[clang] Fix false match on nullPointerConstant for array indices (PR #201893)

[Kay Hicketts via cfe-commits]

https://github.com/KHicketts updated https://github.com/llvm/llvm-project/pull/201893

>From f238457992ea5315c63430927c39c1d1c8d494dd Mon Sep 17 00:00:00 2001
From: khickett <khicketts at bloomberg.net>
Date: Fri, 5 Jun 2026 18:03:02 +0100
Subject: [PATCH] Fix false match on nullPointerConstant for array indices

---
 clang/include/clang/ASTMatchers/ASTMatchers.h            | 2 +-
 clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index bc0f35898a2c9..24d9eea98df9b 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -8369,7 +8369,7 @@ extern const internal::VariadicDynCastAllOfMatcher<Stmt, CUDAKernelCallExpr>
 AST_MATCHER_FUNCTION(internal::Matcher<Expr>, nullPointerConstant) {
   return anyOf(
       gnuNullExpr(), cxxNullPtrLiteralExpr(),
-      integerLiteral(equals(0), hasParent(expr(hasType(pointerType())))));
+      integerLiteral(equals(0), hasParent(castExpr(hasCastKind(CK_NullToPointer)))));
 }
 
 /// Matches the DecompositionDecl the binding belongs to.
diff --git a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
index d9647c201fc30..d51f70b867ac9 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -4049,6 +4049,7 @@ TEST_P(ASTMatchersTest, NullPointerConstant) {
   EXPECT_TRUE(matches("char *cp = (char *)0;", expr(nullPointerConstant())));
   EXPECT_TRUE(matches("int *ip = 0;", expr(nullPointerConstant())));
   EXPECT_FALSE(matches("int i = 0;", expr(nullPointerConstant())));
+  EXPECT_FALSE(matches("int *p[1]; (void)p[0];", expr(nullPointerConstant())));
 }
 
 TEST_P(ASTMatchersTest, NullPointerConstant_GNUNull) {