I don't know if it is a bug (yes of course it is a bug) or maybe a feature to have helpers for generic types through a backdoor.

I don't know if it is a bug (yes of course it is a bug) or maybe a feature to have helpers for generic types through a backdoor.

Given:

unit Unit1;

interface

type
Foo = record
Value: T;
end;

type
FooInteger = Foo;
HelperForFooInteger = record helper for FooInteger
function Multiply( const AValue: Integer ): Integer;
end;
type
FooSingle = Foo;
HelperForFooSingle = record helper for FooSingle
function Multiply( const AValue: Single ): Single;
end;

implementation

{ HelperForFooInteger }

function HelperForFooInteger.Multiply( const AValue: Integer ): Integer;
begin
WriteLn( 'HelperForFooInteger.Multiply' );
Result := Self.Value * AValue;
end;

{ HelperForFooSingle }

function HelperForFooSingle.Multiply( const AValue: Single ): Single;
begin
WriteLn( 'HelperForFooSingle.Multiply' );
Result := Self.Value * AValue;
end;

end.

What do you expect from this code?

var
fooInt : Foo;
begin
fooInt.Value := 5;
WriteLn( fooInt.Multiply( 10 ) );
end;

No, you are wrong ... you will get

HelperForFooSingle.Multiply
7.00649232162409E-0044

https://quality.embarcadero.com/browse/RSP-13574
https://quality.embarcadero.com/browse/RSP-13574