[C++ Patch] PR 71109 ("Misleading diagnostic message with 'virtual' used in out-of-line definitions of class template member functions")

[Paolo Carlini]

Hi,

submitter noticed that for wrong uses of 'virtual' outside of template 
classes (B in the testcase) vs plain classes (A) we wrongly emit the 
"templates may not be %<virtual%>" error message. Simply checking 
current_class_type seems enough to solve the problem. Case C in the 
extended testcase double checks that we still give the "templates may 
not be %<virtual%>" error message when appropriate. Tested x86_64-linux.

Thanks,
Paolo.

//////////////////////////
/cp
2016-05-30  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/71099
        * parser.c (cp_parser_function_specifier_opt): Use current_class_type
        to improve the diagnostic about wrong uses of 'virtual'.

/testsuite
2016-05-30  Paolo Carlini  <paolo.carl...@oracle.com>

        PR c++/71099
        * g++.dg/parse/virtual1.C: New.
Index: cp/parser.c
===================================================================
--- cp/parser.c (revision 236863)
+++ cp/parser.c (working copy)
@@ -12888,7 +12888,8 @@ cp_parser_function_specifier_opt (cp_parser* parse
       /* 14.5.2.3 [temp.mem]
 
         A member function template shall not be virtual.  */
-      if (PROCESSING_REAL_TEMPLATE_DECL_P ())
+      if (PROCESSING_REAL_TEMPLATE_DECL_P ()
+         && current_class_type)
        error_at (token->location, "templates may not be %<virtual%>");
       else
        set_and_check_decl_spec_loc (decl_specs, ds_virtual, token);
Index: testsuite/g++.dg/parse/virtual1.C
===================================================================
--- testsuite/g++.dg/parse/virtual1.C   (revision 0)
+++ testsuite/g++.dg/parse/virtual1.C   (working copy)
@@ -0,0 +1,25 @@
+// PR c++/71099
+
+struct A {
+  virtual void foo();
+};
+
+virtual void A::foo() {}  // { dg-error "'virtual' outside class" }
+
+template<typename>
+struct B {
+  virtual void foo();
+};
+
+template<typename T>
+virtual void B<T>::foo() {}  // { dg-error "'virtual' outside class" }
+
+template<typename>
+struct C {
+  template<typename>
+  virtual void foo();  // { dg-error "templates may not be 'virtual'" }
+};
+
+template<typename T>
+template<typename>
+virtual void C<T>::foo() {}  // { dg-error "'virtual' outside class" }