[fpc-pascal] AnsiStrupper Error

[Daniel Gaspary]

The code bellow is throwing an exception and I don't know why. It used to work.

program Project1;
uses
    sysutils;
var
    s : AnsiString;
begin
     s := 'a';
     AnsiStrupper(PAnsiChar(s));
end.

It works fine with FPC 2.6.4 (Linux x86-64 bits).

I'm using FPC trunk (Revision 27818):

An unhandled exception occurred at $0000000000428E4D:
EAccessViolation: Access violation
  $0000000000428E4D