diff --git a/lib/system/widestrs.nim b/lib/system/widestrs.nim
index 8b08959b5c02..bb348fd6776a 100644
--- a/lib/system/widestrs.nim
+++ b/lib/system/widestrs.nim
@@ -224,3 +224,6 @@ when defined(nimv2):
 
   proc `$`*(s: WideCStringObj): string =
     $(s.data)
+
+  proc len*(w: WideCStringObj): int {.inline.} =
+    len(w.data)
diff --git a/tests/arc/t19862.nim b/tests/arc/t19862.nim
new file mode 100644
index 000000000000..f7146ec2689d
--- /dev/null
+++ b/tests/arc/t19862.nim
@@ -0,0 +1,13 @@
+discard """
+  matrix: "--gc:refc; --gc:arc"
+"""
+
+# bug #19862
+type NewString = object
+
+proc len(s: NewString): int = 10
+
+converter toNewString(x: WideCStringObj): NewString = discard
+
+let w = newWideCString("test")
+doAssert len(w) == 4