Starting with Groovy 2.5.5, unreachable line numbers were added to the byte code. This causes tools like JaCoCo to report uncovered lines. Removing these line numbers after the ARETURN would be helpful.
LINENUMBER 16 L1 <-- new line number that cant be hit after ARETURN
FRAME FULL  [java/lang/Throwable]
LOCALVARIABLE this Lcom/company/Form; L0 L1 0
MAXSTACK = 2
MAXLOCALS = 1