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--></style></head><body lang=ZH-CN style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hello! I found a severe bug when pattern-matching switches are nested.</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>My Java version:</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>openjdk 19 2022-09-20</span></p><p class=MsoNormal><span lang=EN-US>OpenJDK Runtime Environment (build 19+37)</span></p><p class=MsoNormal><span lang=EN-US>OpenJDK 64-Bit Server VM (build 19+37, mixed mode, sharing)</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The code that triggers ICE (just a ordinary unification algorithm):</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>public class Bug {</span></p><p class=MsoNormal><span lang=EN-US> sealed interface Term {</span></p><p class=MsoNormal><span lang=EN-US> record Mula(Formula formula) implements Term {}</span></p><p class=MsoNormal><span lang=EN-US> record I() implements Term {}</span></p><p class=MsoNormal><span lang=EN-US> record U() implements Term {}</span></p><p class=MsoNormal><span lang=EN-US> }</span></p><p class=MsoNormal><span lang=EN-US> sealed interface Formula {</span></p><p class=MsoNormal><span lang=EN-US> record Lit(boolean left) implements Formula {}</span></p><p class=MsoNormal><span lang=EN-US> record Inv(Term i) implements Formula {}</span></p><p class=MsoNormal><span lang=EN-US> }</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US> public static Term compare(Term preLhs, Term preRhs) {</span></p><p class=MsoNormal><span lang=EN-US> return switch (preLhs) {</span></p><p class=MsoNormal><span lang=EN-US> case Term.I i -> new Term.U();</span></p><p class=MsoNormal><span lang=EN-US> case Term.U u -> new Term.U();</span></p><p class=MsoNormal><span lang=EN-US> case Term.Mula lhs -> {</span></p><p class=MsoNormal><span lang=EN-US> if (!(preRhs instanceof Term.Mula rhs)) yield null;</span></p><p class=MsoNormal><span lang=EN-US> var happy = switch (lhs.formula()) {</span></p><p class=MsoNormal><span lang=EN-US> case Formula.Lit ll when rhs.formula() instanceof Formula.Lit rr -> ll.left() == rr.left();</span></p><p class=MsoNormal><span lang=EN-US> case Formula.Inv ll when rhs.formula() instanceof Formula.Inv rr -></span></p><p class=MsoNormal><span lang=EN-US> compare(ll.i(), rr.i()) != null;</span></p><p class=MsoNormal><span lang=EN-US> default -> false;</span></p><p class=MsoNormal><span lang=EN-US> };</span></p><p class=MsoNormal><span lang=EN-US> yield happy ? new Term.I() : null;</span></p><p class=MsoNormal><span lang=EN-US> }</span></p><p class=MsoNormal><span lang=EN-US> };</span></p><p class=MsoNormal><span lang=EN-US> }</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US> public static void main(String[] args) {</span></p><p class=MsoNormal><span lang=EN-US> System.out.println(System.getProperty("java.version"));</span></p><p class=MsoNormal><span lang=EN-US> }</span></p><p class=MsoNormal><span lang=EN-US>}</span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'>Throws this error randomly:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'>An exception has occurred in the compiler (19). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'>java.lang.AssertionError<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.util.Assert.check(Assert.java:46)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.code.Scope$ScopeImpl.leave(Scope.java:386)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1465)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1082)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:687)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:761)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1253)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:912)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:687)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribStat(Attr.java:761)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:5601)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5492)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5316)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.comp.Attr.attrib(Attr.java:5255)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1317)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:946)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:12.0pt;font-family:SimSun'> at org.gradle.internal.compiler.java.IncrementalCompileTask.call(IncrementalCompileTask.java:89)<o:p></o:p></span></p></div></body></html>