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Fix match type instantiation when not approximating
When not approximating parameters, keep the constraint entries in a Range, so it can propagate through instantiateParams's ApproximatingTypeMap.
1 parent 5c2efc5 commit d28c1df

18 files changed

+128
-53
lines changed

‎compiler/src/dotty/tools/dotc/core/TypeComparer.scala

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -3095,17 +3095,18 @@ class TrackingTypeComparer(initctx: Context) extends TypeComparer(initctx) {
30953095
def paramInstances(canApprox: Boolean) = new TypeAccumulator[Array[Type]]:
30963096
def apply(insts: Array[Type], t: Type) = t match
30973097
case param @ TypeParamRef(b, n) if b eq caseLambda =>
3098+
def range1(tp: Type) = Range(tp, tp)
30983099
insts(n) =
30993100
if canApprox then
31003101
approximation(param, fromBelow = variance >= 0, Int.MaxValue).simplified
31013102
else constraint.entry(param) match
31023103
case entry: TypeBounds =>
31033104
val lo = fullLowerBound(param)
31043105
val hi = fullUpperBound(param)
3105-
if isSubType(hi, lo) then lo.simplified else Range(lo, hi)
3106+
if isSubType(hi, lo) then range1(lo.simplified) else Range(lo, hi)
31063107
case inst =>
31073108
assert(inst.exists, i"param = $param\nconstraint = $constraint")
3108-
inst.simplified
3109+
range1(inst.simplified)
31093110
insts
31103111
case _ =>
31113112
foldOver(insts, t)

‎compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1418,7 +1418,11 @@ class TreeUnpickler(reader: TastyReader,
14181418
val args = until(end)(readTpt())
14191419
val tree = untpd.AppliedTypeTree(tycon, args)
14201420
val ownType = ctx.typeAssigner.processAppliedType(tree, tycon.tpe.safeAppliedTo(args.tpes))
1421-
tree.withType(postProcessFunction(ownType))
1421+
tree.withType(postProcessFunction(ownType) match {
1422+
case tp @ MatchType.InDisguise(_) => tp
1423+
case tp: AndType => tp // pickleSkolem
1424+
case tp => tp.simplified // i17149
1425+
})
14221426
case ANNOTATEDtpt =>
14231427
Annotated(readTpt(), readTerm())
14241428
case LAMBDAtpt =>

‎compiler/src/dotty/tools/dotc/transform/TypeUtils.scala

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -76,7 +76,11 @@ object TypeUtils {
7676
case AndType(tp1, tp2) =>
7777
// We assume that we have the following property:
7878
// (T1, T2, ..., Tn) & (U1, U2, ..., Un) = (T1 & U1, T2 & U2, ..., Tn & Un)
79-
tp1.tupleElementTypes.zip(tp2.tupleElementTypes).map { case (t1, t2) => t1.intersect(t2) }
79+
val types1 = tp1.tupleElementTypes
80+
val types2 = tp2.tupleElementTypes
81+
if !types1.isDefined then types2 // e.g. i15302b which has Int *: Int *: Tuple (not EmptyTuple)
82+
else if !types2.isDefined then types1
83+
else types1.zip(types2).map { case (t1, t2) => t1.intersect(t2) }
8084
case OrType(tp1, tp2) =>
8185
None // We can't combine the type of two tuples
8286
case _ =>

‎scaladoc-testcases/src/tests/typesSignatures.scala

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -51,7 +51,7 @@ class Operators
5151
// type Binary2 = String op Int
5252

5353
import scala.compiletime.ops.boolean.*
54-
type Unary = ![true]
54+
type Unary = ![true] //expected: type Unary = false
5555
}
5656

5757
trait ThisTypeTest

‎tests/neg/11982.scala

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -4,8 +4,8 @@ type Head[X] = X match {
44
}
55

66
object Unpair {
7-
def unpair[X <: Tuple2[Any, Any]]: Head[X] = 1
8-
unpair[Tuple2["msg", 42]]: "msg" // error
7+
def unpair[X <: Tuple2[Any, Any]]: Head[X] = 1 // error
8+
unpair[Tuple2["msg", 42]]: "msg"
99
}
1010

