Initial implementation of rainbow highlighting for Kotlin

#KT-12629 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/highlighter/BeforeResolveHighlightingVisitor.kt

@@ -16,11 +16,16 @@
 
 package org.jetbrains.kotlin.idea.highlighter
 
+import com.intellij.codeHighlighting.RainbowHighlighter
 import com.intellij.lang.annotation.AnnotationHolder
 import com.intellij.openapi.application.ApplicationManager
+import com.intellij.openapi.editor.colors.EditorColorsManager
 import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.idea.KotlinLanguage
+import org.jetbrains.kotlin.kdoc.parser.KDocKnownTag
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
+import org.jetbrains.kotlin.kdoc.psi.impl.KDocTag
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.KtExpressionWithLabel
 import org.jetbrains.kotlin.psi.KtLambdaExpression
@@ -34,7 +39,7 @@ internal class BeforeResolveHighlightingVisitor(private val holder: AnnotationHo
     override fun visitElement(element: PsiElement) {
         val elementType = element.node.elementType
         val attributes = when {
-            element is KDocLink -> KotlinHighlightingColors.KDOC_LINK
+            element is KDocLink && !willApplyRainbowHighlight(element) -> KotlinHighlightingColors.KDOC_LINK
 
             elementType in KtTokens.SOFT_KEYWORDS -> {
                 when (elementType) {
@@ -49,6 +54,14 @@ internal class BeforeResolveHighlightingVisitor(private val holder: AnnotationHo
         holder.createInfoAnnotation(element, null).textAttributes = attributes
     }
 
+    private fun willApplyRainbowHighlight(element: KDocLink): Boolean {
+        if (!RainbowHighlighter.isRainbowEnabledWithInheritance(EditorColorsManager.getInstance().globalScheme, KotlinLanguage.INSTANCE)) {
+            return false
+        }
+        // Can't use resolve because it will access indices
+        return (element.parent as? KDocTag)?.knownTag == KDocKnownTag.PARAM
+    }
+
     override fun visitLambdaExpression(lambdaExpression: KtLambdaExpression) {
         if (ApplicationManager.getApplication().isUnitTestMode) return