instance variable initialization: don't warn on nullables (IDEA-120189)

plugins/InspectionGadgets/InspectionGadgetsAnalysis/src/com/siyeh/ig/initialization/InstanceVariableInitializationInspection.java

@@ -15,6 +15,7 @@
  */
 package com.siyeh.ig.initialization;
 
+import com.intellij.codeInsight.NullableNotNullManager;
 import com.intellij.codeInsight.daemon.ImplicitUsageProvider;
 import com.intellij.codeInspection.ui.SingleCheckboxOptionsPanel;
 import com.intellij.openapi.extensions.Extensions;
@@ -93,6 +94,9 @@ public class InstanceVariableInitializationInspection extends BaseInspection {
       if (field.getInitializer() != null) {
         return;
       }
+      if (NullableNotNullManager.isNullable(field)) {
+        return;
+      }
       if (m_ignorePrimitives) {
         final PsiType fieldType = field.getType();
         if (ClassUtils.isPrimitive(fieldType)) {

plugins/InspectionGadgets/test/com/siyeh/igtest/initialization/field/InstanceVariableInitialization.java

@@ -99,4 +99,8 @@ class D {
   D() {
     for (Object o : l = new java.util.ArrayList()) {}
   }
+}
+class WithNullable {
+  @org.jetbrains.annotations.Nullable
+  private String str;
 }