[clang-format] Correctly handle C# where clause (#137295)

Fix #74947

Author: owenca

clang/lib/Format/UnwrappedLineParser.cpp

@@ -295,6 +295,7 @@ void UnwrappedLineParser::parseCSharpGenericTypeConstraint() {
   do {
     switch (FormatTok->Tok.getKind()) {
     case tok::l_brace:
+    case tok::semi:
       return;
     default:
       if (FormatTok->is(Keywords.kw_where)) {

clang/unittests/Format/FormatTestCSharp.cpp

@@ -1315,6 +1315,12 @@ TEST_F(FormatTestCSharp, CSharpGenericTypeConstraints) {
                "}",
                Style);
 
+  verifyFormat("namespace A {\n"
+               "  delegate T MyDelegate<T>()\n"
+               "      where T : new();\n"
+               "}",
+               Style);
+
   // When the "where" line is not to be formatted, following lines should not
   // take on its indentation.
   verifyFormat("class ItemFactory<T>\n"

clang/unittests/Format/TokenAnnotatorTest.cpp

@@ -3099,6 +3099,16 @@ TEST_F(TokenAnnotatorTest, CSharpNullableTypes) {
   EXPECT_TOKEN(Tokens[1], tok::question, TT_ConditionalExpr);
 }
 
+TEST_F(TokenAnnotatorTest, CSharpGenericTypeConstraint) {
+  auto Tokens = annotate("namespace A {\n"
+                         "  delegate T MyDelegate<T>()\n"
+                         "      where T : new();\n"
+                         "}",
+                         getGoogleStyle(FormatStyle::LK_CSharp));
+  ASSERT_EQ(Tokens.size(), 20u) << Tokens;
+  EXPECT_TOKEN(Tokens[18], tok::r_brace, TT_NamespaceRBrace);
+}
+
 TEST_F(TokenAnnotatorTest, UnderstandsLabels) {
   auto Tokens = annotate("{ x: break; }");
   ASSERT_EQ(Tokens.size(), 7u) << Tokens;