check

book.tex

@@ -12790,7 +12790,11 @@ definitions does not matter).
   function parameters, for example, to handle keyword parameters and
   defaults. The type checker in \code{type\_check\_Lfun} converts the
   more commplex syntax into the simpler syntax of
-  Figure~\ref{fig:Rfun-syntax}.}
+  Figure~\ref{fig:Rfun-syntax}. The fourth and sixth parameters of the
+  \code{FunctionDef} constructor are for decorators and a type
+  comment, neither of which are used by our compiler. We recommend
+  replacing them with \code{None} in the \code{shrink} pass.
+}
 %
 The concrete syntax for function application\index{subject}{function
   application} is $\CAPPLY{\Exp}{\Exp \ldots}$ where the first expression

defs.tex

@@ -296,7 +296,7 @@
 \newcommand{\CRETURN}[1]{\key{return}~#1}
 \newcommand{\GOTO}[1]{\key{Goto}\LP #1 \RP}
 \newcommand{\CGOTO}[1]{\key{goto}~#1}
-\newcommand{\FUNDEF}[5]{\key{FunctionDef}\LP#1\key{, }#2\key{, }#3\key{, }#5\RP}
+\newcommand{\FUNDEF}[5]{\key{FunctionDef}\LP#1\key{, }#2\key{, }#3\key{, None}\key{, }#5\key{, None}\RP}
 \fi
 
 \newcommand{\SEQ}[2]{\key{(Seq}~#1~#2\key{)}}