From 9777a9d8f96bc0e1992abb64f3b8f7f28ef38acb Mon Sep 17 00:00:00 2001
From: David Malcolm <dmalcolm@redhat.com>
Date: Fri, 29 Jul 2016 17:53:29 -0400
Subject: [PATCH 1/2] FIXME: matching tokens

---
 gcc/c-family/c-common.c                            |  17 +-
 gcc/c-family/c-common.h                            |   3 +-
 gcc/c/c-parser.c                                   | 659 ++++++++++------
 gcc/c/c-parser.h                                   |   8 +-
 gcc/cp/parser.c                                    | 841 ++++++++++++++-------
 gcc/testsuite/c-c++-common/missing-close-symbol.c  |  33 +
 gcc/testsuite/c-c++-common/missing-symbol.c        |  26 +
 .../g++.dg/diagnostic/unclosed-extern-c.C          |   3 +
 .../g++.dg/diagnostic/unclosed-function.C          |   3 +
 .../g++.dg/diagnostic/unclosed-namespace.C         |   2 +
 gcc/testsuite/g++.dg/diagnostic/unclosed-struct.C  |   3 +
 gcc/testsuite/gcc.dg/unclosed-init.c               |   3 +
 libcpp/include/line-map.h                          |   2 +
 libcpp/line-map.c                                  |  26 +
 14 files changed, 1108 insertions(+), 521 deletions(-)
 create mode 100644 gcc/testsuite/c-c++-common/missing-close-symbol.c
 create mode 100644 gcc/testsuite/c-c++-common/missing-symbol.c
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/unclosed-extern-c.C
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/unclosed-function.C
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/unclosed-namespace.C
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/unclosed-struct.C
 create mode 100644 gcc/testsuite/gcc.dg/unclosed-init.c

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index b4217f3..b168cb5 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -5949,12 +5949,13 @@ catenate_strings (const char *lhs, const char *rhs_start, int rhs_size)
   return result;
 }
 
-/* Issue the error given by GMSGID, indicating that it occurred before
-   TOKEN, which had the associated VALUE.  */
+/* Issue the error given by GMSGID at RICHLOC, indicating that it occurred
+   before TOKEN, which had the associated VALUE.  */
 
 void
 c_parse_error (const char *gmsgid, enum cpp_ttype token_type,
-	       tree value, unsigned char token_flags)
+	       tree value, unsigned char token_flags,
+	       rich_location *richloc)
 {
 #define catenate_messages(M1, M2) catenate_strings ((M1), (M2), sizeof (M2))
 
@@ -5995,7 +5996,7 @@ c_parse_error (const char *gmsgid, enum cpp_ttype token_type,
       else
 	message = catenate_messages (gmsgid, " before %s'\\x%x'");
 
-      error (message, prefix, val);
+      error_at_rich_loc (richloc, message, prefix, val);
       free (message);
       message = NULL;
     }
@@ -6023,7 +6024,7 @@ c_parse_error (const char *gmsgid, enum cpp_ttype token_type,
   else if (token_type == CPP_NAME)
     {
       message = catenate_messages (gmsgid, " before %qE");
-      error (message, value);
+      error_at_rich_loc (richloc, message, value);
       free (message);
       message = NULL;
     }
@@ -6036,16 +6037,16 @@ c_parse_error (const char *gmsgid, enum cpp_ttype token_type,
   else if (token_type < N_TTYPES)
     {
       message = catenate_messages (gmsgid, " before %qs token");
-      error (message, cpp_type2name (token_type, token_flags));
+      error_at_rich_loc (richloc, message, cpp_type2name (token_type, token_flags));
       free (message);
       message = NULL;
     }
   else
-    error (gmsgid);
+    error_at_rich_loc (richloc, gmsgid);
 
   if (message)
     {
-      error (message);
+      error_at_rich_loc (richloc, message);
       free (message);
     }
 #undef catenate_messages
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 7e7efb2..de92701 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1124,7 +1124,8 @@ extern void builtin_define_with_int_value (const char *, HOST_WIDE_INT);
 extern void builtin_define_type_sizeof (const char *, tree);
 extern void c_stddef_cpp_builtins (void);
 extern void fe_file_change (const line_map_ordinary *);
-extern void c_parse_error (const char *, enum cpp_ttype, tree, unsigned char);
+extern void c_parse_error (const char *, enum cpp_ttype, tree, unsigned char,
+			   rich_location *richloc);
 
 /* In c-ppoutput.c  */
 extern void init_pp_output (FILE *);
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index f8fbc92..290b6d2 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -850,21 +850,26 @@ c_parser_peek_conflict_marker (c_parser *parser, enum cpp_ttype tok1_kind,
    MESSAGE (specified by the caller) is usually of the form "expected
    OTHER-TOKEN".
 
+   Use RICHLOC as the location of the diagnostic.
+
    Do not issue a diagnostic if still recovering from an error.
 
+   Return true iff an error was actually emitted.
+
    ??? This is taken from the C++ parser, but building up messages in
    this way is not i18n-friendly and some other approach should be
    used.  */
 
-void
-c_parser_error (c_parser *parser, const char *gmsgid)
+static bool
+c_parser_error_richloc (c_parser *parser, const char *gmsgid,
+			rich_location *richloc)
 {
   c_token *token = c_parser_peek_token (parser);
   if (parser->error)
-    return;
+    return false;
   parser->error = true;
   if (!gmsgid)
-    return;
+    return false;
 
   /* If this is actually a conflict marker, report it as such.  */
   if (token->type == CPP_LSHIFT
@@ -875,13 +880,10 @@ c_parser_error (c_parser *parser, const char *gmsgid)
       if (c_parser_peek_conflict_marker (parser, token->type, &loc))
 	{
 	  error_at (loc, "version control conflict marker in file");
-	  return;
+	  return true;
 	}
     }
 
-  /* This diagnostic makes more sense if it is tagged to the line of
-     the token we just peeked at.  */
-  c_parser_set_source_position_from_token (token);
   c_parse_error (gmsgid,
 		 /* Because c_parse_error does not understand
 		    CPP_KEYWORD, keywords are treated like
@@ -891,18 +893,160 @@ c_parser_error (c_parser *parser, const char *gmsgid)
 		    token, we need to pass 0 here and we will not get
 		    the source spelling of some tokens but rather the
 		    canonical spelling.  */
-		 token->value, /*flags=*/0);
+		 token->value, /*flags=*/0, richloc);
+  return true;
+}
+
+/* As c_parser_error_richloc, but issue the message at the
+   location of PARSER's next token, or at input_location
+   if the next token is EOF.  */
+
+bool
+c_parser_error (c_parser *parser, const char *gmsgid)
+{
+  c_token *token = c_parser_peek_token (parser);
+  c_parser_set_source_position_from_token (token);
+  rich_location richloc (line_table, input_location);
+  return c_parser_error_richloc (parser, gmsgid, &richloc);
+}
+
+/* Some tokens naturally come in pairs e.g.'(' and ')'.
+   This class is for tracking such a matching pair of symbols.
+   In particular, it tracks the location of the first token,
+   so that if the second token is missing, we can highlight the
+   location of the first token when notifying the user about the
+   problem.  */
+
+template <typename token_pair_traits_t>
+class token_pair
+{
+ private:
+  typedef token_pair_traits_t traits_t;
+
+ public:
+  /* token_pair's ctor.  */
+  token_pair () : m_open_loc (UNKNOWN_LOCATION) {}
+
+  /* If the next token is the opening symbol for this pair, consume it and
+     return true.
+     Otherwise, issue an error and return false.
+     In either case, record the location of the opening token.  */
+
+  bool require_open (c_parser *parser)
+  {
+    c_token *token = c_parser_peek_token (parser);
+    if (token)
+      m_open_loc = token->location;
+
+    return c_parser_require (parser, traits_t::open_token_type,
+			     traits_t::open_gmsgid);
+  }
+
+  /* Consume the next token from PARSER, recording its location as
+     that of the opening token within the pair.  */
+
+  void consume_open (c_parser *parser)
+  {
+    c_token *token = c_parser_peek_token (parser);
+    gcc_assert (token->type == traits_t::open_token_type);
+    m_open_loc = token->location;
+    c_parser_consume_token (parser);
+  }
+
+  /* If the next token is the closing symbol for this pair, consume it
+     and return true.
+     Otherwise, issue an error, highlighting the location of the
+     corrsponding opening token, and return false.  */
+
+  bool require_close (c_parser *parser) const
+  {
+    return c_parser_require (parser, traits_t::close_token_type,
+			     traits_t::close_gmsgid, m_open_loc);
+  }
+
+  /* Like token_pair::require_close, except that tokens will be skipped
+     until the desired token is found.  An error message is still produced
+     if the next token is not as expected.  */
+
+  void skip_until_found_close (c_parser *parser) const
+  {
+    c_parser_skip_until_found (parser, traits_t::close_token_type,
+			       traits_t::close_gmsgid, m_open_loc);
+  }
+
+ private:
+  location_t m_open_loc;
+};
+
+/* A subclass of token_pair for tracking matching pairs of parentheses.  */
+
+class matching_parens : public token_pair<matching_parens>
+{
+ public:
+  static const enum cpp_ttype open_token_type;
+  static const char * const open_gmsgid;
+  static const enum cpp_ttype close_token_type;
+  static const char * const close_gmsgid;
+};
+
+/* Constant data for use by matching_parens.  */
+
+const enum cpp_ttype matching_parens::open_token_type = CPP_OPEN_PAREN;
+const char * const matching_parens::open_gmsgid = G_("expected %<(%>");
+const enum cpp_ttype matching_parens::close_token_type = CPP_CLOSE_PAREN;
+const char * const matching_parens::close_gmsgid = G_("expected %<)%>");
+
+/* A subclass of token_pair for tracking matching pairs of braces.  */
+
+class matching_braces : public token_pair<matching_braces>
+{
+ public:
+  static const enum cpp_ttype open_token_type;
+  static const char * const open_gmsgid;
+  static const enum cpp_ttype close_token_type;
+  static const char * const close_gmsgid;
+};
+
+/* Constant data for use by matching_braces.  */
+
+const enum cpp_ttype matching_braces::open_token_type = CPP_OPEN_BRACE;
+const char * const matching_braces::open_gmsgid = G_("expected %<{%>");
+const enum cpp_ttype matching_braces::close_token_type = CPP_CLOSE_BRACE;
+const char * const matching_braces::close_gmsgid = G_("expected %<}%>");
+
+/* Get a description of the matching symbol to TYPE e.g. "(" for
+   CPP_CLOSE_PAREN.  */
+
+static const char *
+get_matching_symbol (enum cpp_ttype type)
+{
+  switch (type)
+    {
+    default:
+      gcc_unreachable ();
+      return "";
+    case CPP_CLOSE_PAREN:
+      return "(";
+    case CPP_CLOSE_BRACE:
+      return "{";
+    }
 }
 
 /* If the next token is of the indicated TYPE, consume it.  Otherwise,
    issue the error MSGID.  If MSGID is NULL then a message has already
    been produced and no message will be produced this time.  Returns
-   true if found, false otherwise.  */
+   true if found, false otherwise.
+
+   If MATCHING_LOCATION is not UNKNOWN_LOCATION, then highlight it
+   within any error as the location of an "opening" token matching
+   the close token TYPE (e.g. the location of the '(' when TYPE is
+   CPP_CLOSE_PAREN).  */
 
 bool
 c_parser_require (c_parser *parser,
 		  enum cpp_ttype type,
-		  const char *msgid)
+		  const char *msgid,
+		  location_t matching_location)
 {
   if (c_parser_next_token_is (parser, type))
     {
@@ -911,7 +1055,23 @@ c_parser_require (c_parser *parser,
     }
   else
     {
-      c_parser_error (parser, msgid);
+      location_t next_token_loc = c_parser_peek_token (parser)->location;
+      rich_location richloc (line_table, next_token_loc);
+
+      /* If matching_location != UNKNOWN_LOCATION, highlight it.
+	 Attempt to consolidate diagnostics by printing it as a
+	 secondary range within the main diagnostic.  */
+      bool on_same_line = false;
+      if (matching_location != UNKNOWN_LOCATION)
+	on_same_line = richloc.add_location_if_nearby (matching_location);
+
+      /* If we weren't able to consolidate matching_location, then
+	 print it as a secondary diagnostic.  */
+      if (c_parser_error_richloc (parser, msgid, &richloc))
+	if (matching_location != UNKNOWN_LOCATION && !on_same_line)
+	  inform (matching_location, "to match this %qs",
+		  get_matching_symbol (type));
+
       return false;
     }
 }
@@ -940,16 +1100,22 @@ c_parser_require_keyword (c_parser *parser,
    desired token is found.  An error message is still produced if the
    next token is not as expected.  If MSGID is NULL then a message has
    already been produced and no message will be produced this
-   time.  */
+   time.
+
+   If MATCHING_LOCATION is not UNKNOWN_LOCATION, then highlight it
+   within any error as the location of an "opening" token matching
+   the close token TYPE (e.g. the location of the '(' when TYPE is
+   CPP_CLOSE_PAREN).  */
 
 void
 c_parser_skip_until_found (c_parser *parser,
 			   enum cpp_ttype type,
-			   const char *msgid)
+			   const char *msgid,
+			   location_t matching_location)
 {
   unsigned nesting_depth = 0;
 
-  if (c_parser_require (parser, type, msgid))
+  if (c_parser_require (parser, type, msgid, matching_location))
     return;
 
   /* Skip tokens until the desired token is found.  */
@@ -2210,7 +2376,8 @@ c_parser_static_assert_declaration_no_semi (c_parser *parser)
     pedwarn_c99 (assert_loc, OPT_Wpedantic,
 		 "ISO C90 does not support %<_Static_assert%>");
   c_parser_consume_token (parser);
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return;
   location_t value_tok_loc = c_parser_peek_token (parser)->location;
   value = c_parser_expr_no_commas (parser, NULL).value;
@@ -2237,7 +2404,7 @@ c_parser_static_assert_declaration_no_semi (c_parser *parser)
       parser->lex_untranslated_string = false;
       return;
     }
-  c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.require_close (parser);
 
   if (!INTEGRAL_TYPE_P (TREE_TYPE (value)))
     {
@@ -2922,7 +3089,8 @@ c_parser_struct_or_union_specifier (c_parser *parser)
 	  tree name;
 	  gcc_assert (c_dialect_objc ());
 	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+	  matching_parens parens;
+	  if (!parens.require_open (parser))
 	    goto end_at_defs;
 	  if (c_parser_next_token_is (parser, CPP_NAME)
 	      && c_parser_peek_token (parser)->id_kind == C_ID_CLASSNAME)
@@ -2936,8 +3104,7 @@ c_parser_struct_or_union_specifier (c_parser *parser)
 	      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
 	      goto end_at_defs;
 	    }
-	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
-				     "expected %<)%>");
+	  parens.skip_until_found_close (parser);
 	  contents = nreverse (objc_get_class_ivars (name));
 	}
     end_at_defs:
@@ -3224,7 +3391,8 @@ c_parser_typeof_specifier (c_parser *parser)
   c_parser_consume_token (parser);
   c_inhibit_evaluation_warnings++;
   in_typeof++;
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     {
       c_inhibit_evaluation_warnings--;
       in_typeof--;
@@ -3265,7 +3433,7 @@ c_parser_typeof_specifier (c_parser *parser)
       if (ret.spec != error_mark_node && TYPE_ATOMIC (ret.spec))
 	ret.spec = c_build_qualified_type (ret.spec, TYPE_UNQUALIFIED);
     }
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return ret;
 }
 
