Internal error in FSI: FS0192: binding null type in envBindTypeRef

[KevinRansom]

Opened by: swlaschin2

I can reproduce this error in FSI in VS2012 , VS2013 and in tryFsharp.org

• In VS2012 and VS2013
  error FS0192: internal error: binding null type in envBindTypeRef
• In tryFsharp.org (as of 2014-12-09)
  error FS0193: internal error: Error 0x2115.
  Here is a minimal example that causes the error:

// fails to compile
// error FS0192: internal error: binding null type in envBindTypeRef
let ``1,`` x = 
    [||] |> Array.fold (+) ","

But minor variants of the code do compile!

// remove comma from function name and it compiles, so the function name is involved?        
let ``1`` x = 
    [||] |> Array.fold (+) ","
// change fold to map and it compiles, so something to do with fold as well?        
let ``1,`` x = 
    [||] |> Array.map ((+) "")

Not sure if it is related to: #10