[clang-format] Improved parser for C# properties

Summary:
Added some examples of properties from Microsoft documentation as test cases.

https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/properties

Configuration support will be added in a follow up patch to address whether automatic properties are formatted as

```
Type MyType { get; set }
```

or

```
Type MyType
{ get; set }
```

Reviewers: krasimir, MyDeveloperDay

Reviewed By: krasimir

Subscribers: cfe-commits

Tags: #clang-format, #clang

Differential Revision: https://reviews.llvm.org/D78915

1 files changed, 58 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTestCSharp.cpp b/clang/unittests/Format/FormatTestCSharp.cpp
index d37a533..75112a7 100644
--- a/clang/unittests/Format/FormatTestCSharp.cpp
+++ b/clang/unittests/Format/FormatTestCSharp.cpp
@@ -613,6 +613,64 @@ public string Name {
   set => _name = value;
 })",
                Style);
+
+  // Examples taken from
+  // https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/properties
+  verifyFormat(R"(
+// Expression body definitions
+public class SaleItem {
+  public decimal Price {
+    get => _cost;
+    set => _cost = value;
+  }
+})",
+               Style);
+
+  verifyFormat(R"(
+// Properties with backing fields
+class TimePeriod {
+  public double Hours {
+    get { return _seconds / 3600; }
+    set {
+      if (value < 0 || value > 24)
+        throw new ArgumentOutOfRangeException(
+            $"{nameof(value)} must be between 0 and 24.");
+      _seconds = value * 3600;
+    }
+  }
+})",
+               Style);
+
+  verifyFormat(R"(
+// Auto-implemented properties
+public class SaleItem {
+  public decimal Price { get; set; }
+})",
+               Style);
+
+  // Add column limit to wrap long lines.
+  Style.ColumnLimit = 100;
+
+  // Examples with assignment to default value.
+  verifyFormat(R"(
+// Long assignment to default value
+class MyClass {
+  public override VeryLongNamedTypeIndeed VeryLongNamedValue { get; set } =
+      VeryLongNamedTypeIndeed.Create(DefaultFirstArgument, DefaultSecondArgument,
+                                     DefaultThirdArgument);
+})",
+               Style);
+
+  verifyFormat(R"(
+// Long assignment to default value with expression body
+class MyClass {
+  public override VeryLongNamedTypeIndeed VeryLongNamedValue {
+    get => veryLongNamedField;
+    set => veryLongNamedField = value;
+  } = VeryLongNamedTypeIndeed.Create(DefaultFirstArgument, DefaultSecondArgument,
+                                     DefaultThirdArgument);
+})",
+               Style);
 }
 
 TEST_F(FormatTestCSharp, CSharpSpaces) {