Lifted anonymous classes clash with non anonymous ones

[nicolasstucki]

class Foo {
  class $anon$1
  new Object { }
}

As the unique name generator does not know about the name on class $anon$1, it will give the same name to the class for new Object { }. The result is a corrupted scope where both names refer to the same symbol and get stuck in an infinite loop.

Same for methods

class Foo {
  def foo = {
    def f() = ()
    f()
  }
  def f$1() = ()
}

There are two possible solutions

• Disallow names
• Register all relevant names for classes and methods in the map of the FreshNameCreator

Which one should we choose? I am more inclined to the first one as it simplifies the interaction with #2999

scalac has the same issue scala/bug#10492

[nicolasstucki]

As mentioned in the language specifications the $ are reserved by the compiler (http://scala-lang.org/files/archive/spec/2.12/01-lexical-syntax.html). We should add warnings/errors when using such identifiers.

[odersky]

The current wording in the spec is something like this: "Names with $'s in them are reserved, and should not be used in programs. If a program does use such names the results are unspecified". I think we should not try to change this.