make tests green again

lib/pure/collections/queues.nim

@@ -198,9 +198,8 @@ when isMainModule:
   assert($q == "[4, 56, 6, 789]")
 
   assert q[0] == q.front and q.front == 4
-  assert q[^1] == q.back and q.back == 789
   q[0] = 42
-  q[^1] = 7
+  q[q.len - 1] = 7
 
   assert 6 in q and 789 notin q
   assert q.find(6) >= 0

tests/errmsgs/tshow_asgn.nim

@@ -7,7 +7,7 @@ discard """
 
 # bug #5430
 
-proc random*[T](x: Slice[T]): T =
+proc random*[T](x: Slice[T, T]): T =
   ## For a slice `a .. b` returns a value in the range `a .. b-1`.
   result = int(x.b - x.a) + x.a
 

tests/exprs/texprstmt.nim

@@ -1,6 +1,6 @@
 discard """
   line: 10
-  errormsg: "expression 'result[1 .. -(len(result), 1)]' is of type 'string' and has to be discarded"
+  errormsg: "expression 'result[1 .. BackwardsIndex(1)]' is of type 'string' and has to be discarded"
 """
 
 # bug #578

tests/iter/tconcat.nim

@@ -9,7 +9,7 @@ discard """
 23'''
 """
 
-proc toIter*[T](s: Slice[T]): iterator: T =
+proc toIter*[T](s: Slice[T, T]): iterator: T =
   iterator it: T {.closure.} =
     for x in s.a..s.b:
       yield x