unjustified overlapping instances error
When compiling hets (http://trac.informatik.uni-bremen.de:8080/hets/wiki/HetsForDevelopers) using ghc-7.6.0.20120810 I get the following error
[489 of 664] Compiling Comorphisms.HasCASL2IsabelleHOL ( Comorphisms/HasCASL2IsabelleHOL.hs, Comorphisms/HasCASL2IsabelleHOL.o )
Comorphisms/HasCASL2IsabelleHOL.hs:61:44:
Overlapping instances for Category Env Morphism
arising from a use of `sourceSublogic'
Matching instances:
instance [incoherent] Category Env Morphism
-- Defined at HasCASL/Logic_HasCASL.hs:74:10
There exists a (perhaps superclass) match:
(The choice depends on the instantiation of `'
To pick the first instance above, use -XIncoherentInstances
when compiling the other instance declarations)
In the second argument of `isSubElem', namely `sourceSublogic cid'
In the expression: sl `isSubElem` sourceSublogic cid
In the expression:
if sl `isSubElem` sourceSublogic cid then Just () else NothingNote, that only a single instance is listed and that the choice is empty. Adding -XIncoherentInstances does also not help to get it compiled.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.6.1-rc1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | Solaris |
| Architecture | x86 |