Permit empty closed type families
At the moment, closed type families without any equations fail with a parse error. In addition, they cannot be created by TH (see #8028 (closed)). Would it be possible to permit these instead?
My use case is in my typechecker plugin for units of measure, where I want to add new type-level operators without any equational theory (because it will be supplied by the plugin) and without users having the ability to introduce their own type family instances.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.8.3 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | goldfire |
| Operating system | |
| Architecture |