Aah okay. Thanks Martok and Jonas. Adding internal errors is
definitely a good haul then. I do think a warning is a bit harsh though
over a hint or a note, but if that is what you desire for the compiler
(since it does reduce errors), then I'll accept it. I just missed the
part where it only does it for small types.
Gareth aka. Kit
On 18/05/2019 13:03, Jonas Maebe wrote:
On 18/05/2019 13:30, J. Gareth Moreton wrote:
So it looks like this new warning has appeared as part of the data
flow analysis of -O4.
The case-completeness warning is not related to any optimization
level, nor to the data flow analysis mentioned in the other thread.
The thing is, I personally have a problem with this being a
warning, because there's nothing inherently wrong with not covering
every case branch or omitting an else block (especially if one isn't
needed). Adding "else ;" everywhere seems to just cause bloat.
The question is whether or not an else block is needed or not (or
perhaps even superfluous). When I adapted the compiler code to compile
warning-free with this new option, about 2/3 of the cases got an empty
else-block and 1/3 got either an internalerror or extra case blocks to
handle options that were not handled previously, but that should have
been handled. I don't think that's a bad haul. There were also a
number of case-statements that handled all possible options and yet
still contained an else block (so the else-block got removed).
However, it is absolutely true that this is not an issue in all cases.
If you do not wish to see such warnings at all, you can always
suppress them using -vm6060 (warning numbers can be discovered with
the -vq command line options).
For information on the background of this warning, see
http://lists.freepascal.org/pipermail/fpc-devel/2019-January/039972.html
Still, code style aside, can I suggest the warning be downgraded into
a hint? Warnings should indicate the possibility of unstable code due
to uninitialised values, for example, and DFA should be able to
detect that anyway as a separate warning (e.g. if a case block
doesn't initialise an output value in all of its branches).
This warning can detect errors that cannot be found by DFA, because
they may not be related to initialising a variable (but e.g. to
modifying an already initialised variable, or to outputting something).
Jonas
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