Bad type resolution on &[T] vs *const T

[philberty]

I tried this code:

struct FatPtr<T> {
    data: *const T,
    len: usize,
}

pub union Repr<T> {
    rust: *const [T],
    rust_mut: *mut [T],
    raw: FatPtr<T>,
}

impl<T> [T] {
    pub const fn is_empty(&self) -> bool {
        self.len() == 0
    }

    pub const fn len(&self) -> usize {
        unsafe { Repr { rust: self }.raw.len }
    }
}

I expected to see this happen: *compile without error

Instead, this happened:

<source>:18:31: error: expected [* const [T=T?]] got [& [T=T REF: 46]]
    7 |     rust: *const [T],
      |           ~                    
......
   18 |         unsafe { Repr { rust: self }.raw.len }
      |                               ^

see https://godbolt.org/z/KGE8qxzWc

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• What version of Rust GCC were you using, git sha if possible. 74e8365