release/20.x: [clang-format] Handle C-style cast of member function pointer type (#126340)

[llvmbot]

Backport 8d373ce

Requested by: @owenca

[llvmbot]

@HazardyKnusperkeks What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: None (llvmbot)

Changes

Backport 8d373ce

Requested by: @owenca

---

Full diff: https://github.com/llvm/llvm-project/pull/126479.diff

2 Files Affected:

• (modified) clang/lib/Format/TokenAnnotator.cpp (+5-2)
• (modified) clang/unittests/Format/TokenAnnotatorTest.cpp (+6)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index a172df5291ae62a..4246ade6e19be53 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -477,8 +477,9 @@ class AnnotatingParser {
     FormatToken *PossibleObjCForInToken = nullptr;
     while (CurrentToken) {
       const auto &Prev = *CurrentToken->Previous;
+      const auto *PrevPrev = Prev.Previous;
       if (Prev.is(TT_PointerOrReference) &&
-          Prev.Previous->isOneOf(tok::l_paren, tok::coloncolon)) {
+          PrevPrev->isOneOf(tok::l_paren, tok::coloncolon)) {
         ProbablyFunctionType = true;
       }
       if (CurrentToken->is(tok::comma))
@@ -486,8 +487,10 @@ class AnnotatingParser {
       if (Prev.is(TT_BinaryOperator))
         Contexts.back().IsExpression = true;
       if (CurrentToken->is(tok::r_paren)) {
-        if (Prev.is(TT_PointerOrReference) && Prev.Previous == &OpeningParen)
+        if (Prev.is(TT_PointerOrReference) &&
+            (PrevPrev == &OpeningParen || PrevPrev->is(tok::coloncolon))) {
           MightBeFunctionType = true;
+        }
         if (OpeningParen.isNot(TT_CppCastLParen) && MightBeFunctionType &&
             ProbablyFunctionType && CurrentToken->Next &&
             (CurrentToken->Next->is(tok::l_paren) ||
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index fc77e277947c563..2147a1b950dd19b 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -845,6 +845,12 @@ TEST_F(TokenAnnotatorTest, UnderstandsCasts) {
   EXPECT_TOKEN(Tokens[14], tok::r_paren, TT_CastRParen);
   EXPECT_TOKEN(Tokens[15], tok::amp, TT_UnaryOperator);
 
+  Tokens = annotate("return (Foo (Bar::*)())&Bar::foo;");
+  ASSERT_EQ(Tokens.size(), 17u) << Tokens;
+  EXPECT_TOKEN(Tokens[3], tok::l_paren, TT_FunctionTypeLParen);
+  EXPECT_TOKEN(Tokens[10], tok::r_paren, TT_CastRParen);
+  EXPECT_TOKEN(Tokens[11], tok::amp, TT_UnaryOperator);
+
   auto Style = getLLVMStyle();
   Style.TypeNames.push_back("Foo");
   Tokens = annotate("#define FOO(bar) foo((Foo)&bar)", Style);

[github-actions]

@owenca (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.