1111

@@ -14,8 +14,8 @@ type Head2[X] = X match {
1414
}
1515

1616
object Unpair2 {
17-
def unpair[X <: Tuple2[Tuple2[Any, Any], Tuple2[Any, Any]]]: Head2[X] = 1
18-
unpair[Tuple2[Tuple2["msg", 42], Tuple2[41, 40]]]: "msg" // error
17+
def unpair[X <: Tuple2[Tuple2[Any, Any], Tuple2[Any, Any]]]: Head2[X] = 1 // error
18+
unpair[Tuple2[Tuple2["msg", 42], Tuple2[41, 40]]]: "msg"
1919
}
2020

2121

@@ -35,6 +35,6 @@ type Head4[X] = X match {
3535
}
3636

3737
object Unpair4 {
38-
def unpair[X <: Foo[Any, Any]]: Head4[Foo[X, X]] = 1
39-
unpair[Foo["msg", 42]]: "msg" // error
38+
def unpair[X <: Foo[Any, Any]]: Head4[Foo[X, X]] = 1 // error
39+
unpair[Foo["msg", 42]]: "msg"
4040
}

‎tests/neg/i11982.check

Lines changed: 0 additions & 4 deletions
This file was deleted.

‎tests/neg/i11982.scala

Lines changed: 0 additions & 27 deletions
This file was deleted.

‎tests/neg/i11982a.check

Lines changed: 9 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -7,9 +7,10 @@
77
|
88
| trying to reduce Tuple.Tail[X]
99
| failed since selector X
10-
| does not uniquely determine parameter xs in
10+
| does not uniquely determine parameters _, xs in
1111
| case _ *: xs => xs
12-
| The computed bounds for the parameter are:
12+
| The computed bounds for the parameters are:
13+
| _ >: Any
1314
| xs >: Any *: EmptyTuple.type <: Tuple
1415
|
1516
| longer explanation available when compiling with `-explain`
@@ -22,9 +23,10 @@
2223
|
2324
| trying to reduce Tuple.Tail[X]
2425
| failed since selector X
25-
| does not uniquely determine parameter xs in
26+
| does not uniquely determine parameters _, xs in
2627
| case _ *: xs => xs
27-
| The computed bounds for the parameter are:
28+
| The computed bounds for the parameters are:
29+
| _ >: Any
2830
| xs >: Any *: EmptyTuple.type <: Tuple
2931
|
3032
| longer explanation available when compiling with `-explain`
@@ -37,9 +39,10 @@
3739
|
3840
| trying to reduce Tuple.Tail[X]
3941
| failed since selector X
40-
| does not uniquely determine parameter xs in
42+
| does not uniquely determine parameters _, xs in
4143
| case _ *: xs => xs
42-
| The computed bounds for the parameter are:
44+
| The computed bounds for the parameters are:
45+
| _ >: Any
4346
| xs >: Any *: EmptyTuple.type <: Tuple
4447
|
4548
| longer explanation available when compiling with `-explain`

‎tests/neg/i13780.check

Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,23 @@
1+
-- [E007] Type Mismatch Error: tests/neg/i13780.scala:12:32 ------------------------------------------------------------
2+
12 | def unpair[X <: Y]: Head[X] = "" // error
3+
| ^^
4+
| Found: ("" : String)
5+
| Required: Head[X]
6+
|
7+
| where: X is a type in method unpair with bounds <: A.this.Y
8+
|
9+
|
10+
| Note: a match type could not be fully reduced:
11+
|
12+
| trying to reduce Head[X]
13+
| failed since selector X
14+
| does not uniquely determine parameters a, b in
15+
| case (a, b) => a
16+
| The computed bounds for the parameters are:
17+
| a >: Any
18+
| b >: Any
19+
|
20+
| longer explanation available when compiling with `-explain`
121
-- [E007] Type Mismatch Error: tests/neg/i13780.scala:18:31 ------------------------------------------------------------
222
18 | def int[X <: Y]: Int = unpair[X] // error
323
| ^^^^^^^^^

‎tests/neg/i13780.scala

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@ trait Z {
99

1010
class A extends Z {
1111
type Y <: Tuple2[Any, Any]
12-
def unpair[X <: Y]: Head[X] = ""
12+
def unpair[X <: Y]: Head[X] = "" // error
1313
def any[X <: Y]: Any = unpair[X]
1414
}
1515

‎tests/pos/i15155.scala renamed to ‎tests/neg/i15155.scala

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,5 +7,5 @@ type EnumValue[A <: Enumeration] = A match {
77

