[clang-format] Fix formatting of requires expressions in braced initializers

When clang-format encountered a requires expression inside a braced
initializer (e.g., `bool foo{requires { 0; }};`), it would incorrectly
format the code to the following:

    bool bar{requires {0;
    }
    }
    ;

The issue was that UnwrappedLineParser::parseBracedList had no explicit
handling for the requires keyword, so it would just call nextToken()
instead of properly parsing the requires expression.

This fix adds a case for tok::kw_requires in parseBracedList, calling
parseRequiresExpression to handle it correctly, matching the existing
behavior in parseParens [1].

Fixes #162984.

[1]: https://github.com/llvm/llvm-project/blob/7eee67202378932d03331ad04e7d07ed4d988381/clang/lib/Format/UnwrappedLineParser.cpp#L2713-L2718

Signed-off-by: Ruoyu Zhong <[email protected]>

Author: ZhongRuoyu

clang/lib/Format/UnwrappedLineParser.cpp

@@ -2569,6 +2569,12 @@ bool UnwrappedLineParser::parseBracedList(bool IsAngleBracket, bool IsEnum) {
       if (IsEnum && !Style.AllowShortEnumsOnASingleLine)
         addUnwrappedLine();
       break;
+    case tok::kw_requires: {
+      auto *RequiresToken = FormatTok;
+      nextToken();
+      parseRequiresExpression(RequiresToken);
+      break;
+    }
     default:
       nextToken();
       break;

clang/unittests/Format/FormatTest.cpp

@@ -26973,6 +26973,12 @@ TEST_F(FormatTest, RequiresExpressionIndentation) {
                Style);
 }
 
+TEST_F(FormatTest, RequiresExpressionInBracedInitializer) {
+  verifyFormat("bool foo{requires { 0; }};");
+  verifyFormat("int bar{requires(T t) { t.f(); }};");
+  verifyFormat("auto baz{requires { typename T::type; } && true};");
+}
+
 TEST_F(FormatTest, StatementAttributeLikeMacros) {
   FormatStyle Style = getLLVMStyle();
   StringRef Source = "void Foo::slot() {\n"