[clang-format] Look ahead before consuming `bool` in requires clause.

The comment handling the bool case says:
"bool is only allowed if it is directly followed by a paren for a cast"

This change more closely follows this directive by looking ahead for
the paren before consuming the bool keyword itself. Without a following
paren, the bool would be part of something else, such as a return type
for a function declaration

Fixes https://github.com/llvm/llvm-project/issues/57538

Reviewed By: HazardyKnusperkeks, owenpan, MyDeveloperDay

Differential Revision: https://reviews.llvm.org/D134325

diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 87a0e43..3919bc0 100644 (file)
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -3530,9 +3530,9 @@ void UnwrappedLineParser::parseConstraintExpression() {
       // concept C = bool(...);
       // and bool is the only type, all other types as cast must be inside a
       // cast to bool an thus are handled by the other cases.
-      nextToken();
-      if (FormatTok->isNot(tok::l_paren))
+      if (Tokens->peekNextToken()->isNot(tok::l_paren))
         return;
+      nextToken();
       parseParens();
       break;
 

diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 6bc295c..c8de8a2 100644 (file)
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -450,6 +450,14 @@ TEST_F(TokenAnnotatorTest, UnderstandsRequiresClausesAndConcepts) {
   EXPECT_TOKEN(Tokens[20], tok::arrow, TT_TrailingReturnArrow);
 
   Tokens = annotate("template <typename T>\n"
+                    "requires Bar<T>\n"
+                    "bool foo(T) { return false; }");
+  ASSERT_EQ(Tokens.size(), 21u) << Tokens;
+  EXPECT_TOKEN(Tokens[5], tok::kw_requires, TT_RequiresClause);
+  EXPECT_TRUE(Tokens[9]->ClosesRequiresClause);
+  EXPECT_TOKEN(Tokens[11], tok::identifier, TT_FunctionDeclarationName);
+
+  Tokens = annotate("template <typename T>\n"
                     "struct S {\n"
                     "  void foo() const requires Bar<T>;\n"
                     "  void bar() const & requires Baz<T>;\n"