Ticket #71 (closed defect: fixed)
Better error message for unimplemented class functions
|Reported by:||benl||Owned by:||erikd|
Description (last modified by benl) (diff)
Added by Jared
The following function fails to compile.
example s = s /= ""
The error message is
ddc: PANIC in Core.Dictionary rewriteOverApp: no instance for Class.Eq.Eq (Data.String.String %rTS1) in (/=) (Data.String.String %rTS1) (Data.String.String %rTC0) %rTS0 (Class.Eq.Eq (Data.String.String %rTS1)) (Base.Shape2 (Data.String.String %rTS1) (Data.String.String %rTC0)) s xCS0
Which is the wrong error. There is an instance, but it doesn't provide an implementation for (/=). For the moment, this can be resolved by requiring implementations of all functions in a class.