test for union types

test/org/jetbrains/java/decompiler/SingleClassesTest.java

@@ -112,6 +112,7 @@ public class SingleClassesTest {
   @Test public void testVarArgCalls() { doTest("pkg/TestVarArgCalls"); }
   @Test public void testLambdaParams() { doTest("pkg/TestLambdaParams"); }
   @Test public void testInterfaceMethods() { doTest("pkg/TestInterfaceMethods"); }
+  //@Test public void testUnionType() { doTest("pkg/TestUnionType"); } //TODO: fix
 
   private void doTest(String testFile, String... companionFiles) {
     ConsoleDecompiler decompiler = fixture.getDecompiler();

testData/results/TestUnionType.dec

@@ -0,0 +1,28 @@
+package pkg;
+
+import java.io.Serializable;
+import java.util.Comparator;
+
+public interface TestUnionType {
+   static Comparator comparingInt() {
+      return (Comparator & Serializable)((c1, c2) -> {// 8
+         return 1;
+      }));
+   }
+}
+
+class 'pkg/TestUnionType' {
+   method 'lambda$comparingInt$ff46620a$1 (Ljava/lang/Object;Ljava/lang/Object;)I' {
+      0      8
+      1      8
+   }
+
+   method 'comparingInt ()Ljava/util/Comparator;' {
+      5      7
+      8      7
+      b      7
+   }
+}
+
+Lines mapping:
+8 <-> 8

testData/src/pkg/TestUnionType.java

@@ -0,0 +1,10 @@
+package pkg;
+
+import java.io.Serializable;
+import java.util.Comparator;
+
+public interface TestUnionType {
+  public static Comparator comparingInt() {
+    return (Comparator & Serializable)(c1, c2) -> 1;
+  }
+}