We observed that in come code produced by Groovy compiler there are missing line number attributes. Consider example: ~~~~~~~~~~~~~~~~~~ class DependencyManager { Map artifactDescriptors = [] } ~~~~~~~~~~~~~~~~~~ In generated .class-file LineNumbertable attribute for initial code of DependencyManager class is absent. In same time if we use class initializer: ~~~~~~~~~~~~~~~~~~ class DependencyManager { { Map artifactDescriptors = [] } } ~~~~~~~~~~~~~~~~~~ we will see correct line number table: LineNumberTable: line 2: 108 line 3: 108 This annoying discrepancy complicates debugger's work.