False positives for classes defined inside methods

[retronym]

The latest release of MiMa, which includes #143, issues these warnings in scala 2.12

    filter {
        problems=[
            {
                matchName="scala.collection.Iterator#Leading#1.hd_="
                problemName=DirectMissingMethodProblem
            },
            {
                matchName="scala.collection.Iterator#Leading#1.hd"
                problemName=DirectMissingMethodProblem
            },
            {
                matchName="scala.collection.Iterator#Leading#1.status_="
                problemName=DirectMissingMethodProblem
            },
            {
                matchName="scala.collection.Iterator#Leading#1.lookahead_="
                problemName=DirectMissingMethodProblem
            },
            {
                matchName="scala.collection.Iterator#Leading#1.status"
                problemName=DirectMissingMethodProblem
            },
            {
                matchName="scala.collection.Iterator#Leading#1.lookahead"
                problemName=DirectMissingMethodProblem
            }
        ]
    }

I believe these are false positives, and we should exclude such classes from analysis by looking at the EnclosingMethod attribute:

scala> :javap scala.collection.Iterator$Leading$1
...
EnclosingMethod: #8.#11                 // scala.collection.Iterator.span
InnerClasses:
     public #12= #2; //Leading$1=class scala/collection/Iterator$Leading$1