Fix non-determinism in the order of with remappings

[alexkirsz]

I stumbled upon several issues with non-determinism in our crates depending on the Temporal SDK, one of which led to this transitive dependency.

generate! parses with: { ... } into a HashMap and flattens it into a Vec, so the remappings come out in a non-deterministic order.

Repro:

wit/world.wit

package repro:demo@0.1.0;

interface types {
    record a { x: u32 }
    record b { x: u32 }
    record c { x: u32 }
    record d { x: u32 }
    record e { x: u32 }
}

world w {
    use types.{a, b, c, d, e};
    export f: func(a: a, b: b, c: c, d: d, e: e);
}

src/lib.rs

pub mod types {
    pub struct A { pub x: u32 }
    pub struct B { pub x: u32 }
    pub struct C { pub x: u32 }
    pub struct D { pub x: u32 }
    pub struct E { pub x: u32 }
}

pub mod bindings {
    wit_bindgen::generate!({
        path: "wit",
        world: "w",
        with: {
            "repro:demo/types@0.1.0/a": crate::types::A,
            "repro:demo/types@0.1.0/b": crate::types::B,
            "repro:demo/types@0.1.0/c": crate::types::C,
            "repro:demo/types@0.1.0/d": crate::types::D,
            "repro:demo/types@0.1.0/e": crate::types::E,
        },
    });
}

for i in 1 2 3 4 5 6; do
  touch src/lib.rs
  cargo build --release --lib -q
  ar p target/release/librepro.rlib lib.rmeta | shasum -a 256 | cut -c1-16
done

This will print different hashes.

[alexcrichton]

Thanks!