# D095 fiber_retired

URL: /docs/errors/D095
Markdown: /docs/errors/D095.md

> On the WASM runtime, join was called on a fiber that had already been retired.

A runtime defect: the running program stops with it; no compile phase reports it, and `try` cannot catch it. `sakura explain D095` prints this explanation offline.

On the WASM runtime, `join` was called on a fiber that had already been retired. Defence in
depth: unreachable from a program that passes the escape check, so this is a runtime or compiler
bug; please report it (`runtime/rt/ABI.md` §13).

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