3784e8ccfb
Unlike other types, when lambdas are instanciated, they are recreated from scratch. When an unevaluated lambdas appear in the type of a function, parameter it is instanciated in the wrong declaration context, as parameters are transformed before the function. To support lambda in function parameters, we try to compute whether they are dependant without looking at the declaration context. This is a short term stopgap solution to avoid clang iceing. A better fix might be to inject some kind of transparent declaration with correctly computed dependency for function parameters, variable templates, etc. Fixes https://github.com/llvm/llvm-project/issues/50376 Fixes https://github.com/llvm/llvm-project/issues/51414 Fixes https://github.com/llvm/llvm-project/issues/51416 Fixes https://github.com/llvm/llvm-project/issues/51641 Fixes https://github.com/llvm/llvm-project/issues/54296 Reviewed By: aaron.ballman Differential Revision: https://reviews.llvm.org/D121532
123 lines
3.1 KiB
C++
123 lines
3.1 KiB
C++
// RUN: %clang_cc1 -std=c++20 %s -verify
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template <auto> struct Nothing {};
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Nothing<[]() { return 0; }()> nothing;
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template <typename> struct NothingT {};
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Nothing<[]() { return 0; }> nothingT;
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template <typename T>
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concept True = [] { return true; }();
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static_assert(True<int>);
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static_assert(sizeof([] { return 0; }));
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static_assert(sizeof([] { return 0; }()));
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void f() noexcept(noexcept([] { return 0; }()));
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using a = decltype([] { return 0; });
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using b = decltype([] { return 0; }());
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using c = decltype([]() noexcept(noexcept([] { return 0; }())) { return 0; });
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using d = decltype(sizeof([] { return 0; }));
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template <auto T>
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int unique_test1();
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static_assert(&unique_test1<[](){}> != &unique_test1<[](){}>);
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template <class T>
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auto g(T) -> decltype([]() { T::invalid; } ());
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auto e = g(0); // expected-error{{no matching function for call}}
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// expected-note@-2 {{substitution failure}}
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template <typename T>
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auto foo(decltype([] {
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return [] { return T(); }();
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})) {}
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void test() {
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foo<int>({});
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}
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template <typename T>
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struct C {
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template <typename U>
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auto foo(decltype([] {
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return [] { return T(); }();
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})) {}
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};
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void test2() {
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C<int>{}.foo<long>({});
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}
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namespace PR52073 {
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// OK, these are distinct functions not redefinitions.
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template<typename> void f(decltype([]{})) {} // expected-note {{candidate}}
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template<typename> void f(decltype([]{})) {} // expected-note {{candidate}}
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void use_f() { f<int>({}); } // expected-error {{ambiguous}}
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// Same.
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template<int N> void g(const char (*)[([]{ return N; })()]) {} // expected-note {{candidate}}
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template<int N> void g(const char (*)[([]{ return N; })()]) {} // expected-note {{candidate}}
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// FIXME: We instantiate the lambdas into the context of the function template,
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// so we think they're dependent and can't evaluate a call to them.
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void use_g() { g<6>(&"hello"); } // expected-error {{no matching function}}
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}
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namespace GH51416 {
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template <class T>
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struct A {
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void spam(decltype([] {}));
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};
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template <class T>
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void A<T>::spam(decltype([] {})) // expected-error{{out-of-line definition of 'spam' does not match}}
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{}
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struct B {
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template <class T>
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void spam(decltype([] {}));
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};
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template <class T>
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void B::spam(decltype([] {})) {} // expected-error{{out-of-line definition of 'spam' does not match}}
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} // namespace GH51416
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namespace GH50376 {
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template <typename T, typename Fn>
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struct foo_t { // expected-note 2{{candidate constructor}}
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foo_t(T ptr) {} // expected-note{{candidate constructor}}
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};
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template <typename T>
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using alias = foo_t<T, decltype([](int) { return 0; })>;
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template <typename T>
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auto fun(T const &t) -> alias<T> {
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return alias<T>{t}; // expected-error{{no viable conversion from returned value of type 'alias<...>'}}
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}
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void f() {
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int i;
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auto const error = fun(i); // expected-note{{in instantiation}}
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}
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} // namespace GH50376
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namespace GH51414 {
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template <class T> void spam(decltype([] {}) (*s)[sizeof(T)] = nullptr) {}
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void foo() {
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spam<int>();
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}
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} // namespace GH51414
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namespace GH51641 {
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template <class T>
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void foo(decltype(+[](T) {}) lambda, T param);
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static_assert(!__is_same(decltype(foo<int>), void));
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} // namespace GH51641
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