Big enum code gen causes rustc 1.45.0 stack overflow

[0xd4d]

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