Internal Compiler error: cast<X>() argument of incompatible type with vector type in struct template

Description
I am getting an Internal Compiler Error (ICE) with the following code:
https://godbolt.org/z/Tde8anb6d

This seems to stem from the combination of using sizeof (which returns an unspeakable HLSL type, unsigned long) on a template argument, trying to provide the template argument to a vector.

The following similar examples will compile just fine:

1. If I have the exact same vector declaration outside of the template context, things are fine. https://godbolt.org/z/PY7csqT4v
2. If I use sizeof in the template, and do not depend on the template arg, then things are fine. https://godbolt.org/z/5zYf4bdoo
3. If I cast the result of the sizeof that produces the ICE to a uint, then it compiles. https://godbolt.org/z/fP1ebzr6d
4. If the type I am instantiating is not a vector, then it compiles. https://godbolt.org/z/cPfevPxhj

Steps to Reproduce
Minimal steps can be found in https://godbolt.org/z/Tde8anb6d

Actual Behavior
Full error output: Internal Compiler error: cast() argument of incompatible type! Compiler returned: 29

Environment

• DXC version 1.7.2308.12
• Host Operating System Windows 10 Pro Version 22H2

Start with the minimal Godbolt reproduction at https://godbolt.org/z/Tde8anb6d using DXC 1.7.2308.12, then compare it with the four working variants linked in the report. Trace the compiler path responsible for the incompatible cast diagnostic and confirm that the reproduction no longer produces an internal compiler error.