Add issue test

test/cgen/reused-names.kk

@@ -0,0 +1,22 @@
+// Issue: https://github.com/koka-lang/koka/issues/186
+alias elem = int
+
+fun sequences(xs : list<elem>)
+  match xs
+    Cons(a, Cons(b, xs)) ->
+        if(a > b) then descending(b, [a], xs)
+        else ascending(b, (fn(x) { Cons(a, x) }), xs)
+    _ -> [xs] // This uses a name both in scope outside the match and inside the other match branch. Uniquify should not substitute this.
+
+fun descending(a : elem, as_, bs)
+  match bs
+    Cons(b, bs) | a > b -> descending(b, Cons(a, as_), bs)
+    _ -> Cons(Cons(a, as_), sequences(bs))
+
+fun ascending(a : elem, as_, bs)
+  match bs
+    Cons(b, bs) | !(a > b) -> ascending(b, fn(ys) { as_(Cons(a, ys)) }, bs)
+    _ -> Cons(as_([a]), sequences(bs))
+
+fun main()
+  sequences([0, 1, 2, 3])

test/cgen/reused-names.kk.out

@@ -0,0 +1 @@
+[[0,1,2,3],[]]