[clang-format] Microsoft style fixes for C# properties

[jbcoe]

Summary

There should be no line break before the opening brace for Microsoft style property accessors when the accessor is a simple { get; set }.

https://docs.microsoft.com/en-us/dotnet/csharp/properties

[krasimir]

Thank you!

clang/lib/Format/UnwrappedLineParser.cpp

bool UnwrappedLineParser::tryToParsePropertyAccessor() {
   if (!HasGetOrSet) {
     Tokens->setPosition(StoredPosition);
     return false;
   }
 
   // Try to parse the property accessor:
   // https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/properties
   Tokens->setPosition(StoredPosition);
-  if (Style.BraceWrapping.AfterFunction == true)
+  if (!IsTrivialPropertyAccessor && Style.BraceWrapping.AfterFunction == true)
     addUnwrappedLine();
   nextToken();
   do {
     switch (FormatTok->Tok.getKind()) {
     case tok::r_brace:
       nextToken();
       if (FormatTok->is(tok::equal)) {
         while (!eof() && FormatTok->isNot(tok::semi))

clang/unittests/Format/FormatTestCSharp.cpp

TEST_F(FormatTestCSharp, Attributes) {
 
   verifyFormat("[Verb(\"start\", HelpText = \"Starts the server listening on "
                "provided port\")]\n"
                "class Test\n"
                "{\n"
                "}");
 
   verifyFormat("[TestMethod]\n"
-               "public string Host\n"
-               "{ set; get; }");
+               "public string Host { set; get; }");
 
   verifyFormat("[TestMethod(\"start\", HelpText = \"Starts the server "
                "listening on provided host\")]\n"
-               "public string Host\n"
-               "{ set; get; }");
+               "public string Host { set; get; }");
 
   verifyFormat(
       "[DllImport(\"Hello\", EntryPoint = \"hello_world\")]\n"
       "// The const char* returned by hello_world must not be deleted.\n"
       "private static extern IntPtr HelloFromCpp();)");
 
   // Class attributes go on their own line and do not affect layout of
   // interfaces. Line wrapping decisions previously caused each interface to be
set => veryLongNamedField = value;
                Style);
 
   // Brace wrapping and single-lining of accessor can be controlled by config.
   Style.AllowShortBlocksOnASingleLine = FormatStyle::SBS_Never;
   Style.BreakBeforeBraces = FormatStyle::BS_Custom;
   Style.BraceWrapping.AfterFunction = true;
 
   verifyFormat(R"(//
-public class SaleItem {
-  public decimal Price
-  { get; set; }
-})",
-               Style);
-
-  verifyFormat(R"(//
 class TimePeriod {
   public double Hours
   {
     get {
       return _seconds / 3600;
     }
     set {
       _seconds = value * 3600;
     }
   }
 })",
                Style);
+ 
+  // Microsoft style trivial property accessors have no line break before the
+  // opening brace.
+  auto MicrosoftStyle = getMicrosoftStyle(FormatStyle::LK_CSharp);
+  verifyFormat(R"(//
+public class SaleItem
+{
+    public decimal Price { get; set; }
+})",
+               MicrosoftStyle);
+
 }
 
 TEST_F(FormatTestCSharp, CSharpSpaces) {
   FormatStyle Style = getGoogleStyle(FormatStyle::LK_CSharp);
   Style.SpaceBeforeSquareBrackets = false;
   Style.SpacesInSquareBrackets = false;
   Style.SpaceBeforeCpp11BracedList = true;
   Style.Cpp11BracedListStyle = false;