The vast majority of available code inspections for groovy code come from Java.
When I look at the Groovy Style guide ( http://groovy-lang.org/style-guide.html ) then there are a lot of rules, that IDEA cannot check.
- unnecessary semicolons
- usage of ' instead of " for regular strings
- a closure as the last parameter inside ()
How about enhancing groovy inspections in general? Does that fit into your priorities/roadmap?
For inspiration you could also look at codenarc: http://codenarc.sourceforge.net/codenarc-rule-index.html
(unfortunately the codenarc plugin for idea has not been updated for a couple of years)
The TypeScript inspections are yet much, much worse. Currently there are only 7 inspections in total.