[fpc-devel] Variant Records and Duplicate Identifiers

[kevin at kdx.me]

Hello,

I was reading the wiki page on records 
(http://wiki.freepascal.org/Record), and I noticed the following quote: 
"The fields of the variable part are only available after assignment of 
its depending variable. It doesn't harm, whether [a particular field] is 
defined multiple times." However, when I tried to use this feature in 
some code, it refused to compile. In order to test the problem, I 
created the following example program, based on the example given on the 
wiki page.


=== begin code ===

program example;

uses sysutils;

type
   maritalStates = (single, married, widowed, divorced);

   TPerson = record
     name: record
       first, middle, last: string;
     end;
     sex: (male, female);
     dob: TDateTime;
     case maritalStatus: maritalStates of
       single: ( );
       married, widowed: (marriageDate: TDateTime);
       divorced: (marriageDate, divorceDate: TDateTime;
         isFirstDivorce: boolean)
   end;

var
   ExPerson: TPerson;

begin
ExPerson.name.first := 'John';
ExPerson.name.middle := 'Bob';
ExPerson.name.last := 'Smith';
ExPerson.sex := male;
ExPerson.dob := StrToDate('05/05/1990');
ExPerson.maritalStatus := married;
ExPerson.marriageDate := StrToDate('04/01/2015');

end.

=== end code ===

When I tried to compile that, I got the following errors:

=== begin error ===

$ fpc ex.pas
Free Pascal Compiler version 3.0.0 [2016/02/14] for x86_64
Copyright (c) 1993-2015 by Florian Klaempfl and others
Target OS: Win64 for x64
Compiling ex.pas
ex.pas(19,18) Error: Duplicate identifier "marriageDate"
ex.pas(21,3) Error: Duplicate identifier "marriageDate"
ex.pas(35,4) Fatal: There were 2 errors compiling module, stopping
Fatal: Compilation aborted
Error: C:\lazarus\fpc\3.0.0\bin\x86_64-win64\ppcx64.exe returned an 
error exitcode

=== end error ===

So the question then becomes: is the wiki in error, or is there 
something I'm missing? Furthermore, if the wiki is in fact wrong, and 
this is a limitation, is there any inherent reason why? It seems to me 
like this should be possible, it's certainly a very useful thing to 
have.

Thanks,
-Kevin