CWG2759 [[no_unique_address] and common initial sequence

Author: burblebee

source/classes.tex

@@ -796,9 +796,10 @@
 \item
 corresponding entities have the same alignment requirements\iref{basic.align},
 \item
-either both entities are declared with
-the \tcode{no_unique_address} attribute\iref{dcl.attr.nouniqueaddr}
-or neither is, and
+if a \grammarterm{has-attribute-expression}\iref{cpp.cond}
+is not \tcode{0} for the \tcode{no_unique_address} attribute,
+then neither entity is declared with
+the \tcode{no_unique_address} attribute\iref{dcl.attr.nouniqueaddr}, and
 \item
 either both entities are bit-fields with the same width
 or neither is a bit-field.