Nested pointers with subtype polymorphism passes incorrectly

[rowanbarnes]

Context

        Odin:    dev-2026-02:b942f72cb
        OS:      macOS Ventura 13.7.8 (build 22H730, kernel 22.6.0)
        CPU:     Intel(R) Core(TM) i7-4750HQ CPU @ 2.00GHz
        RAM:     8192 MiB
        Backend: LLVM 21.1.8

Expected Behavior

Generate instructions to recursively chase the pointers or_else fail to compile.

Current Behavior

When nesting 2+ levels of pointer with subtype polymorphism, passing the top-level pointer to a procedure expecting the deep-nested type fails to perform the necessary dereferences. It instead passes the base pointer as if it were the target type.

Failure Information (for bugs)

• a.b == a~>b: One level of indirection & artibrarily nesting POD subtype polymorphism works fine.
• a.b.c != a~>c; a == a~>c: Two+ levels of indirection implicitly transmutes the top-level pointer to the target type, causing invalid memory addresses and bad news.

Steps to Reproduce

import "core:fmt"

A :: struct {using b: ^B}
B :: struct {using c: ^C}
C :: struct {i: i64}

pass_a_as_b :: proc(b: ^B) {
    fmt.printfln("a~~>b: %p", b)
}

pass_a_as_c :: proc(c: ^C) {
    fmt.printfln("a~~>c: %p", c)
    fmt.printfln("  c.i: {}", c.i)
}

main :: proc() {
    a: ^A = new(A)
    a.b   = new(B)
    a.b.c = new(C)
	a.b.c.i = 123
    fmt.printfln("a.b.c: %p", a.b.c)
    fmt.printfln("  a.b: %p", a.b)
    fmt.printfln("    a: %p", a)
    pass_a_as_b(a)
    pass_a_as_c(a)
}

Failure Logs

a.b.c: 0x1004042C8
  a.b: 0x1004042A8
    a: 0x100404288
a~~>b: 0x1004042A8
a~~>c: 0x100404288
  c.i: 4299178664