Reports any instances of Groovy statements which attempts to put GString object as a key to map. In a general way GString objects are mutable and probably should not be used as keys.

Also, GString entry could not be accessed with java.lang.String object with same value. Example:

    def map = [:]
    def key = 'foo'
    map << ["${key}": 'bar']
    assert  map[key] == null
New in 2017.1