[fpc-pascal] Regression? Problem passing a packed record to a overriden, virtual, abstract method in fpc 2.7.1.

[Mattias Gaertner]

On Mon, 25 Feb 2013 22:54:51 +0100
Mattias Gaertner <nc-gaertnma at netcologne.de> wrote:

> On Sun, 24 Feb 2013 23:20:23 +0100
> Reimar Grabowski <reimgrab at web.de> wrote:
> 
> > Hi,
> > 
> > see the following little program:
> > 
> > program argumentbug;
> > 
> > {$MODE ObjFpc}
> > 
> > uses classes;
> > 
> > type
> > 
> > TVector3 = packed record
> >   X, Y, Z: Single;
> > end;
> > 
> > TClassA = class
> > protected
> >   fVector: TVector3;
> > public
> >   procedure SetVector(AVector: TVector3); virtual; abstract;
> > end;
> > 
> > { TClassB }
> > 
> > TClassB = class(TClassA)
> > public
> >   procedure SetVector(AVector: TVector3); override;
> > end;
> > 
> > { TClassB }
> > 
> > procedure TClassB.SetVector(AVector: TVector3);
> > begin
> >   writeln('TClassB: ',AVector.X,',',AVector.Y,',',AVector.Z);
> >   fVector:=AVector;
> > end;
> > 
> > var
> >   MyVector: TVector3;
> >   MyClassB: TClassB;
> > begin
> >   MyVector.X:=0;
> >   MyVector.Y:=0;
> >   MyVector.Z:=3;
> >   MyClassB:=TClassB.Create;
> >   MyClassB.SetVector(MyVector);
> > end.
> > 
> > Obviously the expected output is 0,0,3 but in fact the output is 0,3,3.
> > I am sure that this used to work as my real code showing the problem is many years old.
> > (The problem stays even if I don't declare the method in TClassA abstract.)
> > 
> > OS: Ubuntu 12.10 64-Bit
> > Compiler: FPC 2.7.1 Rev. 23655
> 
> It works under 2.6.0 and 2.6.2 (Ubuntu 64bit).

And it works under 2.7.1 rev 23661:
TClassB:  0.000000000E+00, 0.000000000E+00, 3.000000000E+00

Mattias