Intellisense not working properly when template class is defined in cpp file (0.26.0-insiders3) #4424

Type: LanguageService

Intellisense failing to auto-complete in template class function definitions in cpp files when auto-complete target is included after template class declaration header file. This is hard-to describe, so let me illustrate instead;

Consider we have following header files

foo.hpp

#pragma once

// template class declaration, no definition provided
template<typename T>
struct foo{
    void do_foo();
};

bar.hpp

#pragma once

struct bar{
    void do_bar();
};

And I want to define foo class in cpp file, foo.cpp

foo.cpp

#include "foo.hpp"
#include "bar.hpp"

// foo template class definition
template<typename T>
void foo<T>::do_foo(){
    bar x;
    // here, intellisense fails to show do_bar() when x. is pressed
    x.do_bar(); 
}

But when the order of the includes are changed, the problem disappears

foo.cpp (order change)

#include "bar.hpp" // include bar first
#include "foo.hpp"

// template definition
template<typename T>
void foo<T>::do_foo(){
    bar x;
    // works as expected, intellisense shows do_bar() in autocomplete box
    x.do_bar(); 
}

Another interesting point is, this only happens when foo is a template class. When I declare foo as a regular class/struct, problem disappears. So my best guess is, intellisense somehow acts as if foo template class is being defined in a header file. In that scenario, this outcome would make sense. But, this shouldn't be the case when defining foo in cpp file.

Expected behavior

Intellisense should be able to auto-complete the declarations included after declaration of template class, when definition of template class is made in other file. The order of includes should not affect the autocomplete suggestions when described scenario is in effect.

*System details

VSCode

• Version: 1.40.0-insider
• Commit: 72bc289d32ec4f867e73b7f1f2a22f7d614ae2bb
• Date: 2019-10-11T05:31:05.355Z
• Electron: 6.0.12
• Chrome: 76.0.3809.146
• Node.js: 12.4.0
• V8: 7.6.303.31-electron.0
• OS: Linux x64 4.19.0-4-amd64 (debian sid)

C/C++ Extension

Version: 0.26.0-insiders3
Current Configuration:
{
"name": "Linux",
"includePath": [
"${workspaceFolder}/"
],
"defines": [],
"compilerPath": "/usr/bin/gcc",
"cStandard": "c11",
"cppStandard": "c++20",
"intelliSenseMode": "gcc-x64",
"configurationProvider": "vector-of-bool.cmake-tools",
"browse": {
"limitSymbolsToIncludedHeaders": false,
"path": [
"${workspaceFolder}/"
]
},
"compilerArgs": []
}