fixes #14498 [backport:1.2] (#14503)

tests/lent/tnot_allowed_lent.nim

@@ -7,10 +7,10 @@ type
 
 proc mytest1(s: MyObject, i: int): lent string =
   ## works fine
-  if i < s.x.len - 1 and s.x[i] != "": 
+  if i < s.x.len - 1 and s.x[i] != "":
     result = s.x[i]
   else: raise newException(KeyError, "err1")
-  
+
 proc mytest2(s: MyObject, i: int): lent string =
   ## reject due to if expr
   if i < s.x.len - 1 and s.x[i] != "": s.x[i]

tests/lent/tnot_allowed_lent2.nim

@@ -0,0 +1,14 @@
+discard """
+  errmsg: "'x' cannot be assigned to"
+  line: 10
+"""
+
+proc bug14498 =
+  var a = @['a', 'b', 'c', 'd', 'e', 'f']
+
+  for x in a:
+    x = 'c'
+
+  echo a
+
+bug14498()