Summary:
Previously, the check would fix
```
using fn = void(int);
void f(fn *);
void test() {
// CHECK-MESSAGES: :[[@LINE+2]]:12: warning: parameter 'I' is unused
// CHECK-FIXES: {{^}} f([](int /*I*/) {
f([](int I) { return; });
}
```
into
`f([]() { return; });` which breaks compilation. Now the check is disabled from Lambdas.
The AST is not so easy to use. For
```
auto l = [](int) { return; };
f(l);
```
one gets
```
`-CallExpr <line:7:5, col:8> 'void'
|-ImplicitCastExpr <col:5> 'void (*)(fn *)' <FunctionToPointerDecay>
| `-DeclRefExpr <col:5> 'void (fn *)' lvalue Function 0x55a91a545e28 'f' 'void (fn *)'
`-ImplicitCastExpr <col:7> 'void (*)(int)' <UserDefinedConversion>
`-CXXMemberCallExpr <col:7> 'void (*)(int)'
`-MemberExpr <col:7> '<bound member function type>' .operator void (*)(int) 0x55a91a546850
`-ImplicitCastExpr <col:7> 'const (lambda at line:6:14)' lvalue <NoOp>
`-DeclRefExpr <col:7> '(lambda at line:6:14)':'(lambda at line:6:14)' lvalue Var 0x55a91a5461c0 'l' '(lambda at line:6:14)':'(lambda at line:6:14)'
```
There is no direct use of the `operator()(int I)` of the lambda, so the `!Indexer->getOtherRefs(Function).empty()`
does not fire. In the future, we might be able to use the conversion operator `operator void (*)(int)` to mark
the call operator as having an "other ref".
Reviewers: aaron.ballman, alexfh, hokein, njames93
Subscribers: xazax.hun, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D77680
#include "UnusedParametersCheck.h"
#include "clang/AST/ASTContext.h"
+#include "clang/AST/ASTLambda.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
// Cannot remove parameter for non-local functions.
if (Function->isExternallyVisible() ||
!Result.SourceManager->isInMainFile(Function->getLocation()) ||
- !Indexer->getOtherRefs(Function).empty() || isOverrideMethod(Function)) {
+ !Indexer->getOtherRefs(Function).empty() || isOverrideMethod(Function) ||
+ isLambdaCallOperator(Function)) {
// It is illegal to omit parameter name here in C code, so early-out.
if (!Result.Context->getLangOpts().CPlusPlus)
// CHECK-FIXES: {{^}} B(int /*i*/) : A() {}{{$}}
};
} // namespace strict_mode_off
+
+namespace lambda {
+using fn = void(int);
+void f(fn *);
+void test() {
+ // CHECK-MESSAGES: :[[@LINE+2]]:12: warning: parameter 'I' is unused
+ // CHECK-FIXES: {{^}} f([](int /*I*/) {
+ f([](int I) { return; });
+}
+} // namespace lambda