@@ -3291,7 +3459,8 @@ c_parser_alignas_specifier (c_parser * parser)
   else
     pedwarn_c99 (loc, OPT_Wpedantic,
 		 "ISO C90 does not support %<_Alignas%>");
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return ret;
   if (c_parser_next_tokens_start_typename (parser, cla_prefer_id))
     {
@@ -3302,7 +3471,7 @@ c_parser_alignas_specifier (c_parser * parser)
     }
   else
     ret = c_parser_expr_no_commas (parser, NULL).value;
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return ret;
 }
 
@@ -3800,7 +3969,7 @@ c_parser_parms_list_declarator (c_parser *parser, tree attrs, tree expr)
 	    return get_parm_info (false, expr);
 	}
       if (!c_parser_require (parser, CPP_COMMA,
-			     "expected %<;%>, %<,%> or %<)%>"))
+			     "expected %<;%>, %<,%> or %<)%>", false))
 	{
 	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
 	  return NULL;
@@ -3953,14 +4122,15 @@ c_parser_simple_asm_expr (c_parser *parser)
      lex_untranslated_string kludge.  */
   parser->lex_untranslated_string = true;
   c_parser_consume_token (parser);
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     {
       parser->lex_untranslated_string = false;
       return NULL_TREE;
     }
   str = c_parser_asm_string_literal (parser);
   parser->lex_untranslated_string = false;
-  if (!c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>"))
+  if (!parens.require_close (parser))
     {
       c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
       return NULL_TREE;
@@ -4143,12 +4313,14 @@ c_parser_attributes (c_parser *parser)
       /* Consume the `__attribute__' keyword.  */
       c_parser_consume_token (parser);
       /* Look for the two `(' tokens.  */
-      if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+      matching_parens outer_parens;
+      if (!outer_parens.require_open (parser))
 	{
 	  parser->lex_untranslated_string = false;
 	  return attrs;
 	}
-      if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+      matching_parens inner_parens;
+      if (!inner_parens.require_open (parser))
 	{
 	  parser->lex_untranslated_string = false;
 	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
@@ -4395,7 +4567,8 @@ c_parser_braced_init (c_parser *parser, tree type, bool nested_p,
   location_t brace_loc = c_parser_peek_token (parser)->location;
   gcc_obstack_init (&braced_init_obstack);
   gcc_assert (c_parser_next_token_is (parser, CPP_OPEN_BRACE));
-  c_parser_consume_token (parser);
+  matching_braces braces;
+  braces.consume_open (parser);
   if (nested_p)
     {
       finish_implicit_inits (brace_loc, outer_obstack);
@@ -4433,7 +4606,7 @@ c_parser_braced_init (c_parser *parser, tree type, bool nested_p,
       ret.value = error_mark_node;
       ret.original_code = ERROR_MARK;
       ret.original_type = NULL;
-      c_parser_skip_until_found (parser, CPP_CLOSE_BRACE, "expected %<}%>");
+      braces.skip_until_found_close (parser);
       pop_init_level (brace_loc, 0, &braced_init_obstack, last_init_list_comma);
       obstack_free (&braced_init_obstack, NULL);
       return ret;
@@ -5456,10 +5629,11 @@ static tree
 c_parser_paren_condition (c_parser *parser)
 {
   tree cond;
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return error_mark_node;
   cond = c_parser_condition (parser);
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return cond;
 }
 
@@ -5727,7 +5901,8 @@ c_parser_switch_statement (c_parser *parser, bool *if_p)
   c_parser_consume_token (parser);
   block = c_begin_compound_stmt (flag_isoc99);
   bool explicit_cast_p = false;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     {
       switch_cond_loc = c_parser_peek_token (parser)->location;
       if (c_parser_next_token_is (parser, CPP_OPEN_PAREN)
@@ -5742,7 +5917,7 @@ c_parser_switch_statement (c_parser *parser, bool *if_p)
 	 "%<_Cilk_spawn%> statement cannot be used as a condition for switch statement",
 			 switch_cond_loc))
         expr = error_mark_node;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   else
     {
@@ -5951,7 +6126,8 @@ c_parser_for_statement (c_parser *parser, bool ivdep, bool *if_p)
   block = c_begin_compound_stmt (flag_isoc99 || c_dialect_objc ());
   cond = error_mark_node;
   incr = error_mark_node;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     {
       /* Parse the initialization declaration or expression.  */
       object_expression = error_mark_node;
@@ -6098,7 +6274,7 @@ c_parser_for_statement (c_parser *parser, bool ivdep, bool *if_p)
 	      incr = c_process_expr_stmt (loc, ce.value);
 	    }
 	}
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   save_break = c_break_label;
   c_break_label = NULL_TREE;
@@ -6191,7 +6367,8 @@ c_parser_asm_statement (c_parser *parser)
   parser->lex_untranslated_string = true;
   ret = NULL;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     goto error;
 
   str = c_parser_asm_string_literal (parser);
@@ -6214,7 +6391,8 @@ c_parser_asm_statement (c_parser *parser)
       if (!c_parser_require (parser, CPP_COLON,
 			     is_goto
 			     ? G_("expected %<:%>")
-			     : G_("expected %<:%> or %<)%>")))
+			     : G_("expected %<:%> or %<)%>"),
+			     is_goto))
 	goto error_close_paren;
 
       /* Once past any colon, we're no longer a simple asm.  */
@@ -6249,7 +6427,7 @@ c_parser_asm_statement (c_parser *parser)
     }
 
  done_asm:
-  if (!c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>"))
+  if (!parens.require_close (parser))
     {
       c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
       goto error;
@@ -6314,7 +6492,8 @@ c_parser_asm_operands (c_parser *parser)
       if (str == NULL_TREE)
 	return NULL_TREE;
       parser->lex_untranslated_string = false;
-      if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	{
 	  parser->lex_untranslated_string = true;
 	  return NULL_TREE;
@@ -6322,7 +6501,7 @@ c_parser_asm_operands (c_parser *parser)
       expr = c_parser_expression (parser);
       mark_exp_read (expr.value);
       parser->lex_untranslated_string = true;
-      if (!c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>"))
+      if (!parens.require_close (parser))
 	{
 	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
 	  return NULL_TREE;
@@ -6931,9 +7110,10 @@ c_parser_cast_expression (c_parser *parser, struct c_expr *after)
       struct c_type_name *type_name;
       struct c_expr ret;
       struct c_expr expr;
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       type_name = c_parser_type_name (parser);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
       if (type_name == NULL)
 	{
 	  ret.value = error_mark_node;
@@ -7160,10 +7340,11 @@ c_parser_sizeof_expression (c_parser *parser)
       /* Either sizeof ( type-name ) or sizeof unary-expression
 	 starting with a compound literal.  */
       struct c_type_name *type_name;
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       expr_loc = c_parser_peek_token (parser)->location;
       type_name = c_parser_type_name (parser);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
       finish = parser->tokens_buf[0].location;
       if (type_name == NULL)
 	{
@@ -7242,11 +7423,12 @@ c_parser_alignof_expression (c_parser *parser)
       location_t loc;
       struct c_type_name *type_name;
       struct c_expr ret;
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       loc = c_parser_peek_token (parser)->location;
       type_name = c_parser_type_name (parser);
       end_loc = c_parser_peek_token (parser)->location;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
       if (type_name == NULL)
 	{
 	  struct c_expr ret;
@@ -7405,7 +7587,8 @@ c_parser_generic_selection (c_parser *parser)
     pedwarn_c99 (generic_loc, OPT_Wpedantic,
 		 "ISO C90 does not support %<_Generic%>");
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return error_expr;
 
   c_inhibit_evaluation_warnings++;
@@ -7547,7 +7730,7 @@ c_parser_generic_selection (c_parser *parser)
       c_parser_consume_token (parser);
     }
 
-  if (!c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>"))
+  if (!parens.require_close (parser))
     {
       c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
       return error_expr;
@@ -7793,7 +7976,7 @@ c_parser_postfix_expression (c_parser *parser)
 	  location_t loc_close_paren = c_parser_peek_token (parser)->location;
 	  set_c_expr_source_range (&expr, loc_open_paren, loc_close_paren);
 	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
-				     "expected %<)%>");
+				     "expected %<)%>", loc_open_paren);
 	}
       break;
     case CPP_KEYWORD:
@@ -7830,7 +8013,8 @@ c_parser_postfix_expression (c_parser *parser)
 	  {
 	    location_t start_loc = loc;
 	    c_parser_consume_token (parser);
-	    if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
 	      {
 		expr.set_error ();
 		break;
@@ -7870,25 +8054,25 @@ c_parser_postfix_expression (c_parser *parser)
 	  }
 	  break;
 	case RID_OFFSETOF:
-	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
-	    {
-	      expr.set_error ();
-	      break;
-	    }
-	  t1 = c_parser_type_name (parser);
-	  if (t1 == NULL)
-	    parser->error = true;
-	  if (!c_parser_require (parser, CPP_COMMA, "expected %<,%>"))
-            gcc_assert (parser->error);
-	  if (parser->error)
-	    {
-	      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
-	      expr.set_error ();
-	      break;
-	    }
-
 	  {
+	    c_parser_consume_token (parser);
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
+	      {
+		expr.set_error ();
+		break;
+	      }
+	    t1 = c_parser_type_name (parser);
+	    if (t1 == NULL)
+	      parser->error = true;
+	    if (!c_parser_require (parser, CPP_COMMA, "expected %<,%>"))
+	      gcc_assert (parser->error);
+	    if (parser->error)
+	      {
+		c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
+		expr.set_error ();
+		break;
+	      }
 	    tree type = groktypename (t1, NULL, NULL);
 	    tree offsetof_ref;
 	    if (type == error_mark_node)
@@ -8005,31 +8189,32 @@ c_parser_postfix_expression (c_parser *parser)
 	    break;
 	  }
 	case RID_TYPES_COMPATIBLE_P:
-	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
-	    {
-	      expr.set_error ();
-	      break;
-	    }
-	  t1 = c_parser_type_name (parser);
-	  if (t1 == NULL)
-	    {
-	      expr.set_error ();
-	      break;
-	    }
-	  if (!c_parser_require (parser, CPP_COMMA, "expected %<,%>"))
-	    {
-	      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
-	      expr.set_error ();
-	      break;
-	    }
-	  t2 = c_parser_type_name (parser);
-	  if (t2 == NULL)
-	    {
-	      expr.set_error ();
-	      break;
-	    }
 	  {
+	    c_parser_consume_token (parser);
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
+	      {
+		expr.set_error ();
+		break;
+	      }
+	    t1 = c_parser_type_name (parser);
+	    if (t1 == NULL)
+	      {
+		expr.set_error ();
+		break;
+	      }
+	    if (!c_parser_require (parser, CPP_COMMA, "expected %<,%>"))
+	      {
+		c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
+		expr.set_error ();
+		break;
+	      }
+	    t2 = c_parser_type_name (parser);
+	    if (t2 == NULL)
+	      {
+		expr.set_error ();
+		break;
+	      }
 	    location_t close_paren_loc = c_parser_peek_token (parser)->location;
 	    c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
 				       "expected %<)%>");
@@ -8198,67 +8383,67 @@ c_parser_postfix_expression (c_parser *parser)
 	    break;
 	  }
 	case RID_AT_SELECTOR:
-	  gcc_assert (c_dialect_objc ());
-	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
-	    {
-	      expr.set_error ();
-	      break;
-	    }
 	  {
+	    gcc_assert (c_dialect_objc ());
+	    c_parser_consume_token (parser);
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
+	      {
+		expr.set_error ();
+		break;
+	      }
 	    tree sel = c_parser_objc_selector_arg (parser);
 	    location_t close_loc = c_parser_peek_token (parser)->location;
-	    c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
-				       "expected %<)%>");
+	    parens.skip_until_found_close (parser);
 	    expr.value = objc_build_selector_expr (loc, sel);
 	    set_c_expr_source_range (&expr, loc, close_loc);
 	  }
 	  break;
 	case RID_AT_PROTOCOL:
-	  gcc_assert (c_dialect_objc ());
-	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
-	    {
-	      expr.set_error ();
-	      break;
-	    }
-	  if (c_parser_next_token_is_not (parser, CPP_NAME))
-	    {
-	      c_parser_error (parser, "expected identifier");
-	      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
-	      expr.set_error ();
-	      break;
-	    }
 	  {
+	    gcc_assert (c_dialect_objc ());
+	    c_parser_consume_token (parser);
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
+	      {
+		expr.set_error ();
+		break;
+	      }
+	    if (c_parser_next_token_is_not (parser, CPP_NAME))
+	      {
+		c_parser_error (parser, "expected identifier");
+		c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
+		expr.set_error ();
+		break;
+	      }
 	    tree id = c_parser_peek_token (parser)->value;
 	    c_parser_consume_token (parser);
 	    location_t close_loc = c_parser_peek_token (parser)->location;
-	    c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
-				       "expected %<)%>");
+	    parens.skip_until_found_close (parser);
 	    expr.value = objc_build_protocol_expr (id);
 	    set_c_expr_source_range (&expr, loc, close_loc);
 	  }
 	  break;
 	case RID_AT_ENCODE:
-	  /* Extension to support C-structures in the archiver.  */
-	  gcc_assert (c_dialect_objc ());
-	  c_parser_consume_token (parser);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
-	    {
-	      expr.set_error ();
-	      break;
-	    }
-	  t1 = c_parser_type_name (parser);
-	  if (t1 == NULL)
-	    {
-	      expr.set_error ();
-	      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
-	      break;
-	    }
 	  {
+	    /* Extension to support C-structures in the archiver.  */
+	    gcc_assert (c_dialect_objc ());
+	    c_parser_consume_token (parser);
+	    matching_parens parens;
+	    if (!parens.require_open (parser))
+	      {
+		expr.set_error ();
+		break;
+	      }
+	    t1 = c_parser_type_name (parser);
+	    if (t1 == NULL)
+	      {
+		expr.set_error ();
+		c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL);
+		break;
+	      }
 	    location_t close_loc = c_parser_peek_token (parser)->location;
-	    c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
-				     "expected %<)%>");
+	    parens.skip_until_found_close (parser);
 	    tree type = groktypename (t1, NULL, NULL);
 	    expr.value = objc_build_encode_expr (type);
 	    set_c_expr_source_range (&expr, loc, close_loc);
@@ -8851,7 +9036,8 @@ c_parser_objc_class_definition (c_parser *parser, tree attributes)
       /* We have a category or class extension.  */
       tree id2;
       tree proto = NULL_TREE;
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       if (c_parser_next_token_is_not (parser, CPP_NAME))
 	{
 	  if (iface_p && c_parser_next_token_is (parser, CPP_CLOSE_PAREN))
@@ -8871,7 +9057,7 @@ c_parser_objc_class_definition (c_parser *parser, tree attributes)
 	  id2 = c_parser_peek_token (parser)->value;
 	  c_parser_consume_token (parser);
 	}
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
       if (!iface_p)
 	{
 	  objc_start_category_implementation (id1, id2);
@@ -9405,9 +9591,10 @@ c_parser_objc_method_decl (c_parser *parser, bool is_class_method,
   *attributes = NULL_TREE;
   if (c_parser_next_token_is (parser, CPP_OPEN_PAREN))
     {
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       type = c_parser_objc_type_name (parser);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   sel = c_parser_objc_selector (parser);
   /* If there is no selector, or a colon follows, we have an
@@ -9613,7 +9800,8 @@ c_parser_objc_try_catch_finally_statement (c_parser *parser)
       bool seen_open_paren = false;
 
       c_parser_consume_token (parser);
-      if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	seen_open_paren = true;
       if (c_parser_next_token_is (parser, CPP_ELLIPSIS))
 	{
@@ -9685,13 +9873,14 @@ c_parser_objc_synchronized_statement (c_parser *parser)
   c_parser_consume_token (parser);
   loc = c_parser_peek_token (parser)->location;
   objc_maybe_warn_exceptions (loc);
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       struct c_expr ce = c_parser_expression (parser);
       ce = convert_lvalue_to_rvalue (loc, ce, false, false);
       expr = ce.value;
       expr = c_fully_fold (expr, false, NULL);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   else
     expr = error_mark_node;
@@ -9985,9 +10174,11 @@ c_parser_objc_at_property_declaration (c_parser *parser)
   /* Parse the optional attribute list...  */
   if (c_parser_next_token_is (parser, CPP_OPEN_PAREN))
     {
+      matching_parens parens;
+
       /* Eat the '(' */
-      c_parser_consume_token (parser);
-      
+      parens.consume_open (parser);
+
       /* Property attribute keywords are valid now.  */
       parser->objc_property_attr_context = true;
 
