From 656af653434cdcd5400d8f2b608cd2b31157fd7a Mon Sep 17 00:00:00 2001
From: Manoj  N Palat <manoj.palat@in.ibm.com>
Date: Wed, 16 Aug 2023 11:18:37 +0530
Subject: [PATCH] Fixes #587 [pattern switch] Parameterized Type check in
 exhaustiveness (#1292)

---
 .../lookup/ParameterizedTypeBinding.java      | 11 ++++++++-
 .../regression/SwitchPatternTest.java         | 24 ++++++++++++++++++-
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/ParameterizedTypeBinding.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/ParameterizedTypeBinding.java
index df833128834..b8a2e4d1b35 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/ParameterizedTypeBinding.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/lookup/ParameterizedTypeBinding.java
@@ -1111,7 +1111,16 @@ public ReferenceBinding[] permittedTypes() {
 		ReferenceBinding[] permTypes = this.type.permittedTypes();
 		List<ReferenceBinding> applicablePermTypes = new ArrayList<>();
 		for (ReferenceBinding pt : permTypes) {
-			if (pt.isCompatibleWith(this))
+			ReferenceBinding permittedTypeAvatar = pt;
+			if (pt.isRawType()) {
+				ReferenceBinding ptRef = pt.actualType();
+				// don't use TypeSystem.getParameterizedType below as this is just for temporary check.
+				ParameterizedTypeBinding ptb = new ParameterizedTypeBinding(ptRef, this.arguments, ptRef.enclosingType(), this.environment);
+				ptb.superclass();
+				ptb.superInterfaces();
+				permittedTypeAvatar = ptb;
+			}
+			if (permittedTypeAvatar.isCompatibleWith(this))
 				applicablePermTypes.add(pt);
 		}
 		return applicablePermTypes.toArray(new ReferenceBinding[0]);
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java
index b6d4e4379b1..3d0fb5929e3 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchPatternTest.java
@@ -33,7 +33,7 @@ public class SwitchPatternTest extends AbstractRegressionTest9 {
 	static {
 //		TESTS_NUMBERS = new int [] { 40 };
 //		TESTS_RANGE = new int[] { 1, -1 };
-//		TESTS_NAMES = new String[] { "testRecPatExhaust"};
+//		TESTS_NAMES = new String[] { "testIssue587_001"};
 	}
 
 	private static String previewLevel = "21";
@@ -6228,4 +6228,26 @@ public void testIssue1126b() {
 				"1\n" +
 				"0");
 	}
+	public void testIssue587_001() {
+		runConformTest(
+				new String[] {
+					"X.java",
+					"public class X {\n"+
+					"  sealed interface I<T> permits A, B {}\n"+
+					"  final static class A<T> implements I<String> {}\n"+
+					"  final static class B<Y> implements I<Y> {}\n"+
+					"\n"+
+					"  static int testGenericSealedExhaustive(I<Integer> i) {\n"+
+					"    return switch (i) {\n"+
+					"      // Exhaustive as no A case possible!\n"+
+					"      case B<Integer> bi -> 42;\n"+
+					"    };\n"+
+					"  }\n"+
+					"  public static void main(String[] args) {\n"+
+					"       System.out.println(testGenericSealedExhaustive(new B<Integer>()));\n"+
+					"  }\n"+
+					"}",
+				},
+				"42");
+	}
 }