Fixes issue #4979 - Unboxed Primitive dominance checked

Author: mpalat

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

@@ -116,12 +116,12 @@ public boolean coversType(TypeBinding type, Scope scope) {
 	public boolean coversValue(Constant cst, BlockScope scope) {
 		if (!isUnguarded())
 			return false;
-		if (!(this.resolvedType instanceof BaseTypeBinding baseType))
+		if (!(this.resolvedType.unboxedType() instanceof BaseTypeBinding baseType))
 			return false;
 		if (!cst.isExactTestingConversion(baseType))
 			return false;
 		int constantTypeID = cst.typeID();
-		PrimitiveConversionRoute route = findPrimitiveConversionRoute(this.resolvedType, TypeBinding.wellKnownBaseType(constantTypeID), scope);
+		PrimitiveConversionRoute route = findPrimitiveConversionRoute(baseType, TypeBinding.wellKnownBaseType(constantTypeID), scope);
 		switch (route) {
 			// JLS §5.7.2:
 			case NARROWING_PRIMITVE_CONVERSION:

org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/PrimitiveInPatternsTest.java

@@ -30,7 +30,7 @@ public class PrimitiveInPatternsTest extends AbstractRegressionTest9 {
 	static {
 //		TESTS_NUMBERS = new int [] { 1 };
 //		TESTS_RANGE = new int[] { 1, -1 };
-//		TESTS_NAMES = new String[] { "testSwitchPrimitiveboolean_04" };
+//		TESTS_NAMES = new String[] { "testDominanceIssue4979_001" };
 	}
 	private String extraLibPath;
 	public static Class<?> testClass() {
@@ -7613,5 +7613,39 @@ public static void main(String[] args) {
 		"		#31 10.0\n";
 		verifyClassFile(expectedOutput, "X.class", ClassFileBytesDisassembler.SYSTEM);
 	}
+	public void testDominanceIssue4979_001() {
+		runNegativeTest(new String[] {
+			"X.java",
+				"""
+				public class X {
+					public int foo(Character c) {
+						int result = 0;
+						switch (c) {
+							case Character c1 -> {
+								result = c1;
+								break;
+							}
+							case 0 -> {  // Same goes for case (int) 0
+								result = 0;
+								break;
+							}
+						}
+						return result;
+					}
+				}
+				"""
+			},
+			"----------\n" +
+			"1. WARNING in X.java (at line 5)\n" +
+			"	case Character c1 -> {\n" +
+			"	     ^^^^^^^^^^^^\n" +
+			"You are using a preview language feature that may or may not be supported in a future release\n" +
+			"----------\n" +
+			"2. ERROR in X.java (at line 9)\n" +
+			"	case 0 -> {  // Same goes for case (int) 0\n" +
+			"	     ^\n" +
+			"This case label is dominated by one of the preceding case labels\n" +
+			"----------\n");
+	}
 
 }