1 files changed, 98 insertions, 0 deletions
diff --git a/tests/compiles/trecursive_generic_in_compiles.nim b/tests/compiles/trecursive_generic_in_compiles.nim
new file mode 100644
index 000000000..77bf0bb02
--- /dev/null
+++ b/tests/compiles/trecursive_generic_in_compiles.nim
@@ -0,0 +1,98 @@
+# bug #3313
+import unittest, future
+
+type
+  ListNodeKind = enum
+    lnkNil, lnkCons
+  List*[T] = ref object
+    ## List ADT
+    case kind: ListNodeKind
+    of lnkNil:
+      discard
+    of lnkCons:
+      value: T
+      next: List[T] not nil
+
+proc Cons*[T](head: T, tail: List[T]): List[T] =
+  ## Constructs non empty list
+  List[T](kind: lnkCons, value: head, next: tail)
+
+proc Nil*[T](): List[T] =
+  ## Constructs empty list
+  List[T](kind: lnkNil)
+
+proc head*[T](xs: List[T]): T =
+  ## Returns list's head
+  xs.value
+
+# TODO
+# proc headOption*[T](xs: List[T]): Option[T] = ???
+
+proc tail*[T](xs: List[T]): List[T] =
+  ## Returns list's tail
+  case xs.kind
+  of lnkCons: xs.next
+  else: xs
+
+proc isEmpty*(xs: List): bool =
+  ## Checks  if list is empty
+  xs.kind == lnkNil
+
+proc `==`*[T](xs, ys: List[T]): bool =
+  ## Compares two lists
+  if (xs.isEmpty, ys.isEmpty) == (true, true): true
+  elif (xs.isEmpty, ys.isEmpty) == (false, false): xs.head == ys.head and xs.tail == ys.tail
+  else: false
+
+proc asList*[T](xs: varargs[T]): List[T] =
+  ## Creates list from varargs
+  proc initListImpl(i: int, xs: openarray[T]): List[T] =
+    if i > high(xs):
+      Nil[T]()
+    else:
+      Cons(xs[i], initListImpl(i+1, xs))
+  initListImpl(0, xs)
+
+proc foldRight*[T,U](xs: List[T], z: U, f: (T, U) -> U): U =
+  case xs.isEmpty
+  of true: z
+  else: f(xs.head, xs.tail.foldRight(z, f))
+
+proc dup*[T](xs: List[T]): List[T] =
+  ## Duplicates the list
+  xs.foldRight(Nil[T](), (x: T, xs: List[T]) => Cons(x, xs))
+
+type
+  ListFormat = enum
+    lfADT, lfSTD
+
+proc asString[T](xs: List[T], f = lfSTD): string =
+  proc asAdt(xs: List[T]): string =
+    case xs.isEmpty
+    of true: "Nil"
+    else: "Cons(" & $xs.head & ", " & xs.tail.asAdt & ")"
+
+  proc asStd(xs: List[T]): string =
+    "List(" & xs.foldLeft("", (s: string, v: T) =>
+      (if s == "": $v else: s & ", " & $v)) & ")"
+
+  case f
+  of lfADT: xs.asAdt
+  else: xs.asStd
+
+proc `$`*[T](xs: List[T]): string =
+  ## Converts list to string
+  result = xs.asString
+
+proc foldLeft*[T,U](xs: List[T], z: U, f: (U, T) -> U): U =
+  case xs.isEmpty
+  of true: z
+  else: foldLeft(xs.tail, f(z, xs.head), f)
+
+suite "unittest compilation error":
+
+  test "issue 3313":
+    let lst = lc[$x | (x <- 'a'..'z'), string].asList
+
+    let lstCopy = lst.dup
+    check: lstCopy == lst