diff options
| -rw-r--r-- | compiler/typecheck/FamInst.hs | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/compiler/typecheck/FamInst.hs b/compiler/typecheck/FamInst.hs index aec8e4153f..7efcb971a9 100644 --- a/compiler/typecheck/FamInst.hs +++ b/compiler/typecheck/FamInst.hs @@ -158,8 +158,10 @@ newFamInst :: FamFlavor -> CoAxiom Unbranched -> TcM FamInst -- Freshen the type variables of the FamInst branches newFamInst flavor axiom@(CoAxiom { co_ax_tc = fam_tc }) = ASSERT2( tyCoVarsOfTypes lhs `subVarSet` tcv_set, text "lhs" <+> pp_ax ) - ASSERT2( tyCoVarsOfType rhs `subVarSet` tcv_set, text "rhs" <+> pp_ax ) ASSERT2( lhs_kind `eqType` rhs_kind, text "kind" <+> pp_ax $$ ppr lhs_kind $$ ppr rhs_kind ) + -- We used to have an assertion that the tyvars of the RHS were bound + -- by tcv_set, but in error situations like F Int = a that isn't + -- true; a later check in checkValidFamInst rejects it do { (subst, tvs') <- freshenTyVarBndrs tvs ; (subst, cvs') <- freshenCoVarBndrsX subst cvs ; dflags <- getDynFlags |