@@ -10075,7 +10266,7 @@ c_parser_objc_at_property_declaration (c_parser *parser)
 	    break;
 	}
       parser->objc_property_attr_context = false;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   /* ... and the property declaration(s).  */
   properties = c_parser_struct_declaration (parser);
@@ -10735,7 +10926,8 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
   vec<tree, va_gc> *args;
   tree t, args_tree;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   args = c_parser_expr_list (parser, false, true, NULL, NULL, NULL, NULL);
@@ -10772,7 +10964,7 @@ c_parser_oacc_wait_list (c_parser *parser, location_t clause_loc, tree list)
     }
 
   release_tree_vector (args);
-  c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.require_close (parser);
   return list;
 }
 
@@ -10930,10 +11122,11 @@ c_parser_omp_var_list_parens (c_parser *parser, enum omp_clause_code kind,
   /* The clauses location.  */
   location_t loc = c_parser_peek_token (parser)->location;
 
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       list = c_parser_omp_variable_list (parser, loc, kind, list);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   return list;
 }
@@ -11070,10 +11263,11 @@ c_parser_omp_clause_collapse (c_parser *parser, tree list)
   check_no_duplicate_clause (list, OMP_CLAUSE_TILE, "tile");
 
   loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       num = c_parser_expr_no_commas (parser, NULL).value;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   if (num == error_mark_node)
     return list;
@@ -11125,7 +11319,8 @@ c_parser_omp_clause_default (c_parser *parser, tree list, bool is_oacc)
   location_t loc = c_parser_peek_token (parser)->location;
   tree c;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
   if (c_parser_next_token_is (parser, CPP_NAME))
     {
@@ -11165,7 +11360,7 @@ c_parser_omp_clause_default (c_parser *parser, tree list, bool is_oacc)
       else
 	c_parser_error (parser, "expected %<none%> or %<shared%>");
     }
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
 
   if (kind == OMP_CLAUSE_DEFAULT_UNSPECIFIED)
     return list;
@@ -11228,7 +11423,8 @@ c_parser_omp_clause_if (c_parser *parser, tree list, bool is_omp)
   location_t location = c_parser_peek_token (parser)->location;
   enum tree_code if_modifier = ERROR_MARK;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (is_omp && c_parser_next_token_is (parser, CPP_NAME))
@@ -11309,7 +11505,7 @@ c_parser_omp_clause_if (c_parser *parser, tree list, bool is_omp)
     }
 
   tree t = c_parser_condition (parser), c;
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
 
   for (c = list; c ; c = OMP_CLAUSE_CHAIN (c))
     if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_IF)
@@ -11408,7 +11604,8 @@ static tree
 c_parser_omp_clause_num_threads (c_parser *parser, tree list)
 {
   location_t num_threads_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -11416,7 +11613,7 @@ c_parser_omp_clause_num_threads (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -11453,7 +11650,8 @@ static tree
 c_parser_omp_clause_num_tasks (c_parser *parser, tree list)
 {
   location_t num_tasks_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -11461,7 +11659,7 @@ c_parser_omp_clause_num_tasks (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -11498,7 +11696,8 @@ static tree
 c_parser_omp_clause_grainsize (c_parser *parser, tree list)
 {
   location_t grainsize_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -11506,7 +11705,7 @@ c_parser_omp_clause_grainsize (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -11543,7 +11742,8 @@ static tree
 c_parser_omp_clause_priority (c_parser *parser, tree list)
 {
   location_t priority_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -11551,7 +11751,7 @@ c_parser_omp_clause_priority (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -11589,7 +11789,8 @@ static tree
 c_parser_omp_clause_hint (c_parser *parser, tree list)
 {
   location_t hint_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -11597,7 +11798,7 @@ c_parser_omp_clause_hint (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -11626,7 +11827,8 @@ c_parser_omp_clause_defaultmap (c_parser *parser, tree list)
   tree c;
   const char *p;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
   if (!c_parser_next_token_is (parser, CPP_NAME))
     {
@@ -11654,14 +11856,14 @@ c_parser_omp_clause_defaultmap (c_parser *parser, tree list)
       goto out_err;
     }
   c_parser_consume_token (parser);
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   check_no_duplicate_clause (list, OMP_CLAUSE_DEFAULTMAP, "defaultmap");
   c = build_omp_clause (loc, OMP_CLAUSE_DEFAULTMAP);
   OMP_CLAUSE_CHAIN (c) = list;
   return c;
 
  out_err:
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return list;
 }
 
@@ -11698,7 +11900,8 @@ c_parser_oacc_single_int_clause (c_parser *parser, omp_clause_code code,
 {
   location_t loc = c_parser_peek_token (parser)->location;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   location_t expr_loc = c_parser_peek_token (parser)->location;
@@ -11707,7 +11910,7 @@ c_parser_oacc_single_int_clause (c_parser *parser, omp_clause_code code,
   tree c, t = expr.value;
   t = c_fully_fold (t, false, NULL);
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
 
   if (t == error_mark_node)
     return list;
@@ -11952,7 +12155,8 @@ c_parser_oacc_clause_tile (c_parser *parser, tree list)
   check_no_duplicate_clause (list, OMP_CLAUSE_COLLAPSE, "collapse");
 
   loc = c_parser_peek_token (parser)->location;
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   do
@@ -12037,9 +12241,10 @@ c_parser_omp_clause_ordered (c_parser *parser, tree list)
   location_t loc = c_parser_peek_token (parser)->location;
   if (c_parser_next_token_is (parser, CPP_OPEN_PAREN))
     {
-      c_parser_consume_token (parser);
+      matching_parens parens;
+      parens.consume_open (parser);
       num = c_parser_expr_no_commas (parser, NULL).value;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   if (num == error_mark_node)
     return list;
@@ -12093,7 +12298,8 @@ static tree
 c_parser_omp_clause_reduction (c_parser *parser, tree list)
 {
   location_t clause_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       enum tree_code code = ERROR_MARK;
       tree reduc_id = NULL_TREE;
@@ -12191,7 +12397,7 @@ c_parser_omp_clause_reduction (c_parser *parser, tree list)
 
 	  list = nl;
 	}
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   return list;
 }
@@ -12219,7 +12425,8 @@ c_parser_omp_clause_schedule (c_parser *parser, tree list)
   location_t loc = c_parser_peek_token (parser)->location;
   int modifiers = 0, nmodifiers = 0;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   c = build_omp_clause (loc, OMP_CLAUSE_SCHEDULE);
@@ -12330,7 +12537,7 @@ c_parser_omp_clause_schedule (c_parser *parser, tree list)
       else
 	c_parser_error (parser, "expected integer expression");
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   else
     c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
@@ -12443,7 +12650,8 @@ static tree
 c_parser_omp_clause_num_teams (c_parser *parser, tree list)
 {
   location_t num_teams_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -12451,7 +12659,7 @@ c_parser_omp_clause_num_teams (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -12487,7 +12695,8 @@ static tree
 c_parser_omp_clause_thread_limit (c_parser *parser, tree list)
 {
   location_t num_thread_limit_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expression (parser);
@@ -12495,7 +12704,7 @@ c_parser_omp_clause_thread_limit (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -12535,7 +12744,8 @@ c_parser_omp_clause_aligned (c_parser *parser, tree list)
   location_t clause_loc = c_parser_peek_token (parser)->location;
   tree nl, c;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   nl = c_parser_omp_variable_list (parser, clause_loc,
@@ -12562,7 +12772,7 @@ c_parser_omp_clause_aligned (c_parser *parser, tree list)
 	OMP_CLAUSE_ALIGNED_ALIGNMENT (c) = alignment;
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return nl;
 }
 
@@ -12581,7 +12791,8 @@ c_parser_omp_clause_linear (c_parser *parser, tree list, bool is_cilk_simd_fn)
   tree nl, c, step;
   enum omp_clause_linear_kind kind = OMP_CLAUSE_LINEAR_DEFAULT;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (!is_cilk_simd_fn
@@ -12604,7 +12815,7 @@ c_parser_omp_clause_linear (c_parser *parser, tree list, bool is_cilk_simd_fn)
 				   OMP_CLAUSE_LINEAR, list);
 
   if (kind != OMP_CLAUSE_LINEAR_DEFAULT)
-    c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+    parens.skip_until_found_close (parser);
 
   if (c_parser_next_token_is (parser, CPP_COLON))
     {
@@ -12636,7 +12847,7 @@ c_parser_omp_clause_linear (c_parser *parser, tree list, bool is_cilk_simd_fn)
       OMP_CLAUSE_LINEAR_KIND (c) = kind;
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return nl;
 }
 
@@ -12649,7 +12860,8 @@ c_parser_omp_clause_safelen (c_parser *parser, tree list)
   location_t clause_loc = c_parser_peek_token (parser)->location;
   tree c, t;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   location_t expr_loc = c_parser_peek_token (parser)->location;
@@ -12666,7 +12878,7 @@ c_parser_omp_clause_safelen (c_parser *parser, tree list)
       t = NULL_TREE;
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   if (t == NULL_TREE || t == error_mark_node)
     return list;
 
@@ -12687,7 +12899,8 @@ c_parser_omp_clause_simdlen (c_parser *parser, tree list)
   location_t clause_loc = c_parser_peek_token (parser)->location;
   tree c, t;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   location_t expr_loc = c_parser_peek_token (parser)->location;
@@ -12704,7 +12917,7 @@ c_parser_omp_clause_simdlen (c_parser *parser, tree list)
       t = NULL_TREE;
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   if (t == NULL_TREE || t == error_mark_node)
     return list;
 
@@ -12816,7 +13029,8 @@ c_parser_omp_clause_depend (c_parser *parser, tree list)
   enum omp_clause_depend_kind kind = OMP_CLAUSE_DEPEND_INOUT;
   tree nl, c;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (c_parser_next_token_is (parser, CPP_NAME))
@@ -12846,7 +13060,7 @@ c_parser_omp_clause_depend (c_parser *parser, tree list)
       OMP_CLAUSE_DEPEND_KIND (c) = kind;
       OMP_CLAUSE_DECL (c) = NULL_TREE;
       OMP_CLAUSE_CHAIN (c) = list;
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
       return c;
     }
 
@@ -12864,13 +13078,13 @@ c_parser_omp_clause_depend (c_parser *parser, tree list)
 	OMP_CLAUSE_DEPEND_KIND (c) = kind;
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return nl;
 
  invalid_kind:
   c_parser_error (parser, "invalid depend kind");
  resync_fail:
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return list;
 }
 
@@ -12898,7 +13112,8 @@ c_parser_omp_clause_map (c_parser *parser, tree list)
   tree always_id = NULL_TREE;
   tree nl, c;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (c_parser_next_token_is (parser, CPP_NAME))
@@ -12965,7 +13180,7 @@ c_parser_omp_clause_map (c_parser *parser, tree list)
       if (always_id_kind != C_ID_ID)
 	{
 	  c_parser_error (parser, "expected identifier");
-	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+	  parens.skip_until_found_close (parser);
 	  return list;
 	}
 
@@ -12985,7 +13200,7 @@ c_parser_omp_clause_map (c_parser *parser, tree list)
 	}
       if (always == 1)
 	{
-	  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+	  parens.skip_until_found_close (parser);
 	  return list;
 	}
     }
@@ -12995,7 +13210,7 @@ c_parser_omp_clause_map (c_parser *parser, tree list)
   for (c = nl; c != list; c = OMP_CLAUSE_CHAIN (c))
     OMP_CLAUSE_SET_MAP_KIND (c, kind);
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return nl;
 }
 
@@ -13006,7 +13221,8 @@ static tree
 c_parser_omp_clause_device (c_parser *parser, tree list)
 {
   location_t clause_loc = c_parser_peek_token (parser)->location;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       location_t expr_loc = c_parser_peek_token (parser)->location;
       c_expr expr = c_parser_expr_no_commas (parser, NULL);
@@ -13014,7 +13230,7 @@ c_parser_omp_clause_device (c_parser *parser, tree list)
       tree c, t = expr.value;
       t = c_fully_fold (t, false, NULL);
 
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (!INTEGRAL_TYPE_P (TREE_TYPE (t)))
 	{
@@ -13043,7 +13259,8 @@ c_parser_omp_clause_dist_schedule (c_parser *parser, tree list)
   tree c, t = NULL_TREE;
   location_t loc = c_parser_peek_token (parser)->location;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (!c_parser_next_token_is_keyword (parser, RID_STATIC))
@@ -13064,7 +13281,7 @@ c_parser_omp_clause_dist_schedule (c_parser *parser, tree list)
       expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
       t = expr.value;
       t = c_fully_fold (t, false, NULL);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   else
     c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
@@ -13093,7 +13310,8 @@ c_parser_omp_clause_proc_bind (c_parser *parser, tree list)
   enum omp_clause_proc_bind_kind kind;
   tree c;
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (c_parser_next_token_is (parser, CPP_NAME))
@@ -13112,7 +13330,7 @@ c_parser_omp_clause_proc_bind (c_parser *parser, tree list)
     goto invalid_kind;
 
   c_parser_consume_token (parser);
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   c = build_omp_clause (clause_loc, OMP_CLAUSE_PROC_BIND);
   OMP_CLAUSE_PROC_BIND_KIND (c) = kind;
   OMP_CLAUSE_CHAIN (c) = list;
@@ -13120,7 +13338,7 @@ c_parser_omp_clause_proc_bind (c_parser *parser, tree list)
 
  invalid_kind:
   c_parser_error (parser, "invalid proc_bind kind");
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
   return list;
 }
 
@@ -13151,11 +13369,12 @@ c_parser_omp_clause_uniform (c_parser *parser, tree list)
   /* The clauses location.  */
   location_t loc = c_parser_peek_token (parser)->location;
 
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       list = c_parser_omp_variable_list (parser, loc, OMP_CLAUSE_UNIFORM,
 					 list);
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
     }
   return list;
 }
@@ -14948,7 +15167,8 @@ c_parser_omp_for_loop (location_t loc, c_parser *parser, enum tree_code code,
     {
       int bracecount = 0;
 
