unnecessary_cast suggestion for type aliasses

[mgacek8]

Lint name: unnecessary_cast

I tried this code:

#[allow(non_camel_case_types)]
pub type size_t = usize;

pub struct Foo {
    pub len: size_t,
} 

impl Foo {
    #[allow(dead_code)]
    fn new() -> Foo {
        Foo {
            len: 0 as size_t,
        }
    }
}

I expected to see this happen:
No lint triggered, or, ideally, a suggestion to omit the cast completely and write just len: 0,

Instead, this happened:
Clippy suggested using 0_usize instead of 0 as size_t.
The suggestion is not good, because then changing size_t to e.g. u64 causes the compiler error.

Meta

• clippy 0.1.52 (2021-03-16 f5d8117)
• rustc the Stable version: 1.50.0