Unsound generic tuple type test #9056
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Minimized to assert(((): Any).isInstanceOf[Tuple])
assert((1, 2).isInstanceOf[Tuple])
assert((1, 2, 3).isInstanceOf[Tuple])
assert(!"".isInstanceOf[Tuple]) // fail
assert(!Some("").isInstanceOf[Tuple]) // fail
assert(!((): Any).isInstanceOf[NonEmptyTuple])
assert((1, 2).isInstanceOf[NonEmptyTuple])
assert((1, 2, 3).isInstanceOf[NonEmptyTuple])
assert(!("": Any).isInstanceOf[NonEmptyTuple])
assert(!(Some(""): Any).isInstanceOf[NonEmptyTuple]) // fail
assert(!((): Any).isInstanceOf[_ *: _])
assert((1, 2).isInstanceOf[_ *: _])
assert((1, 2, 3).isInstanceOf[_ *: _])
assert(!("": Any).isInstanceOf[_ *: _])
assert(!(Some(""): Any).isInstanceOf[_ *: _]) // failAll these assertions should pass |
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Maybe we could erase instance tests on tuples in the following way x.isInstanceOf[NonEmptyTuple]isInstanceOfNonEmptyTuple(x)// In scala.runtime.Tuple
def isInstanceOfNonEmptyTuple(x: Any): Boolean =
x.isInstanceOf[Tuple1[_]]
|| x.isInstanceOf[Tuple2[_, _]]
|| ...
|| x.isInstanceOf[Tuple22[_, ..., _]]
|| x.isInstanceOf[TupleXXL] ||
|
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We also have a similar issue with |
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This is a blocker for #9049 |
nicolasstucki
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area:erasure
prio:blocker
and removed
itype:language enhancement
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We change to the following hierarchy where all generic tuple types erase to `Product`.
```
Product -- Tuple -+- EmptyTuple
|
+- NonEmptyTuple -- *:[Head, Tail <: Tuple]
```
These are encoded using the following compile-time only classes
```scalla
sealed trait Tuple extends Product { ... }
object EmptyTuple extends Tuple { ... }
type EmptyTuple = EmptyTuple.type
sealed trait NonEmptyTuple extends Tuple { ... }
sealed abstract class *:[+H, +T <: Tuple] extends NonEmptyTuple { ... }
```
`TupleN` classes for `1 < N <= 22` are made subtypes of `*:` with precise type (as done before). But `Unit` is not anymore related to `Tuple`.
Construction of empty tuples can be done with `Tuple()`, tuples with one element with `Tuple(e)` while any other tuple are created with `(e1, ..., en)`.
nicolasstucki
added a commit
to dotty-staging/dotty
that referenced
this issue
Jun 8, 2020
We change to the following hierarchy where all generic tuple types erase to `Product`.
```
Product -- Tuple -+- EmptyTuple
|
+- NonEmptyTuple -- *:[Head, Tail <: Tuple]
```
These are encoded using the following compile-time only classes
```scalla
sealed trait Tuple extends Product { ... }
object EmptyTuple extends Tuple { ... }
type EmptyTuple = EmptyTuple.type
sealed trait NonEmptyTuple extends Tuple { ... }
sealed abstract class *:[+H, +T <: Tuple] extends NonEmptyTuple { ... }
```
`TupleN` classes for `1 < N <= 22` are made subtypes of `*:` with precise type (as done before). But `Unit` is not anymore related to `Tuple`.
Construction of empty tuples can be done with `Tuple()`, tuples with one element with `Tuple(e)` while any other tuple are created with `(e1, ..., en)`.
nicolasstucki
added a commit
to dotty-staging/dotty
that referenced
this issue
Jun 8, 2020
We change to the following hierarchy where all generic tuple types erase to `Product`.
```
Product -- Tuple -+- EmptyTuple
|
+- NonEmptyTuple -- *:[Head, Tail <: Tuple]
```
These are encoded using the following compile-time only classes
```scalla
sealed trait Tuple extends Product { ... }
object EmptyTuple extends Tuple { ... }
type EmptyTuple = EmptyTuple.type
sealed trait NonEmptyTuple extends Tuple { ... }
sealed abstract class *:[+H, +T <: Tuple] extends NonEmptyTuple { ... }
```
`TupleN` classes for `1 < N <= 22` are made subtypes of `*:` with precise type (as done before). But `Unit` is not anymore related to `Tuple`.
Construction of empty tuples can be done with `Tuple()`, tuples with one element with `Tuple(e)` while any other tuple are created with `(e1, ..., en)`.
nicolasstucki
added a commit
to dotty-staging/dotty
that referenced
this issue
Jun 8, 2020
We change to the following hierarchy where all generic tuple types erase to `Product`.
```
Product -- Tuple -+- EmptyTuple
|
+- NonEmptyTuple -- *:[Head, Tail <: Tuple]
```
These are encoded using the following compile-time only classes
```scalla
sealed trait Tuple extends Product { ... }
object EmptyTuple extends Tuple { ... }
type EmptyTuple = EmptyTuple.type
sealed trait NonEmptyTuple extends Tuple { ... }
sealed abstract class *:[+H, +T <: Tuple] extends NonEmptyTuple { ... }
```
`TupleN` classes for `1 < N <= 22` are made subtypes of `*:` with precise type (as done before). But `Unit` is not anymore related to `Tuple`.
Construction of empty tuples can be done with `Tuple()`, tuples with one element with `Tuple(e)` while any other tuple are created with `(e1, ..., en)`.
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The following two matches succeed when they should not.
Tuple,NonEmptyTuple,*:erase toObjectorProductand therefore the test is performed on those classes.As these classes do not exist at runtime we should handle them as abstract types which would yield the unchecked warning. This approach could be combined with TypeTest to provide a type test that does the correct checks at runtime.
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