error explicit-interface

Интерфейс @explicit требует impl или @derive.

What it means#

An @explicit interface is satisfied only by an explicit impl I for T or by @derive(I) (§4.6); having methods of the right shape is not enough. Standard interfaces such as Copy, Drop and Serializable are explicit.

Example#

@explicit interface Persistent { fn key() -> str }

data Doc { id: u64 }

impl Doc {
  fn key() -> str => "doc"
}

assert Doc: Persistent      // <- explicit-interface

explicit-interface

How to fix#

@explicit interface Persistent { fn key() -> str }

data Doc { id: u64 }

impl Persistent for Doc {
  fn key() -> str => "doc"
}

assert Doc: Persistent

Write impl I for T { ... } (allowed when I or T is declared in your package) or add @derive(I) when the interface can be derived.

See also#

• interface-not-satisfied
• impl-foreign-type