Hi,
this fixes the PR by checking for zero in check_default_argument and, in
case, replacing it with nullptr to avoid further warnings later on.
Should be safe enough for 4.7.1 too.
Tested x86_64-linux.
Thanks,
Paolo.
/////////////////////
/cp
2012-03-29 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/52718
* decl.c (check_default_argument): With -Wzero-as-null-pointer-constant
warn for a zero as null pointer constant default argument.
/testsuite
2012-03-29 Paolo Carlini <paolo.carl...@oracle.com>
PR c++/52718
* g++.dg/warn/Wzero-as-null-pointer-constant-5.C: New.
Index: testsuite/g++.dg/warn/Wzero-as-null-pointer-constant-5.C
===================================================================
--- testsuite/g++.dg/warn/Wzero-as-null-pointer-constant-5.C (revision 0)
+++ testsuite/g++.dg/warn/Wzero-as-null-pointer-constant-5.C (revision 0)
@@ -0,0 +1,20 @@
+// PR c++/52718
+// { dg-options "-Wzero-as-null-pointer-constant" }
+
+struct foo
+{
+ foo(void* a = 0) {}; // { dg-warning "zero as null pointer" }
+};
+
+void* fun(void* a = 0) {}; // { dg-warning "zero as null pointer" }
+
+struct bar: foo
+{
+ bar() {};
+};
+
+struct baz
+{
+ baz(const foo& f1 = foo(),
+ void* f2 = fun()) {};
+};
Index: cp/decl.c
===================================================================
--- cp/decl.c (revision 185969)
+++ cp/decl.c (working copy)
@@ -10596,6 +10602,17 @@ check_default_argument (tree decl, tree arg)
return error_mark_node;
}
+ if (warn_zero_as_null_pointer_constant
+ && c_inhibit_evaluation_warnings == 0
+ && (POINTER_TYPE_P (decl_type) || TYPE_PTR_TO_MEMBER_P (decl_type))
+ && null_ptr_cst_p (arg)
+ && !NULLPTR_TYPE_P (TREE_TYPE (arg)))
+ {
+ warning (OPT_Wzero_as_null_pointer_constant,
+ "zero as null pointer constant");
+ return nullptr_node;
+ }
+
/* [dcl.fct.default]
Local variables shall not be used in default argument
