[ASTMatchers] fix captureVars assertion failure on capturesVariables

[danix800]

Matcher capturesVar should check for capturesVariables() before calling getCaptureVar() since it asserts this LambdaCapture does capture a variable.

Fixes #76425

[llvmbot]

@llvm/pr-subscribers-clang

Author: Ding Fei (danix800)

Changes

Fixes #76425

---

Full diff: https://github.com/llvm/llvm-project/pull/76619.diff

2 Files Affected:

• (modified) clang/include/clang/ASTMatchers/ASTMatchers.h (+2)
• (modified) clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp (+2)

diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index 82a26356c58f55..91c33e4b1163e6 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -4817,6 +4817,8 @@ AST_MATCHER_P(LambdaExpr, hasAnyCapture, internal::Matcher<LambdaCapture>,
 /// capturesVar(hasName("x")) matches `x` and `x = 1`.
 AST_MATCHER_P(LambdaCapture, capturesVar, internal::Matcher<ValueDecl>,
               InnerMatcher) {
+  if (!Node.capturesVariable())
+    return false;
   auto *capturedVar = Node.getCapturedVar();
   return capturedVar && InnerMatcher.matches(*capturedVar, Finder, Builder);
 }
diff --git a/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
index 8f0dd5602307c5..eb493f9c3050ac 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp
@@ -2308,6 +2308,8 @@ TEST_P(ASTMatchersTest, LambdaCaptureTest_BindsToCaptureOfVarDecl) {
       matches("int main() { int cc; auto f = [=](){ return cc; }; }", matcher));
   EXPECT_TRUE(
       matches("int main() { int cc; auto f = [&](){ return cc; }; }", matcher));
+  EXPECT_TRUE(matches(
+      "void f(int a) { int cc[a]; auto f = [&](){ return cc;}; }", matcher));
 }
 
 TEST_P(ASTMatchersTest, LambdaCaptureTest_BindsToCaptureWithInitializer) {

[shafik]

Thank you for the fix, can you add more details to your summary. The summary is what usually goes into the git log. We would like those to be as descriptive as possible to avoid having to do extra digging to understand the change at a high level.

[danix800]

Thank you for the fix, can you add more details to your summary. The summary is what usually goes into the git log. We would like those to be as descriptive as possible to avoid having to do extra digging to understand the change at a high level.

Thanks for reminding. Summary updated, please take another look.

[AaronBallman]

LGTM but please add a release note so users know about the bug fix.

[danix800]

LGTM but please add a release note so users know about the bug fix.

Release note added.