1 files changed, 15 insertions, 0 deletions
diff --git a/tests/ccgbugs/twrong_tupleconv.nim b/tests/ccgbugs/twrong_tupleconv.nim
index 7a887d183..031712dac 100644
--- a/tests/ccgbugs/twrong_tupleconv.nim
+++ b/tests/ccgbugs/twrong_tupleconv.nim
@@ -1,3 +1,8 @@
+discard """
+  targets: "c cpp"
+  matrix: "--gc:refc; --gc:arc"
+"""
+
 # bug #1833
 iterator myitems*[T](a: var seq[T]): var T {.inline.} =
   ## iterates over each item of `a` so that you can modify the yielded value.
@@ -18,3 +23,13 @@ var ys = @[(1,"a"),(2,"b"),(3,"c")]
 for y in myitems(ys):
   inc y[0]
 
+# bug #16331
+type T1 = tuple[a, b: int]
+
+proc p(b: bool): string =
+  var x: T1 = (10, 20)
+  x = if b: (x.b, x.a) else: (-x.b, -x.a)
+  $x
+
+assert p(false) == "(a: -20, b: -10)"
+assert p(true) == "(a: 20, b: 10)"