Implement bracket insertion for Objective-C instance message sends as

part of parser recovery. For example, given:

  a method1:arg];

we detect after parsing the expression "a" that we have the start of a
message send expression. We pretend we've seen a '[' prior to the a,
then parse the remainder as a message send. We'll then give a
diagnostic+fix-it such as:

fixit-objc-message.m:17:3: error: missing '[' at start of message
      send expression
  a method1:arg];
  ^
  [

The algorithm here is very simple, and always assumes that the open
bracket goes at the beginning of the message send. It also only works
for non-super instance message sends at this time.

llvm-svn: 113968

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Parse/ParseObjc.cpp b/clang/lib/Parse/ParseObjc.cpp
index 5f5b716a61c..c29c618b014 100644
--- a/clang/lib/Parse/ParseObjc.cpp
+++ b/clang/lib/Parse/ParseObjc.cpp
@@ -13,6 +13,7 @@
 
 #include "clang/Parse/ParseDiagnostic.h"
 #include "clang/Parse/Parser.h"
+#include "RAIIObjectsForParser.h"
 #include "clang/Sema/DeclSpec.h"
 #include "clang/Sema/PrettyDeclStackTrace.h"
 #include "clang/Sema/Scope.h"
@@ -1785,6 +1786,8 @@ ExprResult Parser::ParseObjCAtExpression(SourceLocation AtLoc) {
 ///     simple-type-specifier
 ///     typename-specifier
 bool Parser::ParseObjCXXMessageReceiver(bool &IsExpr, void *&TypeOrExpr) {
+  InMessageExpressionRAIIObject InMessage(*this, true);
+
   if (Tok.is(tok::identifier) || Tok.is(tok::coloncolon) || 
       Tok.is(tok::kw_typename) || Tok.is(tok::annot_cxxscope))
     TryAnnotateTypeOrScopeToken();
@@ -1879,6 +1882,8 @@ ExprResult Parser::ParseObjCMessageExpression() {
     return ExprError();
   }
   
+  InMessageExpressionRAIIObject InMessage(*this, true);
+  
   if (getLang().CPlusPlus) {
     // We completely separate the C and C++ cases because C++ requires
     // more complicated (read: slower) parsing. 
@@ -1992,6 +1997,8 @@ Parser::ParseObjCMessageExpressionBody(SourceLocation LBracLoc,
                                        SourceLocation SuperLoc,
                                        ParsedType ReceiverType,
                                        ExprArg ReceiverExpr) {
+  InMessageExpressionRAIIObject InMessage(*this, true);
+
   if (Tok.is(tok::code_completion)) {
     if (SuperLoc.isValid())
       Actions.CodeCompleteObjCSuperMessage(getCurScope(), SuperLoc, 0, 0);