warnings (totype, expr, fn, argnum))
+ issue_conversion_warnings = false;
switch (convs->kind)
{
