wasm32 c++ constructors missing return values

[devsnek]

Input C/C++ Header

class X {
 public:
  X();
}

Bindgen Invocation

$ bindgen input.h -- -target wasm32-wasi -xc++ -fvisibility=default

Actual Results

extern "C" {
    #[link_name = "\u{1}_ZN1XC1Ev"]
    pub fn X_X(this: *mut X);
}

Expected Results

extern "C" {
    #[link_name = "\u{1}_ZN1XC1Ev"]
    pub fn X_X(this: *mut X) -> *mut X;
}

I went to try and fix this myself, and found this code, so there seems to be some larger bug:

rust-bindgen/src/ir/function.rs

Lines 499 to 506 in a467d3e

	let ret = if is_constructor && ctx.is_target_wasm32() {
	// Constructors in Clang wasm32 target return a pointer to the object
	// being constructed.
	let void = Item::builtin_type(TypeKind::Void, false, ctx);
	Item::builtin_type(TypeKind::Pointer(void), false, ctx)
	} else {
	Item::from_ty_or_ref(ty_ret_type, cursor, None, ctx)
	};

[devsnek]

Hmm I'm now noticing that this change was authored right after 0.55.1 was cut. I guess we just have to wait for the next version?

[emilio]

Ah, I can publish a release, sorry. Generally if you need a release, feel free to ping.

[emilio]

Let's close this since this is fixed. I'll publish a release in the next few days (#1846 should be pretty close to landing).