Don't ICE on anonymous struct in enum variant Fixes #121446 Computing `adt_def` for the anon struct calls `adt_def` on the parent to find its repr. If the parent is a non-item (e.g. an enum variant) we should have already emitted at least one error, so we just use the repr of the anonymous struct to avoid an ICE. cc ``@frank-king``
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.