<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi Alice,<div class=""><br class=""></div><div class="">You'll need mkTemplateTyConBinders, not the two variants of that function you use below. The problem is that both mkTemplateKindTyConBinders and mkTemplateAnonTyConBinders pull Uniques starting from the same value, and so GHC gets very confused when multiple arguments to your TyCon have the same Uniques. mkTemplateTyConBinders, on the other hand, allows you to specify dependency among your arguments without confusing Uniques. You can see a usage of this function in TysPrim.proxyPrimTyCon.</div><div class=""><br class=""></div><div class="">I hope this helps!</div><div class="">Richard</div><div class=""><br class=""></div><div class="">PS: I've made this mistake myself several times, and it's quite baffling to debug!</div><div class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Apr 30, 2018, at 8:27 AM, alice <<a href="mailto:alicekoroleva239@gmail.com" class="">alicekoroleva239@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">Hello. I’m trying to make a type family with resolving it inside type checking classes, like CmpNat. Its type signature is «type family Cmp (a :: k1) (b :: k2) :: Ordering», so the function is poly kinded. But it seems unclear how to make its TyCon. I’ve tried to follow the CmpNat and CmpSymbol style, and also saw Any TyCon in TysWiredIn. So this is my attempt:</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">typeCmpTyCon :: TyCon</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">typeCmpTyCon =</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> mkFamilyTyCon name</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> (binders ++ (mkTemplateAnonTyConBinders [ input_kind1, input_kind2 ]))</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> orderingKind</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> Nothing</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> (BuiltInSynFamTyCon ops)</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> Nothing</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> NotInjective</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> where</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> name = mkWiredInTyConName UserSyntax gHC_TYPELITS (fsLit "Cmp")</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> typeCmpTyFamNameKey typeCmpTyCon</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> ops = BuiltInSynFamily</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> { sfMatchFam = matchFamCmpType</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> , sfInteractTop = interactTopCmpType</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> , sfInteractInert = \_ _ _ _ -> []</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> }</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> binders@[kv1, kv2] = mkTemplateKindTyConBinders [ liftedTypeKind, liftedTypeKind ]</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> input_kind1 = mkTyVarTy (binderVar kv1)</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""> input_kind2 = mkTyVarTy (binderVar kv2)</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">ghci says this:</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">:kind Cmp </div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">Cmp :: forall {k0} {k1}. k0 -> k1 -> Ordering</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">But then I try to apply it to some values and get this exception:</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class="">:kind! Cmp 4 5</div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69); min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; font-family: 'Helvetica Neue'; color: rgb(69, 69, 69);" class=""><div style="margin: 0px; line-height: normal;" class=""><interactive>:1:15: error:</div><div style="margin: 0px; line-height: normal;" class=""> • Expected kind ‘k0’, but ‘4’ has kind ‘Nat’</div><div style="margin: 0px; line-height: normal;" class=""> • In the first argument of ‘Cmp’, namely ‘4’</div><div style="margin: 0px; line-height: normal;" class=""> In the type ‘Cmp 4 5’</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><interactive>:1:17: error:</div><div style="margin: 0px; line-height: normal;" class=""> • Expected kind ‘k1’, but ‘5’ has kind ‘Nat’</div><div style="margin: 0px; line-height: normal;" class=""> • In the second argument of ‘Cmp’, namely ‘5’</div><div style="margin: 0px; line-height: normal;" class=""> In the type ‘Cmp 4 5’</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Does anyone know where I made a mistake? Any help would be appreciated.</div></div></div></div>_______________________________________________<br class="">ghc-devs mailing list<br class=""><a href="mailto:ghc-devs@haskell.org" class="">ghc-devs@haskell.org</a><br class="">http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs<br class=""></div></blockquote></div><br class=""></div></body></html>