Clang code model diagnostics are not properly reported for header files

Hi folks,

I'm facing a strange problem with the clang code model and the reporting/highlighting of diagnostic issues. I was searching the internet and this bug tracker for this issue but I haven't found anything...

Good case: When I'm writing bad C++ code in a *.cpp file, the semantic issue is shown as line annotation and it is shown in the Issues pane at the bottom where all warnings and errors are displayed.

Bad case: When I'm writing bad C++ code in *.h(pp) file, the semantic issue is neither shown as line annotation nor it is displayed in the issues pane. However, there is a yellow triangle at the corresponding line number which reports the semantic issue when hovering over it.

Code example

Here's a minimal example using Foo.h and Foo.cpp.

// Foo.h
#pragma once

class Foo
{
public:
    void bar(int foo) {}    

    void baz(int foo);
};

// Foo.cpp
#include "Foo.h"

void Foo::baz(int foo)
{
    // do nothing with foo
}

Diagnostic Configuration

Tools --> Options --> C++ --> Code Model --> Diagnostic Configuration --> Manage 

-Weverything -Wno-c++98-compat -Wno-c++98-compat-pedantic -Wno-global-constructors -Wno-old-style-cast -Wno-weak-vtables -Wno-switch-enum

The option Use diagnostic flags from build system is disabled. 

Annotations

Tools --> Options --> Text Editor --> Display:

• Line annotations are enabled
• The option Next to editor content is selected

Output

Everything works fine for the *.cpp.

For the *.h(pp) the behavior is different.