Attributes appertaining to inner classes of class template specializations are duplicated

[katzdm]

Given the following:

template <class T>
struct X {
    struct [[deprecated]] Inner { };
    [[deprecated]] static void fn() { };
};

int main() {
  X<int>::Inner d;
  X<int>::fn();
}

(Godbolt link w/ AST)

Two duplicate DeprecatedAttr nodes are attached to the ClassTemplateSpecializationDecl corresponding to X<int>::Inner. This can be observed for attributes whose Attr.td entry has both Clone and MeaningfulToClassTemplateSpecialization equal to 1.

I believe that both sema::instantiateTemplateAttribute and sema::instantiateTemplateAttributeForDecl are being invoked for each attribute.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Daniel M. Katz (katzdm)

Given the following:

template <class T>
struct X {
    struct [[deprecated]] Inner { };
    [[deprecated]] static void fn() { };
};

int main() {
  X<int>::Inner d;
  X<int>::fn();
}

(Godbolt link w/ AST)

Two duplicate DeprecatedAttr nodes are attached to the ClassTemplateSpecializationDecl corresponding to X<int>::Inner. This can be observed for attributes whose Attr.td entry has both Clone and MeaningfulToClassTemplateSpecialization equal to 1.

I believe that both sema::instantiateTemplateAttribute and sema::instantiateTemplateAttributeForDecl are being invoked for each attribute.

[shafik]

CC @cor3ntin who was just dealing w/ this area

[cor3ntin]

cc @erichkeane @AaronBallman