You are misunderstanding. The issue you have observed is caused by binary incompatibility between Scala versions. Java has an almost one-to-one mapping to JVM bytecode. Scala, having many features that Java does not, does not have such a direct mapping. Sometimes the way Scala is compiled to JVM bytecode changes, to fix bugs or to improve performance (e.g. compilation of lambdas will change now that Java 8 supports them). This leads to binary incompatibility between Scala versions, though the problem is decreasing with time.
This effort is aiming to keep binary compatibility, so it will have no effect of users of Typesafe's compiler. To quote: "programs which are valid when compiled with the Typesafe Scala compiler would have the same meaning and binary representation when compiled with the fixes in place."
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You are misunderstanding. The issue you have observed is caused by binary incompatibility between Scala versions. Java has an almost one-to-one mapping to JVM bytecode. Scala, having many features that Java does not, does not have such a direct mapping. Sometimes the way Scala is compiled to JVM bytecode changes, to fix bugs or to improve performance (e.g. compilation of lambdas will change now that Java 8 supports them). This leads to binary incompatibility between Scala versions, though the problem is decreasing with time.
This effort is aiming to keep binary compatibility, so it will have no effect of users of Typesafe's compiler. To quote: "programs which are valid when compiled with the Typesafe Scala compiler would have the same meaning and binary representation when compiled with the fixes in place."