CWG2627 Bit-fields and narrowing conversions

Author: burblebee

source/declarations.tex

@@ -5993,8 +5993,18 @@
 original type, or
 
 \item from an integer type or unscoped enumeration type to an integer type that cannot
-represent all the values of the original type, except where the source is a constant
+represent all the values of the original type, except where
+\begin{itemize}
+\item
+the source is a bit-field whose width $w$ is less than that of its type
+(or, for an enumeration type, its underlying type) and
+the target type can represent all the values
+of a hypothetical extended integer type
+with width $w$ and with the same signedness as the original type or
+\item
+the source is a constant
 expression whose value after integral promotions will fit into the target type, or
+\end{itemize}
 
 \item from a pointer type or a pointer-to-member type to \tcode{bool}.
 \end{itemize}