diff --git a/compiler/transf.nim b/compiler/transf.nim
index 399a8c468a..3059d8fe6b 100644
--- a/compiler/transf.nim
+++ b/compiler/transf.nim
@@ -702,6 +702,11 @@ proc putArgInto(arg: PNode, formal: PType): TPutArgInto =
   of nkAddr, nkHiddenAddr:
     result = putArgInto(arg[0], formal)
     if result == paViaIndirection: result = paFastAsgn
+  of nkHiddenStdConv, nkHiddenSubConv, nkConv:
+    if compareTypes(arg.typ, arg[1].typ, dcEqIgnoreDistinct, {IgnoreRangeShallow}):
+      result = putArgInto(arg[1], formal)
+    else:
+      result = paFastAsgn
   of nkCurly, nkBracket:
     for i in 0..<arg.len:
       if putArgInto(arg[i], formal) != paDirectMapping:
diff --git a/tests/arc/tdistinct_for_nodup.nim b/tests/arc/tdistinct_for_nodup.nim
new file mode 100644
index 0000000000..427f6b2b02
--- /dev/null
+++ b/tests/arc/tdistinct_for_nodup.nim
@@ -0,0 +1,33 @@
+discard """
+  cmd: '''nim c --mm:arc --expandArc:foo $file'''
+  nimout: '''
+--expandArc: foo
+
+var broken_cursor
+block :tmp:
+  var i
+  var i_1 = 0
+  let L = len(seq[Large](broken_cursor))
+  block :tmp_1:
+    while i_1 < L:
+      i = seq[Large](broken_cursor)[i_1]
+      discard i
+      {.push, overflowChecks: false.}
+      inc(i_1, 1)
+      {.pop.}
+-- end of expandArc ------------------------
+'''
+"""
+
+
+type
+  Large = array[1024, byte]
+  List = distinct seq[Large]
+
+proc foo =
+  var
+    broken: List
+  for i in seq[Large](broken):
+    discard i
+
+foo()
\ No newline at end of file