[Switch Expression][Sealed types] Switching on sealed interface insta…

…nce compiles even when the switch expression does not cover all possible input values (#2621)

* Fixes #2503

org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/ast/SwitchStatement.java

@@ -21,10 +21,8 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.function.IntPredicate;
@@ -1431,7 +1429,6 @@ private boolean checkAndFlagDefaultRecord(BlockScope skope, CompilerOptions comp
 		return false;
 	}
 	private boolean isExhaustiveWithCaseTypes(List<ReferenceBinding> allAllowedTypes,  List<TypeBinding> listedTypes) {
-		// first KISS (Keep It Simple Stupid)
 		int pendingTypes = allAllowedTypes.size();
 		for (ReferenceBinding pt : allAllowedTypes) {
 			/* Per JLS 14.11.1.1: A type T that names an abstract sealed class or sealed interface is covered
@@ -1450,63 +1447,7 @@ private boolean isExhaustiveWithCaseTypes(List<ReferenceBinding> allAllowedTypes
 				}
 			}
 		}
-		if (pendingTypes == 0)
-			return true;
-		// else - #KICKME (Keep It Complicated Keep Me Employed)"
-		List<TypeBinding> coveredTypes = new ArrayList<>(listedTypes);
-		List<ReferenceBinding> remainingTypes = new ArrayList<>(allAllowedTypes);
-		remainingTypes.removeAll(coveredTypes);
-
-		Map<TypeBinding, List<TypeBinding>> impliedTypes = new HashMap<>();
-
-		for (ReferenceBinding type : remainingTypes) {
-			impliedTypes.put(type, new ArrayList<>());
-			List<ReferenceBinding> typesToAdd = new ArrayList<>();
-			for (ReferenceBinding impliedType : allAllowedTypes) {
-				if (impliedType.equals(type)) continue;
-				if (type.isClass()) {
-					if (impliedType.isAbstract() && type.superclass().equals(impliedType)) {
-						typesToAdd.add(impliedType);
-					}
-					if (Arrays.asList(type.superInterfaces()).contains(impliedType))
-						typesToAdd.add(impliedType);
-				} else if (type.isInterface()) {
-					if (Arrays.asList(impliedType.superInterfaces()).contains(type))
-						typesToAdd.add(impliedType);
-				}
-			}
-			if (!typesToAdd.isEmpty()) {
-				impliedTypes.get(type).addAll(typesToAdd);
-			}
-		}
-		boolean delta = true;
-		while (delta) {
-			delta = false;
-			List<ReferenceBinding> typesToAdd = new ArrayList<>();
-			for (ReferenceBinding type : remainingTypes) {
-				boolean add = false;
-				if (type.isClass()) {
-					for (TypeBinding tb : impliedTypes.get(type)) {
-						if (coveredTypes.contains(tb)) {
-							add = true;
-							break;
-						}
-					}
-				} else if (type.isInterface()) {
-					add = coveredTypes.containsAll(impliedTypes.get(type));
-				}
-				if (add) {
-					typesToAdd.add(type);
-				}
-			}
-			if (!typesToAdd.isEmpty()) {
-				remainingTypes.removeAll(typesToAdd);
-				coveredTypes.addAll(typesToAdd);
-				typesToAdd.clear();
-				delta = true;
-			}
-		}
-		return remainingTypes.isEmpty();
+		return pendingTypes == 0;
 	}
 	private boolean needPatternDispatchCopy() {
 		if (this.containsPatterns || (this.switchBits & QualifiedEnum) != 0)