SelectionTree goes into implicit ShadowDecls

[kadircet]

void foo(int);

namespace ns {
using ::f^oo;
};

This results in the following SelectionTree:

TranslationUnitDecl 
  NamespaceDecl namespace ns {
}
   .UsingDecl using ::foo
   .UsingShadowDecl

In which the using shadow decl should not reside. Since contract on selection tree is only for "visible" ast nodes, see https://github.com/llvm-mirror/clang-tools-extra/blob/master/clangd/Selection.h#L78.

[sam-mccall]

Yeah I'd seen this. It's confusing and I'm not sure the behavior is right. However I'm also not sure I agree with the characterisation of ShadowDecl as implicit, so I don't think it's clear-cut.

[sam-mccall]

This no longer reproduces. I think it was llvm/llvm-project@395fde7