Silence clang warnings in C++03 mode

C++03 forbid the use of local or unnamed type as template parameter.
But in C++11 that is allowed, and clang accept them even in C++03
mode, but with a warning.

The Warning happen for example with this code:

  enum { Foo = 3 };
  int x = 3 << Foo;

Then the compiler issues warnings:

metatype.h:1379:31: warning: template argument uses local type [-Wlocal-type-template-args]
        enum { Value = sizeof(qt_getEnumMetaObject(declval())) == sizeof(QMetaObject*) };
                              ^~~~~~~~~~~~~~~~~~~~
qdebug.h:269:42: note: in instantiation of template class 'QtPrivate::IsQEnumHelper<(anonymous enum)>' requested here
typename QtPrivate::QEnableIf<QtPrivate::IsQEnumHelper<T>::Value, QDebug>::Type operator<<(QDebug dbg, T value)

Normaly the compiler should not even try to instantiate the operator<<
with such types in C++03 mode.

Change-Id: I48c7d5d1836fd87986835fe15c7e0b1beb73c728
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index 55f8fc9b2c..aa8d826ed9 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -1364,6 +1364,11 @@ namespace QtPrivate
         enum { Value = sizeof(checkType(static_cast<T*>(0))) == sizeof(void*)  };
     };
 
+
+QT_WARNING_PUSH
+// In C++03 mode, clang consider local or unnamed type and throw a warning instead of ignoring them
+QT_WARNING_DISABLE_CLANG("-Wunnamed-type-template-args")
+QT_WARNING_DISABLE_CLANG("-Wlocal-type-template-args")
     template<typename T> char qt_getEnumMetaObject(const T&);
 
     template<typename T>
@@ -1375,6 +1380,7 @@ namespace QtPrivate
         // qt_getEnumMetaObject(T) which returns 'char'
         enum { Value = sizeof(qt_getEnumMetaObject(declval())) == sizeof(QMetaObject*) };
     };
+QT_WARNING_POP
 
     template<typename T, typename Enable = void>
     struct MetaObjectForType