testdata for IDEA-136581

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/newMethodRef/IDEA136581.java

@@ -0,0 +1,57 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static java.util.stream.Collectors.*;
+
+class Main {
+  public static void main(String... args) {
+    final List<TestReferences> entities = new ArrayList<>();
+    entities.add(new TestReferences(1, 2));
+    entities.add(new TestReferences(3, 4));
+
+    process(entities);
+  }
+
+  private static Map<Integer, Set<Integer>> process(List<? extends References> entities) {
+    return entities.stream()
+      .collect(groupingBy(References::getGroupById,
+                          mapping(References::getOtherId, toSet())));
+  }
+
+  public static interface References {
+    int getGroupById();
+
+    int getOtherId();
+  }
+
+  public static class TestReferences implements References {
+    private int groupById;
+
+    private int otherId;
+
+    public TestReferences(int groupById, int otherId) {
+      this.groupById = groupById;
+      this.otherId = otherId;
+    }
+
+    @Override
+    public int getGroupById() {
+      return groupById;
+    }
+
+    public void setGroupById(int groupById) {
+      this.groupById = groupById;
+    }
+
+    @Override
+    public int getOtherId() {
+      return otherId;
+    }
+
+    public void setOtherId(int otherId) {
+      this.otherId = otherId;
+    }
+  }
+}