Make unknown LANGUAGE pragmas a warning, not an error
Currently, if I say {-# LANGUAGE Foo #-} at the top of my file, it fails to compile. This failure seems unnecessary, especially because any new language feature Foo enables will fail to compile later on down the file. Is it possible to have a "stern warning" that is produced even when other parts of the file produce errors?
The reason I'm bringing this up is that, when 7.8 came out with its role annotations, users needed CPP in two different places: both to protect the RoleAnnotations pragma and to protect the role annotations themselves. This may be unavoidable on the role annotations directly, but I think we can improve the situation around LANGUAGE pragmas.
Is there a downside to this?
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.8.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |