Fix issue #18262
This MR fixes the issue raised in #18262 (closed), notably that when an instance mentioned a TypeError
, the result was reported incorrectly, showing the constraint as a random type variable.
instance [safe] s0 => Err 'A -- Defined at ../Bug2.hs:8:10
The solution was to zonk the wanted constraints after solving and to relax the test to allow residual constraints which mention a TypeError
. After this change the same result would be reported as:
instance [safe] (TypeError ...) => Err 'A
-- Defined at ../Bug2.hs:8:10