invalid cast; use parsing, a predicate, or a domain conversion

Why this fires¶

as only performs compiler-known casts. It does not parse text, compute truthiness, serialize data, or run a conversion implemented by a user type.

let port = "8080" as u16 // error[TE835]

Fix it¶

Choose the operation that matches the intent:

let port = "8080".parse::<u16>()?
let text = value.to_string()
let user = raw.try_into::<User>()?

Use an explicit comparison instead of casting a value to bool.

See also¶

• TE836 — an exact checked cast cannot succeed.
• TE837 — a numeric cast can lose information.