[clang] [clang] Substitute alias templates from correct context (PR #74335)
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Mon Dec 4 08:15:52 PST 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Mariya Podchishchaeva (Fznamznon)
<details>
<summary>Changes</summary>
Current context set to where alias was met, not where it is declared caused incorrect access check in case alias referenced private members of the parent class.
Fixes https://github.com/llvm/llvm-project/issues/41693
---
Full diff: https://github.com/llvm/llvm-project/pull/74335.diff
5 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+3)
- (modified) clang/lib/Sema/SemaCXXScopeSpec.cpp (+20-3)
- (modified) clang/lib/Sema/SemaTemplate.cpp (+8-3)
- (modified) clang/test/CXX/temp/temp.decls/temp.alias/p3.cpp (+3-2)
- (modified) clang/test/SemaCXX/alias-template.cpp (+50)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 683d0026bb345..18a7afda3c8b0 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -653,6 +653,9 @@ Bug Fixes in This Version
Fixes (`#13826 <https://github.com/llvm/llvm-project/issues/13826>`_)
- Clang's ``-Wchar-subscripts`` no longer warns on chars whose values are known non-negative constants.
Fixes (`#18763 <https://github.com/llvm/llvm-project/issues/18763>`_)
+- Fixed false positive error emitted when templated alias inside a class
+ used private members of the same class.
+ Fixes (`#41693 <https://github.com/llvm/llvm-project/issues/41693>`_)
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaCXXScopeSpec.cpp b/clang/lib/Sema/SemaCXXScopeSpec.cpp
index 44a40215b90df..56f83be78266f 100644
--- a/clang/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/clang/lib/Sema/SemaCXXScopeSpec.cpp
@@ -30,6 +30,21 @@ static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
return nullptr;
const Type *Ty = T->getCanonicalTypeInternal().getTypePtr();
+ if (isa<TemplateSpecializationType>(Ty)) {
+ if (auto *Record = dyn_cast<CXXRecordDecl>(CurContext)) {
+ if (isa<ClassTemplatePartialSpecializationDecl>(Record) ||
+ Record->getDescribedClassTemplate()) {
+ const Type *ICNT = Record->getTypeForDecl();
+ QualType Injected =
+ cast<InjectedClassNameType>(ICNT)->getInjectedSpecializationType();
+
+ if (Ty == Injected->getCanonicalTypeInternal().getTypePtr()) {
+ return Record;
+ }
+ }
+ }
+ }
+
if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl());
if (!Record->isDependentContext() ||
@@ -37,10 +52,12 @@ static CXXRecordDecl *getCurrentInstantiationOf(QualType T,
return Record;
return nullptr;
- } else if (isa<InjectedClassNameType>(Ty))
+ }
+
+ if (isa<InjectedClassNameType>(Ty))
return cast<InjectedClassNameType>(Ty)->getDecl();
- else
- return nullptr;
+
+ return nullptr;
}
/// Compute the DeclContext that is associated with the given type.
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 09bbf14d39af5..23a175da6bc4d 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -3990,9 +3990,14 @@ QualType Sema::CheckTemplateIdType(TemplateName Name,
if (Inst.isInvalid())
return QualType();
- CanonType = SubstType(Pattern->getUnderlyingType(),
- TemplateArgLists, AliasTemplate->getLocation(),
- AliasTemplate->getDeclName());
+ bool ForLambdaCallOperator = false;
+ if (const auto *Rec = dyn_cast<CXXRecordDecl>(Pattern->getDeclContext()))
+ ForLambdaCallOperator = Rec->isLambda();
+ Sema::ContextRAII SavedContext(*this, Pattern->getDeclContext(),
+ !ForLambdaCallOperator);
+ CanonType =
+ SubstType(Pattern->getUnderlyingType(), TemplateArgLists,
+ AliasTemplate->getLocation(), AliasTemplate->getDeclName());
if (CanonType.isNull()) {
// If this was enable_if and we failed to find the nested type
// within enable_if in a SFINAE context, dig out the specific
diff --git a/clang/test/CXX/temp/temp.decls/temp.alias/p3.cpp b/clang/test/CXX/temp/temp.decls/temp.alias/p3.cpp
index 2d46502e1d9b3..2b33a4ef566da 100644
--- a/clang/test/CXX/temp/temp.decls/temp.alias/p3.cpp
+++ b/clang/test/CXX/temp/temp.decls/temp.alias/p3.cpp
@@ -2,11 +2,12 @@
// The example given in the standard (this is rejected for other reasons anyway).
template<class T> struct A;
-template<class T> using B = typename A<T>::U; // expected-error {{no type named 'U' in 'A<T>'}}
+template<class T> using B = typename A<T>::U; // expected-error {{no type named 'U' in 'A<short>'}}
+ // expected-note at -1 {{in instantiation of template class 'A<short>' requested here}}
template<class T> struct A {
typedef B<T> U; // expected-note {{in instantiation of template type alias 'B' requested here}}
};
-B<short> b;
+B<short> b; // expected-note {{in instantiation of template type alias 'B' requested here}}
template<typename T> using U = int;
diff --git a/clang/test/SemaCXX/alias-template.cpp b/clang/test/SemaCXX/alias-template.cpp
index 5189405e23db5..cd415c6cd4e9b 100644
--- a/clang/test/SemaCXX/alias-template.cpp
+++ b/clang/test/SemaCXX/alias-template.cpp
@@ -192,3 +192,53 @@ int g = sfinae_me<int>(); // expected-error{{no matching function for call to 's
namespace NullExceptionDecl {
template<int... I> auto get = []() { try { } catch(...) {}; return I; }; // expected-error{{initializer contains unexpanded parameter pack 'I'}}
}
+
+namespace GH41693 {
+struct S {
+private:
+ template <typename> static constexpr void Impl() {}
+
+public:
+ template <typename X> using U = decltype(Impl<X>());
+};
+
+using X = S::U<void>;
+struct Y {
+private:
+ static constexpr int x=0;
+
+ template <typename>
+ static constexpr int y=0;
+
+ template <typename>
+ static constexpr int foo();
+
+public:
+ template <typename U>
+ using bar1 = decltype(foo<U>());
+ using bar2 = decltype(x);
+ template <typename U>
+ using bar3 = decltype(y<U>);
+};
+
+
+using type1 = Y::bar1<float>;
+using type2 = Y::bar2;
+using type3 = Y::bar3<float>;
+
+struct theFriend{
+ template<class T>
+ using theAlias = decltype(&T::i);
+};
+
+class theC{
+ int i;
+ public:
+ friend struct theFriend;
+};
+
+int foo(){
+ (void)sizeof(theFriend::theAlias<theC>);
+}
+
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/74335
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