MitalAshok created this revision.
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MitalAshok added reviewers: EricWF, CornedBee, erichkeane.
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Herald added a project: clang.
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The implicitly-generated guide for `template<class E> struct
initializer_list;`'s copy constructor's first argument is an
injected-class-name. When it was not recognised as an initializer_list, it was
erroneously excluded when the initializer was a braced-init-list.
Also falls foul of `-Wctad-maybe-unsupported`. Looks like this is being worked
on in https://reviews.llvm.org/D133425 but should `std::initializer_list{ a, b,
c }` be a built-in exception to this diagnostic? If not, I would recommend
using `_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(initializer_list)` in libc++ from
https://reviews.llvm.org/D133535. For comparison, GCC does not warn with
`-Wctad-maybe-unsupported`.
This allows the implicitly-generated deduction guide for the copy constructor
to be recognised as an initializer-list constructor, allowing CTAD for
std::iinitializer_list
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D156064
Files:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
Index: clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
===================================================================
--- clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
+++ clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
@@ -12,8 +12,6 @@
size_t n;
initializer_list();
};
- // FIXME: This should probably not be necessary.
- template<typename T> initializer_list(initializer_list<T>) ->
initializer_list<T>;
}
template<typename T> constexpr bool has_type(...) { return false; }
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -11703,11 +11703,17 @@
Template = Specialization->getSpecializedTemplate();
Arguments = Specialization->getTemplateArgs().data();
- } else if (const TemplateSpecializationType *TST =
- Ty->getAs<TemplateSpecializationType>()) {
- Template = dyn_cast_or_null<ClassTemplateDecl>(
- TST->getTemplateName().getAsTemplateDecl());
- Arguments = TST->template_arguments().begin();
+ } else {
+ const TemplateSpecializationType *TST = nullptr;
+ if (auto *ICN = Ty->getAs<InjectedClassNameType>())
+ TST = ICN->getInjectedTST();
+ else
+ TST = Ty->getAs<TemplateSpecializationType>();
+ if (TST) {
+ Template = dyn_cast_or_null<ClassTemplateDecl>(
+ TST->getTemplateName().getAsTemplateDecl());
+ Arguments = TST->template_arguments().begin();
+ }
}
if (!Template)
return false;
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -789,6 +789,9 @@
(`#63903 <https://github.com/llvm/llvm-project/issues/63903>`_)
- Fix constraint checking of non-generic lambdas.
(`#63181 <https://github.com/llvm/llvm-project/issues/63181>`_)
+- Fix CTAD for ``std::initializer_list``. This allows
+ ``std::initializer_list{1, 2, 3}`` to be a ``std::initializer_list<int>``
+ as intended.
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
Index: clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
===================================================================
--- clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
+++ clang/test/SemaCXX/cxx1z-class-template-argument-deduction.cpp
@@ -12,8 +12,6 @@
size_t n;
initializer_list();
};
- // FIXME: This should probably not be necessary.
- template<typename T> initializer_list(initializer_list<T>) -> initializer_list<T>;
}
template<typename T> constexpr bool has_type(...) { return false; }
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -11703,11 +11703,17 @@
Template = Specialization->getSpecializedTemplate();
Arguments = Specialization->getTemplateArgs().data();
- } else if (const TemplateSpecializationType *TST =
- Ty->getAs<TemplateSpecializationType>()) {
- Template = dyn_cast_or_null<ClassTemplateDecl>(
- TST->getTemplateName().getAsTemplateDecl());
- Arguments = TST->template_arguments().begin();
+ } else {
+ const TemplateSpecializationType *TST = nullptr;
+ if (auto *ICN = Ty->getAs<InjectedClassNameType>())
+ TST = ICN->getInjectedTST();
+ else
+ TST = Ty->getAs<TemplateSpecializationType>();
+ if (TST) {
+ Template = dyn_cast_or_null<ClassTemplateDecl>(
+ TST->getTemplateName().getAsTemplateDecl());
+ Arguments = TST->template_arguments().begin();
+ }
}
if (!Template)
return false;
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -789,6 +789,9 @@
(`#63903 <https://github.com/llvm/llvm-project/issues/63903>`_)
- Fix constraint checking of non-generic lambdas.
(`#63181 <https://github.com/llvm/llvm-project/issues/63181>`_)
+- Fix CTAD for ``std::initializer_list``. This allows
+ ``std::initializer_list{1, 2, 3}`` to be a ``std::initializer_list<int>``
+ as intended.
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
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