1 files changed, 45 insertions, 0 deletions
diff --git a/tests/constraint.ur b/tests/constraint.ur
new file mode 100644
index 0000000..e350a4e
--- /dev/null
+++ b/tests/constraint.ur
@@ -0,0 +1,45 @@
+signature S = sig
+        con nm :: Name
+        con r :: {Type}
+
+        constraint [nm] ~ r
+end
+
+structure M : S = struct
+        con nm = #A
+        con r = [B = float, C = string]
+
+        constraint [A] ~ [B]
+        constraint [nm] ~ r
+        constraint [C] ~ [D]
+end
+
+structure M' = struct
+        open M
+
+        con combo = [nm = int] ++ r
+end
+
+structure M' = struct
+        open constraints M
+
+        con nm' = M.nm
+        con r' = M.r
+        con combo = [nm' = int] ++ r'
+end
+
+
+signature S' = sig
+        con r1 :: {Type}
+        con r2 :: {Type}
+
+        constraint r1 ~ r2
+end
+
+functor F (M : S) : S' = struct
+        con r1 = [M.nm = int]
+        con r2 = M.r
+
+        open constraints M
+        constraint r1 ~ r2
+end