Reminder to Self: `TProc` is incompatible with parameterless procedures on interfaces
Posted by jpluimers on 2018/04/19
I knew that methods on interfaces were not compatible with the procedure of object (like [WayBack] TProc)or function of object construct, but they are also not compatible with the reference to procedure or reference to function construct.
Via: [WayBack] I try to call an Interface method from TThread.Syncrhonize()…and Berlin don’t accept that… – Paul TOTH – Google+
If you want it fixed, vote for [RSP-13007] Interface methods are not assignable to anonymous method variable – Embarcadero Technologies (Thanks Stefan Glienke).
You can work around it with an anonymous method.
This won’t work:
program Project1;
{$APPTYPE CONSOLE}
uses
SysUtils;
type
ITest = interface
['{B5AD87E8-A3DF-4B83-BE14-997C2E76A06C}']
procedure Run;
end;
TTest = class(TInterfacedObject, ITest)
procedure Run;
end;
procedure TTest.Run;
begin
Writeln('PASS')
end;
var
test: ITest; // <- change this to TTest and it compiles
proc: TProc;
begin
test := TTest.Create;
proc := procedure begin test.Run; end; // <- this compiles
proc := test.Run; // E2010 Incompatible types: 'TProc' and 'procedure, untyped pointer or untyped parameter'
proc();
Readln;
end.
–jeroen
The Wiert Corner - irregular stream of stuff 
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