re PR c++/90842 (ICE in poplevel, at cp/decl.c:585)

	PR c++/90842
	* parser.c (cp_parser_decl_specifier_seq): For concept or typedef
	break early if CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR.
	For type specifiers, set CP_PARSER_FLAGS_NO_TYPE_DEFINITIONS
	if CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR is set.

	* g++.dg/cpp1y/lambda-generic-90842.C: New test.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r278538

gcc/cp/ChangeLog

+2019-11-21  Jakub Jelinek  <jakub@redhat.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/90842
+	* parser.c (cp_parser_decl_specifier_seq): For concept or typedef
+	break early if CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR.
+	For type specifiers, set CP_PARSER_FLAGS_NO_TYPE_DEFINITIONS
+	if CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR is set.
+
 2019-11-20  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* typeck2.c (build_x_arrow): Early return if decay_conversion

gcc/cp/parser.c

@@ -14097,6 +14097,9 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
           ds = ds_concept;
           cp_lexer_consume_token (parser->lexer);
 
+	  if (flags & CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR)
+	    break;
+
           /* Warn for concept as a decl-specifier. We'll rewrite these as
              concept declarations later.  */
           if (!flag_concepts_ts)
@@ -14139,6 +14142,10 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
 	  ds = ds_typedef;
 	  /* Consume the token.  */
 	  cp_lexer_consume_token (parser->lexer);
+
+	  if (flags & CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR)
+	    break;
+
 	  /* A constructor declarator cannot appear in a typedef.  */
 	  constructor_possible_p = false;
 	  /* The "typedef" keyword can only occur in a declaration; we
@@ -14235,6 +14242,9 @@ cp_parser_decl_specifier_seq (cp_parser* parser,
 	  bool is_cv_qualifier;
 	  tree type_spec;
 
+	  if (flags & CP_PARSER_FLAGS_ONLY_MUTABLE_OR_CONSTEXPR)
+	    flags |= CP_PARSER_FLAGS_NO_TYPE_DEFINITIONS;
+
 	  type_spec
 	    = cp_parser_type_specifier (parser, flags,
 					decl_specs,

gcc/testsuite/ChangeLog

+2019-11-21  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/90842
+	* g++.dg/cpp1y/lambda-generic-90842.C: New test.
+
 2019-11-20  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/92443

gcc/testsuite/g++.dg/cpp1y/lambda-generic-90842.C

+// PR c++/90842
+// { dg-do compile { target c++14 } }
+
+auto a = [](auto x) struct C { void foo (); } {};	// { dg-error "expected" }
+							// { dg-error "type-specifier invalid in lambda" "" { target *-*-* } .-1 }
+auto b = [](auto x) mutable typedef {};			// { dg-error "'typedef' invalid in lambda" }
+#if __cpp_concepts >= 201907L
+auto c = [](auto x) constexpr concept {};		// { dg-error "'concept' invalid in lambda" "" { target c++2a } }
+#endif
+auto d = [](auto x) mutable friend {};			// { dg-error "'friend' invalid in lambda" }