[clang-tools-extra] [clang-tidy] Handle implicit casts in hicpp-signed-bitwise for IgnorePositiveIntegerLiterals (PR #90621)

[Piotr Zegar via cfe-commits]

https://github.com/PiotrZSL created https://github.com/llvm/llvm-project/pull/90621

Improved hicpp-signed-bitwise check by ignoring false positives involving positive integer literals behind implicit casts when IgnorePositiveIntegerLiterals is enabled.

Closes #89367

>From b61a47b8c98adbdb0aabcbc571a35bb67da87101 Mon Sep 17 00:00:00 2001
From: Piotr Zegar <me at piotrzegar.pl>
Date: Tue, 30 Apr 2024 15:35:07 +0000
Subject: [PATCH] [clang-tidy] Handle implicit casts in hicpp-signed-bitwise
 for IgnorePositiveIntegerLiterals

Improved hicpp-signed-bitwise check by ignoring false positives involving
positive integer literals behind implicit casts when IgnorePositiveIntegerLiterals
is enabled.

Closes #89367
---
 clang-tools-extra/clang-tidy/hicpp/SignedBitwiseCheck.cpp    | 5 +++--
 clang-tools-extra/docs/ReleaseNotes.rst                      | 4 ++++
 .../checkers/hicpp/signed-bitwise-integer-literals.cpp       | 3 +++
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/clang-tools-extra/clang-tidy/hicpp/SignedBitwiseCheck.cpp b/clang-tools-extra/clang-tidy/hicpp/SignedBitwiseCheck.cpp
index 51cc26400f7f38..bf09a6662d9552 100644
--- a/clang-tools-extra/clang-tidy/hicpp/SignedBitwiseCheck.cpp
+++ b/clang-tools-extra/clang-tidy/hicpp/SignedBitwiseCheck.cpp
@@ -9,6 +9,7 @@
 #include "SignedBitwiseCheck.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
 
 using namespace clang::ast_matchers;
 using namespace clang::ast_matchers::internal;
@@ -29,8 +30,8 @@ void SignedBitwiseCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
 void SignedBitwiseCheck::registerMatchers(MatchFinder *Finder) {
   const auto SignedIntegerOperand =
       (IgnorePositiveIntegerLiterals
-           ? expr(ignoringImpCasts(hasType(isSignedInteger())),
-                  unless(integerLiteral()))
+           ? expr(ignoringImpCasts(
+                 allOf(hasType(isSignedInteger()), unless(integerLiteral()))))
            : expr(ignoringImpCasts(hasType(isSignedInteger()))))
           .bind("signed-operand");
 
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 3038d2b125f20d..cdf4c132c0cf1f 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -247,6 +247,10 @@ Changes in existing checks
 - Improved :doc:`google-runtime-int <clang-tidy/checks/google/runtime-int>`
   check performance through optimizations.
 
+- Improved :doc:`hicpp-signed-bitwise <clang-tidy/checks/hicpp/signed-bitwise>`
+  check by ignoring false positives involving positive integer literals behind
+  implicit casts when `IgnorePositiveIntegerLiterals` is enabled.
+
 - Improved :doc:`hicpp-ignored-remove-result <clang-tidy/checks/hicpp/ignored-remove-result>`
   check by ignoring other functions with same prefixes as the target specific
   functions.
diff --git a/clang-tools-extra/test/clang-tidy/checkers/hicpp/signed-bitwise-integer-literals.cpp b/clang-tools-extra/test/clang-tidy/checkers/hicpp/signed-bitwise-integer-literals.cpp
index edbb56f90cb0e1..aca7ae1fd76fbe 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/hicpp/signed-bitwise-integer-literals.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/hicpp/signed-bitwise-integer-literals.cpp
@@ -11,6 +11,7 @@ void examples() {
   // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: use of a signed integer operand with a binary bitwise operator
 
   unsigned URes2 = URes << 1; //Ok
+  unsigned URes3 = URes & 1; //Ok
 
   int IResult;
   IResult = 10 & 2; //Ok
@@ -21,6 +22,8 @@ void examples() {
   IResult = Int << 1;
   // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use of a signed integer operand with a binary bitwise operator
   IResult = ~0; //Ok
+  IResult = -1 & 1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: use of a signed integer operand with a binary bitwise operator [hicpp-signed-bitwise]
 }
 
 enum EnumConstruction {