[java-intention] When creating a new method, declare it with fresh generic type to allow more flexible inference

Fixes IDEA-314907 code generation: return type not recognized by idea when it is a generic type

GitOrigin-RevId: 878d6f9d48315fdadb499a65dc8cfe5db57234d7

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/createMethodFromUsage/afterFailedInference.java

@@ -0,0 +1,26 @@
+// "Create method 'list'" "true-preview"
+import java.util.List;
+
+class MainService {
+    public List<Data> list() {
+        <selection><caret>return null;</selection>
+    }
+}
+
+class MainController {
+  private final MainService service = new MainService();
+  public Wrapper<List<Data>> listData() {
+    return Wrapper.wrap(service.list());
+  }
+}
+
+class Wrapper<T> {
+  private T data;
+  public static <T> Wrapper<T> wrap(T t) {
+    Wrapper<T> res = new Wrapper<>();
+    res.data = t;
+    return res;
+  }
+}
+
+interface Data {}

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/createMethodFromUsage/beforeFailedInference.java

@@ -0,0 +1,23 @@
+// "Create method 'list'" "true-preview"
+import java.util.List;
+
+class MainService {
+}
+
+class MainController {
+  private final MainService service = new MainService();
+  public Wrapper<List<Data>> listData() {
+    return Wrapper.wrap(service.<caret>list());
+  }
+}
+
+class Wrapper<T> {
+  private T data;
+  public static <T> Wrapper<T> wrap(T t) {
+    Wrapper<T> res = new Wrapper<>();
+    res.data = t;
+    return res;
+  }
+}
+
+interface Data {}