Strange compiler bug when import critibits and nre

[ziyu4huang]

    import sequtils
    import critbits
    import nre
    
    proc test() =
      var tb : CritBitTree[void]
      tb.incl "Abc"
      tb.incl "def"
      echo $( toSeq(tb.keys) )
    

> test.nim(9, 19) Error: undeclared field: 'keys'

if you comment-out nre, it will be fine. Now, I use partial import nre to 
work-around this issues

This bug not happens in 0.14, but happens when I update to recent.