System.IndexOutOfRangeException from Microsoft.DotNet.Cli.CommandLine.StringExtensions.HasPrefix

[tmat]

>dotnet.exe msbuild ""
System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at System.String.get_Chars(Int32 index)
   at Microsoft.DotNet.Cli.CommandLine.StringExtensions.HasPrefix(String arg)
   at Microsoft.DotNet.Cli.CommandLine.StringExtensions.<Lex>d__7.MoveNext()
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source, Int32& length)
   at System.Collections.Generic.Queue`1..ctor(IEnumerable`1 collection)
   at Microsoft.DotNet.Cli.CommandLine.Parser.Parse(IReadOnlyCollection`1 rawArgs, Boolean isProgressive)
   at Microsoft.DotNet.Cli.CommandLine.Parser.Parse(String[] args)
   at Microsoft.DotNet.Cli.ParserExtensions.ParseFrom(Parser parser, String context, String[] args)
   at Microsoft.DotNet.Cli.Program.ProcessArgs(String[] args, ITelemetry telemetryClient)
   at Microsoft.DotNet.Cli.Program.Main(String[] args)

[peterhuene]

The check on

CliCommandLineParser/src/source/CommandLine/OptionError.cs

Line 19 in ed4799b

if (string.IsNullOrWhiteSpace(token))

should simply be for null, not for null or whitespace.