[fpc-devel] [Suggestion] Enumeration range-check intrinsic

[Ondrej Pokorny]

On 05.07.2019 16:51, Pierre Muller wrote:
> Just one point from current compiler implementation:
>
> in trunk/fpcsrc/compiler/ninl.pas (around line 3180)
>
>                in_pred_x,
>                in_succ_x:
>                  begin
>                     set_varstate(left,vs_read,[vsf_must_be_valid]);
>                     resultdef:=left.resultdef;
>                     if is_ordinal(resultdef) or is_typeparam(resultdef) then
>                       begin
>                         if (resultdef.typ=enumdef) and
>                            (tenumdef(resultdef).has_jumps) and
>                            not(m_delphi in current_settings.modeswitches) and
>                            not(nf_internal in flags) then
>                           CGMessage(type_e_succ_and_pred_enums_with_assign_not_possible);
>                       end
>
>
> This means that using pred() or succ() intrinsics on enumerated types with
> holes will generate a Compile Time Error.

Only for non-Delphi modes, see: not(m_delphi in 
current_settings.modeswitches)


>    To be consistent, I would propose that we also generate
> a Compile Time Error if 'is' or 'as' keyword is used on such a type,
> unless there is a code that really check that the value is not in
> one of the holes ...

See this thread: 
https://lists.freepascal.org/pipermail/fpc-devel/2019-May/040865.html

Ondrej