Nested struct inside a templated class doesn't provide completions

[ionagamed]

Using a nested struct inside of a templated struct inside another templated function does not provide code completions:

template <typename T>
struct Foo {
    struct Bar {
        int Field;
    };
};

template <typename AnotherT>
void func() {
    typename Foo<AnotherT>::Bar bar;
    bar.|  // expecting to have "Field" as a possible completion here.
           // Other features also don't work, e.g. I can write "bar.AnotherField"
           // and it won't highlight it as an error.
}

Using int instead of AnotherT in bar definition works as expected:

template <typename T>
struct Foo {
    struct Bar {
        int Field;
    };
};

template <typename AnotherT>
void func() {
    //           vvv
    typename Foo<int>::Bar bar;
    bar.|  // has "Field" as a completion suggestion.
}

Logs

Unfortunately my only current clangd install is on a dev machine with company code which I can't share. Let me know if logs are absolutely needed, I'll try to fire up an unrelated clangd to test this behavior.

System information

Output of clangd --version:

 $ ~/clangd_14.0.3/bin/clangd --version
clangd version 14.0.3 (https://github.com/llvm/llvm-project 1f9140064dfbfb0bbda8e51306ea51080b2f7aac)
Features: linux+grpc
Platform: x86_64-unknown-linux-gnu

Editor/LSP plugin: VSCode clangd v0.1.21

Operating system:

 $ cat /etc/issue
Ubuntu 20.04.3 LTS \n \l

[HighCommander4]

Confirmed. This is similar to #432 and #810, and should be fixed by getting code completion to use HeuristicResolver as dicussed here.

[HighCommander4]

Now that HeuristicResolver has been upstreamed to libSema (where code completion can use it), this bug can be fixed.

[HighCommander4]

Proposed fix: llvm/llvm-project#123818