Fix some type-class detection

4 files changed, 12 insertions, 0 deletions

diff --git a/lib/basis.urs b/lib/basis.urs
index a344b3ce..ca81c95f 100644
--- a/lib/basis.urs
+++ b/lib/basis.urs
@@ -56,6 +56,7 @@ val show_float : show float
 val show_string : show string
 val show_bool : show bool
 val show_time : show time
+val mkShow : t ::: Type -> (t -> string) -> show t
 
 class read
 val read : t ::: Type -> read t -> string -> option t
diff --git a/src/elab_env.sml b/src/elab_env.sml
index 2732de13..6b762abd 100644
--- a/src/elab_env.sml
+++ b/src/elab_env.sml
@@ -419,6 +419,7 @@ fun class_pair_in (c, _) =
         (case (class_name_in f, class_key_in x) of
              (SOME f, SOME x) => SOME (f, x)
            | _ => NONE)
+      | CUnif (_, _, _, ref (SOME c)) => class_pair_in c
       | _ => NONE
 
 fun resolveClass (env : env) c =
diff --git a/src/elaborate.sml b/src/elaborate.sml
index 38c03f6e..b0f2d331 100644
--- a/src/elaborate.sml
+++ b/src/elaborate.sml
@@ -1398,6 +1398,7 @@ fun normClassConstraint envs (c, loc) =
         in
             ((L'.CApp (f, x), loc), gs)
         end
+      | L'.CUnif (_, _, _, ref (SOME c)) => normClassConstraint envs c
       | _ => ((c, loc), [])
 
 
diff --git a/src/monoize.sml b/src/monoize.sml
index 79940842..0bdc1c70 100644
--- a/src/monoize.sml
+++ b/src/monoize.sml
@@ -844,6 +844,15 @@ fun monoExp (env, st, fm) (all as (e, loc)) =
             ((L'.EFfi ("Basis", "boolToString"), loc), fm)
           | L.EFfi ("Basis", "show_time") =>
             ((L'.EFfi ("Basis", "timeToString"), loc), fm)
+          | L.ECApp ((L.EFfi ("Basis", "mkShow"), _), t) =>
+            let
+                val t = monoType env t
+                val b = (L'.TFfi ("Basis", "string"), loc)
+                val dom = (L'.TFun (t, b), loc)
+            in
+                ((L'.EAbs ("f", dom, dom,
+                           (L'.ERel 0, loc)), loc), fm)
+            end
 
           | L.ECApp ((L.EFfi ("Basis", "read"), _), t) =>
             let