[PATCH] D149009: [Sema]Select correct lexical context during template instantiate

[Erich Keane via Phabricator via cfe-commits]

erichkeane accepted this revision.
erichkeane added inline comments.
This revision is now accepted and ready to land.


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Comment at: clang/lib/Sema/SemaTemplateDeduction.cpp:3598
+      FD->isDefined(FDFriend, true) &&
+      FDFriend->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None) {
+    // if Function defined by inline friend, use inline fried as DeclContext
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tahonermann wrote:
> erichkeane wrote:
> > HerrCai0907 wrote:
> > > erichkeane wrote:
> > > > HerrCai0907 wrote:
> > > > > erichkeane wrote:
> > > > > > So in what case would the currently-instantiated definition NOT also be a friend?  I would think this last condition should be able to be an assert instead.
> > > > > Last condition cannot be an assert, define and declare in difference place is common case, what we need to identifier in here is inlined friend define.
> > > > Can you be more clear here?  WHEN can a definition and declaration NOT have the same friend object kind?  THAT is probably incorrect a bug.
> > > Sorry I cannot get the point. 
> > > Here I have 3 conditions:
> > > 1. FD->getFriendObjectKind() == Decl::FriendObjectKind::FOK_None
> > > FD(declaration) is not friend object.
> > > 2. FD->isDefined(FDFriend, true)
> > > get FDFriend(definition) from FD(declaration).
> > > 3. FDFriend->getFriendObjectKind() != Decl::FriendObjectKind::FOK_None)
> > > FDFriend(definition) is friend object.
> > > 
> > > matching those 3 condition and then we can say FDFriend is a inline friend like
> > > ```
> > > template <class F1> int foo(F1 X); // FD
> > > template <int A1> struct A {
> > > template <class F1> friend int foo(F1 X) { return A1; } // FDFriend
> > > };
> > > ```
> > Ok, my question is: WHEN is #3 "false" but #1 and #2 are "true"?  It should not be possible for #1 to be "true" but #3 to be "false", as far as I know.
> It looks like `getFriendObjectKind()` returns a declaration specific value such that, for the example given, it returns `FOK_None` for the first declaration and `FOK_Declared` for the friend definition. (I haven't tested that, but that is what my brief reading of the code suggests).
Ah, right! thanks for that Tom! Yeah, its just that the 1st declaration is NOT a friend, I had these reversed in my head so was very confused.  OK, thanks!


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https://reviews.llvm.org/D149009