javac printed a scary message that looks like a javac bug when invoked with a modulepath to a JAR file that does not exist:

$ javac -mp missing.jar Test.java
An exception has occurred in the compiler (9-internal). 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 and the following diagnostic in your report. Thank you.
java.nio.file.FileSystemNotFoundException: missing.jar
at jdk.nio.zipfs.ZipFileSystem.<init>(jdk.zipfs@9-internal/ZipFileSystem.java:102)
at jdk.nio.zipfs.ZipFileSystemProvider.newFileSystem(jdk.zipfs@9-internal/ZipFileSystemProvider.java:136)
at java.nio.file.FileSystems.newFileSystem(java.base@9-internal/FileSystems.java:411)
at com.sun.tools.javac.file.Locations$ModulePathLocationHandler$ModulePathIterator.inferModuleName(jdk.compiler@9-internal/Locations.java:1055)
at com.sun.tools.javac.file.Locations$ModulePathLocationHandler$ModulePathIterator.scanFile(jdk.compiler@9-internal/Locations.java:1030)
at com.sun.tools.javac.file.Locations$ModulePathLocationHandler$ModulePathIterator.hasNext(jdk.compiler@9-internal/Locations.java:953)
at com.sun.tools.javac.code.ModuleFinder$ModuleLocationIterator.hasNext(jdk.compiler@9-internal/ModuleFinder.java:122)
at com.sun.tools.javac.code.ModuleFinder.scanModulePath(jdk.compiler@9-internal/ModuleFinder.java:239)
at com.sun.tools.javac.code.ModuleFinder.findAllModules(jdk.compiler@9-internal/ModuleFinder.java:175)
at com.sun.tools.javac.comp.Modules.getUnnamedModuleCompleter(jdk.compiler@9-internal/Modules.java:945)
at com.sun.tools.javac.comp.Modules.setCompilationUnitModules(jdk.compiler@9-internal/Modules.java:362)
at com.sun.tools.javac.comp.Modules.enter(jdk.compiler@9-internal/Modules.java:212)
at com.sun.tools.javac.main.JavaCompiler.initModules(jdk.compiler@9-internal/JavaCompiler.java:1020)
at com.sun.tools.javac.main.JavaCompiler.initModules(jdk.compiler@9-internal/JavaCompiler.java:1012)
at com.sun.tools.javac.main.JavaCompiler.compile(jdk.compiler@9-internal/JavaCompiler.java:906)
at com.sun.tools.javac.main.Main.compile(jdk.compiler@9-internal/Main.java:269)
at com.sun.tools.javac.main.Main.compile(jdk.compiler@9-internal/Main.java:144)
at com.sun.tools.javac.Main.compile(jdk.compiler@9-internal/Main.java:55)
at com.sun.tools.javac.Main.main(jdk.compiler@9-internal/Main.java:41)