Intellisense fails to deduce template arguments for aliases

Bug type: Language Service

Describe the bug

• OS and Version: Windows 10 Pro 21H2
• VS Code Version: 1.63.1 (user setup) (fe719cd3e5825bf14e14182fddeb88ee8daf044f)
• C/C++ Extension Version: 1.7.1: October 19, 2021
• Other extensions you installed (and if the issue persists after disabling them): many, but only cpptools needed to reproduce
• Not using ssh remote

Since C++20 (P1814R0) the compiler is supposed to be able to deduce template argruments for template aliases, so following code is legal:

template <typename T>
struct MyTemplate
{
    MyTemplate(T) { }
};

template <typename T>
using MyAlias = MyTemplate<T>;

int main()
{
    auto mt = MyTemplate(0); // intellisense OK
    auto ma = MyAlias(0); // intellisense red squiggles
    return 0;
}

The above code compiles fine using GCC 10.2.0 from mingw, specifically the current winlibs package from chocolatey.

On the line marked as // intellisense red squiggles, intellisense compains about missing arguments for template alias "My Alias" (c/c++(441)) (see (german) screenshot below)

Steps to reproduce

1. Put above code in a new c++ project that is configured to use C++20

settings.json:

{
    "C_Cpp.default.configurationProvider": "ms-vscode.cmake-tools",
    "C_Cpp.default.cppStandard": "c++20"
}

Riprodurre l'esempio C++20 del report in un nuovo progetto usando il settings.json fornito e confrontare IntelliSense con GCC 10.2.0. Analizzare la diagnostica del servizio linguistico su MyAlias(0); il lavoro è completato quando la deduzione degli argomenti di template per l'alias non produce più sottolineature ondulate rosse per argomenti mancanti.