https://github.com/emaxx-google created
https://github.com/llvm/llvm-project/pull/122286
Don't suggest to comment-out the parameter name if the parameter has an
attribute that's spelled after the parameter name.
This prevents the parameter's attributes from being wrongly applied to the
parameter's type (#122191).
>From 187db1850185f669306f387ff5741444d6d26660 Mon Sep 17 00:00:00 2001
From: Maksim Ivanov <em...@google.com>
Date: Thu, 9 Jan 2025 14:59:35 +0000
Subject: [PATCH] [clang-tidy] Fix misc-unused-parameters on params with attrs
Don't suggest to comment-out the parameter name if the parameter has an
attribute that's spelled after the parameter name.
This prevents the parameter's attributes from being wrongly applied to
the parameter's type.
---
.../clang-tidy/misc/UnusedParametersCheck.cpp | 16 ++++++++++++++++
.../checkers/misc/unused-parameters.cpp | 5 +++++
2 files changed, 21 insertions(+)
diff --git a/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
b/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
index c2d9286312dc4a..e7dfcd9859f64d 100644
--- a/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/UnusedParametersCheck.cpp
@@ -26,6 +26,17 @@ bool isOverrideMethod(const FunctionDecl *Function) {
return MD->size_overridden_methods() > 0 || MD->hasAttr<OverrideAttr>();
return false;
}
+
+bool hasAttrAfterParam(const clang::SourceManager *SourceManager,
+ const ParmVarDecl *Param) {
+ for (const auto *Attr : Param->attrs()) {
+ if (SourceManager->isBeforeInTranslationUnit(Param->getLocation(),
+ Attr->getLocation())) {
+ return true;
+ }
+ }
+ return false;
+}
} // namespace
void UnusedParametersCheck::registerMatchers(MatchFinder *Finder) {
@@ -189,6 +200,11 @@ void UnusedParametersCheck::check(const
MatchFinder::MatchResult &Result) {
if (Param->isUsed() || Param->isReferenced() || !Param->getDeclName() ||
Param->hasAttr<UnusedAttr>())
continue;
+ if (hasAttrAfterParam(Result.SourceManager, Param)) {
+ // Due to how grammar works, attributes would be wrongly applied to the
+ // type if we remove the preceding parameter name.
+ continue;
+ }
// In non-strict mode ignore function definitions with empty bodies
// (constructor initializer counts for non-empty body).
diff --git
a/clang-tools-extra/test/clang-tidy/checkers/misc/unused-parameters.cpp
b/clang-tools-extra/test/clang-tidy/checkers/misc/unused-parameters.cpp
index a3fcf30f273ef7..86b00ee56c3ce0 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/misc/unused-parameters.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/unused-parameters.cpp
@@ -33,6 +33,10 @@ void f(void (*fn)()) {;}
// CHECK-MESSAGES: :[[@LINE-1]]:15: warning: parameter 'fn' is unused
[misc-unused-parameters]
// CHECK-FIXES: {{^}}void f(void (* /*fn*/)()) {;}{{$}}
+int *k([[clang::lifetimebound]] int *i) {;}
+// CHECK-MESSAGES: :[[@LINE-1]]:38: warning: parameter 'i' is unused
[misc-unused-parameters]
+// CHECK-FIXES: {{^}}int *k({{\[\[clang::lifetimebound\]\]}} int * /*i*/)
{;}{{$}}
+
// Unchanged cases
// ===============
void f(int i); // Don't remove stuff in declarations
@@ -41,6 +45,7 @@ void h(int i[]);
void s(int i[1]);
void u(void (*fn)());
void w(int i) { (void)i; } // Don't remove used parameters
+int *x(int *i [[clang::lifetimebound]]) { return nullptr; } // Don't reanchor
attribute to the type.
bool useLambda(int (*fn)(int));
static bool static_var = useLambda([] (int a) { return a; });
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