Scala Programming Language
  1. Scala Programming Language
  2. SI-7974

scala.Symbol's CleanUp code is broken and never used


    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: Scala 2.9.3, Scala 2.10.2, Scala 2.11.0-M6
    • Fix Version/s: Scala 2.11.0-M8
    • Component/s: None
    • Labels:


      The comment in CleanUp says:

      This transformation should identify Scala symbol
      invocations in the tree and replace them with
      references to a static member. Also, whenever
      a class has at least a single symbol invocation
      somewhere in its methods, a new static member
      should be created and initialized for that symbol.
      The reasoning behind this transformation is the
      following. Symbols get interned - they are stored
      in a global map which is protected with a lock.
      The reason for this is making equality checks
      quicker. But calling Symbol.apply, although it
      does return a unique symbol, accesses a locked
      object, making symbol access slow. To solve this,
      the unique symbol from the global symbol map
      in Symbol is accessed only once during class
      loading, and after that, the unique symbol is in
      the static member. Hence, it is cheap to both
      reach the unique symbol and do equality
      checks on it.

      It seems like this transformation was never executed because the pattern did never match, and if it had, it would have broken horribly due bugs in the implementation.


        Simon Ochsenreither added a comment -


          • Assignee:
            Simon Ochsenreither
            Simon Ochsenreither
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