[Parser] Support alternative operator token keyword args in Objective-C++

rdar://30741878

Differential revision: https://reviews.llvm.org/D50527

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340301 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Parse/ParseExpr.cpp

@@ -315,6 +315,19 @@ Parser::ParseRHSOfBinaryExpression(ExprResult LHS, prec::Level MinPrec) {
       return LHS;
     }
 
+    // In Objective-C++, alternative operator tokens can be used as keyword args
+    // in message expressions. Unconsume the token so that it can reinterpreted
+    // as an identifier in ParseObjCMessageExpressionBody. i.e., we support:
+    //   [foo meth:0 and:0];
+    //   [foo not_eq];
+    if (getLangOpts().ObjC1 && getLangOpts().CPlusPlus &&
+        Tok.isOneOf(tok::colon, tok::r_square) &&
+        OpToken.getIdentifierInfo() != nullptr) {
+      PP.EnterToken(Tok);
+      Tok = OpToken;
+      return LHS;
+    }
+
     // Special case handling for the ternary operator.
     ExprResult TernaryMiddle(true);
     if (NextTokPrec == prec::Conditional) {

test/Parser/message-expr-alt-op.mm

@@ -0,0 +1,41 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+@interface WeirdInterface
+-(void)allOfThem:(int)a
+             and:(int)b
+          and_eq:(int)c
+          bitand:(int)d
+           bitor:(int)e
+           compl:(int)f
+             not:(int)g
+          not_eq:(int)h
+              or:(int)i
+           or_eq:(int)j
+             xor:(int)k
+          xor_eq:(int)l;
+
+-(void)justAnd:(int)x and:(int)y;
+-(void)and;
+-(void)and:(int)x;
+@end
+
+void call_it(WeirdInterface *x) {
+  [x allOfThem:0
+           and:0
+        and_eq:0
+        bitand:0
+         bitor:0
+         compl:0
+           not:0
+        not_eq:0
+            or:0
+         or_eq:0
+           xor:0
+        xor_eq:0];
+
+  [x and];
+  [x and:0];
+  [x &&:0]; // expected-error{{expected expression}};
+  [x justAnd:0 and:1];
+  [x and: 0 ? : 1];
+}