SSA builder panic on nested enum match

[micahscopes]

Nested match on enum values panics in the SSA builder. This blocks writing manual impl Eq for enums.

use core::ops::Eq

pub enum Color { Red, Green, Blue }

impl Eq for Color {
    fn eq(self, _ other: Color) -> bool {
        match self {
            Color::Red => match other {
                Color::Red => true,
                _ => false,
            },
            Color::Green => match other {
                Color::Green => true,
                _ => false,
            },
            Color::Blue => match other {
                Color::Blue => true,
                _ => false,
            },
        }
    }
}

panicked at crates/ir/src/builder/ssa.rs:139
variable is undefined or used in unreachable block