    OPT -Wrdlow ; test various tricky cases of syntax, enable rdlow warning
    adc     a , (   ( 3 ) + ( 4 )   )
    ld      a , (   ( 3 ) + ( 4 )   )   // extra warning about if low address is ok
    ld      a ,     ( 3 ) + ( 4 )
    ld      a ,     ( 3 ) | ( 4 )
    ld      a ,       ( 3 | 4 )         // rdlow-ok. (warning suppressed by comment)
    ld      a,((3|4))       // fake (should NOT suppress warning about low address)
    ld      a,(+(3|4))      //rdlow-ok (should suppress)
    ld      a,+((3|4))

    ; test all IXY variants recognized by parser
    ld      a,hx, a,xh, a,ixh, a,HX, a,XH, a,IXH, a,high ix, a,high IX, a,HIGH ix, a,HIGH IX
    ld      a,lx, a,xl, a,ixl, a,LX, a,XL, a,IXL, a,low  ix, a,low  IX, a,LOW  ix, a,LOW  IX
    ld      a,hy, a,yh, a,iyh, a,HY, a,YH, a,IYH, a,high iy, a,high IY, a,HIGH iy, a,HIGH IY
    ld      a,ly, a,yl, a,iyl, a,LY, a,YL, a,IYL, a,low  iy, a,low  IY, a,LOW  iy, a,LOW  IY
    push    ix, IX
    push    iy, IY

    jp      (hl), hl, (ix), ix, (iy), iy        ; valid
    ; invalid
    jp      ((hl))
    jp      ((ix))
    jp      ((iy))

    ; ld r16,nnnn vs ld r16,(nnnn) heuristics in default syntax mode
    ld      bc, $1230 + 4  , bc, ($1230) + (4)  , bc,+($1230 + 4)
    ld      bc,($1230 + 4) , bc,(($1230) + (4)) , bc, [$1230 + 4] , bc,[($1230  +  4)]

    ld      de, $1230 + 4  , de, ($1230) + (4)  , de,+($1230 + 4)
    ld      de,($1230 + 4) , de,(($1230) + (4)) , de, [$1230 + 4] , de,[($1230  +  4)]

    ld      hl, $1230 + 4  , hl, ($1230) + (4)  , hl,+($1230 + 4)
    ld      hl,($1230 + 4) , hl,(($1230) + (4)) , hl, [$1230 + 4] , hl,[($1230  +  4)]

    ld      ix, $1230 + 4  , ix, ($1230) + (4)  , ix,+($1230 + 4)
    ld      ix,($1230 + 4) , ix,(($1230) + (4)) , ix, [$1230 + 4] , ix,[($1230  +  4)]

    ld      iy, $1230 + 4  , iy, ($1230) + (4)  , iy,+($1230 + 4)
    ld      iy,($1230 + 4) , iy,(($1230) + (4)) , iy, [$1230 + 4] , iy,[($1230  +  4)]

    ld      sp, $1230 + 4  , sp, ($1230) + (4)  , sp,+($1230 + 4)
    ld      sp,($1230 + 4) , sp,(($1230) + (4)) , sp, [$1230 + 4] , sp,[($1230  +  4)]

    ld      bc,(hl), de,(hl)                    ; valid fake instructions
    ld      hl,(ix+1), hl,(ix-128), hl,(ix+126)
    ld      hl,(iy+1), hl,(iy-128), hl,(iy+126)
    ; invalid
    ld      hl,(hl)
    ld      sp,(hl)
    ld      ix,(hl)
    ld      iy,(hl)
    ld      hl,(ix+127)
    ld      hl,(ix-129)
    ld      hl,(iy+127)
    ld      hl,(iy-129)

    ex      de,hl
    ex      hl,de
    ex      af
    ex      af,af
    ex      af,af'

    ld      a  ,  low  hl   : ld a,l
    ld      e  ,  high  bc  : ld e,b
    ld      a  ,  LOW  hl   : ld a,l
    ld      e  ,  HIGH  bc  : ld e,b
    ld      a  ,  low  h
h:
    ld      a  ,  low  label
label:
    ld      a  ,  Low  hl   ; error
    ld      a  ,  high  d
d:

    ex      (sp),hl     ; #E3
    ex      hl,(sp)     ; #E3
    ex      (sp),ix     ; #DDE3
    ex      ix,(sp)     ; #DDE3
    ex      (sp),iy     ; #FDE3
    ex      iy,(sp)     ; #FDE3
    ; invalid
    ex      af,
    ex      af,hl
    ex      af,(sp)
    ex      af',af      ; does leak `ex af,af` machine code, but also reports error
    ex      de,bc
    ex      hl,bc
    ex      sp,hl
    ex      (sp,hl
    ex      de,(sp)
    ex      (sp),de
    ex      hl,sp
    ex      ix,sp
    ex      iy,sp
