re PR c++/89767 (ICE with tuple and optimization)

	PR c++/89767
	* parser.c (cp_parser_lambda_introducer): Add ids and first_capture_id
	variables, check for duplicates in this function.
	* lambda.c (add_capture): Don't check for duplicates nor use
	IDENTIFIER_MARKED.
	(register_capture_members): Don't clear IDENTIFIER_MARKED here.

	* g++.dg/cpp1y/lambda-init18.C: New test.
	* g++.dg/cpp1y/lambda-init19.C: New test.
	* g++.dg/cpp1y/pr89767.C: New test.

From-SVN: r269860

1 files changed, 40 insertions, 15 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 81aff35..c669e49 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -10547,6 +10547,8 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
 	error ("non-local lambda expression cannot have a capture-default");
     }
 
+  hash_set<tree, true> ids;
+  tree first_capture_id = NULL_TREE;
   while (cp_lexer_next_token_is_not (parser->lexer, CPP_CLOSE_SQUARE))
     {
       cp_token* capture_token;
@@ -10582,11 +10584,14 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
 	    pedwarn (loc, 0, "explicit by-copy capture of %<this%> redundant "
 		     "with by-copy capture default");
 	  cp_lexer_consume_token (parser->lexer);
-	  add_capture (lambda_expr,
-		       /*id=*/this_identifier,
-		       /*initializer=*/finish_this_expr (),
-		       /*by_reference_p=*/true,
-		       explicit_init_p);
+	  if (LAMBDA_EXPR_THIS_CAPTURE (lambda_expr))
+	    pedwarn (input_location, 0,
+		     "already captured %qD in lambda expression",
+		     this_identifier);
+	  else
+	    add_capture (lambda_expr, /*id=*/this_identifier,
+			 /*initializer=*/finish_this_expr (),
+			 /*by_reference_p=*/true, explicit_init_p);
 	  continue;
 	}
 
@@ -10600,11 +10605,14 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
 			     "%<-std=c++17%> or %<-std=gnu++17%>");
 	  cp_lexer_consume_token (parser->lexer);
 	  cp_lexer_consume_token (parser->lexer);
-	  add_capture (lambda_expr,
-		       /*id=*/this_identifier,
-		       /*initializer=*/finish_this_expr (),
-		       /*by_reference_p=*/false,
-		       explicit_init_p);
+	  if (LAMBDA_EXPR_THIS_CAPTURE (lambda_expr))
+	    pedwarn (input_location, 0,
+		     "already captured %qD in lambda expression",
+		     this_identifier);
+	  else
+	    add_capture (lambda_expr, /*id=*/this_identifier,
+			 /*initializer=*/finish_this_expr (),
+			 /*by_reference_p=*/false, explicit_init_p);
 	  continue;
 	}
 
@@ -10753,11 +10761,28 @@ cp_parser_lambda_introducer (cp_parser* parser, tree lambda_expr)
 		     "default", capture_id);
 	}
 
-      add_capture (lambda_expr,
-		   capture_id,
-		   capture_init_expr,
-		   /*by_reference_p=*/capture_kind == BY_REFERENCE,
-		   explicit_init_p);
+      /* Check for duplicates.
+	 Optimize for the zero or one explicit captures cases and only create
+	 the hash_set after adding second capture.  */
+      bool found = false;
+      if (ids.elements ())
+	found = ids.add (capture_id);
+      else if (first_capture_id == NULL_TREE)
+	first_capture_id = capture_id;
+      else if (capture_id == first_capture_id)
+	found = true;
+      else
+	{
+	  ids.add (first_capture_id);
+	  ids.add (capture_id);
+	}
+      if (found)
+	pedwarn (input_location, 0,
+		 "already captured %qD in lambda expression", capture_id);
+      else
+	add_capture (lambda_expr, capture_id, capture_init_expr,
+		     /*by_reference_p=*/capture_kind == BY_REFERENCE,
+		     explicit_init_p);
 
       /* If there is any qualification still in effect, clear it
 	 now; we will be starting fresh with the next capture.  */