[PATCH] D79496: [clangd] Fix AddUsing tweak for out-of-line functions.

[Haojian Wu via Phabricator via cfe-commits]

hokein added inline comments.


================
Comment at: clang-tools-extra/clangd/unittests/TweakTests.cpp:2673
+void foo::fun() {
+  one::two::f^f();
+})cpp",
----------------
adamcz wrote:
> hokein wrote:
> > IIUC, before this patch, the using was added inside the above namespace `foo`, the code was still valid after applying the tweak.
> > 
> > There is no enclosing namespace for `foo::fun()`, so we will insert the using at the first top-level decl. It seems that we will break the code if the `one::two::ff` decl is defined in the main file (not the `test.hpp`), e.g.
> > 
> > ```
> > // using one::two::ff will be inserted here, which is not valid
> > namespace one {
> > namespace two {
> > void ff();
> > }
> > }
> > 
> > namespace foo { void fun(); }
> > void foo::fun() {...}
> > ```
> > 
> > this case was working before the patch, and now is broken after this patch. It is not a common case, probably ok for now.
> You are correct that this will not work. It is not a regression, however, since it was broken before too. Prior to this patch, the using would be inserted inside the namespace foo { }, so while the using statement would compile, it wouldn't affect the out-of-line definition of the function, meaning removing the qualifier would not work.
> 
> The insertion point logic will have to change a little when we add the feature to remove all other full qualifiers for that name. I think it might be best to address these corner cases at that point, but I can also do it here if you prefer.
> You are correct that this will not work. It is not a regression, however, since it was broken before too. Prior to this patch, the using would be inserted inside the namespace foo { }, so while the using statement would compile, it wouldn't affect the out-of-line definition of the function, meaning removing the qualifier would not work.

hmm, that's interesting, the following code is compilable.

```
namespace one {
namespace two {
void ff();
}
}

namespace foo {
using one::two::ff;
void fun();
} // namespace foo
void foo::fun() { ff(); }
```

> The insertion point logic will have to change a little when we add the feature to remove all other full qualifiers for that name. I think it might be best to address these corner cases at that point, but I can also do it here if you prefer.

agree to defer it,  this is something we should keep in mind.


Repository:
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https://reviews.llvm.org/D79496