GHC.Tc.Solver.Rewrite

Documentation

rewrite :: CtEvidence -> TcType -> TcS (Reduction, RewriterSet)

See Note [Rewriting]. If (xi, co, rewriters) <- rewrite mode ev ty, then co :: xi ~r ty where r is the role in ev. rewriters is the set of coercion holes that have been used to rewrite See Note [Wanteds rewrite Wanteds] in GHC.Tc.Types.Constraint

rewriteForErrors :: CtEvidence -> TcType -> TcS (Reduction, RewriterSet)

See Note [Rewriting] This variant of rewrite rewrites w.r.t. nominal equality only, as this is better than full rewriting for error messages. Specifically, we want to avoid unwrapping newtypes, as doing so can end up causing an otherwise-unnecessary stack overflow.

rewriteArgsNom :: CtEvidence -> TyCon -> [TcType] -> TcS (Reductions, RewriterSet)

rewriteType :: CtLoc -> TcType -> TcS TcType

Rewrite a type w.r.t. nominal equality. This is useful to rewrite a type w.r.t. any givens. It does not do type-family reduction. This will never emit new constraints. Call this when the inert set contains only givens.