ADDITIONAL SYSTEM INFORMATION :
> javac -version
javac 21.0.2

A DESCRIPTION OF THE PROBLEM :
Attempting to compile "instanceof" pattern matching with record destructuring, using 'var' for member type and an annotation on the member makes javac fail with an AssertionError (not a regular compilation error!).

Example expression which causes compiler to fail - note using an annotation and 'var':

    other instanceof Record(@Annotation var y)

See also "Steps to Reproduce" for full source code which reproduces the problem.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Attempt to compile the following file (Record.java) using javac, version 21.0.2:

package com.example.bugreport.java21;

import java.util.Objects;

record Record(
        @Annotation long x
) {

    public boolean isEqual(Object other) {
        return (other instanceof Record(@Annotation var y)) // Error here: both an annotation and 'var' must be present
                && x == y;
    }

}

@interface Annotation {}


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Code either compiles or a (reasonable) compilation error is printed.
ACTUAL -
An exception has occurred in the compiler (21.0.2). Please file a bug against the Java compiler via the Java bug reporting page (https://bugreport.java.com) after checking the Bug Database (https://bugs.java.com) for duplicates. Include your program, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
java.lang.AssertionError
        at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:155)
        at jdk.compiler/com.sun.tools.javac.util.Assert.checkNonNull(Assert.java:62)
        at jdk.compiler/com.sun.tools.javac.comp.Check.validateTypeAnnotation(Check.java:3332)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitAnnotation(Attr.java:5725)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCAnnotation.accept(JCTree.java:3039)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:58)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitModifiers(TreeScanner.java:399)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCModifiers.accept(JCTree.java:3068)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitVarDef(Attr.java:5765)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:1022)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitBindingPattern(TreeScanner.java:309)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBindingPattern.accept(JCTree.java:2310)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:58)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitRecordPattern(TreeScanner.java:334)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCRecordPattern.accept(JCTree.java:2463)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitTypeTest(TreeScanner.java:305)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitTypeTest(Attr.java:5779)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCInstanceOf.accept(JCTree.java:2236)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitParens(TreeScanner.java:276)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCParens.accept(JCTree.java:2033)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitBinary(TreeScanner.java:294)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBinary.accept(JCTree.java:2175)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.visitReturn(TreeScanner.java:235)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1728)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:58)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitBlock(Attr.java:5822)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1092)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitMethodDef(Attr.java:5758)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:916)
        at jdk.compiler/com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:50)
        at jdk.compiler/com.sun.tools.javac.comp.Attr$TypeAnnotationsValidator.visitClassDef(Attr.java:5817)
        at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:814)
        at jdk.compiler/com.sun.tools.javac.comp.Attr.validateTypeAnnotations(Attr.java:5714)
        at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:5688)
        at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5543)
        at jdk.compiler/com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5367)
        at jdk.compiler/com.sun.tools.javac.comp.Attr.attrib(Attr.java:5306)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1359)
        at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:976)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
        at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)
        at org.codehaus.plexus.compiler.javac.JavaxToolsCompiler.compileInProcess(JavaxToolsCompiler.java:126)
        at org.codehaus.plexus.compiler.javac.JavacCompiler.performCompile(JavacCompiler.java:169)
        at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:1188)
        at org.apache.maven.plugin.compiler.CompilerMojo.execute(CompilerMojo.java:212)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:126)
        at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2(MojoExecutor.java:328)
        at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute(MojoExecutor.java:316)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:174)
        at org.apache.maven.lifecycle.internal.MojoExecutor.access$000(MojoExecutor.java:75)
        at org.apache.maven.lifecycle.internal.MojoExecutor$1.run(MojoExecutor.java:162)
        at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute(DefaultMojosExecutionStrategy.java:39)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:159)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:105)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:73)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:53)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:118)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:261)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:173)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:101)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:906)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:283)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:206)
        at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
        at java.base/java.lang.reflect.Method.invoke(Method.java:580)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:283)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:226)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:407)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:348)


CUSTOMER SUBMITTED WORKAROUND :
Use explicit type instead of 'var'.

FREQUENCY : always