From 71a555b3b9c9d741380db25fd2fdc47211b5ecdf Mon Sep 17 00:00:00 2001 From: Robert Dewar Date: Wed, 28 May 2008 15:05:35 +0200 Subject: [PATCH] gnat_rm.texi: Add note on Old giving warning when applied to constant 2008-05-28 Robert Dewar * gnat_rm.texi: Add note on Old giving warning when applied to constant * sem_attr.adb (Analyze_Attribute, case Old): Give warning if prefix is a constant From-SVN: r136078 --- gcc/ada/gnat_rm.texi | 4 ++++ gcc/ada/sem_attr.adb | 7 +++++++ 2 files changed, 11 insertions(+) diff --git a/gcc/ada/gnat_rm.texi b/gcc/ada/gnat_rm.texi index 0d2d0ff..69baaa2 100644 --- a/gcc/ada/gnat_rm.texi +++ b/gcc/ada/gnat_rm.texi @@ -5803,6 +5803,10 @@ package body Old_Pkg is end Old_Pkg; @end smallexample +@noindent +Note that it is allowed to apply 'Old to a constant entity, but this will +result in a warning, since the old and new values will always be the same. + @node Passed_By_Reference @unnumberedsec Passed_By_Reference @cindex Parameters, when passed by reference diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb index 0cb2ace..14f9102 100644 --- a/gcc/ada/sem_attr.adb +++ b/gcc/ada/sem_attr.adb @@ -3501,6 +3501,13 @@ package body Sem_Attr is Error_Attr ("attribute % cannot apply to limited objects", P); end if; + if Is_Entity_Name (P) + and then Is_Constant_Object (Entity (P)) + then + Error_Msg_N + ("?attribute Old applied to constant has no effect", P); + end if; + -- Check that the expression does not refer to local entities Check_Local : declare -- 2.7.4