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Fix unnecesary type unrolling #2105

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Merged
cyrus- merged 1 commit into from
Feb 5, 2026
+45 −30
Merged

Fix unnecesary type unrolling #2105

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23 changes: 8 additions & 15 deletions src/language/dynamics/transition/Ascriptions.re
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Original file line number Diff line number Diff line change
Expand Up @@ -27,17 +27,10 @@ let rec transition = (~recursive=false, d: DHExp.t): option(DHExp.t) => {
switch (DHExp.term_of(d)) {
| Asc(e, t) =>
switch (DHExp.term_of(e), Typ.term_of(Typ.unroll(t))) {
| (Asc(e, t'), t)
| (Asc(e, t'), _)
// This is only necessary because sometimes we add two ascriptions and aren't marking it as a non-value
when
Typ.is_consistent(
Ctx.empty,
Typ.unroll(t |> Typ.temp),
Typ.unroll(t'),
) =>
switch (
Typ.meet(Ctx.empty, Typ.unroll(t |> Typ.temp), Typ.unroll(t'))
) {
when Typ.is_consistent(Ctx.empty, Typ.unroll(t), Typ.unroll(t')) =>
switch (Typ.meet(Ctx.empty, Typ.unroll(t), Typ.unroll(t'))) {
| Some(t) => Some(recur(Asc(e, t) |> DHExp.fresh))
| None => None //TODO This is an impossible case since we checked consistency
}
Expand Down Expand Up @@ -133,26 +126,26 @@ let rec transition = (~recursive=false, d: DHExp.t): option(DHExp.t) => {
|> DHExp.fresh,
),
);
| (If(cond, e1, e2), t) =>
| (If(cond, e1, e2), _) =>
Some(
IdTagged.fast_copy(
DHExp.rep_id(e),
If(
recur(cond),
recur(Asc(e1, t |> Typ.temp) |> DHExp.fresh),
recur(Asc(e2, t |> Typ.temp) |> DHExp.fresh),
recur(Asc(e1, t) |> DHExp.fresh),
recur(Asc(e2, t) |> DHExp.fresh),
)
|> DHExp.fresh,
),
)
| (Match(scrut, rules), t) =>
| (Match(scrut, rules), _) =>
Some(
IdTagged.fast_copy(
DHExp.rep_id(e),
Match(
scrut,
List.map(
((p, body)) => (p, Asc(body, t |> Typ.temp) |> DHExp.fresh),
((p, body)) => (p, Asc(body, t) |> DHExp.fresh),
rules,
),
)
Expand Down
52 changes: 37 additions & 15 deletions test/evaluator/Test_Evaluator_Sum_Types.re
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Original file line number Diff line number Diff line change
Expand Up @@ -28,25 +28,47 @@ let tests = (
)
}),
test_case(
"Constructors can pass through consistent ascriptions", `Quick, () => {
evaluation_test(
{|A : (+A +B) : (+A + ?)|},
constructor(
"A",
Some(
"Constructors can pass through consistent ascriptions",
`Quick,
() => {
evaluation_test(
{|A : (+A +B) : (+A + ?)|},
constructor(
"A",
Some(
Typ.(
sum([
Variant("A", ConstructorMap.empty_variant_ann, None),
Variant("B", ConstructorMap.empty_variant_ann, None),
])
Some(
Typ.(
sum([
Variant("A", ConstructorMap.empty_variant_ann, None),
Variant("B", ConstructorMap.empty_variant_ann, None),
])
),
),
),
),
),
elaborate(parse_exp({|A : (+A +B) : (+A + ?)|})),
)
}),
elaborate(parse_exp({|A : (+A +B) : (+A + ?)|})),
);
evaluation_test(
"Ascriptions don't do unnecessary unrolling",
asc(
empty_hole(),
Typ.rec_(
TPat.var("X"),
Typ.sum([
Variant(
"A",
ConstructorMap.empty_variant_ann,
Some(Typ.var("X")),
),
]),
),
),
elaborate(
parse_exp("(if true then ? else ?) : (rec X -> + A(X))"),
),
);
},
),
test_case(
"Constructors don't pass through inconsistent ascriptions", `Quick, () => {
evaluation_test(
Expand Down