Java: Add conditional return when replacing duplicate fragment (IDEA-180601)

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

@@ -0,0 +1,24 @@
+class Conditional {
+    int[] bar(String[] s) {
+        <selection>
+        if (s != null) {
+            int[] n = new int[s.length];
+            for (int i = 0; i < s.length; i++) {
+                n[i] = s[i].length();
+            }
+            return n;
+        }</selection>
+        return new int[0];
+    }
+
+    int[] baz(String[] z) {
+        if (z != null) {
+            int[] n = new int[z.length];
+            for (int i = 0; i < z.length; i++) {
+                n[i] = z[i].length();
+            }
+            return n;
+        }
+        return new int[0];
+    }
+}

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

@@ -0,0 +1,25 @@
+class Conditional {
+    int[] bar(String[] s) {
+
+        int[] n = newMethod(s);
+        if (n != null) return n;
+        return new int[0];
+    }
+
+    private int[] newMethod(String[] s) {
+        if (s != null) {
+            int[] n = new int[s.length];
+            for (int i = 0; i < s.length; i++) {
+                n[i] = s[i].length();
+            }
+            return n;
+        }
+        return null;
+    }
+
+    int[] baz(String[] z) {
+        int[] n = newMethod(z);
+        if (n != null) return n;
+        return new int[0];
+    }
+}

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

@@ -0,0 +1,18 @@
+class Conditional {
+    int bar(String s) {<selection>
+        if (s != null) {
+            int n = s.length;
+            return n;
+        }</selection>
+        return 0;
+    }
+
+    int baz(String z) {
+        int x = -1;
+        if (z != null) {
+            int n = z.length;
+            x = n;
+        }
+        return 0;
+    }
+}

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

@@ -0,0 +1,27 @@
+import org.jetbrains.annotations.Nullable;
+
+class Conditional {
+    int bar(String s) {
+        Integer n = newMethod(s);
+        if (n != null) return n;
+        return 0;
+    }
+
+    @Nullable
+    private Integer newMethod(String s) {
+        if (s != null) {
+            int n = s.length;
+            return n;
+        }
+        return null;
+    }
+
+    int baz(String z) {
+        int x = -1;
+        if (z != null) {
+            int n = z.length;
+            x = n;
+        }
+        return 0;
+    }
+}