Fix ClangFormat issue of recognizing ObjC subscript as C++ attributes when message target is a result of a C-style method.

[Wizard]

Summary

The issue is that for array subscript like:

arr[[Foo() bar]];

ClangFormat will recognize it as C++11 attribute syntax and put a space between 'arr' and first '[', like:

arr [[Foo() bar]];

Now it is fixed. Tested with:

ninja FormatTests

[Wizard]

remove blank lines

lib/Format/TokenAnnotator.cpp

if (AttrTok->startsSequence(tok::kw_using, tok::identifier, tok::colon))
       return true;
     if (AttrTok->isNot(tok::identifier))
       return false;
     while (AttrTok && !AttrTok->startsSequence(tok::r_square, tok::r_square)) {
       // ObjC message send. We assume nobody will use : in a C++11 attribute
       // specifier parameter, although this is technically valid:
       // [[foo(:)]]
       if (AttrTok->is(tok::colon) ||
-          AttrTok->startsSequence(tok::identifier, tok::identifier))
+          AttrTok->startsSequence(tok::identifier, tok::identifier) || 
+          AttrTok->startsSequence(tok::r_paren, tok::identifier))
         return false;
       if (AttrTok->is(tok::ellipsis))
         return true;
       AttrTok = AttrTok->Next;
     }
     return AttrTok && AttrTok->startsSequence(tok::r_square, tok::r_square);
   }
 

unittests/Format/FormatTest.cpp

TEST_F(FormatTest, UnderstandsSquareAttributes) {
   verifyFormat("[[gsl::suppress(\"clang-tidy-check-name\")]] void f() {}");
   verifyFormat("void f() [[deprecated(\"so sorry\")]];");
   verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
                "    [[unused]] aaaaaaaaaaaaaaaaaaaaaaa(int i);");
 
   // Make sure we do not mistake attributes for array subscripts.
   verifyFormat("int a() {}\n"
                "[[unused]] int b() {}\n");
+  verifyFormat("NSArray *arr;\n"
+               "arr[[Foo() bar]];");
 
   // On the other hand, we still need to correctly find array subscripts.
   verifyFormat("int a = std::vector<int>{1, 2, 3}[0];");
 
   // Make sure we do not parse attributes as lambda introducers.
   FormatStyle MultiLineFunctions = getLLVMStyle();
   MultiLineFunctions.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_None;
   verifyFormat("[[unused]] int b() {\n"