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From: dewar@cs.nyu.edu (Robert Dewar)
Newsgroups: comp.lang.ada
Subject: Re: Need help with DEC Ada
Date: 20 Jan 1995 00:22:54 -0500
Organization: Courant Institute of Mathematical Sciences
Message-ID: <3fnhbe$4lq@gnat.cs.nyu.edu>
References: <19950117.160119.606@vnet.ibm.com>
 <Mats.Weber-1801951923090001@mlma11.matrix.ch>
NNTP-Posting-Host: gnat.cs.nyu.edu
Date: 1995-01-20T00:22:54-05:00
List-Id: <comp.lang.ada>

Mats says:

"the original (2**31)-1 should not cause any problem. Ae you really sure it
generates a warning ?"

sorry Mats, that is wrong, in Ada 83, this expression was not a static
expression evaluated at compile time, and hence a compiler is allowed to
compute it at runtime, insisting that all intermediate values are in 
range of the type (in this case a 32 bit integer).

So Dec Ada is perfectly correct (just not very friendly) in raising CE
in this situation.

Whatever model you have that says that this should not cause any problem
is flawed with respect to Ada 83. However, as I pointed out in a previous
message, Ada 95 has "fixed" this "problem" by requiring static expressions
to be evaluated exactly, even when they appear as subexpressions of non
static exprssions, or in contexts not requiring static expressions.