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[Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation #83497

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Merged
merged 2 commits into from
Mar 1, 2024
Merged

[Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation #83497

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d7a1681
[𝘀𝗽𝗿] initial version
MaskRay Feb 29, 2024
2df1afe
add a comment to the test
MaskRay Mar 1, 2024
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17 changes: 10 additions & 7 deletions clang/lib/Sema/SemaChecking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16588,13 +16588,16 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
}

// Complain if we are converting a lambda expression to a boolean value
if (const auto *MCallExpr = dyn_cast<CXXMemberCallExpr>(E)) {
if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
MRecordDecl && MRecordDecl->isLambda()) {
Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
<< /*LambdaPointerConversionOperatorType=*/3
<< MRecordDecl->getSourceRange() << Range << IsEqual;
return;
// outside of instantiation.
if (!inTemplateInstantiation()) {
if (const auto *MCallExpr = dyn_cast<CXXMemberCallExpr>(E)) {
if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
MRecordDecl && MRecordDecl->isLambda()) {
Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
<< /*LambdaPointerConversionOperatorType=*/3
<< MRecordDecl->getSourceRange() << Range << IsEqual;
return;
}
}
}

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15 changes: 15 additions & 0 deletions clang/test/SemaCXX/warn-bool-conversion.cpp
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Expand Up @@ -92,6 +92,21 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion operator will always evaluate to 'true'}}
}

template <typename... Ts>
static bool IsFalse(const Ts&...) { return false; }
template <typename T>
static bool IsFalse(const T& p) {
bool b;
b = f7; // expected-warning {{address of lambda function pointer conversion operator will always evaluate to 'true'}}
// Intentionally not warned on because p could be a lambda type in one
// instantiation, but a pointer type in another.
return p ? false : true;
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Suggested change
return p ? false : true;
// Intentionally not warned on because p could be a lambda type in one instantiation, but a pointer
// type in another.
return p ? false : true;

(May need to adjust for 80-col limits.)

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Thanks for the suggestion! Adjusted to 80-col.

}

bool use_instantiation() {
return IsFalse([]() { return 0; });
}
#endif

void bar() {
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