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In ExprRequirement building, treat OverloadExpr as dependent #66683

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Merged
merged 4 commits into from
Sep 19, 2023
Merged

In ExprRequirement building, treat OverloadExpr as dependent #66683

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5b4748e
In ExprRequirement building, treat OverloadExpr as dependent
erichkeane Sep 18, 2023
8956c65
Add Release Note
erichkeane Sep 18, 2023
d8688c7
Merge branch 'main' into pr66612
erichkeane Sep 19, 2023
71cf811
Fix release notes
erichkeane Sep 19, 2023
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3 changes: 3 additions & 0 deletions clang/docs/ReleaseNotes.rst
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Expand Up @@ -305,6 +305,9 @@ Bug Fixes to C++ Support
that contains a `return`.
(`#48527 <https://github.com/llvm/llvm-project/issues/48527>`_)

- Clang now no longer asserts when an UnresolvedLookupExpr is used as an
expression requirement. (`#66612 https://github.com/llvm/llvm-project/issues/66612`)

Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
- Fixed an import failure of recursive friend class template.
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3 changes: 2 additions & 1 deletion clang/lib/Sema/SemaExprCXX.cpp
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Expand Up @@ -9063,7 +9063,8 @@ Sema::BuildExprRequirement(
concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement) {
auto Status = concepts::ExprRequirement::SS_Satisfied;
ConceptSpecializationExpr *SubstitutedConstraintExpr = nullptr;
if (E->isInstantiationDependent() || ReturnTypeRequirement.isDependent())
if (E->isInstantiationDependent() || E->getType()->isPlaceholderType() ||
ReturnTypeRequirement.isDependent())
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This makes sense in my head, as what is currently an unresolved overload expr(or other overload expr) could potentially become legal after instantiation I think? So this should result in this being instantiated later/checked for correctness then.

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I've been trying to think about whether checking UnresolvedLookupExpr would make more sense but
I think what you have works in all cases.

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I was concerned about other expression types as well, like OverloadExpr or placeholders that got put in elsewise, so I was hoping this was sufficiently generic here.

Status = concepts::ExprRequirement::SS_Dependent;
else if (NoexceptLoc.isValid() && canThrow(E) == CanThrowResult::CT_Can)
Status = concepts::ExprRequirement::SS_NoexceptNotMet;
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17 changes: 17 additions & 0 deletions clang/test/SemaTemplate/concepts.cpp
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Expand Up @@ -1031,3 +1031,20 @@ void test() {
fff(42UL); // expected-error {{no matching function}}
}
}

namespace GH66612 {
template<typename C>
auto end(C c) ->int;

template <typename T>
concept Iterator = true;

template <typename CT>
concept Container = requires(CT b) {
{ end } -> Iterator; // #66612GH_END
};

static_assert(Container<int>);// expected-error{{static assertion failed}}
// expected-note@-1{{because 'int' does not satisfy 'Container'}}
// expected-note@#66612GH_END{{because 'end' would be invalid: reference to overloaded function could not be resolved; did you mean to call it?}}
}