Using freshly installed Eclipse:
Version: 2023-06 (4.28.0)
Build id: 20230608-1333
and
Eclipse Groovy Development Tools 5.0.0.v202306301519-e2306
with Groovy Compiler Version
set to 3.0.18
the code
if( methodNode.code !in BlockStatement ) return false
Needless to say, that the code compiles and runs just fine.
Am I missing something or is it a bug?
Created an issue
As per comment in the issue, I added
-Dgroovy.antlr4=true
to the bottom of my eclipse.ini
and it solved the problem