[Oberon] NEW on POINTER TO RECORD always results in NIL (RISC Oberon) - bug?

[Michael Schierl]

[I tried to post this message about a month ago and never received any
feedback - seems that it never got approved. Now that I'm subscribed to
the list, I'll try again :)]


Hello,


When trying to compile this short example in RISC Oberon (using the
Windows emulator/distribution from projectoberon.com):

-------------------------------------------
MODULE BugTest;
  IMPORT Texts, Oberon;
  TYPE
    P1 = POINTER TO P1Desc;
    P1Desc = RECORD a: INTEGER END;
    P2 = POINTER TO RECORD a: INTEGER END;


  PROCEDURE DebugPrint(VAR str : ARRAY OF CHAR);
  VAR w : Texts.Writer;
  BEGIN
    Texts.OpenWriter(w);
    Texts.WriteString(w,str);
    Texts.WriteLn(w);
    Texts.Append(Oberon.Log, w.buf);
  END DebugPrint;

  PROCEDURE TestAlloc*();
    VAR
      v1: P1;
      v2: P2;
      v3: POINTER TO P1Desc;
      v4: POINTER TO RECORD a: INTEGER END;
  BEGIN
    NEW(v1);
    IF v1 # NIL THEN DebugPrint("OK1") ELSE DebugPrint("NIL1") END;
    NEW(v2);
    IF v2 # NIL THEN DebugPrint("OK2") ELSE DebugPrint("NIL2") END;
    NEW(v3);
    IF v3 # NIL THEN DebugPrint("OK3") ELSE DebugPrint("NIL3") END;
    NEW(v4);
    IF v4 # NIL THEN DebugPrint("OK4") ELSE DebugPrint("NIL4") END;
  END TestAlloc;
END BugTest.
-------------------------------------------

It always outputs "OK1 OK2 OK3 NIL4" into the Log (I'd have expected
that it printed OK4 as well).

Is that a bug in the compiler, or actually intended behavior?

The actual code I'm using is a bit more complex (I'm playing with adding
paravirtualized clipboard support and some more things to the emulator;
if I ever get it working fine, I'll release patches of course, unless
anyone beats me to it  [edit: which I succeeded and a changed version
that did not require the kludge that made me find this bug was
successfully merged into Peter De Wachter's emulator]), and it took me
quite some time to track down that issue...


Regards,


Michael