some null checks and cleanup
EA-54370 - IAE: GrIntroduceHandlerBase.getAnchor
anchor should be @Nullable to get appropriate log message in case of null
EA-53885 - CCE: GrIntroduceParameterProcessor.findUsages
in-place introduce parameter is supported only for methods right now
redundant code
Groovy: infrastructure for @ClosureParams support.
FromString closure signature hint is supported
Groovy: update mock groovy-2.3 build
FromString hint: support options with a single String arg instead of an array of Strings
ClosureSignatureHint works for closures with several parameters without declared types
FromString hint: support correcr format. it describes a whole signature inside a single string.
Groovy: Support all ClosureSignatureHints
Duplicated error messages in @CompileStatic context fixed. Recoursive visitor is replaced with simple visitor, so we don't go inside child psi elements which can be inside @CompileStatic context
Groovy: inference of closure parameter types: checks for explicitly declared types.
check for closure parameters: use method call conversion rules