[clang-format] Do not interpret C# deconstruction in a foreach as a cast

[krasimir]

Nice!

[jbcoe]

Format patch

clang/lib/Format/TokenAnnotator.cpp

if (LeftOfParens) {
       if (LeftOfParens->isOneOf(tok::at, tok::r_square, TT_OverloadedOperator,
                                 TT_TemplateCloser, tok::ellipsis))
         return false;
     }
 
     if (Tok.Next->is(tok::question))
       return false;
 
+    // `foreach((A a, B b) in someList)` should not be seen as a cast.
+    if (Tok.Next->is(Keywords.kw_in) && Style.isCSharp())
+      return false;
+
     // Functions which end with decorations like volatile, noexcept are unlikely
     // to be casts.
     if (Tok.Next->isOneOf(tok::kw_noexcept, tok::kw_volatile, tok::kw_const,
                           tok::kw_throw, tok::arrow, Keywords.kw_override,
                           Keywords.kw_final) ||
         isCpp11AttributeSpecifier(*Tok.Next))
       return false;
 

clang/unittests/Format/FormatTestCSharp.cpp

 
 TEST_F(FormatTestCSharp, CSharpSpaces) {
   FormatStyle Style = getGoogleStyle(FormatStyle::LK_CSharp);
   Style.SpaceBeforeSquareBrackets = false;
   Style.SpacesInSquareBrackets = false;
   Style.SpaceBeforeCpp11BracedList = true;
   Style.Cpp11BracedListStyle = false;
   Style.SpacesInContainerLiterals = false;
+  Style.SpaceAfterCStyleCast = false;
 
   verifyFormat(R"(new Car { "Door", 0.1 })", Style);
   verifyFormat(R"(new Car { 0.1, "Door" })", Style);
   verifyFormat(R"(new string[] { "A" })", Style);
   verifyFormat(R"(new string[] {})", Style);
   verifyFormat(R"(new Car { someVariableName })", Style);
   verifyFormat(R"(new Car { someVariableName })", Style);
   verifyFormat(R"(new Dictionary<string, string> { ["Key"] = "Value" };)",
                Style);
   verifyFormat(R"(Apply(x => x.Name, x => () => x.ID);)", Style);
   verifyFormat(R"(bool[] xs = { true, true };)", Style);
   verifyFormat(R"(taskContext.Factory.Run(async () => doThing(args);)", Style);
   verifyFormat(R"(catch (TestException) when (innerFinallyExecuted))", Style);
   verifyFormat(R"(private float[,] Values;)", Style);
   verifyFormat(R"(Result this[Index x] => Foo(x);)", Style);
 
   verifyFormat(R"(char[,,] rawCharArray = MakeCharacterGrid();)", Style);
 
+  // Not seen as a C-style cast.
+  verifyFormat(R"(//
+foreach ((A a, B b) in someList) {
+})",
+               Style);
+
   Style.SpacesInSquareBrackets = true;
   verifyFormat(R"(private float[ , ] Values;)", Style);
   verifyFormat(R"(string dirPath = args?[ 0 ];)", Style);
   verifyFormat(R"(char[ ,, ] rawCharArray = MakeCharacterGrid();)", Style);
 }
 
 TEST_F(FormatTestCSharp, CSharpNullableTypes) {
   FormatStyle Style = getGoogleStyle(FormatStyle::LK_CSharp);