[clang-format] Don't insert space between ObjC class and lightweight generic

[benhamilton]

Summary

In D45185, I added clang-format parser support for Objective-C
generics. However, I didn't touch the whitespace logic, so they
got the same space logic as Objective-C protocol lists.

In every example in the Apple SDK and in the documentation,
there is no space between the class name and the opening <
for the lightweight generic specification, so this diff
removes the space and updates the tests.

Test Plan: Tests updated. Ran tests with:

% make -j16 FormatTests && ./tools/clang/unittests/Format/FormatTests

[djasper]

Looks good.

lib/Format/TokenAnnotator.cpp

2357

Don't use else after return.
https://llvm.org/docs/CodingStandards.html#don-t-use-else-after-a-return

I'd have a slight preference for writing:

bool IsLightweightGeneric = 
    Right.MatchingParen && Right.MatchingParen->Next &&
    Right.MatchingParen->Next->is(tok::colon);
return !IsLightweightGeneric && Style.ObjCSpaceBeforeProtocolList;

Then I think it might not even need a comment (or a shorter one).

[benhamilton]

Avoid else after return. Clean up logic so it doesn't need a comment.

lib/Format/TokenAnnotator.cpp

if (Left.is(tok::l_paren) && Right.is(tok::r_paren))
     return Style.SpaceInEmptyParentheses;
   if (Left.is(tok::l_paren) || Right.is(tok::r_paren))
     return (Right.is(TT_CastRParen) ||
             (Left.MatchingParen && Left.MatchingParen->is(TT_CastRParen)))
                ? Style.SpacesInCStyleCastParentheses
                : Style.SpacesInParentheses;
   if (Right.isOneOf(tok::semi, tok::comma))
     return false;
-  if (Right.is(tok::less) && Line.Type == LT_ObjCDecl &&
-      Style.ObjCSpaceBeforeProtocolList)
-    return true;
+  if (Right.is(tok::less) && Line.Type == LT_ObjCDecl) {
+    if (Right.MatchingParen && Right.MatchingParen->Next &&
+        Right.MatchingParen->Next->is(tok::colon))
+      // Lightweight generic -> no space. @interface Foo<KeyType> : Bar <Baz>
+      return false;
+    else
+      // Protocol list -> space if configured. @interface Foo : Bar <Baz>
+      return Style.ObjCSpaceBeforeProtocolList;
+  }
   if (Right.is(tok::less) && Left.is(tok::kw_template))
     return Style.SpaceAfterTemplateKeyword;
   if (Left.isOneOf(tok::exclaim, tok::tilde))
     return false;
   if (Left.is(tok::at) &&
       Right.isOneOf(tok::identifier, tok::string_literal, tok::char_constant,
                     tok::numeric_constant, tok::l_paren, tok::l_brace,
                     tok::kw_true, tok::kw_false))

unittests/Format/FormatTestObjC.cpp

verifyFormat("@interface Foo : Bar {\n"
                "@end");
 
   verifyFormat("@interface Foo : Bar <Baz, Quux> {\n"
                "  int _i;\n"
                "}\n"
                "+ (id)init;\n"
                "@end");
 
-  verifyFormat("@interface Foo <Baz : Blech> : Bar <Baz, Quux> {\n"
+  verifyFormat("@interface Foo<Baz : Blech> : Bar <Baz, Quux> {\n"
                "  int _i;\n"
                "}\n"
                "+ (id)init;\n"
                "@end");
 
-  verifyFormat("@interface Foo <Bar : Baz <Blech>> : Xyzzy <Corge> {\n"
+  verifyFormat("@interface Foo<Bar : Baz <Blech>> : Xyzzy <Corge> {\n"
                "  int _i;\n"
                "}\n"
                "+ (id)init;\n"
                "@end");
 
   verifyFormat("@interface Foo (HackStuff) {\n"
                "  int _i;\n"
                "}\n"