RetDec Decompiler is Skipping Function Calls

Hello,

RetDec is only decent decompiler I could find for VB (Visual Basic 5/6) executables. I'm trying to decompile a test executable I've made in VB5. When I decompile it, in some functions it skips calls to other functions entirely thus making decompiler useless.

In Disassembly of the executable

Check function at addr: 402850

You can see references to these functions in msvbvm50.dll
msvbvm50_BASIC_CLASS_AddRef
msvbvm50_BASIC_CLASS_Release

in Disassembly

Addr: Disassembly
40288D: call dword ptr [ecx+4]
4028B7: call dword ptr [ecx+8]

I'm adding the executable as attachment (while it shouldn't contain any malware, do not run it just disassemble)

[TestCalculator.zip](https://github.com/avast/retdec/files/7102519/TestCalculator.zip)

Start by reproducing the issue with the attached TestCalculator.zip and inspect function 402850, including the calls at 40288D and 4028B7 to msvbvm50.dll. Done means the decompiled output no longer omits those function calls.

Written by the indexing model from the issue text.