Also reduce term projections #19389
Also reduce term projections #19389
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test performance please |
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@mbovel Performance tests seem to be inoperational |
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I am afraid this PR needs a performance test to be mergeable. |
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test performance please |
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performance test scheduled: 1 job(s) in queue, 0 running. |
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Performance test finished successfully: Visit https://dotty-bench.epfl.ch/19389/ to see the changes. Benchmarks is based on merging with main (bfabc31) |
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test performance please |
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performance test scheduled: 1 job(s) in queue, 0 running. |
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Performance test finished successfully: Visit https://dotty-bench.epfl.ch/19389/ to see the changes. Benchmarks is based on merging with main (bfabc31) |
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Looks like it does not affect performance, so I think we should adopt this, since it can make dependent types smaller. |
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Is there any way we could write a test for this?
This works:
type T
type T1 = { type A = T } # A
def test = summon[T1 =:= T]But I can't do:
type S <: Singleton
type S1 = { val x: S } # x
def test = summon[S1 =:= S]-- [E007] Type Mismatch Error: tests/pos/projection-term-singleton.scala:2:10 --
2 |type S1 = { val x: S } # x
| ^^^^^^^^^^^^
| Found: Object{val x: S}
| Required: ?{ x: ? }
I guess this is because in R # x, the typer expects R to have a type member named x, not a term member?
I also tried:
import scala.reflect.Selectable.reflectiveSelectable
type S <: Singleton
def test =
def foo: { val x: S } = ???
val x: S = foo.xand
import scala.reflect.Selectable.reflectiveSelectable
def getX[S, R <: {val x: S}](r: R) = r.xbut both already pass before your PR.
We already reduce `R { type A = T } # A` to `T` in most situations when we
create types. We now also reduce `R { val x: S } # x` to `S` if `S` is a
singleton type.
This will simplify types as we go to more term-dependent typing. As a concrete
benefit, it will avoid several test-pickling failures due to pickling differences
when using dependent types.
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We already reduce
R { type A = T } # AtoTin most situations when we create types. We now also reduceR { val x: S } # xtoSifSis a singleton type.This will simplify types as we go to more term-dependent typing. As a concrete benefit, it will avoid several test-pickling failures due to pickling differences when using dependent types.