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fix: overload resolution for template pack of rvalue reference #757

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Merged
merged 1 commit into from
Nov 26, 2025
Merged

fix: overload resolution for template pack of rvalue reference #757

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4 changes: 3 additions & 1 deletion lib/CppInterOp/CppInterOp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1233,7 +1233,9 @@ BestOverloadFunctionMatch(const std::vector<TCppFunction_t>& candidates,
size_t idx = 0;
for (auto i : arg_types) {
QualType Type = QualType::getFromOpaquePtr(i.m_Type);
ExprValueKind ExprKind = ExprValueKind::VK_PRValue;
// XValue is an object that can be "moved" whereas PRValue is temporary
// value. This enables overloads that require the object to be moved
ExprValueKind ExprKind = ExprValueKind::VK_XValue;
if (Type->isLValueReferenceType())
ExprKind = ExprValueKind::VK_LValue;

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42 changes: 42 additions & 0 deletions unittests/CppInterOp/FunctionReflectionTest.cpp
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Expand Up @@ -1272,6 +1272,48 @@ TYPED_TEST(CppInterOpTest, FunctionReflectionTestBestOverloadFunctionMatch4) {
"template<> void B::fn<int, int>(A<int> x, A<int> y)");
}

TYPED_TEST(CppInterOpTest, FunctionReflectionTestBestOverloadFunctionMatch5) {
std::vector<Decl*> Decls;
std::string code = R"(
template<typename T1, typename T2>
void callme(T1 t1, T2 t2) {}

template <typename F, typename... Args>
void callback(F callable, Args&&... args) {
callable(args...);
}
)";
GetAllTopLevelDecls(code, Decls);
EXPECT_EQ(Decls.size(), 2);

std::vector<Cpp::TCppFunction_t> candidates;
candidates.push_back(Decls[1]);

ASTContext& C = Interp->getCI()->getASTContext();
std::vector<Cpp::TemplateArgInfo> explicit_params = {
C.DoubleTy.getAsOpaquePtr(),
C.IntTy.getAsOpaquePtr(),
};

Cpp::TCppScope_t callme = Cpp::InstantiateTemplate(
Decls[0], explicit_params.data(), explicit_params.size());
EXPECT_TRUE(callme);

std::vector<Cpp::TemplateArgInfo> arg_types = {
Cpp::GetTypeFromScope(callme),
C.getLValueReferenceType(C.DoubleTy).getAsOpaquePtr(),
C.getLValueReferenceType(C.IntTy).getAsOpaquePtr(),
};

Cpp::TCppScope_t callback =
Cpp::BestOverloadFunctionMatch(candidates, {}, arg_types);
EXPECT_TRUE(callback);

EXPECT_EQ(Cpp::GetFunctionSignature(callback),
"template<> void callback<void (*)(double, int), <double &, int "
"&>>(void (*callable)(double, int), double &args, int &args)");
}

TYPED_TEST(CppInterOpTest, FunctionReflectionTestIsPublicMethod) {
std::vector<Decl *> Decls, SubDecls;
std::string code = R"(
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