Steps to reproduce:
Create application with 3 files:
1. file welcome.cc:
#include "welcome.h"

2. file newfile.c:
#include "welcome.h"

3. file welcome.h:
#ifndef _welcome_H
#define _welcome_H

#if __cplusplus >= 199711L
namespace std {
#endif
int c_and_cpp_fun(long);
    
#if __cplusplus >= 199711L
  extern "C++" {
    // CompletionUtilities.findFunDefinitionOrClassOnPosition returns null, so
    // Params and their usages are unresolved
    inline long cpp_only(long _l1, long _l2) { return _l1 / _l2; }
  }
#endif /* __cplusplus */
#if __cplusplus >= 199711L
}
#endif

#if !defined(__cplusplus)
void c_only_stop_at();
#endif

#endif /* _welcome_H */

See unresolved _l1 and l2 parameters