-      if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	goto pop_scopes;
 
       /* Parse the initialization declaration or expression.  */
@@ -15055,7 +15275,7 @@ c_parser_omp_for_loop (location_t loc, c_parser *parser, enum tree_code code,
 	  incr = c_process_expr_stmt (incr_loc,
 				      c_parser_expression (parser).value);
 	}
-      c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+      parens.skip_until_found_close (parser);
 
       if (decl == NULL || decl == error_mark_node || init == error_mark_node)
 	fail = true;
@@ -16900,6 +17120,7 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
   tree reduc_id = NULL_TREE;
   tree type;
   location_t rloc = c_parser_peek_token (parser)->location;
+  matching_parens parens;
 
   if (context == pragma_struct || context == pragma_param)
     {
@@ -16907,7 +17128,7 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
       goto fail;
     }
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  if (!parens.require_open (parser))
     goto fail;
 
   switch (c_parser_peek_token (parser)->type)
@@ -17120,7 +17341,8 @@ c_parser_omp_declare_reduction (c_parser *parser, enum pragma_context context)
 	  DECL_ARTIFICIAL (omp_orig) = 1;
 	  DECL_CONTEXT (omp_orig) = fndecl;
 	  pushdecl (omp_orig);
-	  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+	  matching_parens parens;
+	  if (!parens.require_open (parser))
 	    bad = true;
 	  else if (!c_parser_next_token_is (parser, CPP_NAME))
 	    {
@@ -17562,7 +17784,8 @@ c_parser_cilk_clause_vectorlength (c_parser *parser, tree clauses,
      clause.  Represent it in OpenMP terms.  */
     check_no_duplicate_clause (clauses, OMP_CLAUSE_SAFELEN, "vectorlength");
 
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return clauses;
 
   location_t loc = c_parser_peek_token (parser)->location;
@@ -17598,7 +17821,7 @@ c_parser_cilk_clause_vectorlength (c_parser *parser, tree clauses,
 	}
     }
 
-  c_parser_require (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.require_close (parser);
 
   return clauses;
 }
@@ -17620,7 +17843,8 @@ c_parser_cilk_clause_vectorlength (c_parser *parser, tree clauses,
 static tree
 c_parser_cilk_clause_linear (c_parser *parser, tree clauses)
 {
-  if (!c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return clauses;
 
   location_t loc = c_parser_peek_token (parser)->location;
@@ -17682,7 +17906,7 @@ c_parser_cilk_clause_linear (c_parser *parser, tree clauses)
       c_parser_consume_token (parser);
     }
 
-  c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, "expected %<)%>");
+  parens.skip_until_found_close (parser);
 
   return clauses;
 }
@@ -18046,7 +18270,8 @@ c_parser_transaction_expression (c_parser *parser, enum rid keyword)
     }
 
   parser->in_transaction = this_in;
-  if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
+  matching_parens parens;
+  if (parens.require_open (parser))
     {
       tree expr = c_parser_expression (parser).value;
       ret.original_type = TREE_TYPE (expr);
diff --git a/gcc/c/c-parser.h b/gcc/c/c-parser.h
index 1e344c4..01a7b72 100644
--- a/gcc/c/c-parser.h
+++ b/gcc/c/c-parser.h
@@ -136,11 +136,13 @@ extern c_token * c_parser_peek_token (c_parser *parser);
 extern c_token * c_parser_peek_2nd_token (c_parser *parser);
 extern c_token * c_parser_peek_nth_token (c_parser *parser, unsigned int n);
 extern bool c_parser_require (c_parser *parser, enum cpp_ttype type,
-			      const char *msgid);
-extern void c_parser_error (c_parser *parser, const char *gmsgid);
+			      const char *msgid,
+			      location_t matching_location = UNKNOWN_LOCATION);
+extern bool c_parser_error (c_parser *parser, const char *gmsgid);
 extern void c_parser_consume_token (c_parser *parser);
 extern void c_parser_skip_until_found (c_parser *parser, enum cpp_ttype type,
-				       const char *msgid);
+				       const char *msgid,
+				       location_t = UNKNOWN_LOCATION);
 extern bool c_parser_next_token_starts_declspecs (c_parser *parser);
 bool c_parser_next_tokens_start_declaration (c_parser *parser);
 bool c_token_starts_typename (c_token *token);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index c81b1a1f..e42758c 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -2551,9 +2551,9 @@ static void set_and_check_decl_spec_loc
 static bool cp_parser_friend_p
   (const cp_decl_specifier_seq *);
 static void cp_parser_required_error
-  (cp_parser *, required_token, bool);
+  (cp_parser *, required_token, bool, location_t);
 static cp_token *cp_parser_require
-  (cp_parser *, enum cpp_ttype, required_token);
+  (cp_parser *, enum cpp_ttype, required_token, location_t = UNKNOWN_LOCATION);
 static cp_token *cp_parser_require_keyword
   (cp_parser *, enum rid, required_token);
 static bool cp_parser_token_starts_function_definition_p
@@ -2804,12 +2804,13 @@ cp_parser_error (cp_parser* parser, const char* gmsgid)
 	    }
 	}
 
+      rich_location richloc (line_table, input_location);
       c_parse_error (gmsgid,
 		     /* Because c_parser_error does not understand
 			CPP_KEYWORD, keywords are treated like
 			identifiers.  */
 		     (token->type == CPP_KEYWORD ? CPP_NAME : token->type),
-		     token->u.value, token->flags);
+		     token->u.value, token->flags, &richloc);
     }
 }
 
@@ -4503,6 +4504,110 @@ struct tentative_firewall
   }
 };
 
+/* Some tokens naturally come in pairs e.g.'(' and ')'.
+   This class is for tracking such a matching pair of symbols.
+   In particular, it tracks the location of the first token,
+   so that if the second token is missing, we can highlight the
+   location of the first token when notifying the user about the
+   problem.  */
+
+template <typename token_pair_traits_t>
+class token_pair
+{
+ private:
+  typedef token_pair_traits_t traits_t;
+
+ public:
+  /* token_pair's ctor.  */
+  token_pair () : m_open_loc (UNKNOWN_LOCATION) {}
+
+  /* If the next token is the opening symbol for this pair, consume it and
+     return true.
+     Otherwise, issue an error and return false.
+     In either case, record the location of the opening token.  */
+
+  bool require_open (cp_parser *parser)
+  {
+    m_open_loc = cp_lexer_peek_token (parser->lexer)->location;
+    return cp_parser_require (parser, traits_t::open_token_type,
+                              traits_t::required_token_open);
+  }
+
+  /* Consume the next token from PARSER, recording its location as
+     that of the opening token within the pair.  */
+
+  cp_token * consume_open (cp_parser *parser)
+  {
+    cp_token *tok = cp_lexer_consume_token (parser->lexer);
+    gcc_assert (tok->type == traits_t::open_token_type);
+    m_open_loc = tok->location;
+    return tok;
+  }
+
+  /* Peek the next token from PARSER, recording its location as
+     that of the opening token within the pair.  */
+
+  void peek_open (cp_parser *parser)
+  {
+    cp_token *tok = cp_lexer_peek_token (parser->lexer);
+    gcc_assert (tok->type == traits_t::open_token_type);
+    m_open_loc = tok->location;
+  }
+
+  /* If the next token is the closing symbol for this pair, consume it
+     and return it.
+     Otherwise, issue an error, highlighting the location of the
+     corrsponding opening token, and return NULL.  */
+
+  cp_token *require_close (cp_parser *parser) const
+  {
+    return cp_parser_require (parser, traits_t::close_token_type,
+                              traits_t::required_token_close,
+                              m_open_loc);
+  }
+
+ private:
+  location_t m_open_loc;
+};
+
+/* A subclass of token_pair for tracking matching pairs of parentheses.  */
+
+class matching_parens : public token_pair<matching_parens>
+{
+ public:
+  static const enum cpp_ttype open_token_type;
+  static const enum required_token required_token_open;
+  static const enum cpp_ttype close_token_type;
+  static const enum required_token required_token_close;
+};
+
+/* Constant data for class matching_parens.  */
+
+const enum cpp_ttype matching_parens::open_token_type = CPP_OPEN_PAREN;
+const enum required_token matching_parens::required_token_open = RT_OPEN_PAREN;
+const enum cpp_ttype matching_parens::close_token_type = CPP_CLOSE_PAREN;
+const enum required_token matching_parens::required_token_close
+  = RT_CLOSE_PAREN;
+
+/* A subclass of token_pair for tracking matching pairs of braces.  */
+
+class matching_braces : public token_pair<matching_braces>
+{
+ public:
+  static const enum cpp_ttype open_token_type;
+  static const enum required_token required_token_open;
+  static const enum cpp_ttype close_token_type;
+  static const enum required_token required_token_close;
+};
+
+/* Constant data for class matching_braces.  */
+
+const enum cpp_ttype matching_braces::open_token_type = CPP_OPEN_BRACE;
+const enum required_token matching_braces::required_token_open = RT_OPEN_BRACE;
+const enum cpp_ttype matching_braces::close_token_type = CPP_CLOSE_BRACE;
+const enum required_token matching_braces::required_token_close
+  = RT_CLOSE_BRACE;
+
 /* Parse a GNU statement-expression, i.e. ({ stmts }), except for the
    enclosing parentheses.  */
 
@@ -4513,7 +4618,8 @@ cp_parser_statement_expr (cp_parser *parser)
 
   /* Consume the '('.  */
   location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;
-  cp_lexer_consume_token (parser->lexer);
+  matching_parens parens;
+  parens.consume_open (parser);
   /* Start the statement-expression.  */
   tree expr = begin_stmt_expr ();
   /* Parse the compound-statement.  */
@@ -4522,7 +4628,7 @@ cp_parser_statement_expr (cp_parser *parser)
   expr = finish_stmt_expr (expr, false);
   /* Consume the ')'.  */
   location_t finish_loc = cp_lexer_peek_token (parser->lexer)->location;
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     cp_parser_skip_to_end_of_statement (parser);
 
   cp_parser_end_tentative_firewall (parser, start, expr);
@@ -4928,7 +5034,8 @@ cp_parser_primary_expression (cp_parser *parser,
 	location_t open_paren_loc = token->location;
 
 	/* Consume the `('.  */
-	cp_lexer_consume_token (parser->lexer);
+	matching_parens parens;
+	parens.consume_open (parser);
 	/* Within a parenthesized expression, a `>' token is always
 	   the greater-than operator.  */
 	saved_greater_than_is_operator_p
@@ -4976,7 +5083,7 @@ cp_parser_primary_expression (cp_parser *parser,
 	token = cp_lexer_peek_token (parser->lexer);
 	location_t close_paren_loc = token->location;
 	expr.set_range (open_paren_loc, close_paren_loc);
-	if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN)
+	if (!parens.require_close (parser)
 	    && !cp_parser_uncommitted_to_tentative_parse_p (parser))
 	  cp_parser_skip_to_end_of_statement (parser);
 
@@ -5098,7 +5205,8 @@ cp_parser_primary_expression (cp_parser *parser,
 	       `va_arg'.  Consume the `__builtin_va_arg' token.  */
 	    cp_lexer_consume_token (parser->lexer);
 	    /* Look for the opening `('.  */
-	    cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	    matching_parens parens;
+	    parens.require_open (parser);
 	    /* Now, parse the assignment-expression.  */
 	    expression = cp_parser_assignment_expression (parser);
 	    /* Look for the `,'.  */
@@ -5112,7 +5220,7 @@ cp_parser_primary_expression (cp_parser *parser,
 	    /* Look for the closing `)'.  */
 	    location_t finish_loc
 	      = cp_lexer_peek_token (parser->lexer)->location;
-	    cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	    parens.require_close (parser);
 	    /* Using `va_arg' in a constant-expression is not
 	       allowed.  */
 	    if (cp_parser_non_integral_constant_expression (parser,
@@ -6465,7 +6573,8 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	parser->greater_than_is_operator_p = true;
 
 	/* And the expression which is being cast.  */
-	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	matching_parens parens;
+	parens.require_open (parser);
 	expression = cp_parser_expression (parser, & idk, /*cast_p=*/true);
 	cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
 						   RT_CLOSE_PAREN);
@@ -6526,7 +6635,8 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	/* Consume the `typeid' token.  */
 	cp_lexer_consume_token (parser->lexer);
 	/* Look for the `(' token.  */
-	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	matching_parens parens;
+	parens.require_open (parser);
 	/* Types cannot be defined in a `typeid' expression.  */
 	saved_message = parser->type_definition_forbidden_message;
 	parser->type_definition_forbidden_message
@@ -6542,8 +6652,7 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	/* Look for the `)' token.  Otherwise, we can't be sure that
 	   we're not looking at an expression: consider `typeid (int
 	   (3))', for example.  */
-	cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
-						   RT_CLOSE_PAREN);
+	cp_token *close_paren = parens.require_close (parser);
 	/* If all went well, simply lookup the type-id.  */
 	if (cp_parser_parse_definitely (parser))
 	  postfix_expression = get_typeid (type, tf_warning_or_error);
@@ -6557,8 +6666,7 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
 	    /* Compute its typeid.  */
 	    postfix_expression = build_typeid (expression, tf_warning_or_error);
 	    /* Look for the `)' token.  */
-	    close_paren
-	      = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	    close_paren = parens.require_close (parser);
 	  }
 	/* Restore the saved message.  */
 	parser->type_definition_forbidden_message = saved_message;
@@ -7561,7 +7669,8 @@ cp_parser_parenthesized_expression_list (cp_parser* parser,
   if (non_constant_p)
     *non_constant_p = false;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return NULL;
 
   expression_list = make_tree_vector ();
@@ -7657,7 +7766,7 @@ cp_parser_parenthesized_expression_list (cp_parser* parser,
   if (close_paren_loc)
     *close_paren_loc = cp_lexer_peek_token (parser->lexer)->location;
 
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     {
       int ending;
 
@@ -7957,7 +8066,8 @@ cp_parser_unary_expression (cp_parser *parser, cp_id_kind * pidk,
 	    bool saved_greater_than_is_operator_p;
 
 	    cp_lexer_consume_token (parser->lexer);
-	    cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	    matching_parens parens;
+	    parens.require_open (parser);
 
 	    saved_message = parser->type_definition_forbidden_message;
 	    parser->type_definition_forbidden_message
@@ -7991,7 +8101,7 @@ cp_parser_unary_expression (cp_parser *parser, cp_id_kind * pidk,
 
 	    parser->type_definition_forbidden_message = saved_message;
 
-	    cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	    parens.require_close (parser);
 	    return finish_noexcept_expr (expr, tf_warning_or_error);
 	  }
 
@@ -8235,7 +8345,8 @@ cp_parser_new_expression (cp_parser* parser)
       const char *saved_message = parser->type_definition_forbidden_message;
 
       /* Consume the `('.  */
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       /* Parse the type-id.  */
       parser->type_definition_forbidden_message
@@ -8247,7 +8358,7 @@ cp_parser_new_expression (cp_parser* parser)
       parser->type_definition_forbidden_message = saved_message;
 
