use Optional.of() instead ofNullable() in "opt" postfix template when expression is not null

java/java-tests/testData/codeInsight/template/postfix/templates/opt/notNullMethodCall.java

@@ -0,0 +1,12 @@
+import org.jetbrains.annotations.NotNull;
+
+class Test {
+  @NotNull
+  String foo() {
+    return "";
+  }
+
+  void m() {
+    foo().opt<caret>
+  }
+}

java/java-tests/testData/codeInsight/template/postfix/templates/opt/notNullMethodCall_after.java

@@ -0,0 +1,12 @@
+import org.jetbrains.annotations.NotNull;
+
+class Test {
+  @NotNull
+  String foo() {
+    return "";
+  }
+
+  void m() {
+      java.util.Optional.of(foo())
+  }
+}

java/java-tests/testSrc/com/intellij/java/codeInsight/template/postfix/templates/OptionalPostfixTemplateTest.java

@@ -80,6 +80,12 @@ public class OptionalPostfixTemplateTest extends PostfixTemplateTestCase {
   public void testLong() {
     doTest();
   }
+
+  public void testNotNullMethodCall() {
+    myFixture.addClass("package org.jetbrains.annotations;" +
+                       "public @interface NotNull {}");
+    doTest();
+  }
   
   public void testDoNotExpandOnJavaLess8() {
     IdeaTestUtil.setModuleLanguageLevel(myModule, LanguageLevel.JDK_1_6, myFixture.getTestRootDisposable());