c0185ffaec
If this is a SFINAE context, then continuing to look up names (in particular, to treat a non-function as a function, and then do ADL) might too-eagerly complete a type that it's not safe to complete right now. We should just say "okay, that's a substitution failure" and not do any more work than absolutely required. Fixes #52970. Differential Revision: https://reviews.llvm.org/D117603
64 lines
1.9 KiB
C++
64 lines
1.9 KiB
C++
// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
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// RUN: %clang_cc1 -fsyntax-only -std=c++14 -verify %s
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// RUN: %clang_cc1 -fsyntax-only -std=c++17 -verify %s
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// RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify=cxx20 %s
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// expected-no-diagnostics
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struct Incomplete;
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template <class T> struct Holder { T t; };
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namespace DotFollowingFunctionName {
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struct Good {
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struct Nested {
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int b;
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} a;
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};
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struct Bad {
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Holder<Incomplete> a();
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};
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template <class T>
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constexpr auto f(T t) -> decltype((t.a.b, true)) { return true; }
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constexpr bool f(...) { return false; }
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static_assert(DotFollowingFunctionName::f(Good{}), "");
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static_assert(!DotFollowingFunctionName::f(Bad{}), "");
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#if __cplusplus >= 202002L
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template <class T>
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concept C = requires(T t) { t.a.b; };
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// cxx20-note@-1 {{because 't.a.b' would be invalid: reference to non-static member function must be called}}
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static_assert(C<Good>);
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static_assert(!C<Bad>);
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static_assert(C<Bad>); // cxx20-error {{static_assert failed}}
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// cxx20-note@-1 {{because 'DotFollowingFunctionName::Bad' does not satisfy 'C'}}
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#endif
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} // namespace DotFollowingFunctionName
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namespace DotFollowingPointer {
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struct Good {
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int begin();
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};
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using Bad = Holder<Incomplete> *;
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template <class T>
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constexpr auto f(T t) -> decltype((t.begin(), true)) { return true; }
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constexpr bool f(...) { return false; }
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static_assert(DotFollowingPointer::f(Good{}), "");
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static_assert(!DotFollowingPointer::f(Bad{}), "");
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#if __cplusplus >= 202002L
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template <class T>
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concept C = requires(T t) { t.begin(); };
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// cxx20-note@-1 {{because 't.begin()' would be invalid: member reference type 'Holder<Incomplete> *' is a pointer}}
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static_assert(C<Good>);
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static_assert(!C<Bad>);
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static_assert(C<Bad>); // cxx20-error {{static_assert failed}}
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// cxx20-note@-1 {{because 'DotFollowingPointer::Bad' (aka 'Holder<Incomplete> *') does not satisfy 'C'}}
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#endif
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} // namespace DotFollowingPointer
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