On Tue, 5 Jul 2011, Jonas Maebe wrote:
On 05 Jul 2011, at 18:27, Alexander Klenin wrote:
2) All such incorrect usage should be removed from LCL and FCL
(for example: event handlers in LCL and TStrings methods in FCL).
Changing TStrings like that would break the compilation of any code that
overrides its methods (since they also have to repeat/leave out const).
Personally, I think this solution is inferior to my proposal of
implementing the optimization
correctly by default.
Your suggestions about the "safe" cases were wrong, as far as I can tell.
As soon as a field, global variable or variable from a parent function (in
case of nested functions) is changed, the parameter may also change if it
is declared as const (because the field/(global) variable may contain the
value that was passed in as "const" parameter). Any pointer may also
alias them.
Since the behaviour of "const" for automated types is explicitly defined
by Borland as not causing any changes in reference counting (see the note
at the bottom of
http://docwiki.embarcadero.com/RADStudio/en/Using_Reference_Counting ), I
think Martin/Florian's proposal to add the ability for adding extra
compiler checks is best. It's similar to how range and overflow checking
are optional.
I agree with this proposal.
Michael.
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