CFG: provide "used as expression" in enum constant constructor

This allows to avoid
"unused return value of a function with lambda expression body"
for such a situation
So #KT-20429 Fixed

compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowProcessor.kt

@@ -1447,6 +1447,14 @@ class ControlFlowProcessor(private val trace: BindingTrace) {
             generateCallOrMarkUnresolved(call)
         }
 
+        override fun visitInitializerList(list: KtInitializerList) {
+            list.initializers
+                    .filterIsInstance<KtSuperTypeCallEntry>()
+                    .forEach {
+                        generateCallOrMarkUnresolved(it)
+                    }
+        }
+
         private fun generateCallOrMarkUnresolved(call: KtCallElement) {
             if (!generateCall(call)) {
                 val arguments = call.valueArguments.mapNotNull(ValueArgument::getArgumentExpression)

idea/testData/inspectionsLocal/unusedLambdaExpressionBody/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.UnusedLambdaExpressionBodyInspection

idea/testData/inspectionsLocal/unusedLambdaExpressionBody/inEnumEntry.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+enum class Test(f: () -> Unit) {
+    A(<caret>getFunc())
+}
+
+fun getFunc(): () -> Unit = {}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -3861,6 +3861,21 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
         }
     }
 
+    @TestMetadata("idea/testData/inspectionsLocal/unusedLambdaExpressionBody")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class UnusedLambdaExpressionBody extends AbstractLocalInspectionTest {
+        public void testAllFilesPresentInUnusedLambdaExpressionBody() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/inspectionsLocal/unusedLambdaExpressionBody"), Pattern.compile("^([\\w\\-_]+)\\.(kt|kts)$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("inEnumEntry.kt")
+        public void testInEnumEntry() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/unusedLambdaExpressionBody/inEnumEntry.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("idea/testData/inspectionsLocal/unusedReceiverParameter")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)