TY: improve type inference around call expressions

[vlad20012]

Not the plugin should support these cases:

fn foo(f: &&fn() -> i32) {
    let a = f();
    a;
} //^ i32

and

use std::rc::Rc;
fn foo(f: Rc<fn() -> i32>) {
    let a = f();
    a;
} //^ i32

and

struct S();
impl S {
    fn new() {
        let a = Self();
        a;
    } //^ S
}

Also, I moved E0618 implementation into the type inference engine, so it should work more precisely.

Fixes #6682
Fixes #8311

[vlad20012]

bors r+

[bors]

Canceled.

[vlad20012]

bors r+

[bors]

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