C++ PATCH for c++/70781 (ICE with ill-formed lambda)

[Jason Merrill]

Here we were returning OK from cp_parser_lambda_declarator_opt even
though we had encountered parse errors, and so parsing the inner
lambda aborted due to seeing an error_mark_node expression-statement
without ever having emitted any errors.

Fixed by clearing OK if there were parse errors.

Tested x86_64-pc-linux-gnu, applying to trunk and 6.

commit 17fea383f9a2861903ae6d144b3ba7e6a4bf191a
Author: Jason Merrill <ja...@redhat.com>
Date:   Wed Jul 20 17:03:50 2016 -0400

        PR c++/70781 - ICE on ill-formed lambda.
    
        * parser.c (cp_parser_lambda_expression): Unset OK if there was an
        error parsing the lambda-declarator.

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 9bdb108..b71b9e5 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -9771,10 +9771,12 @@ cp_parser_lambda_expression (cp_parser* parser)
 
     ok &= cp_parser_lambda_declarator_opt (parser, lambda_expr);
 
+    if (ok && cp_parser_error_occurred (parser))
+      ok = false;
+
     if (ok)
       {
-       if (!cp_parser_error_occurred (parser)
-           && cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE)
+       if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_BRACE)
            && cp_parser_start_tentative_firewall (parser))
          start = token;
        cp_parser_lambda_body (parser, lambda_expr);
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice16.C 
b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice16.C
new file mode 100644
index 0000000..e94a0b6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice16.C
@@ -0,0 +1,8 @@
+// PR c++/70781
+// { dg-do compile { target c++11 } }
+
+template < typename T >  
+void foo ()
+{
+  T ([=] (S) { [=] {}; });     // { dg-error "" }
+}