This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: PING: [PATCH: c++/diagnostic/18313] Warn for pointless qualifiers on return type
On Tuesday, 28. November 2006 12:28, Gabriel Dos Reis wrote:
> | If you have a better way to describe this behaviour, please tell me. I'd
> | also be interested if the TREE_NO_WARNING on the type node has any
> | undesired side-effect (there was none exposed by the testsuite).
> But actually, we wanted to suppress the warning for that particular
> decl, so we should be saying that. Do you think you can arrange for
> the TREE_NO_WARNING be set on the FUNCTION_DECL (or maybe on its
> DECL_RESULT I'm not sure which is better) instead of its type?
I'm not 100% sure I understood you correctly, but the patch below works as
well and survives bootstrap and regtest with no failures.
2006-11-29 Dirk Mueller <dmueller@suse.de>
PR c++/18313
* decl.c (grokdeclarator): Warn for type qualifiers on return
type for non-dependent types.
* pt.c (tsubst_function_type): Warn for type qualifiers on
return type for dependent types.
* g++.dg/warn/Wreturn-type-4.C: New testcase.
--- gcc/cp/decl.c
+++ gcc/cp/decl.c
@@ -6884,6 +6884,7 @@ grokdeclarator (const cp_declarator *dec
cp_storage_class storage_class;
bool unsigned_p, signed_p, short_p, long_p, thread_p;
bool type_was_error_mark_node = false;
+ bool set_no_warning = false;
signed_p = declspecs->specs[(int)ds_signed];
unsigned_p = declspecs->specs[(int)ds_unsigned];
@@ -7530,9 +7531,16 @@ grokdeclarator (const cp_declarator *dec
/* Declaring a function type.
Make sure we have a valid type for the function to return. */
- /* We now know that the TYPE_QUALS don't apply to the
- decl, but to its return type. */
- type_quals = TYPE_UNQUALIFIED;
+ if (type_quals != TYPE_UNQUALIFIED)
+ {
+ if (SCALAR_TYPE_P (type) || VOID_TYPE_P (type))
+ warning (OPT_Wreturn_type,
+ "type qualifiers ignored on function return type");
+ /* We now know that the TYPE_QUALS don't apply to the
+ decl, but to its return type. */
+ type_quals = TYPE_UNQUALIFIED;
+ set_no_warning = true;
+ }
/* Warn about some types functions can't return. */
@@ -8612,6 +8620,9 @@ grokdeclarator (const cp_declarator *dec
if (!processing_template_decl)
cp_apply_type_quals_to_decl (type_quals, decl);
+ if (set_no_warning)
+ TREE_NO_WARNING (decl) = 1;
+
return decl;
}
}
--- gcc/cp/pt.c
+++ gcc/cp/pt.c
@@ -7123,6 +7123,13 @@ tsubst_function_type (tree t,
if (arg_types == error_mark_node)
return error_mark_node;
+ if (TYPE_QUALS (return_type) != TYPE_UNQUALIFIED
+ && in_decl != NULL_TREE
+ && !TREE_NO_WARNING (in_decl)
+ && (SCALAR_TYPE_P (return_type) || VOID_TYPE_P (return_type)))
+ warning (OPT_Wreturn_type,
+ "type qualifiers ignored on function return type");
+
/* Construct a new type node and return it. */
if (TREE_CODE (t) == FUNCTION_TYPE)
fntype = build_function_type (return_type, arg_types);
--- testsuite/g++.dg/warn/Wreturn-type-4.C
+++ testsuite/g++.dg/warn/Wreturn-type-4.C
@@ -0,0 +1,43 @@
+/* PR c++/18313 */
+/* { dg-do compile } */
+/* { dg-options "-Wreturn-type" } */
+
+volatile void bar(); /* { dg-warning "type qualifiers ignored" } */
+
+struct A
+{
+ const int bla(); /* { dg-warning "type qualifiers ignored" } */
+ static const A getA(); /* { dg-bogus "type qualifiers" } */
+};
+
+template<typename T> const T getfoo(const T def) /* { dg-bogus "type
qualifiers ignored" } */
+{ return def; }
+
+template<typename T> class Pair
+{
+ public:
+ T getLeft() const { return T(); } /* { dg-warning "type qualifiers
ignored" } */
+ const T getRight() const { return T(); } /* { dg-bogus "type
qualifiers ignored" } */
+};
+
+template <typename T> struct S {
+ const int f(); /* { dg-warning "type qualifiers
ignored" } */
+ const T g(); /* { dg-bogus "type qualifiers
ignored" } */
+ T h();
+};
+
+int* testtemplate()
+{
+ int i;
+
+ Pair<const int> a;
+
+ a.getLeft();
+ a.getRight();
+
+ S<bool> b;
+ b.h(); /* { dg-bogus "type qualifiers ignored" } */
+ b.g(); /* { dg-bogus "type qualifiers ignored" } */
+
+ return getfoo<int*>(&i);
+}