PR c++/18747

	* pt.c (check_template_variable): New.
	(num_template_headers_for_class): Split out...
	* decl.c (grokdeclarator): ...from here.
	(start_decl): Remove redundant diagnostic.
	* cp-tree.h: Declare them
	* parser.c (cp_parser_single_declaration): Call check_template_variable.
.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@190842 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 103 insertions, 35 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5fb1b41c149..c36ed8888dd 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,14 @@
+2012-08-31  Paolo Carlini  <paolo.carlini@oracle.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/18747
+	* pt.c (check_template_variable): New.
+	(num_template_headers_for_class): Split out...
+	* decl.c (grokdeclarator): ...from here.
+	(start_decl): Remove redundant diagnostic.
+	* cp-tree.h: Declare them
+	* parser.c (cp_parser_single_declaration): Call check_template_variable.
+
 2012-08-31  Ollie Wild  <aaw@google.com>
 
 	PR c++/54197
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 1b085bd1609..bd57b92c961 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5316,6 +5316,8 @@ extern void end_specialization			(void);
 extern void begin_explicit_instantiation	(void);
 extern void end_explicit_instantiation		(void);
 extern tree check_explicit_specialization	(tree, tree, int, int);
+extern int num_template_headers_for_class	(tree);
+extern void check_template_variable		(tree);
 extern tree make_auto				(void);
 extern tree do_auto_deduction			(tree, tree, tree);
 extern tree type_uses_auto			(tree);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index c909dea1775..8b94e26ac0c 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4461,11 +4461,6 @@ start_decl (const cp_declarator *declarator,
 			       context, DECL_NAME (decl));
 		  DECL_CONTEXT (decl) = DECL_CONTEXT (field);
 		}
-	      if (processing_specialization
-		  && template_class_depth (context) == 0
-		  && CLASSTYPE_TEMPLATE_SPECIALIZATION (context))
-		error ("template header not allowed in member definition "
-		       "of explicitly specialized class");
 	      /* Static data member are tricky; an in-class initialization
 		 still doesn't provide a definition, so the in-class
 		 declaration will have DECL_EXTERNAL set, but will have an
@@ -9564,36 +9559,9 @@ grokdeclarator (const cp_declarator *declarator,
       && declarator->u.id.qualifying_scope
       && MAYBE_CLASS_TYPE_P (declarator->u.id.qualifying_scope))
     {
-      tree t;
-
       ctype = declarator->u.id.qualifying_scope;
       ctype = TYPE_MAIN_VARIANT (ctype);
-      t = ctype;
-      while (t != NULL_TREE && CLASS_TYPE_P (t))
-	{
-	  /* You're supposed to have one `template <...>' for every
-	     template class, but you don't need one for a full
-	     specialization.  For example:
-
-	       template <class T> struct S{};
-	       template <> struct S<int> { void f(); };
-	       void S<int>::f () {}
-
-	     is correct; there shouldn't be a `template <>' for the
-	     definition of `S<int>::f'.  */
-	  if (CLASSTYPE_TEMPLATE_SPECIALIZATION (t)
-	      && !any_dependent_template_arguments_p (CLASSTYPE_TI_ARGS (t)))
-	    /* T is an explicit (not partial) specialization.  All
-	       containing classes must therefore also be explicitly
-	       specialized.  */
-	    break;
-	  if ((CLASSTYPE_USE_TEMPLATE (t) || CLASSTYPE_IS_TEMPLATE (t))
-	      && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (t)))
-	    template_count += 1;
-
-	  t = TYPE_MAIN_DECL (t);
-	  t = DECL_CONTEXT (t);
-	}
+      template_count = num_template_headers_for_class (ctype);
 
       if (ctype == current_class_type)
 	{
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 091a96728ad..60ba380cf74 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -21310,8 +21310,8 @@ cp_parser_perform_template_parameter_access_checks (VEC (deferred_access_check,g
 }
 
 /* Parse a `decl-specifier-seq [opt] init-declarator [opt] ;' or
-   `function-definition' sequence.  MEMBER_P is true, this declaration
-   appears in a class scope.
+   `function-definition' sequence that follows a template header.
+   If MEMBER_P is true, this declaration appears in a class scope.
 
