src/Doc/Isar_Ref/Inner_Syntax.thy

   \item Type constraints for terms bind very weakly.  For example,
   @{text "x < y :: nat"} is normally parsed as @{text "(x < y) ::
   nat"}, unless @{text "<"} has a very low priority, in which case the
   input is likely to be ambiguous.  The correct form is @{text "x < (y
   :: nat)"}.
-
-  \item Constraints may be either written with two literal colons
-  ``@{verbatim "::"}'' or the double-colon symbol @{verbatim "\<Colon>"},
-  which actually looks exactly the same in some {\LaTeX} styles.
 
   \item Dummy variables (written as underscore) may occur in different
   roles.
 
   \begin{description}