Java: Detect trivial duplicates containing conditional 'return' (IDEA-182195)

java/java-tests/testData/refactoring/extractMethod/NullableCheckVoidDuplicate_after.java

@@ -0,0 +1,29 @@
+import org.jetbrains.annotations.Nullable;
+
+public class NullableCheckVoidDuplicate {
+    void foo() {
+        Object o = newMethod();
+        if (o == null) return;
+        System.out.println(o);
+    }
+
+    @Nullable
+    private Object newMethod() {
+        Object o = "";
+        for (int i = 0; i < 5; i++) {
+            if (i == 10) {
+                o = null;
+            }
+        }
+        if (o == null) {
+            return null;
+        }
+        return o;
+    }
+
+    void bar() {
+        Object o = newMethod();
+        if (o == null) return;
+        System.out.println(o);
+    }
+}