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 e
However, 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 |