| LambdaExpr -- Patterns of a lambda
| CaseAlt -- Patterns and guards on a case alternative
| ProcExpr -- Patterns of a proc
- | PatBindRhs -- Patterns in the *guards* of a pattern binding
+ | PatBindRhs -- A pattern binding, or its guards
+ -- [x] = e, or x | [y] <- e = e
| RecUpd -- Record update [used only in DsExpr to
-- tell matchWrapper what sort of
-- runtime error message to generate]