diff options
Diffstat (limited to 'compiler/typecheck/TcSimplify.hs')
| -rw-r--r-- | compiler/typecheck/TcSimplify.hs | 14 |
1 files changed, 0 insertions, 14 deletions
diff --git a/compiler/typecheck/TcSimplify.hs b/compiler/typecheck/TcSimplify.hs index ea95a0b4ad..868be78c68 100644 --- a/compiler/typecheck/TcSimplify.hs +++ b/compiler/typecheck/TcSimplify.hs @@ -2432,7 +2432,6 @@ floatEqualities skols given_ids ev_binds_var no_given_eqs is_float_eq_candidate ct | pred <- ctPred ct , EqPred NomEq ty1 ty2 <- classifyPredType pred - , tcTypeKind ty1 `tcEqType` tcTypeKind ty2 = case (tcGetTyVar_maybe ty1, tcGetTyVar_maybe ty2) of (Just tv1, _) -> float_tv_eq_candidate tv1 ty2 (_, Just tv2) -> float_tv_eq_candidate tv2 ty1 @@ -2479,19 +2478,6 @@ happen. In particular, float out equalities that are: case, floating out won't help either, and it may affect grouping of error messages. -* Homogeneous (both sides have the same kind). Why only homogeneous? - Because heterogeneous equalities have derived kind equalities. - See Note [Equalities with incompatible kinds] in TcCanonical. - If we float out a hetero equality, then it will spit out the same - derived kind equality again, which might create duplicate error - messages. - - Instead, we do float out the kind equality (if it's worth floating - out, as above). If/when we solve it, we'll be able to rewrite the - original hetero equality to be homogeneous, and then perhaps make - progress / float it out. The duplicate error message was spotted in - typecheck/should_fail/T7368. - * Nominal. No point in floating (alpha ~R# ty), because we do not unify representational equalities even if alpha is touchable. See Note [Do not unify representational equalities] in TcInteract. |