8371480: VerifyError after JDK-8369654

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java

@@ -3971,7 +3971,7 @@ else if (compound.tail.isEmpty())
      * Return the minimum types of a closure, suitable for computing
      * compoundMin or glb.
      */
-    private List<Type> closureMin(List<Type> cl) {
+    public List<Type> closureMin(List<Type> cl) {
         ListBuffer<Type> classes = new ListBuffer<>();
         ListBuffer<Type> interfaces = new ListBuffer<>();
         Set<Type> toSkip = new HashSet<>();

src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/Code.java

@@ -1854,14 +1854,17 @@ private Type erasedSuper(Type t1, Type t2) {
             } else {
                 t1 = types.skipTypeVars(t1, false);
                 t2 = types.skipTypeVars(t2, false);
-                List<Type> intersection = types.intersect(
-                        t1.hasTag(ARRAY) ?
-                                List.of(syms.serializableType, syms.cloneableType, syms.objectType) :
-                                types.erasedSupertypes(t1),
-                        t2.hasTag(ARRAY) ?
-                                List.of(syms.serializableType, syms.cloneableType, syms.objectType) :
-                                types.erasedSupertypes(t2));
-                return intersection.head;
+                List<Type> result = types.closureMin(
+                        types.intersect(
+                            t1.hasTag(ARRAY) ?
+                                    List.of(syms.serializableType, syms.cloneableType, syms.objectType) :
+                                    types.erasedSupertypes(t1),
+                            t2.hasTag(ARRAY) ?
+                                    List.of(syms.serializableType, syms.cloneableType, syms.objectType) :
+                                    types.erasedSupertypes(t2)
+                        )
+                );
+                return result.head;
             }
         }
 

test/langtools/tools/javac/switchexpr/VerifierErrorWrongSuperTypeTest.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @summary VerifyError after JDK-8369654, incorrect supertype
+ * @library /tools/lib
+ * @modules jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.main
+ *          jdk.compiler/com.sun.tools.javac.util
+ *          jdk.compiler/com.sun.tools.javac.code
+ * @build toolbox.ToolBox toolbox.JavacTask
+ * @run main VerifierErrorWrongSuperTypeTest
+ */
+
+import java.util.*;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import toolbox.TestRunner;
+import toolbox.ToolBox;
+import toolbox.JavaTask;
+import toolbox.JavacTask;
+import toolbox.Task;
+import toolbox.Task.OutputKind;
+
+public class VerifierErrorWrongSuperTypeTest extends TestRunner {
+    ToolBox tb;
+
+    VerifierErrorWrongSuperTypeTest() {
+        super(System.err);
+        tb = new ToolBox();
+    }
+
+    protected void runTests() throws Exception {
+        runTests(m -> new Object[]{Paths.get(m.getName())});
+    }
+
+    Path[] findJavaFiles(Path... paths) throws IOException {
+        return tb.findJavaFiles(paths);
+    }
+
+    public static void main(String... args) throws Exception {
+        VerifierErrorWrongSuperTypeTest t = new VerifierErrorWrongSuperTypeTest();
+        t.runTests();
+    }
+
+    @Test
+    public void testCompatibilityAfterMakingSuperclassSealed(Path base) throws Exception {
+        Path src = base.resolve("src");
+        Path pkg = src.resolve("p");
+        Path v = pkg.resolve("V");
+        tb.writeJavaFiles(v,
+                """
+                package p;
+                public abstract class V {}
+                """
+        );
+        Path d = pkg.resolve("D");
+        tb.writeJavaFiles(d,
+                """
+                package p;
+                public abstract class D extends V implements Cloneable {}
+                """
+        );
+        Path a = pkg.resolve("A");
+        tb.writeJavaFiles(a,
+                """
+                package p;
+                public class A extends V implements Cloneable {}
+                """
+        );
+        Path t = src.resolve("T");
+        tb.writeJavaFiles(t,
+                """
+                import p.A;
+                import p.D;
+                import p.V;
+                class T {
+                    public static void main(String[] args) {
+                        new T().foo(false, null);
+                    }
+                    void foo(boolean b, D d) {
+                        V u = b ? d : new A();
+                        g(u);
+                    }
+                    void g(V u) {}
+                }
+                """
+        );
+        Path out = base.resolve("out");
+        Files.createDirectories(out);
+        new JavacTask(tb)
+                .outdir(out)
+                .files(findJavaFiles(src))
+                .run();
+
+        try {
+            new JavaTask(tb)
+                    .classpath(out.toString())
+                    .classArgs("T")
+                    .run();
+        } catch (Throwable error) {
+            throw new AssertionError("execution failed");
+        }
+    }
+}