PR c++/87781 - detect invalid elaborated-type-specifier.

	* parser.c (cp_parser_elaborated_type_specifier): Ensure that
	typename follows a nested-name-specifier.

	* g++.dg/parse/elab3.C: New test.
	* g++.dg/template/crash115.C: Adjust dg-error.

From-SVN: r266285

gcc/cp/ChangeLog

+2018-11-19  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/87781 - detect invalid elaborated-type-specifier.
+	* parser.c (cp_parser_elaborated_type_specifier): Ensure that
+	typename follows a nested-name-specifier.
+
 2018-11-18  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* decl2.c (grokfield): Remove obsolete _vptr check; fix

gcc/cp/parser.c

@@ -18009,6 +18009,14 @@ cp_parser_elaborated_type_specifier (cp_parser* parser,
 	 template-id or not.  */
       if (!template_p)
 	cp_parser_parse_tentatively (parser);
+      /* The `template' keyword must follow a nested-name-specifier.  */
+      else if (!nested_name_specifier)
+	{
+	  cp_parser_error (parser, "%<template%> must follow a nested-"
+			   "name-specifier");
+	  return error_mark_node;
+	}
+
       /* Parse the template-id.  */
       token = cp_lexer_peek_token (parser->lexer);
       decl = cp_parser_template_id (parser, template_p,

gcc/testsuite/ChangeLog

+2018-11-19  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/87781 - detect invalid elaborated-type-specifier.
+	* g++.dg/parse/elab3.C: New test.
+	* g++.dg/template/crash115.C: Adjust dg-error.
+
 2018-11-19  Peter Bergner  <bergner@linux.ibm.com>
 
 	PR rtl-optimization/88033

gcc/testsuite/g++.dg/parse/elab3.C

+// PR c++/87781
+// { dg-do compile }
+// { dg-options "" }
+
+template<class> class A;
+class template A<int> *p; // { dg-error ".template. must follow|invalid" }

gcc/testsuite/g++.dg/template/crash115.C

 // PR c++/56534
 
-template < struct template rebind < > // { dg-error "expected" }
+template < struct template rebind < > // { dg-error "expected|must follow" }