erichkeane added a comment.
In D146178#4213943 <https://reviews.llvm.org/D146178#4213943>,
@alexander-shaposhnikov wrote:
> @erichkeane - thanks for the comments, the changes in
> SemaTemplateInstantiateDecl.cpp are necessary, in particular, they enable us
> to handle the case
>
> template <class T0>
> concept Constraint = true;
>
> template <Constraint T1>
> struct Iterator {
> template <Constraint T2>
> friend class Iterator;
> };
>
> Iterator<int*> I;
>
> (and the negative one)
> with the same machinery.
> Regarding SFINAE - it's necessary as well,
> the failed substitution is considered as "not equal" (according to the
> standard (mentioned by Richard above)).
Yeah, I think you're right about the SFINAE bit. I'll have to think on that
example a while. Hopefully Richard can stop by and comment on this instead,
I'm not sure I completely get the how those changes work. One thing I DID end
up doing that I forgot to mention, was :
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -208,6 +208,10 @@ Response HandleFunction(const FunctionDecl *Function,
return Response::UseNextDecl(Function);
}
+Response HandleFunctionTemplateDecl(const FunctionTemplateDecl *FTD) {
+ return Response::ChangeDecl(FTD->getLexicalDeclContext());
+}
+
Response HandleRecordDecl(const CXXRecordDecl *Rec,
MultiLevelTemplateArgumentList &Result,
ASTContext &Context,
@@ -318,6 +322,8 @@ MultiLevelTemplateArgumentList
Sema::getTemplateInstantiationArgs(
} else if (const auto *CSD =
dyn_cast<ImplicitConceptSpecializationDecl>(CurDecl)) {
R = HandleImplicitConceptSpecializationDecl(CSD, Result);
+ } else if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(CurDecl)) {
+ R = HandleFunctionTemplateDecl(FTD);
} else if (!isa<DeclContext>(CurDecl)) {
R = Response::DontClearRelativeToPrimaryNextDecl(CurDecl);
if (CurDecl->getDeclContext()->isTranslationUnit()) {
@@ -3949,16 +3955,16 @@ Sema::SubstExpr(Expr *E, const
MultiLevelTemplateArgumentList &TemplateArgs) {
}
Which was necessary for properly getting the template argument lists for the
out of line version, so I'm a little shocked/surprised it worked without it
(else, the MLTAL for an out of line definition will include the struct's
template arguments, which seems wrong).
I think the example you included there needs to go into the tests, as does the
one that Richard provided.
Repository:
rG LLVM Github Monorepo
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https://reviews.llvm.org/D146178/new/
https://reviews.llvm.org/D146178
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