This and other RFCs are available on the web at
http://dev.perl.org/rfc/
=head1 TITLE
Emit warnings and errors based on unoptimized code
=head1 VERSION
Maintainer: Nathan Torkington <[EMAIL PROTECTED]>
Date: Sep 12 2000
Mailing List: [EMAIL PROTECTED]
Number: 214
Version: 1
Status: Developing
=head1 ABSTRACT
When code triggers warnings or errors, those warnings
or errors should report the code that caused them.
If the code has been rewritten or altered by the optimizer,
the unoptimized code should be be what's cited in the
text of the warning or error message.
=head1 DESCRIPTION
In perl5 it's easy to get warnings about code you
didn't write (this is from perl5.6.0, but similar problems
with "use" turning into a "BEGIN" block have been present
in Perl for a long time):
print "what's that, $perl?";
Use of uninitialized value in concatenation (.) at -e line 1.
Perl has rewritten the double-quoted string as
"what's that, " . $perl . "?"
and when the uninitialized value warning is generated,
Perl reports it as coming from the concatenation operation.
This is misleading and confuses users. When Perl needs to report
errors or warnings, it should describe the code the programmer wrote,
regardless of how that's been translated within Perl.
=head1 IMPLEMENTATION
Each op could keep track of the name of the construct that it came
from. Instead of reporting errors in terms of ops, report errors in
terms of source-level constructs.
This may bloat the op tree/bytecode. There could be an option to
strip these debugging symbols from the bytecode, much as strip(1)
works on Unix, if this overhead is not welcome.
perl526 will not be able to successfully translate any code that
relies on parsing warnings or error messages.
=head1 REFERENCES
perldiag manpage for Perl's error messages and warnings
