FULL PRODUCT VERSION :
java version "9"
Java(TM) SE Runtime Environment (build 9+179)
Java HotSpot(TM) 64-Bit Server VM (build 9+179, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.3.9600]

A DESCRIPTION OF THE PROBLEM :
Jshell crashing on autocompletion when tab is pressed more than 3 times

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Open jshell and press tab key 4 times

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Autocompletion in console

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1
        at java.base/java.lang.String.substring(String.java:1852)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext$AllSuggestionsCompletionTask.lambda$perform$1(ConsoleIOContext.java:524)
        at java.base/java.util.Optional.map(Optional.java:257)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext$AllSuggestionsCompletionTask.perform(ConsoleIOContext.java:524)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext.complete(ConsoleIOContext.java:287)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext.access$000(ConsoleIOContext.java:69)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext$1.complete(ConsoleIOContext.java:100)
        at jdk.internal.le/jdk.internal.jline.console.ConsoleReader.readLine(ConsoleReader.java:2684)
        at jdk.internal.le/jdk.internal.jline.console.ConsoleReader.readLine(ConsoleReader.java:2279)
        at jdk.jshell/jdk.internal.jshell.tool.ConsoleIOContext.readLine(ConsoleIOContext.java:139)
        at jdk.jshell/jdk.internal.jshell.tool.JShellTool.run(JShellTool.java:1140)
        at jdk.jshell/jdk.internal.jshell.tool.JShellTool.start(JShellTool.java:929)
        at jdk.jshell/jdk.internal.jshell.tool.JShellToolBuilder.run(JShellToolBuilder.java:239)
        at jdk.jshell/jdk.internal.jshell.tool.JShellToolProvider.main(JShellToolProvider.java:119)

REPRODUCIBILITY :
This bug can be reproduced always.