Manuel, Simon,
I've spotted a hopefully small but for us quite annoying bug in GHC's
type checker: it loops when overloading resolving involves a circular
constraint graph containing type-family applications.
The following program (also attached) demonstrates the problem:
{-# LANGUAGE
Your example must loop because as you show below
the instance declaration leads to a cycle.
By black-holing you probably mean co-induction. That is,
if the statement to proven appears again, we assume it must hold.
However, type classes are by default inductive, so there's no
easy fix to offer to
Dear Martin,
Your example must loop because as you show below
the instance declaration leads to a cycle.
By black-holing you probably mean co-induction. That is,
if the statement to proven appears again, we assume it must hold.
However, type classes are by default inductive, so there's no