       /* Look for the closing `)'.  */
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
       token = cp_lexer_peek_token (parser->lexer);
       /* There should not be a direct-new-declarator in this production,
 	 but GCC used to allowed this, so we check and emit a sensible error
@@ -8787,7 +8898,8 @@ cp_parser_cast_expression (cp_parser *parser, bool address_p, bool cast_p,
       parser->type_definition_forbidden_message
 	= G_("types may not be defined in casts");
       /* Consume the `('.  */
-      cp_token *open_paren = cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      cp_token *open_paren = parens.consume_open (parser);
       location_t open_paren_loc = open_paren->location;
       location_t close_paren_loc = UNKNOWN_LOCATION;
 
@@ -8852,8 +8964,7 @@ cp_parser_cast_expression (cp_parser *parser, bool address_p, bool cast_p,
 	  /* Look for the type-id.  */
 	  type = cp_parser_type_id (parser);
 	  /* Look for the closing `)'.  */
-	  cp_token *close_paren
-	    = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	  cp_token *close_paren = parens.require_close (parser);
 	  if (close_paren)
 	    close_paren_loc = close_paren->location;
 	  parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
@@ -9638,7 +9749,8 @@ cp_parser_builtin_offsetof (cp_parser *parser)
   /* Consume the "__builtin_offsetof" token.  */
   cp_lexer_consume_token (parser->lexer);
   /* Consume the opening `('.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   /* Parse the type-id.  */
   location_t loc = cp_lexer_peek_token (parser->lexer)->location;
   type = cp_parser_type_id (parser);
@@ -9688,7 +9800,7 @@ cp_parser_builtin_offsetof (cp_parser *parser)
 	default:
 	  /* Error.  We know the following require will fail, but
 	     that gives the proper error message.  */
-	  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	  parens.require_close (parser);
 	  cp_parser_skip_to_closing_parenthesis (parser, true, false, true);
 	  expr = error_mark_node;
 	  goto failure;
@@ -9834,7 +9946,8 @@ cp_parser_trait_expr (cp_parser* parser, enum rid keyword)
   /* Consume the token.  */
   cp_lexer_consume_token (parser->lexer);
 
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
 
   {
     type_id_in_expr_sentinel s (parser);
@@ -9873,7 +9986,7 @@ cp_parser_trait_expr (cp_parser* parser, enum rid keyword)
 	}
     }
 
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   /* Complete the trait expression, which may mean either processing
      the trait expr now or saving it for template instantiation.  */
@@ -10354,7 +10467,8 @@ cp_parser_lambda_declarator_opt (cp_parser* parser, tree lambda_expr)
      opening parenthesis if present.  */
   if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
     {
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       begin_scope (sk_function_parms, /*entity=*/NULL_TREE);
 
@@ -10369,7 +10483,7 @@ cp_parser_lambda_declarator_opt (cp_parser* parser, tree lambda_expr)
 	    pedwarn (DECL_SOURCE_LOCATION (TREE_VALUE (t)), OPT_Wpedantic,
 		     "default argument specified for lambda parameter");
 
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
 
       attributes = cp_parser_attributes_opt (parser);
 
@@ -10526,7 +10640,8 @@ cp_parser_lambda_body (cp_parser* parser, tree lambda_expr)
     start_lambda_scope (fco);
     body = begin_function_body ();
 
-    if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+    matching_braces braces;
+    if (!braces.require_open (parser))
       goto out;
 
     /* Push the proxies for any explicit captures.  */
@@ -10567,7 +10682,7 @@ cp_parser_lambda_body (cp_parser* parser, tree lambda_expr)
 	expr = cp_parser_expression (parser, &idk);
 
 	cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
-	cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+	braces.require_close (parser);
 
 	if (cp_parser_parse_definitely (parser))
 	  {
@@ -10591,7 +10706,7 @@ cp_parser_lambda_body (cp_parser* parser, tree lambda_expr)
 	while (cp_lexer_next_token_is_keyword (parser->lexer, RID_LABEL))
 	  cp_parser_label_declaration (parser);
 	cp_parser_statement_seq_opt (parser, NULL_TREE);
-	cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+	braces.require_close (parser);
       }
 
     finish_compound_stmt (compound_stmt);
@@ -11127,9 +11242,10 @@ cp_parser_compound_statement (cp_parser *parser, tree in_statement_expr,
 			      int bcs_flags, bool function_body)
 {
   tree compound_stmt;
+  matching_braces braces;
 
   /* Consume the `{'.  */
-  if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  if (!braces.require_open (parser))
     return error_mark_node;
   if (DECL_DECLARED_CONSTEXPR_P (current_function_decl)
       && !function_body && cxx_dialect < cxx14)
@@ -11145,7 +11261,7 @@ cp_parser_compound_statement (cp_parser *parser, tree in_statement_expr,
   /* Finish the compound-statement.  */
   finish_compound_stmt (compound_stmt);
   /* Consume the `}'.  */
-  cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+  braces.require_close (parser);
 
   return compound_stmt;
 }
@@ -11266,7 +11382,8 @@ cp_parser_selection_statement (cp_parser* parser, bool *if_p,
 	  }
 
 	/* Look for the `('.  */
-	if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+	matching_parens parens;
+	if (!parens.require_open (parser))
 	  {
 	    cp_parser_skip_to_end_of_statement (parser);
 	    return error_mark_node;
@@ -11295,7 +11412,7 @@ cp_parser_selection_statement (cp_parser* parser, bool *if_p,
 	/* Parse the condition.  */
 	condition = cp_parser_condition (parser);
 	/* Look for the `)'.  */
-	if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+	if (!parens.require_close (parser))
 	  cp_parser_skip_to_closing_parenthesis (parser, true, false,
 						 /*consume_paren=*/true);
 
@@ -12082,12 +12199,13 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep)
 	/* Begin the while-statement.  */
 	statement = begin_while_stmt ();
 	/* Look for the `('.  */
-	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	matching_parens parens;
+	parens.require_open (parser);
 	/* Parse the condition.  */
 	condition = cp_parser_condition (parser);
 	finish_while_stmt_cond (condition, statement, ivdep);
 	/* Look for the `)'.  */
-	cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	parens.require_close (parser);
 	/* Parse the dependent statement.  */
 	parser->in_statement = IN_ITERATION_STMT;
 	cp_parser_already_scoped_statement (parser, if_p, guard_tinfo);
@@ -12111,13 +12229,14 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep)
 	/* Look for the `while' keyword.  */
 	cp_parser_require_keyword (parser, RID_WHILE, RT_WHILE);
 	/* Look for the `('.  */
-	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	matching_parens parens;
+	parens.require_open (parser);
 	/* Parse the expression.  */
 	expression = cp_parser_expression (parser);
 	/* We're done with the do-statement.  */
 	finish_do_stmt (expression, statement, ivdep);
 	/* Look for the `)'.  */
-	cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	parens.require_close (parser);
 	/* Look for the `;'.  */
 	cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
       }
@@ -12126,12 +12245,13 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep)
     case RID_FOR:
       {
 	/* Look for the `('.  */
-	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+	matching_parens parens;
+	parens.require_open (parser);
 
 	statement = cp_parser_for (parser, ivdep);
 
 	/* Look for the `)'.  */
-	cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	parens.require_close (parser);
 
 	/* Parse the body of the for-statement.  */
 	parser->in_statement = IN_ITERATION_STMT;
@@ -12481,13 +12601,14 @@ cp_parser_already_scoped_statement (cp_parser* parser, bool *if_p,
     {
       /* Avoid calling cp_parser_compound_statement, so that we
 	 don't create a new scope.  Do everything else by hand.  */
-      cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE);
+      matching_braces braces;
+      braces.require_open (parser);
       /* If the next keyword is `__label__' we have a label declaration.  */
       while (cp_lexer_next_token_is_keyword (parser->lexer, RID_LABEL))
 	cp_parser_label_declaration (parser);
       /* Parse an (optional) statement-seq.  */
       cp_parser_statement_seq_opt (parser, NULL_TREE);
-      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      braces.require_close (parser);
     }
 }
 
@@ -13709,11 +13830,12 @@ cp_parser_linkage_specification (cp_parser* parser)
       cp_ensure_no_oacc_routine (parser);
 
       /* Consume the `{' token.  */
-      cp_lexer_consume_token (parser->lexer);
+      matching_braces braces;
+      braces.consume_open (parser)->location;
       /* Parse the declarations.  */
       cp_parser_declaration_seq_opt (parser);
       /* Look for the closing `}'.  */
-      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      braces.require_close (parser);
     }
   /* Otherwise, there's just one declaration.  */
   else
@@ -13765,7 +13887,8 @@ cp_parser_static_assert(cp_parser *parser, bool member_p)
     cp_parser_commit_to_tentative_parse (parser);
 
   /* Parse the `(' starting the static assertion condition.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
 
   /* Parse the constant-expression.  Allow a non-constant expression
      here in order to give better diagnostics in finish_static_assert.  */
@@ -13797,7 +13920,7 @@ cp_parser_static_assert(cp_parser *parser, bool member_p)
                                 	  /*wide_ok=*/true);
 
       /* A `)' completes the static assertion.  */
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, 
                                                /*recovering=*/true, 
                                                /*or_comma=*/false,
@@ -13951,7 +14074,8 @@ cp_parser_decltype (cp_parser *parser)
     return error_mark_node;
 
   /* Parse the opening `('.  */
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return error_mark_node;
 
   /* decltype (auto) */
@@ -13959,7 +14083,7 @@ cp_parser_decltype (cp_parser *parser)
       && cp_lexer_next_token_is_keyword (parser->lexer, RID_AUTO))
     {
       cp_lexer_consume_token (parser->lexer);
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	return error_mark_node;
       expr = make_decltype_auto ();
       AUTO_IS_DECLTYPE (expr) = true;
@@ -14014,7 +14138,7 @@ cp_parser_decltype (cp_parser *parser)
     = saved_non_integral_constant_expression_p;
 
   /* Parse to the closing `)'.  */
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     {
       cp_parser_skip_to_closing_parenthesis (parser, true, false,
 					     /*consume_paren=*/true);
@@ -14713,11 +14837,14 @@ cp_parser_operator (cp_parser* parser)
       break;
 
     case CPP_OPEN_PAREN:
-      /* Consume the `('.  */
-      cp_lexer_consume_token (parser->lexer);
-      /* Look for the matching `)'.  */
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
-      return cp_operator_id (CALL_EXPR);
+      {
+        /* Consume the `('.  */
+        matching_parens parens;
+        parens.consume_open (parser);
+        /* Look for the matching `)'.  */
+        parens.require_close (parser);
+        return cp_operator_id (CALL_EXPR);
+      }
 
     case CPP_OPEN_SQUARE:
       /* Consume the `['.  */
@@ -18090,7 +18217,8 @@ cp_parser_enum_specifier (cp_parser* parser)
 	begin_scope (sk_scoped_enum, type);
 
       /* Consume the opening brace.  */
-      cp_lexer_consume_token (parser->lexer);
+      matching_braces braces;
+      braces.consume_open (parser);
 
       if (type == error_mark_node)
 	; /* Nothing to add */
@@ -18123,7 +18251,7 @@ cp_parser_enum_specifier (cp_parser* parser)
 	cp_parser_enumerator_list (parser, type);
 
       /* Consume the final '}'.  */
-      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      braces.require_close (parser);
 
       if (scoped_enum_p)
 	finish_scope ();
@@ -18416,13 +18544,14 @@ cp_parser_namespace_definition (cp_parser* parser)
   warning  (OPT_Wnamespaces, "namespace %qD entered", current_namespace);
 
   /* Look for the `{' to validate starting the namespace.  */
-  if (cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  matching_braces braces;
+  if (braces.require_open (parser))
     {
       /* Parse the body of the namespace.  */
       cp_parser_namespace_body (parser);
 
       /* Look for the final `}'.  */
-      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      braces.require_close (parser);
     }
 
   if (has_visibility)
@@ -18936,7 +19065,8 @@ cp_parser_asm_definition (cp_parser* parser)
       cp_lexer_consume_token (parser->lexer);
     }
   /* Look for the opening `('.  */
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return;
   /* Look for the string.  */
   string = cp_parser_string_literal (parser, false, false);
@@ -19803,7 +19933,8 @@ cp_parser_direct_declarator (cp_parser* parser,
 		cp_parser_parse_tentatively (parser);
 
 	      /* Consume the `('.  */
-	      cp_lexer_consume_token (parser->lexer);
+	      matching_parens parens;
+	      parens.consume_open (parser);
 	      if (first)
 		{
 		  /* If this is going to be an abstract declarator, we're
@@ -19818,7 +19949,7 @@ cp_parser_direct_declarator (cp_parser* parser,
 	      params = cp_parser_parameter_declaration_clause (parser);
 
 	      /* Consume the `)'.  */
-	      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	      parens.require_close (parser);
 
 	      /* If all went well, parse the cv-qualifier-seq,
 		 ref-qualifier and the exception-specification.  */
@@ -19914,7 +20045,8 @@ cp_parser_direct_declarator (cp_parser* parser,
 	      parser->in_declarator_p = saved_in_declarator_p;
 
 	      /* Consume the `('.  */
-	      cp_lexer_consume_token (parser->lexer);
+	      matching_parens parens;
+	      parens.consume_open (parser);
 	      /* Parse the nested declarator.  */
 	      saved_in_type_id_in_expr_p = parser->in_type_id_in_expr_p;
 	      parser->in_type_id_in_expr_p = true;
@@ -19925,7 +20057,7 @@ cp_parser_direct_declarator (cp_parser* parser,
 	      parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
 	      first = false;
 	      /* Expect a `)'.  */
-	      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+	      if (!parens.require_close (parser))
 		declarator = cp_error_declarator;
 	      if (declarator == cp_error_declarator)
 		break;
@@ -21773,7 +21905,8 @@ cp_parser_braced_list (cp_parser* parser, bool* non_constant_p)
   location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;
 
   /* Consume the `{' token.  */
-  cp_lexer_consume_token (parser->lexer);
+  matching_braces braces;
+  braces.consume_open (parser);
   /* Create a CONSTRUCTOR to represent the braced-initializer.  */
   initializer = make_node (CONSTRUCTOR);
   /* If it's not a `}', then there is a non-trivial initializer.  */
@@ -21790,7 +21923,7 @@ cp_parser_braced_list (cp_parser* parser, bool* non_constant_p)
     *non_constant_p = false;
   /* Now, there should be a trailing `}'.  */
   location_t finish_loc = cp_lexer_peek_token (parser->lexer)->location;
-  cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+  braces.require_close (parser);
   TREE_TYPE (initializer) = init_list_type_node;
 
   cp_expr result (initializer);
@@ -22217,7 +22350,8 @@ cp_parser_class_specifier_1 (cp_parser* parser)
     }
 
   /* Look for the `{'.  */
-  if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  matching_braces braces;
+  if (!braces.require_open (parser))
     {
       pop_deferring_access_checks ();
       return error_mark_node;
@@ -22269,7 +22403,7 @@ cp_parser_class_specifier_1 (cp_parser* parser)
     cp_parser_member_specification_opt (parser);
 
