Type-mismatch error boxed Trait

[villem]

Hi,

The latest nightly 3-25-2022 ( 0.3.989) on Mac vscode gives me this error. Cargo build this is ok. Also the RA build 0.3.986 don't
give this error. rustc -V
rustc 1.58.0 (02072b482 2022-01-11)

[{
"resource": "/Users/ville.mattila/src/smc_umbrella/backend/src/manager/policy.rs",
"owner": "rustc",
"code": {
"value": "type-mismatch",
"target": {
"$mid": 1,
"external": "https://rust-analyzer.github.io/manual.html#type-mismatch",
"path": "/manual.html",
"scheme": "https",
"authority": "rust-analyzer.github.io",
"fragment": "type-mismatch"
}
},
"severity": 8,
"message": "expected Box<dyn Foo<FooItem = ::BarItem>, Global>, found Box<F, Global>",
"source": "rust-analyzer",
"startLineNumber": 33,
"startColumn": 26,
"endLineNumber": 33,
"endColumn": 39
}]

Here is source code. I grant this may be most correct rust, but it works for me. You can give suggestion better code too :-) ,
but RA should not give error, where rustc is happy.

trait Foo {
    type FooItem;
}

trait Bar {
    type BarItem: Foo;
    fn add_foo(&self, bar: Box<dyn Foo<FooItem=Self::BarItem>>) {

    }
}

struct Baz<B> {
    bar: B,
}

impl<B:Bar>  Baz<B> {
    fn add_rule<F: 'static>(&mut self, mut foo: F)
    where F: Foo<FooItem = <B as Bar>::BarItem> {
        self.bar.add_foo(Box::new(foo)); // <<-- THIS line give RA Error now
    }
}

[flodiebold]

This will be fixed by rust-lang/chalk#754 once that gets merged. Also, #11809 will hide the diagnostic unless you explicitly enable experimental errors 🙂

[flodiebold]

Considering that, let's close this already.

[villem]

Ok thanks!