[Clang-Tidy][NFC] Simplify check cppcoreguidelines-missing-std-forward

[zwuis]

Remove CaptureInCopy because the cases handled by it are covered by CaptureByRefExplicit.

[llvmbot]

@llvm/pr-subscribers-clang-tools-extra

@llvm/pr-subscribers-clang-tidy

Author: Yanzuo Liu (zwuis)

Changes

Remove CaptureInCopy because function parameters captured by copy should not be considered forwarded.

No functional changes because implicit captures are not added to capture list until the function is instantiated (P0588R1 is not implemented currently), so that CaptureInCopy never matches anything.

---

Full diff: https://github.com/llvm/llvm-project/pull/138504.diff

1 Files Affected:

• (modified) clang-tools-extra/clang-tidy/cppcoreguidelines/MissingStdForwardCheck.cpp (+1-4)

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/MissingStdForwardCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/MissingStdForwardCheck.cpp
index bbb35228ce47f..2e8d4f7860021 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/MissingStdForwardCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/MissingStdForwardCheck.cpp
@@ -98,13 +98,10 @@ void MissingStdForwardCheck::registerMatchers(MatchFinder *Finder) {
       allOf(hasCaptureDefaultKind(LambdaCaptureDefault::LCD_ByRef),
             unless(hasAnyCapture(
                 capturesVar(varDecl(hasSameNameAsBoundNode("param"))))));
-  auto CaptureInCopy = allOf(
-      hasCaptureDefaultKind(LambdaCaptureDefault::LCD_ByCopy), HasRefToParm);
   auto CaptureByRefExplicit = hasAnyCapture(
       allOf(hasCaptureKind(LambdaCaptureKind::LCK_ByRef), RefToParm));
 
-  auto CapturedInBody =
-      lambdaExpr(anyOf(CaptureInRef, CaptureInCopy, CaptureByRefExplicit));
+  auto CapturedInBody = lambdaExpr(anyOf(CaptureInRef, CaptureByRefExplicit));
   auto CapturedInCaptureList = hasAnyCapture(capturesVar(
       varDecl(hasInitializer(ignoringParenImpCasts(equalsBoundNode("call"))))));
 

[carlosgalvezp]

because the cases handled by it are covered by CaptureByRefExplicit.

Strange, can you explain why that's the case? Are we missing tests?

[zwuis]

Strange, can you explain why that's the case?

CaptureInCopy matches lambda expressions whose default capture kind is copy and which have an explicit capture referencing function parameter.

CaptureByRefExplicit matches lambda expressions which have an explicit capture captured by reference and referencing function parameter, not requiring default capture kind.

Are we missing tests?

I don't think we miss tests.

[zwuis]

Thank you for your review!

I don't have commit access. Please help me merge this PR if it's ready.