JSON: implement rainbow highlighter

json/src/com/intellij/json/highlighting/JsonRainbowVisitor.java

@@ -0,0 +1,30 @@
+// Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.json.highlighting;
+
+import com.intellij.codeInsight.daemon.RainbowVisitor;
+import com.intellij.codeInsight.daemon.impl.HighlightVisitor;
+import com.intellij.json.psi.JsonFile;
+import com.intellij.json.psi.JsonProperty;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.PsiFile;
+import org.jetbrains.annotations.NotNull;
+
+public class JsonRainbowVisitor extends RainbowVisitor {
+  @Override
+  public boolean suitableForFile(@NotNull PsiFile file) {
+    return file instanceof JsonFile;
+  }
+
+  @Override
+  public void visit(@NotNull PsiElement element) {
+    if (element instanceof JsonProperty) {
+      addInfo(getInfo(element.getContainingFile(), element, ((JsonProperty)element).getName(), JsonSyntaxHighlighterFactory.JSON_PROPERTY_KEY));
+    }
+  }
+
+  @NotNull
+  @Override
+  public HighlightVisitor clone() {
+    return new JsonRainbowVisitor();
+  }
+}

platform/platform-resources/src/META-INF/JsonPlugin.xml

@@ -108,6 +108,7 @@
     <lang.lineWrapStrategy language="JSON" implementationClass="com.intellij.json.formatter.JsonLineWrapPositionStrategy"/>
     <gotoDeclarationHandler implementation="com.jetbrains.jsonSchema.impl.JsonSchemaGotoDeclarationHandler"/>
     <copyPastePostProcessor implementation="com.intellij.json.editor.JsonCopyPastePostProcessor"/>
+    <highlightVisitor implementation="com.intellij.json.highlighting.JsonRainbowVisitor"/>
   </extensions>
   <extensions defaultExtensionNs="JavaScript">
     <JsonSchema.ProviderFactory implementation="com.jetbrains.jsonSchema.extension.JsonSchemaUserDefinedProviderFactory"/>