# D030 option_expect_none

URL: /docs/errors/D030
Markdown: /docs/errors/D030.md

> Option.expect was called on None.

A runtime defect: the running program stops with it; no compile phase reports it, and `try` cannot catch it. `sakura explain D030` prints this explanation offline.

`Option.expect` was called on `None`. Use `expect` only where `None` is a bug; otherwise match
on the option or use `Option.unwrap_or(o, default)`.

Runtime defects come from running programs, so `compiler/tests/ui` has no fixture for them; the explanation above names the repair.