From eacb16dc798d06acfb9741a2496584ab0728257a Mon Sep 17 00:00:00 2001
From: David Malcolm <dmalcolm@redhat.com>
Date: Thu, 28 Jun 2018 20:24:49 +0000
Subject: [PATCH] C++: less verbose error-recovery for version conflict markers

gcc/cp/ChangeLog:
	* parser.c (cp_parser_error_1): After issuing a conflict marker
	error, consume tokens until the end of the source line.

gcc/testsuite/ChangeLog:
	* g++.dg/conflict-markers-2.C: New test.

From-SVN: r262232
---
 gcc/cp/ChangeLog                          |  5 +++++
 gcc/cp/parser.c                           | 14 ++++++++++++++
 gcc/testsuite/g++.dg/conflict-markers-2.C | 17 +++++++++++++++++
 3 files changed, 36 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/conflict-markers-2.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 862b7370b7e..906f0b41678 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-28  David Malcolm  <dmalcolm@redhat.com>
+
+	* parser.c (cp_parser_error_1): After issuing a conflict marker
+	error, consume tokens until the end of the source line.
+
 2018-06-28  Jason Merrill  <jason@redhat.com>
 
 	PR c++/86342 - -Wdeprecated-copy and system headers.
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index a02091e0a5d..a076de146e6 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -2862,6 +2862,20 @@ cp_parser_error_1 (cp_parser* parser, const char* gmsgid,
       if (cp_lexer_peek_conflict_marker (parser->lexer, token->type, &loc))
 	{
 	  error_at (loc, "version control conflict marker in file");
+	  expanded_location token_exploc = expand_location (token->location);
+	  /* Consume tokens until the end of the source line.  */
+	  while (1)
+	    {
+	      cp_lexer_consume_token (parser->lexer);
+	      cp_token *next = cp_lexer_peek_token (parser->lexer);
+	      if (next == NULL)
+		break;
+	      expanded_location next_exploc = expand_location (next->location);
+	      if (next_exploc.file != token_exploc.file)
+		break;
+	      if (next_exploc.line != token_exploc.line)
+		break;
+	    }
 	  return;
 	}
     }
diff --git a/gcc/testsuite/g++.dg/conflict-markers-2.C b/gcc/testsuite/g++.dg/conflict-markers-2.C
new file mode 100644
index 00000000000..4fc38207184
--- /dev/null
+++ b/gcc/testsuite/g++.dg/conflict-markers-2.C
@@ -0,0 +1,17 @@
+// { dg-do compile { target c++11 } }
+
+extern void f1 (void);
+extern void f2 (void);
+extern void f3 (void);
+extern void f4 (void);
+
+void test ()
+{
+  f1 ();
+<<<<<<< HEAD // { dg-error "conflict marker" }
+  f2 ();
+======= // { dg-error "conflict marker" }
+  f3 ();
+>>>>>>> 252be53... Some commit message // { dg-error "conflict marker" }
+  f4 ();
+}
-- 
2.30.2