re PR c++/17132 (GCC fails to eliminate function template specialization when…

re PR c++/17132 (GCC fails to eliminate function template specialization when argument deduction fails)

	PR c++/17132
	* pt.c (instantiate_class_template): Increment
	processing_template_decl when substituting into a member class
	template.

	PR c++/17132
	* g++.dg/template/memclass3.C: New test.

From-SVN: r89778

gcc/cp/ChangeLog

+2004-10-28  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/17132
+	* pt.c (instantiate_class_template): Increment
+	processing_template_decl when substituting into a member class
+	template.
+
 2004-10-27  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/17435

gcc/cp/pt.c

@@ -5621,14 +5621,28 @@ instantiate_class_template (tree type)
 	      tree tag = t;
 	      tree name = TYPE_IDENTIFIER (tag);
 	      tree newtag;
-
+	      bool class_template_p;
+
+	      class_template_p = (TREE_CODE (tag) != ENUMERAL_TYPE
+				  && TYPE_LANG_SPECIFIC (tag)
+				  && CLASSTYPE_IS_TEMPLATE (tag));
+	      /* If the member is a class template, then -- even after
+		 substituition -- there may be dependent types in the
+		 template argument list for the class.  We increment
+		 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
+		 that function will assume that no types are dependent
+		 when outside of a template.  */
+	      if (class_template_p)
+		++processing_template_decl;
 	      newtag = tsubst (tag, args, tf_error, NULL_TREE);
+	      if (class_template_p)
+		--processing_template_decl;
 	      if (newtag == error_mark_node)
 		continue;
 
 	      if (TREE_CODE (newtag) != ENUMERAL_TYPE)
 		{
-		  if (TYPE_LANG_SPECIFIC (tag) && CLASSTYPE_IS_TEMPLATE (tag))
+		  if (class_template_p)
 		    /* Unfortunately, lookup_template_class sets
 		       CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
 		       instantiation (i.e., for the type of a member

gcc/testsuite/ChangeLog

+2004-10-28  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/17132
+	* g++.dg/template/memclass3.C: New test.
+
 2004-10-28  Adam Nemet  <anemet@lnxw.com>
 
 	PR middle-end/18160  

gcc/testsuite/g++.dg/template/memclass3.C

+// PR c++/17132
+
+template <typename T>
+struct has_deref
+{
+    struct impl
+    {
+        template <
+            typename Type,
+            typename Type::reference (Type::*Func)(void) const>
+        struct func_tag;
+
+        template <typename Type>
+        static char (& test(
+            Type *,
+            func_tag<Type, &Type::operator*> * = 0
+        ))[2];
+        static char test(void *);
+    };
+
+    static const bool value = (sizeof(impl::test((T *) 0)) == 2);
+};
+
+template <typename T>
+struct container
+{
+    struct iterator
+    {
+        typedef T & reference;
+        reference operator*() const;
+    };
+};
+
+int main()
+{
+    typedef container<int>::iterator iter;
+    int result = has_deref<iter>::value;
+    return result;
+}