Simon Peyton Jones authored May 16, 2022 and Marge Bot committed May 17, 2022

This MR fixes a bad bug, where the withDict was inlined too
vigorously, which in turn made the type-class Specialiser generate
a bogus specialisation, because it saw the same overloaded function
applied to two /different/ dictionaries.

Solution: inline `withDict` later.  See (WD8) of Note [withDict]
in GHC.HsToCore.Expr

See #21575, which is fixed by this change.