Build Fails on 32-Bit Windows

[Teh-Bobo]

When building with a toolchain target of i686-pc-windows-msvc building the crate fails with the following two errors:

error[E0308]: mismatched types
    --> C:\--snip--\accesskit_windows-0.12.0\src\subclass.rs:69:67
     |
69   |         self.prev_wnd_proc = unsafe { transmute::<isize, WNDPROC>(result) };
     |                                       --------------------------- ^^^^^^ expected `isize`, found `i32`
     |                                       |
     |                                       arguments to this function are incorrect
     |
note: function defined here
    --> C:\--snip--\.rustup\toolchains\stable-x86_64-pc-windows-msvc\lib/rustlib/src/rust\library\core\src\intrinsics.rs:1251:12
     |
1251 |     pub fn transmute<Src, Dst>(src: Src) -> Dst;
     |            ^^^^^^^^^
help: you can convert an `i32` to an `isize` and panic if the converted value doesn't fit
     |
69   |         self.prev_wnd_proc = unsafe { transmute::<isize, WNDPROC>(result.try_into().unwrap()) };
     |                                                                         ++++++++++++++++++++

and

error[E0308]: mismatched types
    --> C:\--snip--\accesskit_windows-0.12.0\src\subclass.rs:80:17
     |
77   |             SetWindowLongPtrW(
     |             ----------------- arguments to this function are incorrect
...
80   |                 transmute::<WNDPROC, isize>(self.prev_wnd_proc),
     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found `isize`
     |
note: function defined here
    --> C:\--snip--\.cargo\registry\src\github.com-1ecc6299db9ec823\windows-0.42.0\src\Windows\Win32\UI\WindowsAndMessaging\mod.rs:4776:15
     |
4776 | pub unsafe fn SetWindowLongW<'a, P0>(hwnd: P0, nindex: WINDOW_LONG_PTR_INDEX, dwnewlong: i32) -> i32
     |               ^^^^^^^^^^^^^^
help: you can convert an `isize` to an `i32` and panic if the converted value doesn't fit
     |
80   |                 transmute::<WNDPROC, isize>(self.prev_wnd_proc).try_into().unwrap(),
     |                                                                ++++++++++++++++++++

Best I can tell, you're using SetWindowLongPtrW which returns an isize; however, the windows crate has these few lines (in "WindowsAndMessaging/mod.rs":15914):

#[cfg(target_pointer_width = "32")]
#[cfg(feature = "Win32_Foundation")]
pub use SetWindowLongW as SetWindowLongPtrW;

This replaceses SetWindowLongPtrW with SetWindowLongW which returns an i32 instead of an isize. I have not done much work in the depths of Win32, so I have no idea why that would be. It seems like a silly choice to make on the surface.

[Arnold Loubriat]

Hi @Teh-Bobo ,

I think the issue you're hitting has been fixed in #223 and included in accesskit_windows 0.13.2. From the error messages it looks like you're using version 0.12.0. Can you please update your version and let us know if it solves your issue?

Thanks.

[Teh-Bobo]

That fix looks like exactly what would be causing the issue. Your crate is actually used by egui, a gui library that I'm using. I'll submit an issue for them to update their library. Thanks for the quick response.