   /* Look for the trailing `}'.  */
-  closing_brace = cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+  closing_brace = braces.require_close (parser);
   /* Look for trailing attributes to apply to this class.  */
   if (cp_parser_allow_gnu_extensions_p (parser))
     attributes = cp_parser_gnu_attributes_opt (parser);
@@ -23748,11 +23882,12 @@ cp_parser_constant_initializer (cp_parser* parser)
       cp_parser_error (parser,
 		       "a brace-enclosed initializer is not allowed here");
       /* Consume the opening brace.  */
-      cp_lexer_consume_token (parser->lexer);
+      matching_braces braces;
+      braces.consume_open (parser);
       /* Skip the initializer.  */
       cp_parser_skip_to_closing_brace (parser);
       /* Look for the trailing `}'.  */
-      cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+      braces.require_close (parser);
 
       return error_mark_node;
     }
@@ -24008,7 +24143,8 @@ cp_parser_noexcept_specification_opt (cp_parser* parser,
 
       if (cp_lexer_peek_token (parser->lexer)->type == CPP_OPEN_PAREN)
 	{
-	  cp_lexer_consume_token (parser->lexer);
+	  matching_parens parens;
+	  parens.consume_open (parser);
 
 	  if (require_constexpr)
 	    {
@@ -24028,7 +24164,7 @@ cp_parser_noexcept_specification_opt (cp_parser* parser,
 	      *consumed_expr = true;
 	    }
 
-	  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	  parens.require_close (parser);
 	}
       else
 	{
@@ -24082,7 +24218,8 @@ cp_parser_exception_specification_opt (cp_parser* parser)
   cp_lexer_consume_token (parser->lexer);
 
   /* Look for the `('.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
 
   /* Peek at the next token.  */
   token = cp_lexer_peek_token (parser->lexer);
@@ -24118,7 +24255,7 @@ cp_parser_exception_specification_opt (cp_parser* parser)
     type_id_list = empty_except_spec;
 
   /* Look for the `)'.  */
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   return type_id_list;
 }
@@ -24265,10 +24402,11 @@ cp_parser_handler (cp_parser* parser)
 
   cp_parser_require_keyword (parser, RID_CATCH, RT_CATCH);
   handler = begin_handler ();
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   declaration = cp_parser_exception_declaration (parser);
   finish_handler_parms (declaration, handler);
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
   cp_parser_compound_statement (parser, NULL, BCS_NORMAL, false);
   finish_handler (handler);
 }
@@ -24384,13 +24522,14 @@ cp_parser_asm_specification_opt (cp_parser* parser)
   /* Consume the `asm' token.  */
   cp_lexer_consume_token (parser->lexer);
   /* Look for the `('.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
 
   /* Look for the string-literal.  */
   asm_specification = cp_parser_string_literal (parser, false, false);
 
   /* Look for the `)'.  */
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   return asm_specification;
 }
@@ -24442,11 +24581,12 @@ cp_parser_asm_operand_list (cp_parser* parser)
       string_literal = cp_parser_string_literal (parser, false, false);
 
       /* Look for the `('.  */
-      cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+      matching_parens parens;
+      parens.require_open (parser);
       /* Parse the expression.  */
       expression = cp_parser_expression (parser);
       /* Look for the `)'.  */
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
 
       if (name == error_mark_node 
 	  || string_literal == error_mark_node 
@@ -24700,8 +24840,10 @@ cp_parser_gnu_attributes_opt (cp_parser* parser)
       /* Consume the `__attribute__' keyword.  */
       cp_lexer_consume_token (parser->lexer);
       /* Look for the two `(' tokens.  */
-      cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
-      cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+      matching_parens outer_parens;
+      outer_parens.require_open (parser);
+      matching_parens inner_parens;
+      inner_parens.require_open (parser);
 
       /* Peek at the next token.  */
       token = cp_lexer_peek_token (parser->lexer);
@@ -24714,9 +24856,9 @@ cp_parser_gnu_attributes_opt (cp_parser* parser)
 	attribute_list = NULL;
 
       /* Look for the two `)' tokens.  */
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!inner_parens.require_close (parser))
 	ok = false;
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!outer_parens.require_close (parser))
 	ok = false;
       if (!ok)
 	cp_parser_skip_to_end_of_statement (parser);
@@ -25139,7 +25281,8 @@ cp_parser_std_attribute_spec (cp_parser *parser)
       cp_lexer_consume_token (parser->lexer);
       maybe_warn_cpp0x (CPP0X_ATTRIBUTES);
 
-      if (cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN) == NULL)
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	{
 	  cp_parser_error (parser, "expected %<(%>");
 	  return error_mark_node;
@@ -25172,7 +25315,7 @@ cp_parser_std_attribute_spec (cp_parser *parser)
       if (alignas_expr == error_mark_node)
 	return error_mark_node;
 
-      if (cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN) == NULL)
+      if (!parens.require_close (parser))
 	{
 	  cp_parser_error (parser, "expected %<)%>");
 	  return error_mark_node;
@@ -25404,12 +25547,13 @@ cp_parser_requires_expression (cp_parser *parser)
 static tree
 cp_parser_requirement_parameter_list (cp_parser *parser)
 {
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return error_mark_node;
 
   tree parms = cp_parser_parameter_declaration_clause (parser);
 
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     return error_mark_node;
 
   return parms;
@@ -25422,12 +25566,13 @@ cp_parser_requirement_parameter_list (cp_parser *parser)
 static tree
 cp_parser_requirement_body (cp_parser *parser)
 {
-  if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  matching_braces braces;
+  if (!braces.require_open (parser))
     return error_mark_node;
 
   tree reqs = cp_parser_requirement_list (parser);
 
-  if (!cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE))
+  if (!braces.require_close (parser))
     return error_mark_node;
 
   return reqs;
@@ -25566,14 +25711,15 @@ static tree
 cp_parser_compound_requirement (cp_parser *parser)
 {
   /* Parse an expression enclosed in '{ }'s. */
-  if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  matching_braces braces;
+  if (!braces.require_open (parser))
     return error_mark_node;
 
   tree expr = cp_parser_expression (parser, NULL, false, false);
   if (!expr || expr == error_mark_node)
     return error_mark_node;
 
-  if (!cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE))
+  if (!braces.require_close (parser))
     return error_mark_node;
 
   /* Parse the optional noexcept. */
@@ -26644,7 +26790,8 @@ cp_parser_template_introduction (cp_parser* parser, bool member_p)
     cp_parser_simulate_error (parser);
 
   /* Look for opening brace for introduction.  */
-  cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE);
+  matching_braces braces;
+  braces.require_open (parser);
 
   if (!cp_parser_parse_definitely (parser))
     return false;
@@ -26664,7 +26811,7 @@ cp_parser_template_introduction (cp_parser* parser, bool member_p)
     }
 
   /* Look for closing brace for introduction.  */
-  if (!cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE))
+  if (!braces.require_close (parser))
     return true;
 
   if (tmpl_decl == error_mark_node)
@@ -27549,9 +27696,10 @@ cp_parser_sizeof_pack (cp_parser *parser)
   cp_lexer_consume_token (parser->lexer);
   maybe_warn_variadic_templates ();
 
+  matching_parens parens;
   bool paren = cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN);
   if (paren)
-    cp_lexer_consume_token (parser->lexer);
+    parens.consume_open (parser);
   else
     permerror (cp_lexer_peek_token (parser->lexer)->location,
 	       "%<sizeof...%> argument must be surrounded by parentheses");
@@ -27576,7 +27724,7 @@ cp_parser_sizeof_pack (cp_parser *parser)
   PACK_EXPANSION_SIZEOF_P (expr) = true;
 
   if (paren)
-    cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+    parens.require_close (parser);
 
   return expr;
 }
@@ -27627,6 +27775,9 @@ cp_parser_sizeof_operand (cp_parser* parser, enum rid keyword)
     {
       tree type = NULL_TREE;
 
+      matching_parens parens;
+      parens.peek_open (parser);
+
       /* We can't be sure yet whether we're looking at a type-id or an
 	 expression.  */
       cp_parser_parse_tentatively (parser);
@@ -27643,7 +27794,7 @@ cp_parser_sizeof_operand (cp_parser* parser, enum rid keyword)
 	  /* Look for the type-id.  */
 	  type = cp_parser_type_id (parser);
 	  /* Look for the closing `)'.  */
-	  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	  parens.require_close (parser);
 	  parser->in_type_id_in_expr_p = saved_in_type_id_in_expr_p;
 	}
 
@@ -27925,187 +28076,244 @@ cp_parser_friend_p (const cp_decl_specifier_seq *decl_specifiers)
   return decl_spec_seq_has_spec_p (decl_specifiers, ds_friend);
 }
 
+/* Get a description of the matching symbol to TOKEN_DESC e.g. "(" for
+   RT_CLOSE_PAREN.  */
+
+static const char *
+get_matching_symbol (required_token token_desc)
+{
+  switch (token_desc)
+    {
+    default:
+      gcc_unreachable ();
+      return "";
+    case RT_CLOSE_BRACE:
+      return "{";
+    case RT_CLOSE_PAREN:
+      return "(";
+    }
+}
+
 /* Issue an error message indicating that TOKEN_DESC was expected.
    If KEYWORD is true, it indicated this function is called by
    cp_parser_require_keword and the required token can only be
-   a indicated keyword. */
+   a indicated keyword.
+
+   If MATCHING_LOCATION is not UNKNOWN_LOCATION, then highlight it
+   within any error as the location of an "opening" token matching
+   the close token TYPE (e.g. the location of the '(' when TOKEN_DESC is
+   RT_CLOSE_PAREN).  */
 
 static void
 cp_parser_required_error (cp_parser *parser,
 			  required_token token_desc,
-			  bool keyword)
+			  bool keyword,
+			  location_t matching_location)
 {
+  if (cp_parser_simulate_error (parser))
+    return;
+
+  const char *gmsgid = NULL;
   switch (token_desc)
     {
       case RT_NEW:
-	cp_parser_error (parser, "expected %<new%>");
-	return;
+	gmsgid = G_("expected %<new%>");
+	break;
       case RT_DELETE:
-	cp_parser_error (parser, "expected %<delete%>");
-	return;
+	gmsgid = G_("expected %<delete%>");
+	break;
       case RT_RETURN:
-	cp_parser_error (parser, "expected %<return%>");
-	return;
+	gmsgid = G_("expected %<return%>");
+	break;
       case RT_WHILE:
-	cp_parser_error (parser, "expected %<while%>");
-	return;
+	gmsgid = G_("expected %<while%>");
+	break;
       case RT_EXTERN:
-	cp_parser_error (parser, "expected %<extern%>");
-	return;
+	gmsgid = G_("expected %<extern%>");
+	break;
       case RT_STATIC_ASSERT:
-	cp_parser_error (parser, "expected %<static_assert%>");
-	return;
+	gmsgid = G_("expected %<static_assert%>");
+	break;
       case RT_DECLTYPE:
-	cp_parser_error (parser, "expected %<decltype%>");
-	return;
+	gmsgid = G_("expected %<decltype%>");
+	break;
       case RT_OPERATOR:
-	cp_parser_error (parser, "expected %<operator%>");
-	return;
+	gmsgid = G_("expected %<operator%>");
+	break;
       case RT_CLASS:
-	cp_parser_error (parser, "expected %<class%>");
-	return;
+	gmsgid = G_("expected %<class%>");
+	break;
       case RT_TEMPLATE:
-	cp_parser_error (parser, "expected %<template%>");
-	return;
+	gmsgid = G_("expected %<template%>");
+	break;
       case RT_NAMESPACE:
-	cp_parser_error (parser, "expected %<namespace%>");
-	return;
+	gmsgid = G_("expected %<namespace%>");
+	break;
       case RT_USING:
-	cp_parser_error (parser, "expected %<using%>");
-	return;
+	gmsgid = G_("expected %<using%>");
+	break;
       case RT_ASM:
-	cp_parser_error (parser, "expected %<asm%>");
-	return;
+	gmsgid = G_("expected %<asm%>");
+	break;
       case RT_TRY:
-	cp_parser_error (parser, "expected %<try%>");
-	return;
+	gmsgid = G_("expected %<try%>");
+	break;
       case RT_CATCH:
-	cp_parser_error (parser, "expected %<catch%>");
-	return;
+	gmsgid = G_("expected %<catch%>");
+	break;
       case RT_THROW:
-	cp_parser_error (parser, "expected %<throw%>");
-	return;
+	gmsgid = G_("expected %<throw%>");
+	break;
       case RT_LABEL:
-	cp_parser_error (parser, "expected %<__label__%>");
-	return;
+	gmsgid = G_("expected %<__label__%>");
+	break;
       case RT_AT_TRY:
-	cp_parser_error (parser, "expected %<@try%>");
-	return;
+	gmsgid = G_("expected %<@try%>");
+	break;
       case RT_AT_SYNCHRONIZED:
-	cp_parser_error (parser, "expected %<@synchronized%>");
-	return;
+	gmsgid = G_("expected %<@synchronized%>");
+	break;
       case RT_AT_THROW:
-	cp_parser_error (parser, "expected %<@throw%>");
-	return;
+	gmsgid = G_("expected %<@throw%>");
+	break;
       case RT_TRANSACTION_ATOMIC:
-	cp_parser_error (parser, "expected %<__transaction_atomic%>");
-	return;
+	gmsgid = G_("expected %<__transaction_atomic%>");
+	break;
       case RT_TRANSACTION_RELAXED:
-	cp_parser_error (parser, "expected %<__transaction_relaxed%>");
-	return;
+	gmsgid = G_("expected %<__transaction_relaxed%>");
+	break;
       default:
 	break;
     }
-  if (!keyword)
+
+  if (!gmsgid && !keyword)
     {
       switch (token_desc)
         {
 	  case RT_SEMICOLON:
-	    cp_parser_error (parser, "expected %<;%>");
-	    return;
+	    gmsgid = G_("expected %<;%>");
+	    break;
 	  case RT_OPEN_PAREN:
-	    cp_parser_error (parser, "expected %<(%>");
-	    return;
+	    gmsgid = G_("expected %<(%>");
+	    break;
 	  case RT_CLOSE_BRACE:
-	    cp_parser_error (parser, "expected %<}%>");
-	    return;
+	    gmsgid = G_("expected %<}%>");
+	    break;
 	  case RT_OPEN_BRACE:
-	    cp_parser_error (parser, "expected %<{%>");
-	    return;
+	    gmsgid = G_("expected %<{%>");
+	    break;
 	  case RT_CLOSE_SQUARE:
-	    cp_parser_error (parser, "expected %<]%>");
-	    return;
+	    gmsgid = G_("expected %<]%>");
+	    break;
 	  case RT_OPEN_SQUARE:
-	    cp_parser_error (parser, "expected %<[%>");
-	    return;
+	    gmsgid = G_("expected %<[%>");
+	    break;
 	  case RT_COMMA:
-	    cp_parser_error (parser, "expected %<,%>");
-	    return;
+	    gmsgid = G_("expected %<,%>");
+	    break;
 	  case RT_SCOPE:
-	    cp_parser_error (parser, "expected %<::%>");
-	    return;
+	    gmsgid = G_("expected %<::%>");
+	    break;
 	  case RT_LESS:
-	    cp_parser_error (parser, "expected %<<%>");
-	    return;
+	    gmsgid = G_("expected %<<%>");
+	    break;
 	  case RT_GREATER:
-	    cp_parser_error (parser, "expected %<>%>");
-	    return;
+	    gmsgid = G_("expected %<>%>");
+	    break;
 	  case RT_EQ:
-	    cp_parser_error (parser, "expected %<=%>");
-	    return;
+	    gmsgid = G_("expected %<=%>");
+	    break;
 	  case RT_ELLIPSIS:
-	    cp_parser_error (parser, "expected %<...%>");
-	    return;
+	    gmsgid = G_("expected %<...%>");
+	    break;
 	  case RT_MULT:
-	    cp_parser_error (parser, "expected %<*%>");
-	    return;
+	    gmsgid = G_("expected %<*%>");
+	    break;
 	  case RT_COMPL:
-	    cp_parser_error (parser, "expected %<~%>");
-	    return;
+	    gmsgid = G_("expected %<~%>");
+	    break;
 	  case RT_COLON:
-	    cp_parser_error (parser, "expected %<:%>");
-	    return;
+	    gmsgid = G_("expected %<:%>");
+	    break;
 	  case RT_COLON_SCOPE:
-	    cp_parser_error (parser, "expected %<:%> or %<::%>");
-	    return;
+	    gmsgid = G_("expected %<:%> or %<::%>");
+	    break;
 	  case RT_CLOSE_PAREN:
-	    cp_parser_error (parser, "expected %<)%>");
-	    return;
+	    gmsgid = G_("expected %<)%>");
+	    break;
 	  case RT_COMMA_CLOSE_PAREN:
-	    cp_parser_error (parser, "expected %<,%> or %<)%>");
-	    return;
+	    gmsgid = G_("expected %<,%> or %<)%>");
+	    break;
 	  case RT_PRAGMA_EOL:
-	    cp_parser_error (parser, "expected end of line");
-	    return;
+	    gmsgid = G_("expected end of line");
+	    break;
 	  case RT_NAME:
-	    cp_parser_error (parser, "expected identifier");
-	    return;
+	    gmsgid = G_("expected identifier");
+	    break;
 	  case RT_SELECT:
-	    cp_parser_error (parser, "expected selection-statement");
-	    return;
+	    gmsgid = G_("expected selection-statement");
+	    break;
 	  case RT_ITERATION:
-	    cp_parser_error (parser, "expected iteration-statement");
-	    return;
+	    gmsgid = G_("expected iteration-statement");
+	    break;
 	  case RT_JUMP:
-	    cp_parser_error (parser, "expected jump-statement");
-	    return;
+	    gmsgid = G_("expected jump-statement");
+	    break;
 	  case RT_CLASS_KEY:
-	    cp_parser_error (parser, "expected class-key");
-	    return;
+	    gmsgid = G_("expected class-key");
+	    break;
 	  case RT_CLASS_TYPENAME_TEMPLATE:
-	    cp_parser_error (parser,
-	  	 "expected %<class%>, %<typename%>, or %<template%>");
-	    return;
+	    gmsgid = G_("expected %<class%>, %<typename%>, or %<template%>");
+	    break;
 	  default:
 	    gcc_unreachable ();
 	}
     }
-  else
-    gcc_unreachable ();
-}
 