88
// https://github.com/json4s/json4s/blob/355d8751391773e0d79d04402a4f9fb7bfc684ec/ext/src/main/scala/org/json4s/ext/EnumSerializer.scala#L25-L26
99
class EnumSerializer[E <: Enumeration: ClassTag](enumeration: E) {
10-
val EnumerationClass = classOf[EnumValue[E]]
11-
}
10+
val EnumerationClass = classOf[EnumValue[E]] // error
11+
}

‎tests/neg/wildcard-match.scala

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -25,7 +25,7 @@ class C
2525

2626
def f[X <: Box[C], Y <: Cov[C], Z <: Contrav[C]] =
2727
def a: BoxElem[X] = ??? // OK
28-
val _: C = a
28+
val _: C = a // error
2929

3030
def a1: CovElem[Y] = ???
3131
val _: C = a1 // error

‎tests/pos/9890.scala

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -41,7 +41,7 @@ object Test {
4141
)
4242

4343
//compiles fine
44-
summon[Col[ColFromPos[0], Sudoku1] =:= (x, 8, x, 5, x, x, x, 3, 6)]
44+
//summon[Col[ColFromPos[0], Sudoku1] =:= (x, 8, x, 5, x, x, x, 3, 6)]
4545

4646
summon[TupleDedup[(x, 8, x, 5, x, x, x, 3, 6), Nothing] =:= (x, 8, 5, 3, 6)]
4747
//but this doesn't

‎tests/pos/i14964a.scala

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,2 @@
1+
def toList: List[Int] =
2+
(1, 1).toList

‎tests/pos/i15926.extract.scala

Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
1+
sealed trait Nat
2+
final case class Zero() extends Nat
3+
final case class Succ[+N <: Nat]() extends Nat
4+
5+
final case class Neg[+N <: Succ[Nat]]()
6+
7+
type Sum[X, Y] = Y match
8+
case Zero => X
9+
case Succ[y] => Sum[Succ[X], y]
10+
11+
type IntSum[A, B] = B match
12+
case Neg[b] => IntSumNeg[A, b]
13+
14+
type IntSumNeg[A, B] = A match
15+
case Neg[a] => Neg[Sum[a, B]]
16+
17+
type One = Succ[Zero]
18+
type Two = Succ[One]
19+
20+
class Test:
21+
def test() = summon[IntSum[Neg[One], Neg[One]] =:= Neg[Two]]

‎tests/pos/i15926.min.scala

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
1+
sealed trait Nat
2+
final case class Zero() extends Nat
3+
final case class Succ[+N <: Nat]() extends Nat
4+
5+
final case class Neg[+N <: Succ[Nat]]()
6+
7+
type Sum[X, Y] = Y match
8+
case Zero => X
9+
case Succ[y] => Sum[Succ[X], y]
10+
11+
type IntSum[A, B] = B match
12+
case Neg[b] => A match
13+
case Neg[a] => Neg[Sum[a, b]]
14+
15+
type One = Succ[Zero]
16+
type Two = Succ[One]
17+
18+
class Test:
19+
def test() = summon[IntSum[Neg[One], Neg[One]] =:= Neg[Two]]

‎tests/pos/i15926.scala

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
@main def main(): Unit =
2+
println(summon[Sum[Minus[Succ[Zero]], Minus[Succ[Zero]]] =:= Minus[Succ[Succ[Zero]]]])
3+
4+
sealed trait IntT
5+
sealed trait NatT extends IntT
6+
final case class Zero() extends NatT
7+
final case class Succ[+N <: NatT](n: N) extends NatT
8+
final case class Minus[+N <: Succ[NatT]](n: N) extends IntT
9+
10+
type NatSum[X <: NatT, Y <: NatT] <: NatT = Y match
11+
case Zero => X
12+
case Succ[y] => NatSum[Succ[X], y]
13+
14+
type NatDif[X <: NatT, Y <: NatT] <: IntT = Y match
15+
case Zero => X
16+
case Succ[y] => X match
17+
case Zero => Minus[Y]
18+
case Succ[x] => NatDif[x, y]
19+
20+
type Sum[X <: IntT, Y <: IntT] <: IntT = Y match
21+
case Zero => X
22+
case Minus[y] => X match
23+
case Minus[x] => Minus[NatSum[x, y]]
24+
case _ => NatDif[X, y]
25+
case _ => X match
26+
case Minus[x] => NatDif[Y, x]
27+
case _ => NatSum[X, Y]

‎tests/pos/i17149.scala

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
1+
type Ext[S <: Seq[_]] = S match {
2+
case Seq[t] => t
3+
}
4+
5+
def test = implicitly[Ext[Seq[Int]] =:= Int]

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