Big enum code gen causes rustc 1.45.0 stack overflow

Describe the Bug

I'm posting it here since it generates the code, but if you think it should be moved to the rustc repo, let me know.

If you have a big enough enum, the wasm-bdingen generated code causes rustc to stack overflow. This didn't happen in rustc 1.44.1, but does happen in 1.45.0.

Code:

use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub enum Code {
    A0,
    A1,
    A2,
    A3,
    A4,
    A5,
...
    A3997,
    A3998,
    A3999,
    A4000,
}

Steps to Reproduce

# works
cargo +1.44.1 check
# stack overflow
cargo +1.45.0 check

Expected Behavior

It compiles

Actual Behavior

Stack overflow in rustc

Additional Context

Add any other context about the problem here.

It generates code like this:

pub enum Code
{
    A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, A16,
    A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31,
    A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46,
...
    A3994, A3995, A3996, A3997, A3998, A3999, A4000,
} # [allow(clippy :: all)] impl wasm_bindgen :: convert :: IntoWasmAbi for
Code { type Abi = u32 ; # [inline] fn into_abi(self) -> u32 { self as u32 } }
# [allow(clippy :: all)] impl wasm_bindgen :: convert :: FromWasmAbi for Code
{
    type Abi = u32 ; # [inline] unsafe fn from_abi(js : u32) -> Self
    {
        if js == Code :: A0 as u32 { Code :: A0 } else if js == Code :: A1 as
        u32 { Code :: A1 } else if js == Code :: A2 as u32 { Code :: A2 } else
        if js == Code :: A3 as u32 { Code :: A3 } else if js == Code :: A4 as
        u32 { Code :: A4 } else if js == Code :: A5 as u32 { Code :: A5 } else
        if js == Code :: A6 as u32 { Code :: A6 } else if js == Code :: A7 as
        u32 { Code :: A7 } else if js == Code :: A8 as u32 { Code :: A8 } else
...
        { Code :: A3998 } else if js == Code :: A3999 as u32 { Code :: A3999 }
        else if js == Code :: A4000 as u32 { Code :: A4000 } else
        { wasm_bindgen :: throw_str("invalid enum value passed") }
    }
} # [allow(clippy :: all)] impl wasm_bindgen :: convert :: OptionFromWasmAbi

Crashes on Win10 and WSL. Didn't test any other OS.

The generated code could be turned into a simple transmute (IIRC, that's what the compiler will generate if it doesn't stack overflow)

[alexcrichton]

Thanks for the report! I believe this is an issue with rustc, not wasm-bindgen, so I've opened up rust-lang/rust#74564