+  if (gmsgid)
+    {
+      /* Emulate rest of cp_parser_error.  */
+      cp_token *token = cp_lexer_peek_token (parser->lexer);
+      cp_lexer_set_source_position_from_token (token);
+
+      rich_location richloc (line_table, input_location);
+
+      /* If matching_location != UNKNOWN_LOCATION, highlight it.
+	 Attempt to consolidate diagnostics by printing it as a
+	secondary range within the main diagnostic.  */
+      bool on_same_line = false;
+      if (matching_location != UNKNOWN_LOCATION)
+	on_same_line = richloc.add_location_if_nearby (matching_location);
+
+      c_parse_error (gmsgid,
+		     (token->type == CPP_KEYWORD ? CPP_NAME : token->type),
+		     token->u.value, token->flags, &richloc);
+
+      /* If we weren't able to consolidate matching_location, then
+	 print it as a secondary diagnostic.  */
+      if (matching_location != UNKNOWN_LOCATION && !on_same_line)
+	inform (matching_location, "to match this %qs",
+		get_matching_symbol (token_desc));
+    }
+}
 
 
 /* If the next token is of the indicated TYPE, consume it.  Otherwise,
    issue an error message indicating that TOKEN_DESC was expected.
 
    Returns the token consumed, if the token had the appropriate type.
-   Otherwise, returns NULL.  */
+   Otherwise, returns NULL.
+
+   If MATCHING_LOCATION is not UNKNOWN_LOCATION, then highlight it
+   within any error as the location of an "opening" token matching
+   the close token TYPE (e.g. the location of the '(' when TOKEN_DESC is
+   RT_CLOSE_PAREN).  */
 
 static cp_token *
 cp_parser_require (cp_parser* parser,
 		   enum cpp_ttype type,
-		   required_token token_desc)
+		   required_token token_desc,
+		   location_t matching_location)
 {
   if (cp_lexer_next_token_is (parser->lexer, type))
     return cp_lexer_consume_token (parser->lexer);
@@ -28113,7 +28321,8 @@ cp_parser_require (cp_parser* parser,
     {
       /* Output the MESSAGE -- unless we're parsing tentatively.  */
       if (!cp_parser_simulate_error (parser))
-	cp_parser_required_error (parser, token_desc, /*keyword=*/false);
+	cp_parser_required_error (parser, token_desc, /*keyword=*/false,
+				  matching_location);
       return NULL;
     }
 }
@@ -28215,7 +28424,8 @@ cp_parser_require_keyword (cp_parser* parser,
 
   if (token && token->keyword != keyword)
     {
-      cp_parser_required_error (parser, token_desc, /*keyword=*/true); 
+      cp_parser_required_error (parser, token_desc, /*keyword=*/true,
+                                UNKNOWN_LOCATION);
       return NULL;
     }
 
@@ -29026,10 +29236,11 @@ cp_parser_objc_encode_expression (cp_parser* parser)
   location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;
 
   cp_lexer_consume_token (parser->lexer);  /* Eat '@encode'.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   token = cp_lexer_peek_token (parser->lexer);
   type = complete_type (cp_parser_type_id (parser));
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   if (!type)
     {
@@ -29071,9 +29282,10 @@ cp_parser_objc_defs_expression (cp_parser *parser)
   tree name;
 
   cp_lexer_consume_token (parser->lexer);  /* Eat '@defs'.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   name = cp_parser_identifier (parser);
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   return objc_get_class_ivars (name);
 }
@@ -29092,9 +29304,10 @@ cp_parser_objc_protocol_expression (cp_parser* parser)
   location_t start_loc = cp_lexer_peek_token (parser->lexer)->location;
 
   cp_lexer_consume_token (parser->lexer);  /* Eat '@protocol'.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   proto = cp_parser_identifier (parser);
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   /* Build a location of the form:
        @protocol(prot)
@@ -29132,7 +29345,8 @@ cp_parser_objc_selector_expression (cp_parser* parser)
   location_t loc = cp_lexer_peek_token (parser->lexer)->location;
 
   cp_lexer_consume_token (parser->lexer);  /* Eat '@selector'.  */
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   token = cp_lexer_peek_token (parser->lexer);
 
   while (cp_parser_objc_selector_p (token->type) || token->type == CPP_COLON
@@ -29179,7 +29393,7 @@ cp_parser_objc_selector_expression (cp_parser* parser)
     }
 
  finish_selector:
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
 
   /* Build a location of the form:
@@ -29386,7 +29600,8 @@ cp_parser_objc_typename (cp_parser* parser)
     {
       tree proto_quals, cp_type = NULL_TREE;
 
-      cp_lexer_consume_token (parser->lexer);  /* Eat '('.  */
+      matching_parens parens;
+      parens.consume_open (parser); /* Eat '('.  */
       proto_quals = cp_parser_objc_protocol_qualifiers (parser);
 
       /* An ObjC type name may consist of just protocol qualifiers, in which
@@ -29412,7 +29627,7 @@ cp_parser_objc_typename (cp_parser* parser)
 	    }
 	}
 
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
       type_name = build_tree_list (proto_quals, cp_type);
     }
 
@@ -30026,7 +30241,8 @@ cp_parser_objc_superclass_or_category (cp_parser *parser,
     }
   else if (next->type == CPP_OPEN_PAREN)
     {
-      cp_lexer_consume_token (parser->lexer);  /* Eat '('.  */
+      matching_parens parens;
+      parens.consume_open (parser);  /* Eat '('.  */
 
       /* If there is no category name, and this is an @interface, we
 	 have a class extension.  */
@@ -30038,7 +30254,7 @@ cp_parser_objc_superclass_or_category (cp_parser *parser,
       else
 	*categ = cp_parser_identifier (parser);
 
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
     }
 }
 
@@ -30226,9 +30442,10 @@ cp_parser_objc_try_catch_finally_statement (cp_parser *parser)
       cp_parameter_declarator *parm;
       tree parameter_declaration = error_mark_node;
       bool seen_open_paren = false;
+      matching_parens parens;
 
       cp_lexer_consume_token (parser->lexer);
-      if (cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+      if (parens.require_open (parser))
 	seen_open_paren = true;
       if (cp_lexer_next_token_is (parser->lexer, CPP_ELLIPSIS))
 	{
@@ -30254,7 +30471,7 @@ cp_parser_objc_try_catch_finally_statement (cp_parser *parser)
 						    /*attrlist=*/NULL);
 	}
       if (seen_open_paren)
-	cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+	parens.require_close (parser);
       else
 	{
 	  /* If there was no open parenthesis, we are recovering from
@@ -30308,9 +30525,10 @@ cp_parser_objc_synchronized_statement (cp_parser *parser)
 
   location = cp_lexer_peek_token (parser->lexer)->location;
   objc_maybe_warn_exceptions (location);
-  cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+  matching_parens parens;
+  parens.require_open (parser);
   lock = cp_parser_expression (parser);
-  cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+  parens.require_close (parser);
 
   /* NB: The @synchronized block needs to be wrapped in its own STATEMENT_LIST
      node, lest it get absorbed into the surrounding block.  */
@@ -30551,7 +30769,8 @@ cp_parser_objc_at_property_declaration (cp_parser *parser)
   if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
     {
       /* Eat the '('.  */
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       while (true)
 	{
@@ -30639,7 +30858,7 @@ cp_parser_objc_at_property_declaration (cp_parser *parser)
 	 "error: expected ‘)’ before ‘,’ token".  This is because
 	 cp_parser_require, unlike the C counterpart, will produce an
 	 error even if we are in error recovery.  */
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	{
 	  cp_parser_skip_to_closing_parenthesis (parser,
 						 /*recovering=*/true,
@@ -31330,13 +31549,14 @@ cp_parser_oacc_single_int_clause (cp_parser *parser, omp_clause_code code,
 {
   location_t loc = cp_lexer_peek_token (parser->lexer)->location;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   tree t = cp_parser_assignment_expression (parser, NULL, false, false);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     {
       cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					     /*or_comma=*/false,
@@ -31383,7 +31603,8 @@ cp_parser_oacc_shape_clause (cp_parser *parser, omp_clause_code kind,
 
   if (cp_lexer_next_token_is (lexer, CPP_OPEN_PAREN))
     {
-      cp_lexer_consume_token (lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       do
 	{
@@ -31457,7 +31678,7 @@ cp_parser_oacc_shape_clause (cp_parser *parser, omp_clause_code kind,
 	}
       while (1);
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	goto cleanup_error;
     }
 
@@ -31495,7 +31716,8 @@ cp_parser_oacc_clause_tile (cp_parser *parser, location_t clause_loc, tree list)
   check_no_duplicate_clause (list, OMP_CLAUSE_COLLAPSE, "collapse",
 			     clause_loc);
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   do
@@ -31603,12 +31825,13 @@ cp_parser_omp_clause_collapse (cp_parser *parser, tree list, location_t location
   HOST_WIDE_INT n;
 
   loc = cp_lexer_peek_token (parser->lexer)->location;
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   num = cp_parser_constant_expression (parser);
 
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31647,7 +31870,8 @@ cp_parser_omp_clause_default (cp_parser *parser, tree list,
   enum omp_clause_default_kind kind = OMP_CLAUSE_DEFAULT_UNSPECIFIED;
   tree c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
   if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
     {
@@ -31690,7 +31914,7 @@ cp_parser_omp_clause_default (cp_parser *parser, tree list,
     }
 
   if (kind == OMP_CLAUSE_DEFAULT_UNSPECIFIED
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31714,13 +31938,14 @@ cp_parser_omp_clause_final (cp_parser *parser, tree list, location_t location)
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_condition (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31751,7 +31976,8 @@ cp_parser_omp_clause_if (cp_parser *parser, tree list, location_t location,
   tree t, c;
   enum tree_code if_modifier = ERROR_MARK;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (is_omp && cp_lexer_next_token_is (parser->lexer, CPP_NAME))
@@ -31834,7 +32060,7 @@ cp_parser_omp_clause_if (cp_parser *parser, tree list, location_t location,
   t = cp_parser_condition (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31929,13 +32155,14 @@ cp_parser_omp_clause_num_threads (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31959,13 +32186,14 @@ cp_parser_omp_clause_num_tasks (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -31989,13 +32217,14 @@ cp_parser_omp_clause_grainsize (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32019,13 +32248,14 @@ cp_parser_omp_clause_priority (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32049,13 +32279,14 @@ cp_parser_omp_clause_hint (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32079,7 +32310,8 @@ cp_parser_omp_clause_defaultmap (cp_parser *parser, tree list,
   tree c, id;
   const char *p;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (!cp_lexer_next_token_is (parser->lexer, CPP_NAME))
@@ -32111,7 +32343,7 @@ cp_parser_omp_clause_defaultmap (cp_parser *parser, tree list,
       goto out_err;
     }
   cp_lexer_consume_token (parser->lexer);
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     goto out_err;
 
   check_no_duplicate_clause (list, OMP_CLAUSE_DEFAULTMAP, "defaultmap",
@@ -32146,11 +32378,12 @@ cp_parser_omp_clause_ordered (cp_parser *parser,
 
