[MLKit-devel] Bug in pattern matching of IntInf values

[Vesa K. <ves...@gm...>]

Consider the following program:

<-- intinf-pat.mlb -->
$(SML_LIB)/basis/basis.mlb
intinf-pat.sml
<-- intinf-pat.mlb -->

<-- intinf-pat.sml -->
fun is0 (0 : IntInf.int) = true
  | is0 _                = false
<-- intinf-pat.sml -->

Compiling it with MLKit (SVN rev 2287) gives the output:

<--->
[reading source file:   intinf-pat.sml]
Impossible: LambdaStatSem.SWITCH_I

(case var1 of 0 => true | _ => false)


LambdaStatEnv: [
  ConEnv: {
   IntInf -> \/().((int list*bool)->intinf),
   :: -> \/('a2).(('a2*'a2 list)->'a2 list),
   nil -> \/('a0).'a0 list,
   false -> \/().bool,
   true -> \/().bool
  };
  TyNameEnv: {
   exn -> [],
   vector -> [],
   ref -> [],
   list -> [nil,::],
   char -> [],
   string -> [],
   real -> [],
   word32 -> [],
   word -> [],
   word8 -> [],
   intinf -> [IntInf],
   int32 -> [],
   int -> [],
   bool -> [true,false]
  };
  LvarEnv: {
   >= -> \/().((intinf*intinf)->bool),
   <= -> \/().((intinf*intinf)->bool),
   > -> \/().((intinf*intinf)->bool),
   < -> \/().((intinf*intinf)->bool),
   abs -> \/().(intinf->intinf),
   mod -> \/().((intinf*intinf)->intinf),
   div -> \/().((intinf*intinf)->intinf),
   - -> \/().(<intinf, intinf>->intinf),
   + -> \/().((intinf*intinf)->intinf),
   * -> \/().(<intinf, intinf>->intinf),
   ~ -> \/().(intinf->intinf),
   toWord31 -> \/().(intinf->word),
   fromWord31 -> \/().(word->intinf),
   toWord8 -> \/().(intinf->word),
   fromWord8X -> \/().(word->intinf),
   fromWord8 -> \/().(word->intinf),
   toWord -> \/().(intinf->word),
   fromWord -> \/().(word->intinf),
   toWord32 -> \/().(intinf->word32),
   fromWordX -> \/().(word->intinf),
   fromWord31X -> \/().(word->intinf),
   fromWord32X -> \/().(word32->intinf),
   fromWord32 -> \/().(word32->intinf),
   fromInt31 -> \/().(int->intinf),
   fromInt32 -> \/().(int32->intinf),
   fromInt -> \/().(int->intinf),
   toInt -> \/().(intinf->int),
   toInt32 -> \/().(intinf->int32),
   toInt31 -> \/().(intinf->int),
   var1 -> \/().intinf,
   is0 -> \/().(intinf->bool)
  };
  ExConEnv: {Bind -> NONE, Match -> NONE, Div -> NONE}
]


let fun is0 var1 = (case var1 of 0 => true | _ => false) in FRAME(is0:
FORALL'a0.'a0) end

Stopping compilation of MLB-file due to error (code 1).
<--->

-Vesa Karvonen