[clang-format] square parens with one token are not Objective-C message sends

The commit r322690 introduced support for ObjC detection in header files.
Unfortunately some C headers that use designated initializers are now
incorrectly detected as Objective-C.
This commit fixes it by ensuring that `[ token ]` is not annotated as an
Objective-C message send.

rdar://45504376

Differential Revision: https://reviews.llvm.org/D56226


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@352125 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/TokenAnnotator.cpp

@@ -494,9 +494,14 @@ private:
       if (CurrentToken->is(tok::r_square)) {
         if (IsCpp11AttributeSpecifier)
           CurrentToken->Type = TT_AttributeSquare;
-        else if (CurrentToken->Next && CurrentToken->Next->is(tok::l_paren) &&
+        else if (((CurrentToken->Next &&
+                   CurrentToken->Next->is(tok::l_paren)) ||
+                  (CurrentToken->Previous &&
+                   CurrentToken->Previous->Previous == Left)) &&
                  Left->is(TT_ObjCMethodExpr)) {
-          // An ObjC method call is rarely followed by an open parenthesis.
+          // An ObjC method call is rarely followed by an open parenthesis. It
+          // also can't be composed of just one token, unless it's a macro that
+          // will be expanded to more tokens.
           // FIXME: Do we incorrectly label ":" with this?
           StartsObjCMethodExpr = false;
           Left->Type = TT_Unknown;

unittests/Format/FormatTestObjC.cpp

@@ -165,6 +165,20 @@ TEST(FormatTestObjCStyle, DetectsObjCInHeaders) {
   EXPECT_EQ(FormatStyle::LK_ObjC, Style->Language);
 }
 
+TEST(FormatTestObjCStyle, AvoidDetectingDesignatedInitializersAsObjCInHeaders) {
+  auto Style = getStyle("LLVM", "a.h", "none",
+                        "static const char *names[] = {[0] = \"foo\",\n"
+                        "[kBar] = \"bar\"};");
+  ASSERT_TRUE((bool)Style);
+  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+
+  Style = getStyle("LLVM", "a.h", "none",
+                   "static const char *names[] = {[0] EQ \"foo\",\n"
+                   "[kBar] EQ \"bar\"};");
+  ASSERT_TRUE((bool)Style);
+  EXPECT_EQ(FormatStyle::LK_Cpp, Style->Language);
+}
+
 TEST_F(FormatTestObjC, FormatObjCTryCatch) {
   verifyFormat("@try {\n"
                "  f();\n"