--- a/src/Pure/Syntax/syntax.ML Tue Mar 29 20:53:52 2016 +0200
+++ b/src/Pure/Syntax/syntax.ML Tue Mar 29 21:17:29 2016 +0200
@@ -602,9 +602,9 @@
fun guess_infix (Syntax ({gram, ...}, _)) c =
(case Parser.guess_infix_lr (Lazy.force gram) c of
SOME (s, l, r, j) => SOME
- (if l then Mixfix.Infixl (s, j)
- else if r then Mixfix.Infixr (s, j)
- else Mixfix.Infix (s, j))
+ (if l then Mixfix.Infixl (Input.string s, j, Position.no_range)
+ else if r then Mixfix.Infixr (Input.string s, j, Position.no_range)
+ else Mixfix.Infix (Input.string s, j, Position.no_range))
| NONE => NONE);