union member already defined?

[theos <theosjp@xxxxxxxxx>]

hi,

i started to learn myrddin recently and was going through the tutorial.
i am getting - somewhat unexpected - an "already defined" error for the 
below union example. this is with the latest version on linux.

is this supposed to be this way?  and if so what am i doing wrong?

% mbld -R u2.myr
u2.myr:2: `a already defined on u2.myr:7
FAIL: 6m u2.myr

% 6m u2.myr
u2.myr:2: `a already defined on u2.myr:7

% cat u2.myr
type u1 = union
        `a int
        `b flt
;;

type u2 = union
        `a flt
        `b char
;;

const main = {

}

its error-ing out in stab.c - i've poked a bit around in putucon and 
gram.y, but had to confess to myself that i dont really know what i am 
looking for/at.

Breakpoint 3, putucon (st=0x5555557d1070, uc=0x5555557dc460) at stab.c:495
495                     lfatal(old->loc, "`%s already defined on %s:%d",
(gdb) bt
#0  putucon (st=0x5555557d1070, uc=0x5555557dc460) at stab.c:495
#1  0x0000555555578d30 in installucons (st=0x5555557d1070, 
t=0x5555557dc6a0) at gram.y:1252
#2  0x0000555555574484 in yyparse () at gram.y:248
#3  0x0000555555563e3b in main (argc=2, argv=0x7fffffffe728) at main.c:276

thank you,
theo.