OutOfMemoryException in HelpText.AddLine

[qmfrederik]

After upgrading to the latest prerelease version, I'm seeing some of my unit tests fail because of what appears to be an infinite loop in HelpText.AddLine.

Basically, it looks like the same value is being added to the StringBuilder in a loop, until the system runs out of memory.

Stack trace:

System.OutOfMemoryException : Insufficient memory to continue the execution of the program.
at System.Text.StringBuilder.ExpandByABlock(Int32 minBlockCharCount)
at System.Text.StringBuilder.Append(Char* value, Int32 valueCount)
at System.Text.StringBuilder.AppendHelper(String value)
at System.Text.StringBuilder.Append(String value)
at CommandLine.Text.HelpText.AddLine(StringBuilder builder, String value, Int32 maximumLength)
at CommandLine.Text.HelpText.DefaultParsingErrorsHandler[T](ParserResult`1 parserResult, HelpText current)
at CommandLine.Text.HelpText.AutoBuild[T](ParserResult`1 parserResult, Func`2 onError, Func`2 onExample, Boolean verbsIndex, Int32 maxDisplayWidth)
at CommandLine.Parser.<>c__DisplayClass17_0`1.<DisplayHelp>b__1(IEnumerable`1 _, TextWriter writer)
at CSharpx.MaybeExtensions.Do[T1,T2](Maybe`1 maybe, Action`2 action)
at CommandLine.ParserResultExtensions.WithNotParsed[T](ParserResult`1 result, Action`1 action)
at CommandLine.Parser.DisplayHelp[T](ParserResult`1 parserResult, TextWriter helpWriter, Int32 maxDisplayWidth)

[nemec]

Thanks for looking into this!