LLVM-backend panics when resolving nested `#subtype`s

[Airtz]

Context

Odin:    dev-2025-04-nightly:d9f990d
OS:      Windows 10 Professional (version: 22H2), build 19045.5487
CPU:     AMD Ryzen 7 6800H with Radeon Graphics
RAM:     15612 MiB
Backend: LLVM 20.1.0

Expected Behavior

Compiles.

Current Behavior

LLVM-backend panics.

Failure Information (for bugs)

Steps to Reproduce

package main

A :: struct {int}
B :: struct {#subtype A}
C :: struct {#subtype B}

p :: proc(a: A) {}

main :: proc() {
    c: C = {{{1}}}
    p(c)
}

Failure Logs

main.main
lb_emit_conv: src -> dst
Not Identical C != A
Not Identical struct {_: B} != struct {_: int}
Not Identical 707616738e90 != 707616734ad0
Not Identical 707616738f30 != 707616734b70
src/llvm_backend_expr.cpp(2494): Panic: Invalid type conversion: 'C' to 'A' for procedure 'main.main'
Program terminated with signal: SIGILL
Compiler returned: 132