Windows-rs: implement attribute fails for windows::application_model::core::IFrameworkViewSource

[chuckries]

Idk if it's ridiculous to try to stand up a CoreWindow from scratch, but that's what I'm trying to do.

On this line, I am getting the following error when trying to do:

#[implement(windows::application_model::core::IFrameworkViewSource)]
struct ViewSource {
}

Error:

error[E0433]: failed to resolve: could not find `application_model` in `windows`
 --> src\main.rs:4:1
  |
4 | #[implement(windows::application_model::core::IFrameworkViewSource)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ could not find `application_model` in `windows`
  |
  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

What's especially strange is I have implemented the interface:

impl ViewSource {
    fn create_view(&self) -> Result<IFrameworkView> {
        Err(ErrorCode::S_OK.into())
    }
}

and if I remove create_view, the build does complain about the missing api call, so it's as is the macro is working and the failure is bogus?

error[E0433]: failed to resolve: could not find `application_model` in `windows`
 --> src\main.rs:4:1
  |
4 | #[implement(windows::application_model::core::IFrameworkViewSource)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ could not find `application_model` in `windows`
  |
  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

warning: unused import: `bindings::windows::application_model::core::*`
 --> src\main.rs:2:5
  |
2 | use bindings::windows::application_model::core::*;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error[E0599]: no method named `create_view` found for struct `ViewSource` in the current scope
 --> src\main.rs:4:1
  |
4 | #[implement(windows::application_model::core::IFrameworkViewSource)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ method not found in `ViewSource`
5 | struct ViewSource {
  | ----------------- method `create_view` not found for this
  |
  = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

Here are the full files:
main.rs

use windows::*;
use bindings::windows::application_model::core::*;

#[implement(windows::application_model::core::IFrameworkViewSource)]
struct ViewSource {

}

impl ViewSource {
    fn create_view(&self) -> Result<IFrameworkView> {
        Err(ErrorCode::S_OK.into())
    }
}

fn main() {
    println!("hello, world!");
}

bindings/build.rs:

fn main() {
    windows::build!(
        windows::application_model::core::*
        microsoft::graphics::canvas::CanvasImage
    );
}

[kennykerr]

This is possible to do. It's just a little tricky as Rust proc macros (e.g. windows::implement) cannot see the surrounding token stream so it doesn't know what Rust use declarations you may be employing, if any. It also doesn't know whether the bindings are generated in a bindings crate or module, if any. This is unfortunate, but I haven't found a good solution for this yet.

So the macro assumes that the type, windows::application_model::core::IFrameworkViewSource in this case, can be resolved as written in the surrounding scope.

Anyway, you can tweak your use declarations as follows to get it to work:

use bindings::windows;
use bindings::windows::*;
use bindings::windows::application_model::core::*;

Implementation support is still under active development - https://github.com/microsoft/windows-rs/issues/81 - so feel free to chime in with your experiences as I continue to work on that feature.

[robmikh]

I've just updated the uwp branch of Minesweeper if you'd like something to compare against. It implements both IFrameworkViewSource and IFrameworkView.

[chuckries]

Thanks!