[fpc-devel] "Case statement does not handle all possible cases" Warning

Ralf Quint freedos.la at gmail.com
Sat May 18 23:56:49 CEST 2019

On 5/18/2019 4:30 AM, J. Gareth Moreton wrote:
> Hi everyone,
> So it looks like this new warning has appeared as part of the data 
> flow analysis of -O4.  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.
> 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). 

Sorry, but you seem to suffer from the "lazy programmer syndrome". A 
warning is correct, as a case of unhandled */case/* statement can indeed 
lead to unexpected side effects. While there could be cases where you 
might want to react with the /*case*/ statement to only certain 
conditions (and can safely assume that all other conditions don't do ill 
effects), there is also the case where an unknown/unexpected condition 
is passed and that can have dire consequences, and should be properly 
acted upon, by the /*else*/ clause within the case statement...


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