Better discovery of type class instances from recursive definitions

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/newMessage.ur b/tests/newMessage.ur
new file mode 100644
index 00000000..e6ae3b4e
--- /dev/null
+++ b/tests/newMessage.ur
@@ -0,0 +1,15 @@
+datatype message =  NewQuestion of { Id : string}
+                  | Something of {Blah : int}
+
+fun showMessage (message : message) =
+    case message of
+        NewQuestion {Id = a} => a
+      | Something {Blah = x} => "blah"
+
+val show_mes = mkShow showMessage
+
+fun showTwoTuple [a] [b] (_ : show a) (_: show b) = mkShow (fn (two_tuple : {1:a, 2:b}) =>
+                              "(" ^ show two_tuple.1 ^ ", " ^ show two_tuple.2 ^ ")"
+
+                          )
+val om = show  (Something {Blah = 1}, Something {Blah = 2})