Suppress redundant-constraint warnings in case of empty classes
The technique described in
http://www.well-typed.com/blog/2015/07/checked-exceptions/
makes use of a class without any methods, i.e.
class Throws eHowever, this by definition results in redundant constraints, e.g.
readFoo :: Throws IOError => FilePath -> IO Foo
readFoo fn = {- ... -}which GHC 8.0 warns about.
I propose to suppress warnings in case a class which has no methods is used as seemingly redundant constraint.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | highest |
| Resolution | Unresolved |
| Component | Compiler (Type checker) |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | bgamari, edsko |
| Operating system | |
| Architecture |