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delphi - Why does Format reject procedure address arguments starting with XE4

Consider this program:

{$APPTYPE CONSOLE}

uses
  System.SysUtils;

procedure Foo;
begin
end;

type
  TProcedure = procedure;

const
  FooConst: TProcedure = Foo;

var
  FooVar: TProcedure = Foo;
  P: Pointer;

{$TYPEDADDRESS ON}

begin
  P := @Foo;
  Writeln(Format('%p', [P]));
  Writeln(Format('%p', [@FooConst]));
  Writeln(Format('%p', [@FooVar]));
  Writeln(Format('%p', [@Foo]));
  Readln;
end.

This program compiles and runs on XE3 and produces the following output:

00419FB8
00419FB8
00419FB8
00419FB8

On XE4 and later the program fails to compile, with error messages on both of these lines:

Writeln(Format('%p', [@FooConst]));
Writeln(Format('%p', [@FooVar]));
[dcc32 Error] E2250 There is no overloaded version of 'Format' that can be called
with these arguments

On XE4, XE5 and XE6, the program compiles when $TYPEDADDRESS is switched off. On XE7, the program fails to compile irrespective of the setting of $TYPEDADDRESS.

Is this a compiler bug? Or am I using incorrect syntax to obtain the address of a procedure?

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1 Answer

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by (71.8m points)

I believe that this is a compiler bug and have submitted a QC report: QC#127814.

As a work around you can use either of the following:

  1. Use addr() rather than the @ operator.
  2. Cast @FooVar or @FooConst to Pointer, e.g. Pointer(@FooVar).

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