re PR c++/24687 (ICE after error)

PR c++/24687
	* pt.c (check_explicit_specialization): Don't check for C linkage.
	(push_template_decl_real): Likewise.
	* parser.c (cp_parser_explicit_specialization): Check here.
	(cp_parser_template_declaration_after_export): And here.
	PR c++/24687
	* g++.dg/template/crash43.C: New test.

From-SVN: r106909

gcc/cp/ChangeLog

@@ -1,5 +1,11 @@
 2005-11-14  Mark Mitchell  <mark@codesourcery.com>
 
+	PR c++/24687
+	* pt.c (check_explicit_specialization): Don't check for C linkage.
+	(push_template_decl_real): Likewise.
+	* parser.c (cp_parser_explicit_specialization): Check here.
+	(cp_parser_template_declaration_after_export): And here.
+
 	* parser.c (cp_lexer_get_preprocessor_token): Initialize keyword
 	field.
 

gcc/cp/parser.c

@@ -9295,6 +9295,7 @@ cp_parser_explicit_instantiation (cp_parser* parser)
 static void
 cp_parser_explicit_specialization (cp_parser* parser)
 {
+  bool need_lang_pop;
   /* Look for the `template' keyword.  */
   cp_parser_require_keyword (parser, RID_TEMPLATE, "`template'");
   /* Look for the `<'.  */
@@ -9303,9 +9304,22 @@ cp_parser_explicit_specialization (cp_parser* parser)
   cp_parser_require (parser, CPP_GREATER, "`>'");
   /* We have processed another parameter list.  */
   ++parser->num_template_parameter_lists;
+  /* [temp]
+   
+     A template ... explicit specialization ... shall not have C
+     linkage.  */ 
+  if (current_lang_name == lang_name_c)
+    {
+      error ("template specialization with C linkage");
+      /* Give it C++ linkage to avoid confusing other parts of the
+	 front end.  */
+      push_lang_context (lang_name_cplusplus);
+      need_lang_pop = true;
+    }
+  else
+    need_lang_pop = false;
   /* Let the front end know that we are beginning a specialization.  */
   begin_specialization ();
-
   /* If the next keyword is `template', we need to figure out whether
      or not we're looking a template-declaration.  */
   if (cp_lexer_next_token_is_keyword (parser->lexer, RID_TEMPLATE))
@@ -9322,9 +9336,12 @@ cp_parser_explicit_specialization (cp_parser* parser)
     cp_parser_single_declaration (parser,
 				  /*member_p=*/false,
 				  /*friend_p=*/NULL);
-
   /* We're done with the specialization.  */
   end_specialization ();
+  /* For the erroneous case of a template with C linkage, we pushed an
+     implicit C++ linkage scope; exit that scope now.  */
+  if (need_lang_pop)
+    pop_lang_context ();
   /* We're done with this parameter list.  */
   --parser->num_template_parameter_lists;
 }
@@ -15168,6 +15185,7 @@ cp_parser_template_declaration_after_export (cp_parser* parser, bool member_p)
   tree decl = NULL_TREE;
   tree parameter_list;
   bool friend_p = false;
+  bool need_lang_pop;
 
   /* Look for the `template' keyword.  */
   if (!cp_parser_require_keyword (parser, RID_TEMPLATE, "`template'"))
@@ -15176,7 +15194,19 @@ cp_parser_template_declaration_after_export (cp_parser* parser, bool member_p)
   /* And the `<'.  */
   if (!cp_parser_require (parser, CPP_LESS, "`<'"))
     return;
-
+  /* [temp]
+   
+     A template ... shall not have C linkage.  */
+  if (current_lang_name == lang_name_c)
+    {
+      error ("template with C linkage");
+      /* Give it C++ linkage to avoid confusing other parts of the
+	 front end.  */
+      push_lang_context (lang_name_cplusplus);
+      need_lang_pop = true;
+    }
+  else
+    need_lang_pop = false;
   /* If the next token is `>', then we have an invalid
      specialization.  Rather than complain about an invalid template
      parameter, issue an error message here.  */
@@ -15237,7 +15267,10 @@ cp_parser_template_declaration_after_export (cp_parser* parser, bool member_p)
   /* Register member declarations.  */
   if (member_p && !friend_p && decl && !DECL_CLASS_TEMPLATE_P (decl))
     finish_member_declaration (decl);
-
+  /* For the erroneous case of a template with C linkage, we pushed an
+     implicit C++ linkage scope; exit that scope now.  */
+  if (need_lang_pop)
+    pop_lang_context ();
   /* If DECL is a function template, we must return to parse it later.
      (Even though there is no definition, there might be default
      arguments that need handling.)  */

gcc/cp/pt.c

@@ -1895,8 +1895,6 @@ check_explicit_specialization (tree declarator,
 	      ("default argument specified in explicit specialization");
 	    break;
 	  }
-      if (current_lang_name == lang_name_c)
-	error ("template specialization with C linkage");
     }
 
   if (specialization || member_specialization || explicit_instantiation)
@@ -2985,10 +2983,8 @@ push_template_decl_real (tree decl, bool is_friend)
     {
       if (DECL_CLASS_SCOPE_P (decl))
 	member_template_p = true;
-      if (current_lang_name == lang_name_c)
-	error ("template with C linkage");
-      else if (TREE_CODE (decl) == TYPE_DECL
-	       && ANON_AGGRNAME_P (DECL_NAME (decl)))
+      if (TREE_CODE (decl) == TYPE_DECL
+	  && ANON_AGGRNAME_P (DECL_NAME (decl)))
 	error ("template class without a name");
       else if (TREE_CODE (decl) == FUNCTION_DECL)
 	{

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2005-11-14  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/24687
+	* g++.dg/template/crash43.C: New test. 
+
 2005-11-14  Daniel Jacobowitz  <dan@codesourcery.com>
 
 	* gcc.c-torture/unsorted/unsorted.exp: Sort tests before running them.

gcc/testsuite/g++.dg/template/crash43.C

@@ -0,0 +1,8 @@
+// PR c++/24687
+
+extern "C" {
+  template<typename _Tp>  // { dg-error "C" }   
+  struct __is_pod {
+    enum {
+      __value = (sizeof(__gnu_internal::__test_type<_Tp>(0)))}; // { dg-error "declared|expected" }
+