What steps will reproduce the problem? 1. hg clone https://code.google.com/p/fast-member/ 2. cd fast-member 3. C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe .\FastMember.sln

What is the expected output? What do you see instead? Build Successful ( this did work initially when the project was released last night. this is on a different machine )

What version of the product are you using? On what operating system? head 1.0.0.2 i believe

Please provide any additional information below. VS2010 on a Win7 x64 machine.

I've seen the same problem, for some reason the project has the "LangVersion" set to "ISO-1", see http://code.google.com/p/fast-member/source/browse/FastMember/FastMember.csproj#25

A workaround it to manually change it under "Project Properties" -> Build -> Advanced and set "Language Version" to "Default"

I can't build either unless I remove the LangVersion element from the project file, which presumably is the default.