   if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
     {
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       num = cp_parser_constant_expression (parser);
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -32199,7 +32432,8 @@ cp_parser_omp_clause_reduction (cp_parser *parser, tree list)
   enum tree_code code = ERROR_MARK;
   tree nlist, c, id = NULL_TREE;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   switch (cp_lexer_peek_token (parser->lexer)->type)
@@ -32307,7 +32541,8 @@ cp_parser_omp_clause_schedule (cp_parser *parser, tree list, location_t location
   tree c, t;
   int modifiers = 0, nmodifiers = 0;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   c = build_omp_clause (location, OMP_CLAUSE_SCHEDULE);
@@ -32401,7 +32636,7 @@ cp_parser_omp_clause_schedule (cp_parser *parser, tree list, location_t location
       else
 	OMP_CLAUSE_SCHEDULE_CHUNK_EXPR (c) = t;
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	goto resync_fail;
     }
   else if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_COMMA_CLOSE_PAREN))
@@ -32507,13 +32742,14 @@ cp_parser_omp_clause_num_teams (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32537,13 +32773,14 @@ cp_parser_omp_clause_thread_limit (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32568,7 +32805,8 @@ cp_parser_omp_clause_aligned (cp_parser *parser, tree list)
   tree nlist, c, alignment = NULL_TREE;
   bool colon;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   nlist = cp_parser_omp_var_list_no_open (parser, OMP_CLAUSE_ALIGNED, list,
@@ -32578,7 +32816,7 @@ cp_parser_omp_clause_aligned (cp_parser *parser, tree list)
     {
       alignment = cp_parser_constant_expression (parser);
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -32609,7 +32847,8 @@ cp_parser_omp_clause_linear (cp_parser *parser, tree list,
   bool colon;
   enum omp_clause_linear_kind kind = OMP_CLAUSE_LINEAR_DEFAULT;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (!is_cilk_simd_fn
@@ -32639,7 +32878,7 @@ cp_parser_omp_clause_linear (cp_parser *parser, tree list,
       colon = cp_lexer_next_token_is (parser->lexer, CPP_COLON);
       if (colon)
 	cp_parser_require (parser, CPP_COLON, RT_COLON);
-      else if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      else if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -32677,7 +32916,7 @@ cp_parser_omp_clause_linear (cp_parser *parser, tree list,
 	  sorry ("using parameters for %<linear%> step is not supported yet");
 	  step = integer_one_node;
 	}
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -32704,13 +32943,14 @@ cp_parser_omp_clause_safelen (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_constant_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32733,13 +32973,14 @@ cp_parser_omp_clause_simdlen (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_constant_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -32855,7 +33096,8 @@ cp_parser_omp_clause_depend (cp_parser *parser, tree list, location_t loc)
   tree nlist, c;
   enum omp_clause_depend_kind kind = OMP_CLAUSE_DEPEND_INOUT;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
@@ -32887,7 +33129,7 @@ cp_parser_omp_clause_depend (cp_parser *parser, tree list, location_t loc)
       OMP_CLAUSE_DEPEND_KIND (c) = kind;
       OMP_CLAUSE_DECL (c) = NULL_TREE;
       OMP_CLAUSE_CHAIN (c) = list;
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -32938,7 +33180,8 @@ cp_parser_omp_clause_map (cp_parser *parser, tree list)
   enum gomp_map_kind kind = GOMP_MAP_TOFROM;
   bool always = false;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
@@ -33018,13 +33261,14 @@ cp_parser_omp_clause_device (cp_parser *parser, tree list,
 {
   tree t, c;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   t = cp_parser_expression (parser);
 
   if (t == error_mark_node
-      || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      || !parens.require_close (parser))
     cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					   /*or_comma=*/false,
 					   /*consume_paren=*/true);
@@ -33049,7 +33293,8 @@ cp_parser_omp_clause_dist_schedule (cp_parser *parser, tree list,
 {
   tree c, t;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   c = build_omp_clause (location, OMP_CLAUSE_DIST_SCHEDULE);
@@ -33068,7 +33313,7 @@ cp_parser_omp_clause_dist_schedule (cp_parser *parser, tree list,
 	goto resync_fail;
       OMP_CLAUSE_DIST_SCHEDULE_CHUNK_EXPR (c) = t;
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	goto resync_fail;
     }
   else if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_COMMA_CLOSE_PAREN))
@@ -33101,7 +33346,8 @@ cp_parser_omp_clause_proc_bind (cp_parser *parser, tree list,
   tree c;
   enum omp_clause_proc_bind_kind kind;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return list;
 
   if (cp_lexer_next_token_is (parser->lexer, CPP_NAME))
@@ -33154,11 +33400,12 @@ cp_parser_oacc_clause_async (cp_parser *parser, tree list)
 
   if (cp_lexer_peek_token (parser->lexer)->type == CPP_OPEN_PAREN)
     {
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       t = cp_parser_expression (parser);
       if (t == error_mark_node
-	  || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+	  || !parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 						/*or_comma=*/false,
 						/*consume_paren=*/true);
@@ -34208,12 +34455,13 @@ cp_parser_omp_critical (cp_parser *parser, cp_token *pragma_tok, bool *if_p)
 
   if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
     {
-      cp_lexer_consume_token (parser->lexer);
+      matching_parens parens;
+      parens.consume_open (parser);
 
       name = cp_parser_identifier (parser);
 
       if (name == error_mark_node
-	  || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+	  || !parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -34711,7 +34959,8 @@ cp_parser_omp_for_loop (cp_parser *parser, enum tree_code code, tree clauses,
 	}
       loc = cp_lexer_consume_token (parser->lexer)->location;
 
-      if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	return NULL;
 
       init = orig_init = decl = real_decl = NULL;
@@ -34843,7 +35092,7 @@ cp_parser_omp_for_loop (cp_parser *parser, enum tree_code code, tree clauses,
 	    protected_set_expr_location (incr, input_location);
 	}
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	cp_parser_skip_to_closing_parenthesis (parser, /*recovering=*/true,
 					       /*or_comma=*/false,
 					       /*consume_paren=*/true);
@@ -35202,7 +35451,8 @@ cp_parser_omp_sections_scope (cp_parser *parser)
   bool error_suppress = false;
   cp_token *tok;
 
-  if (!cp_parser_require (parser, CPP_OPEN_BRACE, RT_OPEN_BRACE))
+  matching_braces braces;
+  if (!braces.require_open (parser))
     return NULL_TREE;
 
   stmt = push_stmt_list ();
@@ -35239,7 +35489,7 @@ cp_parser_omp_sections_scope (cp_parser *parser)
       substmt = build1 (OMP_SECTION, void_type_node, substmt);
       add_stmt (substmt);
     }
-  cp_parser_require (parser, CPP_CLOSE_BRACE, RT_CLOSE_BRACE);
+  braces.require_close (parser);
 
   substmt = pop_stmt_list (stmt);
 
@@ -37101,7 +37351,8 @@ cp_parser_omp_declare_reduction_exprs (tree fndecl, cp_parser *parser)
   if (strcmp (p, "initializer") == 0)
     {
       cp_lexer_consume_token (parser->lexer);
-      if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+      matching_parens parens;
+      if (!parens.require_open (parser))
 	return false;
 
       p = "";
@@ -37192,12 +37443,13 @@ cp_parser_omp_declare_reduction_exprs (tree fndecl, cp_parser *parser)
       if (ctor)
 	add_decl_expr (omp_orig);
 
-      if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+      if (!parens.require_close (parser))
 	return false;
     }
 
   if (!cp_lexer_next_token_is (parser->lexer, CPP_PRAGMA_EOL))
-    cp_parser_required_error (parser, RT_PRAGMA_EOL, /*keyword=*/false);
+    cp_parser_required_error (parser, RT_PRAGMA_EOL, /*keyword=*/false,
+                              UNKNOWN_LOCATION);
 
   return true;
 }
@@ -37226,7 +37478,8 @@ cp_parser_omp_declare_reduction (cp_parser *parser, cp_token *pragma_tok,
   /* Get the high-water mark for the DECLARATOR_OBSTACK.  */
   p = obstack_alloc (&declarator_obstack, 0);
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     goto fail;
 
   switch (cp_lexer_peek_token (parser->lexer)->type)
@@ -37625,7 +37878,8 @@ cp_parser_oacc_routine (cp_parser *parser, cp_token *pragma_tok,
   /* Look for optional '( name )'.  */
   if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
     {
-      cp_lexer_consume_token (parser->lexer); /* '(' */
+      matching_parens parens;
+      parens.consume_open (parser); /* '(' */
 
       /* We parse the name as an id-expression.  If it resolves to
 	 anything other than a non-overloaded function at namespace
@@ -37642,7 +37896,7 @@ cp_parser_oacc_routine (cp_parser *parser, cp_token *pragma_tok,
 	cp_parser_name_lookup_error (parser, name, decl, NLE_NULL, name_loc);
 
       if (decl == error_mark_node
-	  || !cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+	  || !parens.require_close (parser))
 	{
 	  cp_parser_skip_to_pragma_eol (parser, pragma_tok);
 	  parser->oacc_routine = NULL;
@@ -38074,12 +38328,13 @@ cp_parser_transaction_expression (cp_parser *parser, enum rid keyword)
   if (!noex || !noex_expr
       || cp_lexer_peek_token (parser->lexer)->type == CPP_OPEN_PAREN)
     {
-      cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
+      matching_parens parens;
+      parens.require_open (parser);
 
       expr = cp_parser_expression (parser);
       expr = finish_parenthesized_expr (expr);
 
-      cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
+      parens.require_close (parser);
     }
   else
     {
@@ -38667,7 +38922,8 @@ cp_parser_cilk_simd_vectorlength (cp_parser *parser, tree clauses,
     check_no_duplicate_clause (clauses, OMP_CLAUSE_SIMDLEN, "vectorlength",
 			       loc);
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return error_mark_node;
 
   expr = cp_parser_constant_expression (parser);
@@ -38704,7 +38960,7 @@ cp_parser_cilk_simd_vectorlength (cp_parser *parser, tree clauses,
 	}
     }
 
-  if (!cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN))
+  if (!parens.require_close (parser))
     return error_mark_node;
   return clauses;
 }
@@ -38729,7 +38985,8 @@ cp_parser_cilk_simd_linear (cp_parser *parser, tree clauses)
 {
   location_t loc = cp_lexer_peek_token (parser->lexer)->location;
 
-  if (!cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN))
+  matching_parens parens;
+  if (!parens.require_open (parser))
     return clauses;
   if (cp_lexer_next_token_is_not (parser->lexer, CPP_NAME))
     {
diff --git a/gcc/testsuite/c-c++-common/missing-close-symbol.c b/gcc/testsuite/c-c++-common/missing-close-symbol.c
new file mode 100644
index 0000000..85b96f28
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/missing-close-symbol.c
@@ -0,0 +1,33 @@
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+/* Verify that the C/C++ frontends show the pertinent opening symbol when
+   a closing symbol is missing.  */
+
+/* Verify that, when they are on the same line, that the opening symbol is
+   shown as a secondary range within the main diagnostic.  */
+
+void test_static_assert_same_line (void)
+{
+  _Static_assert(sizeof(int) >= sizeof(char), "msg"; /* { dg-error "expected '\\)' before ';' token" } */
+  /* { dg-begin-multiline-output "" }
+   _Static_assert(sizeof(int) >= sizeof(char), "msg";
+                 ~                                  ^
+     { dg-end-multiline-output "" } */
+}
+
+/* Verify that, when they are on different lines, that the opening symbol is
+   shown via a secondary diagnostic.  */
+
+void test_static_assert_different_line (void)
+{
+  _Static_assert(sizeof(int) >= sizeof(char), /* { dg-message "to match this '\\('" } */
+		 "msg"; /* { dg-error "expected '\\)' before ';' token" } */
+  /* { dg-begin-multiline-output "" }
+    "msg";
+         ^
+     { dg-end-multiline-output "" } */
+  /* { dg-begin-multiline-output "" }
+   _Static_assert(sizeof(int) >= sizeof(char),
+                 ^
+     { dg-end-multiline-output "" } */
+}
diff --git a/gcc/testsuite/c-c++-common/missing-symbol.c b/gcc/testsuite/c-c++-common/missing-symbol.c
new file mode 100644
index 0000000..5a508fe
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/missing-symbol.c
@@ -0,0 +1,26 @@
+/* { dg-options "-fdiagnostics-show-caret" } */
+
+extern int foo (void);
+extern int bar (void);
+
+void missing_close_paren (void)
+{
+  if (foo () /* { dg-line start_of_if } */
+      && bar () 
+    { /* { dg-error "5: expected '\\)' before '.' token" } */
+      /* { dg-begin-multiline-output "" }
+     {
+     ^
+         { dg-end-multiline-output "" } */
+      /* { dg-message "6: to match this '\\('" "" { target *-*-* } start_of_if } */
+      /* { dg-begin-multiline-output "" }
+   if (foo ()
+      ^
+      { dg-end-multiline-output "" } */
+    }
+
+} /* { dg-error "1: expected" } */
+  /* { dg-begin-multiline-output "" }
+ }
+ ^
+     { dg-end-multiline-output "" } */
diff --git a/gcc/testsuite/g++.dg/diagnostic/unclosed-extern-c.C b/gcc/testsuite/g++.dg/diagnostic/unclosed-extern-c.C
new file mode 100644
index 0000000..fda3532
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/unclosed-extern-c.C
@@ -0,0 +1,3 @@
+extern "C" { /* { dg-message "12: to match this '.'" } */
+
+void test (void); /* { dg-error "17: expected '.' at end of input" } */
diff --git a/gcc/testsuite/g++.dg/diagnostic/unclosed-function.C b/gcc/testsuite/g++.dg/diagnostic/unclosed-function.C
new file mode 100644
index 0000000..e1e1550
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/unclosed-function.C
@@ -0,0 +1,3 @@
+void test (void)
+{ /* { dg-message "1: to match this '.'" } */
+  int filler; /* { dg-error "13: expected '.' at end of input" } */
diff --git a/gcc/testsuite/g++.dg/diagnostic/unclosed-namespace.C b/gcc/testsuite/g++.dg/diagnostic/unclosed-namespace.C
new file mode 100644
index 0000000..ff11322
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/unclosed-namespace.C
@@ -0,0 +1,2 @@
+namespace unclosed { /* { dg-message "20: to match this '.'" } */
+int filler; /* { dg-error "11: expected '.' at end of input" } */
diff --git a/gcc/testsuite/g++.dg/diagnostic/unclosed-struct.C b/gcc/testsuite/g++.dg/diagnostic/unclosed-struct.C
new file mode 100644
index 0000000..8c206bb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/unclosed-struct.C
@@ -0,0 +1,3 @@
+struct unclosed { /* { dg-message "17: to match this '.'" } */
+  int dummy; /* { dg-error "12: expected '.' at end of input" } */
+  // { dg-error "expected unqualified-id at end of input" "" { target *-*-* } .-1 }
diff --git a/gcc/testsuite/gcc.dg/unclosed-init.c b/gcc/testsuite/gcc.dg/unclosed-init.c
new file mode 100644
index 0000000..c0e4dd8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/unclosed-init.c
@@ -0,0 +1,3 @@
+int unclosed[] = { /* { dg-message "18: to match this '.'" } */
+  42
+ /* { dg-error "0: expected '.' at end of input" } */
diff --git a/libcpp/include/line-map.h b/libcpp/include/line-map.h
index e696041..e7c506c 100644
--- a/libcpp/include/line-map.h
+++ b/libcpp/include/line-map.h
@@ -1593,6 +1593,8 @@ class rich_location
   set_range (line_maps *set, unsigned int idx, source_location loc,
 	     bool show_caret_p);
 
+  bool add_location_if_nearby (source_location loc);
+
   unsigned int get_num_locations () const { return m_ranges.count (); }
 
   const location_range *get_range (unsigned int idx) const;
diff --git a/libcpp/line-map.c b/libcpp/line-map.c
index 3b65a46..7c050e8 100644
--- a/libcpp/line-map.c
+++ b/libcpp/line-map.c
@@ -2136,6 +2136,32 @@ rich_location::set_range (line_maps * /*set*/, unsigned int idx,
     m_have_expanded_location = false;
 }
 
+/* If LOC is within the spans of lines that will already be printed for
+   this rich_location, then add it as a secondary location and return true.
+
+   Otherwise return false.  */
+
+bool
+rich_location::add_location_if_nearby (source_location loc)
+{
+  expanded_location exploc
+    = linemap_client_expand_location_to_spelling_point (loc,
+							LOCATION_ASPECT_CARET);
+
+  for (unsigned int i = 0; i < get_num_locations (); i++)
+    {
+      expanded_location exploc_i = get_expanded_location (i);
+      if (exploc.file == exploc_i.file
+	  && exploc.line == exploc_i.line)
+	{
+	  add_range (loc, false);
+	  return true;
+	}
+    }
+
+  return false;
+}
+
 /* Methods for adding insertion fix-it hints.  */
 
 /* Add a fixit-hint, suggesting insertion of NEW_CONTENT
-- 
1.8.5.3

