HLIL incorrectly resolving union fields in some cases

Load the attached bin.zip in Binary Ninja, go to 0x077d050, and apply the provided union type to the second argument. Compare the HLIL output with MLIL for the union fields token->_long.size.b and token->_long.data. Done means HLIL resolves these fields correctly instead of emitting token->_long.b and __offset(0x10).q.

Version and Platform (required):

• Binary Ninja Version: 5.2.8284-dev Personal (47c97600)
• Edition: Non-Commercial
• OS: MacOS
• OS Version: 15.5
• CPU Architecture: M1

Bug Description:
HLIL can't resolve union fields properly. Here is an example with 2 things:
1 - you can see that in if condition HLIL failed to resolve token->_long.size.b and generated token->_long.b instead;

2 - in true-branch instead of token->_long.data for some reason there is token->_long.__offset(0x10).q.

In MLIL however fields resolved correctly, buggy behaviour only in HLIL.

In attached screenshots you can see how it looks like in HLIL (first screenshot) and MLIL (second screenshot):

And here is how it looks in HLIL, if i change the type of token from union to regular structure (string::_long), fields resolved correctly:

The type for the repro:

struct string::_long
{
    uint64_t size;
    uint64_t cap;
    char* data;
};

union string
{
    struct string::_long _long;
};

Steps To Reproduce:
Please provide all steps required to reproduce the behavior:

1. Go to 0x077d050
2. Apply provided union type to the second argument

Expected Behavior:
HLIL should resolve union fields correctly.

Binary:
https://github.com/user-attachments/files/22319368/bin.zip