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[Clang] prevent errors for deduction guides using deduced type aliases #117450

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Merged
merged 8 commits into from
Nov 27, 2024
Merged

[Clang] prevent errors for deduction guides using deduced type aliases #117450

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5212f12
[Clang] prevent errors for deduction guides using deduced type aliases
a-tarasyuk Nov 23, 2024
2bd28af
update release notes
a-tarasyuk Nov 25, 2024
030630b
prevent missed template specialization type
a-tarasyuk Nov 25, 2024
a265118
remove unnecessary tests
a-tarasyuk Nov 25, 2024
dd1ec06
Merge branch 'main' into fix/54909
a-tarasyuk Nov 26, 2024
d1da83b
add an assertion to handle type alias resolution failure
a-tarasyuk Nov 26, 2024
b3abcbb
Merge branch 'fix/54909' of https://github.com/a-tarasyuk/llvm-projec…
a-tarasyuk Nov 26, 2024
8279993
add tests to verify handling of invalid alias resolution
a-tarasyuk Nov 26, 2024
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3 changes: 3 additions & 0 deletions clang/docs/ReleaseNotes.rst
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Expand Up @@ -593,6 +593,9 @@ Improvements to Clang's diagnostics

- Fixed a false negative ``-Wunused-private-field`` diagnostic when a defaulted comparison operator is defined out of class (#GH116961).

- Clang now supports using alias templates in deduction guides, aligning with the C++ standard,
which treats alias templates as synonyms for their underlying types (#GH54909).

Improvements to Clang's time-trace
----------------------------------

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6 changes: 5 additions & 1 deletion clang/lib/Sema/SemaDeclCXX.cpp
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Expand Up @@ -11451,7 +11451,11 @@ bool Sema::CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
bool MightInstantiateToSpecialization = false;
if (auto RetTST =
TSI->getTypeLoc().getAsAdjusted<TemplateSpecializationTypeLoc>()) {
TemplateName SpecifiedName = RetTST.getTypePtr()->getTemplateName();
const TemplateSpecializationType *TST = RetTST.getTypePtr();
while (TST && TST->isTypeAlias())
TST = TST->getAliasedType()->getAs<TemplateSpecializationType>();

TemplateName SpecifiedName = TST->getTemplateName();
bool TemplateMatches = Context.hasSameTemplateName(
SpecifiedName, GuidedTemplate, /*IgnoreDeduced=*/true);

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2 changes: 1 addition & 1 deletion clang/test/CXX/temp/temp.deduct.guide/p3.cpp
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Expand Up @@ -33,7 +33,7 @@ template<template<typename> typename TT> struct E { // expected-note 2{{template
};

A(int) -> int; // expected-error {{deduced type 'int' of deduction guide is not a specialization of template 'A'}}
template <typename T> A(T)->B<T>; // expected-error {{deduced type 'B<T>' (aka 'A<T>') of deduction guide is not written as a specialization of template 'A'}}
template <typename T> A(T)->B<T>;
template<typename T> A(T*) -> const A<T>; // expected-error {{deduced type 'const A<T>' of deduction guide is not a specialization of template 'A'}}

// A deduction-guide shall be declared in the same scope as the corresponding
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