Runs in LivePlugin for IntelliJ

plugin.groovy

import com.intellij.openapi.actionSystem.AnActionEvent
import com.intellij.openapi.editor.markup.EffectType
import com.intellij.openapi.editor.markup.HighlighterTargetArea
import com.intellij.openapi.editor.markup.TextAttributes

import com.intellij.openapi.actionSystem.AnActionEvent
import com.intellij.openapi.actionSystem.LangDataKeys
import com.intellij.psi.PsiElement
import com.intellij.psi.PsiFile
import com.intellij.psi.PsiRecursiveElementWalkingVisitor
import com.intellij.psi.PsiReferenceExpression
import com.intellij.psi.search.searches.ReferencesSearch
import com.intellij.psi.util.PsiTreeUtil
import com.intellij.openapi.util.Conditions

import java.awt.*

import static liveplugin.PluginUtil.*


registerAction("HighlightScopesAction", "ctrl shift alt E", TOOLS_MENU) { AnActionEvent event ->

    // 1) analyze scopes

/*
     TODO test these: ReferencesSearch.search()  PsiTreeUtil.getChildren*()  PsiTreeUtil.getParent*() PsiTreeUtil.find*() etc.
     see: http://www.jetbrains.org/intellij/sdk/docs/tutorials/custom_language_support/psi_helper_and_utilities.html?search=util

     also for actions on elements: e.getData(LangDataKeys.PSI_ELEMENT)
*/
    PsiFile psiFile = event.getData(LangDataKeys.PSI_FILE)

    psiFile.accept(new PsiRecursiveElementWalkingVisitor() {
        @Override
        void visitElement(PsiElement element) {
            show("" + element + " CLASS " + element.getClass() + " node " + element.getNode() + " " + element.hashCode())
            show(" reference " + element.getReference()?.resolve()?.hashCode())

            if (element != null && element.getReference() != null) {
                def resolved = element.getReference().resolve()
                if (resolved != null) {
                    show("  first reference by search " + ReferencesSearch.search(resolved).findFirst().resolve().hashCode())
//                    show("  SEARCH references " + ReferencesSearch.search(resolved).findAll())
                }
            }

            def parentsElem = PsiTreeUtil.getParents(element, null)
            show("parents of element " + parentsElem)

            def ref = element.getReference()?.resolve()
//            def parent = PsiTreeUtil.getParentOfType(ref, Class.forName("cursive.psi.impl.list.ClListImpl.class"))
            if (ref != null) {
                def parents = PsiTreeUtil.getParents(ref, null)
                show("parents of reference " + parents)
            }

            super.visitElement(element)
        }
    })

    // 2) colorize !
	runDocumentWriteAction(event.project) {
		def editor = currentEditorIn(event.project)

//        TODO
		def from = editor.document.text.length() - 8
		def to = editor.document.text.length()

		def textAttributes = new TextAttributes(Color.BLACK, Color.YELLOW, Color.YELLOW, EffectType.SEARCH_MATCH, Font.PLAIN)
		editor.markupModel.addRangeHighlighter(from, to, 1, textAttributes, HighlighterTargetArea.EXACT_RANGE)
	}
}

show("Loaded 'HighlightScopesAction'<br/>Use ctrl+alt+shift+E to highlight scopes")