[fpc-pascal] Two possible generics bugs
Testing on 3.3.1. Are these both bugs? I wanted to ask first before filing a
report.
{$mode objfpc}
program test;
uses
FGL;
// No Error specializing TFPGList in parameter list...
generic function CopyList(source: specialize TFPGList): specialize
TFPGList;
begin
end;
// ... but getting an error specializing TFPGObjectList in parameter list
// Class type expected, but got "T"
generic function CopyList(source: specialize TFPGObjectList): specialize
TFPGObjectList;
begin
end;
begin
end.
===
{$mode objfpc}
program test;
uses
FGL;
// Type identifier expected
// Internal error 2019112401
generic function CopyList(source: specialize FGL.TFPGObjectList):
specialize FGL.TFPGObjectList;
begin
end;
begin
end.
Regards,
Ryan Joseph
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Re: [fpc-pascal] Two possible generics bugs
Ryan Joseph via fpc-pascal schrieb am
Do., 28. Nov. 2019, 20:36:
> Testing on 3.3.1. Are these both bugs? I wanted to ask first before filing
> a report.
>
> {$mode objfpc}
>
> program test;
> uses
> FGL;
>
> // No Error specializing TFPGList in parameter list...
> generic function CopyList(source: specialize TFPGList): specialize
> TFPGList;
> begin
> end;
>
> // ... but getting an error specializing TFPGObjectList in parameter list
> // Class type expected, but got "T"
> generic function CopyList(source: specialize TFPGObjectList):
> specialize TFPGObjectList;
> begin
> end;
>
> begin
> end.
>
TFPGObjectList has a constraint to class types, so you need to constrain
your T as well using ": class".
Please note however that you'll likely encounter another bug then once you
move your function to a unit: https://bugs.freepascal.org/view.php?id=35943
> ===
>
> {$mode objfpc}
>
> program test;
> uses
> FGL;
>
> // Type identifier expected
> // Internal error 2019112401
> generic function CopyList(source: specialize FGL.TFPGObjectList):
> specialize FGL.TFPGObjectList;
> begin
> end;
>
> begin
> end.
>
The "specialize" is part of the generic identifier, so it must be
"FGL.specialize TFPGObjectList".
That said however an internal error should not happen (especially the one I
just added some days ago ^^'). Please report this one.
Regards,
Sven
>
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Re: [fpc-pascal] Two possible generics bugs
> On Nov 28, 2019, at 6:38 PM, Sven Barth via fpc-pascal
> wrote:
>
> TFPGObjectList has a constraint to class types, so you need to constrain your
> T as well using ": class".
>
> Please note however that you'll likely encounter another bug then once you
> move your function to a unit: https://bugs.freepascal.org/view.php?id=35943
A better error would be nice but I guess I can't do this anyways until the
other bug is fixed.
> The "specialize" is part of the generic identifier, so it must be
> "FGL.specialize TFPGObjectList".
>
> That said however an internal error should not happen (especially the one I
> just added some days ago ^^'). Please report this one.
>
That doesn't look right to my eyes but ok. I filed a report
(https://bugs.freepascal.org/view.php?id=36377).
It looks like my plan was foiled so I made a non-generic attempt. Can you
explain why I get the EListError at runtime? I checked the itemSize property
and it's the same for both lists.
{$mode objfpc}
program test;
uses
FGL;
type
TNode = class (TInterfacedObject)
end;
TNodeObjectList = specialize TFPGInterfacedObjectList;
function CopyList (source: TFPSList): TFPSList;
begin
result := TFPSList(source.ClassType.Create);
result.Assign(source);
end;
var
a, b: TNodeObjectList;
begin
a := TNodeObjectList.Create;
// EListError: Incompatible item size in source list
b := CopyList(a) as TNodeObjectList;
end.
Regards,
Ryan Joseph
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Re: [fpc-pascal] Two possible generics bugs
Ryan Joseph via fpc-pascal schrieb am
Fr., 29. Nov. 2019, 01:11:
>
>
> > On Nov 28, 2019, at 6:38 PM, Sven Barth via fpc-pascal <
> fpc-pascal@lists.freepascal.org> wrote:
> >
> > TFPGObjectList has a constraint to class types, so you need to constrain
> your T as well using ": class".
> >
> > Please note however that you'll likely encounter another bug then once
> you move your function to a unit:
> https://bugs.freepascal.org/view.php?id=35943
>
> A better error would be nice but I guess I can't do this anyways until the
> other bug is fixed.
>
Why? It does say that a class type is expected. And the column of the error
should point to the correct location.
That's the same error you'd get when specializing outside of a generic with
a non-class type.
>
> > The "specialize" is part of the generic identifier, so it must be
> "FGL.specialize TFPGObjectList".
> >
> > That said however an internal error should not happen (especially the
> one I just added some days ago ^^'). Please report this one.
> >
>
> That doesn't look right to my eyes but ok. I filed a report (
> https://bugs.freepascal.org/view.php?id=36377).
>
The idea is that "specialize" belongs to the identifier just like "generic"
does. This comes especially apparent for nested specializations:
SomeUnit.specialize SomeType<... >.specialize SomeFunc<... >
>
> It looks like my plan was foiled so I made a non-generic attempt. Can you
> explain why I get the EListError at runtime? I checked the itemSize
> property and it's the same for both lists.
>
> {$mode objfpc}
>
> program test;
> uses
> FGL;
>
> type
> TNode = class (TInterfacedObject)
> end;
> TNodeObjectList = specialize TFPGInterfacedObjectList;
>
> function CopyList (source: TFPSList): TFPSList;
> begin
> result := TFPSList(source.ClassType.Create);
> result.Assign(source);
> end;
>
> var
> a, b: TNodeObjectList;
> begin
> a := TNodeObjectList.Create;
> // EListError: Incompatible item size in source list
> b := CopyList(a) as TNodeObjectList;
> end.
>
Can't tell right now from looking at it. Will need to test that later on.
Regards,
Sven
>
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