Trying to find the root cause of https://github.com/Microsoft/visualfsharp/issues/380

gistfile1.fs

#if INTERACTIVE
#r "..\\packages\\FSharp.Compiler.Service.0.0.89\\lib\\net45\\FSharp.Compiler.Service.dll"
#endif

open System
open Microsoft.FSharp.Compiler.SourceCodeServices

let sourceTok = FSharpSourceTokenizer([], "C:\\test.fsx")

let lines = """
type Foo = class end

type Bar = interface
    abstract Baz: Foo: string -> int
end
"""

let rec tokenizeLine (tokenizer:FSharpLineTokenizer) state =
    match tokenizer.ScanToken(state) with
    | Some tok, state ->
        printf "%s " tok.TokenName
        tokenizeLine tokenizer state
    | None, satte -> state

let rec tokenizeLines state count lines =
    match lines with
    | line::lines ->
        printfn "\nLine %d" count
        let tokenizer = sourceTok.CreateLineTokenizer(line)
        let state = tokenizeLine tokenizer state
        tokenizeLines state (count + 1) lines
    | [] -> ()

lines.Split('\r', '\n')
|> List.ofSeq
|> tokenizeLines 0L 1

gistfile2.txt

Line 1

Line 2
TYPE WHITESPACE IDENT WHITESPACE EQUALS WHITESPACE CLASS WHITESPACE END 
Line 3

Line 4
TYPE WHITESPACE IDENT WHITESPACE EQUALS WHITESPACE INTERFACE 
Line 5
WHITESPACE ABSTRACT WHITESPACE IDENT COLON WHITESPACE IDENT COLON WHITESPACE IDENT WHITESPACE RARROW WHITESPACE IDENT 
Line 6
END 
Line 7