    Returns the DECL for the declared entity.  If FRIEND_P is non-NULL,
    *FRIEND_P is set to TRUE iff the declaration is a friend.  */
@@ -21431,6 +21431,9 @@ cp_parser_single_declaration (cp_parser* parser,
 		  "explicit template specialization cannot have a storage class");
         decl = error_mark_node;
       }
+
+    if (decl && TREE_CODE (decl) == VAR_DECL)
+      check_template_variable (decl);
     }
 
   /* Look for a trailing `;' after the declaration.  */
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 5ce6e8af87f..4a3942715b8 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -2208,6 +2208,66 @@ copy_default_args_to_explicit_spec (tree decl)
   TREE_TYPE (decl) = new_type;
 }
 
+/* Return the number of template headers we expect to see for a definition
+   or specialization of CTYPE or one of its non-template members.  */
+
+int
+num_template_headers_for_class (tree ctype)
+{
+  int template_count = 0;
+  tree t = ctype;
+  while (t != NULL_TREE && CLASS_TYPE_P (t))
+    {
+      /* You're supposed to have one `template <...>' for every
+	 template class, but you don't need one for a full
+	 specialization.  For example:
+
+	 template <class T> struct S{};
+	 template <> struct S<int> { void f(); };
+	 void S<int>::f () {}
+
+	 is correct; there shouldn't be a `template <>' for the
+	 definition of `S<int>::f'.  */
+      if (CLASSTYPE_TEMPLATE_SPECIALIZATION (t)
+	  && !any_dependent_template_arguments_p (CLASSTYPE_TI_ARGS (t)))
+	/* T is an explicit (not partial) specialization.  All
+	   containing classes must therefore also be explicitly
+	   specialized.  */
+	break;
+      if ((CLASSTYPE_USE_TEMPLATE (t) || CLASSTYPE_IS_TEMPLATE (t))
+	  && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (t)))
+	template_count += 1;
+
+      t = TYPE_MAIN_DECL (t);
+      t = DECL_CONTEXT (t);
+    }
+
+  return template_count;
+}
+
+/* Do a simple sanity check on the template headers that precede the
+   variable declaration DECL.  */
+
+void
+check_template_variable (tree decl)
+{
+  tree ctx = CP_DECL_CONTEXT (decl);
+  int wanted = num_template_headers_for_class (ctx);
+  if (!TYPE_P (ctx) || !CLASSTYPE_TEMPLATE_INFO (ctx))
+    permerror (DECL_SOURCE_LOCATION (decl),
+	       "%qD is not a static data member of a class template", decl);
+  else if (template_header_count > wanted)
+    {
+      pedwarn (DECL_SOURCE_LOCATION (decl), 0,
+	       "too many template headers for %D (should be %d)",
+	       decl, wanted);
+      if (CLASSTYPE_TEMPLATE_SPECIALIZATION (ctx))
+	inform (DECL_SOURCE_LOCATION (decl),
+		"members of an explicitly specialized class are defined "
+		"without a template header");
+    }
+}
+
 /* Check to see if the function just declared, as indicated in
    DECLARATOR, and in DECL, is a specialization of a function
    template.  We may also discover that the declaration is an explicit
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 685c60dc460..22fcd065e3c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2012-08-31  Paolo Carlini  <paolo.carlini@oracle.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/18747
+	* g++.dg/parse/error50.C: New.
+
 2012-08-31  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/54428
diff --git a/gcc/testsuite/g++.dg/parse/error50.C b/gcc/testsuite/g++.dg/parse/error50.C
new file mode 100644
index 00000000000..dbd8958c360
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/error50.C
@@ -0,0 +1,18 @@
+// PR c++/18747
+
+template<> int i;   // { dg-error "template" }
+
+struct A
+{
+  static int i;
+};
+
+template<> int A::i;     // { dg-error "template" }
+
+template <class T>
+struct B
+{
+  static T i;
+};
+
+template<> template <> int B<int>::i; // { dg-error "should be 1" }