Merge 2016-06 CWG Motion 11

Author: zygoloid

source/declarations.tex

@@ -3679,11 +3679,7 @@
 an \grammarterm{attribute-token}, it is considered an identifier. No name
 lookup~(\ref{basic.lookup}) is performed on any of the identifiers contained in an
 \grammarterm{attribute-token}. The \grammarterm{attribute-token} determines additional
-requirements on the \grammarterm{attribute-argument-clause} (if any). The use of an
-\grammarterm{attribute-scoped-token} is conditionally-supported, with
-\impldef{behavior of attribute scoped token} behavior. \begin{note} Each implementation
-should choose a distinctive name for the \grammarterm{attribute-namespace} in an
-\grammarterm{attribute-scoped-token}. \end{note}
+requirements on the \grammarterm{attribute-argument-clause} (if any).
 
 \pnum
 Each \grammarterm{attribute-specifier-seq} is said to \defn{appertain} to some entity or
@@ -3698,8 +3694,16 @@
 instantiation~(\ref{temp.explicit}).
 
 \pnum
-For an \grammarterm{attribute-token} not specified in this International Standard, the
+For an \grammarterm{attribute-token}
+(including an \grammarterm{attribute-scoped-token})
+not specified in this International Standard, the
 behavior is \impldef{behavior of non-standard attributes}.
+Any \grammarterm{attribute-token} that is not recognized by the implementation
+is ignored.
+\begin{note}
+Each implementation should choose a distinctive name for the
+\grammarterm{attribute-namespace} in an \grammarterm{attribute-scoped-token}.
+\end{note}
 
 \pnum
 Two consecutive left square bracket tokens shall appear only