New JoinVarArgsContains inspection that will detect multiple .contains(), .doesNotContain(), and .containsOnlyOnce() calls within the same statement that could be joined together using variadic arguments.

src/test/resources/inspections/GuavaOptional/GuavaOptionalBefore.java

@@ -31,6 +31,13 @@ public class GuavaOptional {
         assertThat(opt.orNull()).isNotEqualTo(null);
         assertThat(opt.orNull()).isNotNull();
 
+        //assertThat(opt.get()).isEqualTo(opt.get()); // there's a better version than contains(opt.get())
+        assertThat(opt.orNull()).isEqualTo(opt.get());
+        //assertThat(opt.get()).isEqualTo(opt.orNull()); // there's a better version than contains(opt.orNull())
+
+        assertThat(opt).contains(opt.get());
+        assertThat(opt).contains(opt.orNull());
+
         String possibleNullString = System.getProperty("username");
         String notNullString = "Narf";