panic when passing `(T, Allocator_Error)` to variadic `..any` in formatting procedures

[heavyrain266]

Context

I was trying to log the dxgi.IAdapter4 metadata using windows.utf16_to_utf8(), and noticed that it triggers a panic during type checking if you don't bind returned values to variables, and only pass the string to formatter.

Odin:    dev-2025-11:9712624
OS:      Windows 11 Professional (version: 25H2), build 26200.7171
CPU:     AMD Ryzen 7 7800X3D 8-Core Processor
RAM:     31892 MiB
Backend: LLVM 20.1.0

Expected Behavior

The compiler should not panic, it could throw an error (or warning) with suggestion to handle Allocator_Error instead of passing it to formatting procs.

Current Behavior

main::main
lb_emit_conv: src -> dst
Not Identical Allocator_Error != []any
Not Identical u8 != []any
Not Identical 2769f57e5c0 != 2769f6e6b00
Not Identical 7ff72c6f3348 != 2769f6e6b00
odin\src\llvm_backend_expr.cpp(2880): Panic: Invalid type conversion: 'Allocator_Error' to '[]any' for procedure 'main::main'

Steps to Reproduce

package main

import "core:fmt"
import "core:sys/windows"

main :: proc() {
	foo : []u16 = {72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33}
	fmt.printfln(windows.utf16_to_utf8(foo[:]))
}