E0291

An inherent impl for a prelude type, such as impl FsRead { ... }: only the prelude declares methods on its types. Write a free function, or implement a trait. Spans the impl's type.

Machine-applicable fix: none.

Example

This program fails with E0291.

impl FsRead {
    fn size(self) -> Int {
        1
    }
}

Fixed

The same program, fixed.

fn size(fs: FsRead) -> Int {
    1
}

Listed in the checker notes. oskac explain E0291 prints this entry offline.

All error codes