Make scoped type variables work for default methods

[ghc-hetmet.git] / compiler / typecheck / TcInstDcls.lhs

diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs
index 45338d0..8b53e3e 100644 (file)
--- a/compiler/typecheck/TcInstDcls.lhs
+++ b/compiler/typecheck/TcInstDcls.lhs
@@ -451,7 +451,10 @@ tcMethods origin clas inst_tyvars' dfun_theta' inst_tys'
     let
        prag_fn        = mkPragFun uprags
        all_insts      = avail_insts ++ catMaybes meth_insts
-       tc_method_bind = tcMethodBind inst_tyvars' dfun_theta' all_insts prag_fn
+       sig_fn n       = Just []        -- No scoped type variables, but every method has
+                                       -- a type signature, in effect, so that we check
+                                       -- the method has the right type
+       tc_method_bind = tcMethodBind inst_tyvars' dfun_theta' all_insts sig_fn prag_fn
        meth_ids       = [meth_id | (_,meth_id,_) <- meth_infos]
     in