[TODO EXPLAIN] Add capture checking to Mirror and TupleMirror

We need to split the files here, because... ?

Author: natsukagami

TODO.md

@@ -1,3 +1,13 @@
+- [x] library/src/scala/CanEqual.scala
+- [x] library/src/scala/CanThrow.scala
+- [x] library/src/scala/Conversion.scala
+- [x] library/src/scala/IArray.scala
+- [x] library/src/scala/NamedTuple.scala
+- [x] library/src/scala/PolyFunction.scala
+- [x] library/src/scala/Precise.scala
+- [x] library/src/scala/Pure.scala
+- [x] library/src/scala/Selectable.scala
+- [x] library/src/scala/Tuple.scala
 - [ ] library/src/scala/annotation/MacroAnnotation.scala
 - [ ] library/src/scala/annotation/RefiningAnnotation.scala
 - [ ] library/src/scala/annotation/alpha.scala
@@ -10,6 +20,7 @@
 - [ ] library/src/scala/annotation/internal/AnnotationDefault.scala
 - [ ] library/src/scala/annotation/internal/AssignedNonLocally.scala
 - [ ] library/src/scala/annotation/internal/Body.scala
+- [ ] library/src/scala/annotation/internal/CaptureChecked.scala
 - [ ] library/src/scala/annotation/internal/Child.scala
 - [ ] library/src/scala/annotation/internal/ContextResultCount.scala
 - [ ] library/src/scala/annotation/internal/ErasedParam.scala
@@ -38,6 +49,7 @@
 - [ ] library/src/scala/annotation/unchecked/uncheckedCapabilityLeaks.scala
 - [ ] library/src/scala/annotation/unchecked/uncheckedCaptures.scala
 - [ ] library/src/scala/annotation/unroll.scala
+- [ ] library/src/scala/caps/package.scala
 - [ ] library/src/scala/compiletime/ops/any.scala
 - [ ] library/src/scala/compiletime/ops/boolean.scala
 - [ ] library/src/scala/compiletime/ops/double.scala
@@ -46,10 +58,10 @@
 - [ ] library/src/scala/compiletime/ops/long.scala
 - [ ] library/src/scala/compiletime/ops/string.scala
 - [ ] library/src/scala/compiletime/package.scala
-- [ ] library/src/scala/compiletime/testing/Error.scala
-- [ ] library/src/scala/compiletime/testing/ErrorKind.scala
-- [ ] library/src/scala/compiletime/testing/package.scala
-- [ ] library/src/scala/deriving/Mirror.scala
+- [x] library/src/scala/compiletime/testing/Error.scala
+- [x] library/src/scala/compiletime/testing/ErrorKind.scala
+- [x] library/src/scala/compiletime/testing/package.scala
+- [x] library/src/scala/main.scala
 - [ ] library/src/scala/quoted/Expr.scala
 - [ ] library/src/scala/quoted/ExprMap.scala
 - [ ] library/src/scala/quoted/Exprs.scala
@@ -64,3 +76,28 @@
 - [ ] library/src/scala/quoted/runtime/QuoteUnpickler.scala
 - [ ] library/src/scala/quoted/runtime/SplicedType.scala
 - [ ] library/src/scala/quoted/runtime/StopMacroExpansion.scala
+- [x] library/src/scala/reflect/Enum.scala
+- [x] library/src/scala/reflect/Selectable.scala
+- [x] library/src/scala/reflect/TypeTest.scala
+- [x] library/src/scala/reflect/Typeable.scala
+- [x] library/src/scala/runtime/$throws.scala
+- [x] library/src/scala/runtime/Arrays.scala
+- [x] library/src/scala/runtime/EnumValue.scala
+- [x] library/src/scala/runtime/FunctionXXL.scala
+- [x] library/src/scala/runtime/LazyVals.scala
+- [x] library/src/scala/runtime/MatchCase.scala
+- [x] library/src/scala/runtime/Scala3RunTime.scala
+- [x] library/src/scala/runtime/TupleMirror.scala
+- [x] library/src/scala/runtime/TupleXXL.scala
+- [x] library/src/scala/runtime/TupledFunctions.scala
+- [x] library/src/scala/runtime/Tuples.scala
+- [x] library/src/scala/runtime/TypeBox.scala
+- [x] library/src/scala/runtime/coverage/Invoker.scala
+- [ ] library/src/scala/runtime/stdLibPatches/Predef.scala
+- [ ] library/src/scala/runtime/stdLibPatches/language.scala
+- [x] library/src/scala/util/CommandLineParser.scala
+- [x] library/src/scala/util/FromDigits.scala
+- [x] library/src/scala/util/NotGiven.scala
+- [x] library/src/scala/util/TupledFunction.scala
+- [x] library/src/scala/util/boundary.scala
+- [x] library/src/scala/util/control/NonLocalReturns.scala

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

@@ -17,6 +17,8 @@ import util.Spans.Span
 import config.Printers.derive
 import NullOpsDecorator.*
 import scala.runtime.Statics
+import dotty.tools.dotc.config.Feature
+import dotty.tools.dotc.cc.CapturingType
 
 object SyntheticMembers {
 
@@ -688,7 +690,12 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
       addParent(defn.Mirror_SingletonClass.typeRef)
     def makeProductMirror(cls: Symbol, optInfo: Option[MirrorImpl.OfProduct]) = {
       addParent(defn.Mirror_ProductClass.typeRef)
-      addMethod(nme.fromProduct, MethodType(defn.ProductClass.typeRef :: Nil, monoType.typeRef), cls,
+      // fromProduct
+      val productParamType =
+        if Feature.ccEnabled then
+          CapturingType(defn.ProductClass.typeRef, cc.CaptureSet.universal)
+        else defn.ProductClass.typeRef
+      addMethod(nme.fromProduct, MethodType(productParamType :: Nil, monoType.typeRef), cls,
         fromProductBody(_, _, optInfo).ensureConforms(monoType.typeRef))  // t4758.scala or i3381.scala are examples where a cast is needed
     }
     def makeSumMirror(cls: Symbol, optInfo: Option[MirrorImpl.OfSum]) = {

library/src-bootstrapped/scala/deriving/Mirror.scala

@@ -0,0 +1,63 @@
+package scala.deriving
+
+import language.experimental.captureChecking
+
+/** Mirrors allows typelevel access to enums, case classes and objects, and their sealed parents.
+ */
+sealed trait Mirror {
+
+  /** The mirrored *-type */
+  type MirroredMonoType
+
+  /** The name of the type */
+  type MirroredLabel <: String
+
+  /** The names of the product elements */
+  type MirroredElemLabels <: Tuple
+}
+
+object Mirror {
+
+  /** The Mirror for a sum type */
+  trait Sum extends Mirror { self =>
+    /** The ordinal number of the case class of `x`. For enums, `ordinal(x) == x.ordinal` */
+    def ordinal(x: MirroredMonoType): Int
+  }
+
+  /** The Mirror for a product type */
+  trait Product extends Mirror {
+
+    /** Create a new instance of type `T` with elements taken from product `p`. */
+    def fromProduct(p: scala.Product^): MirroredMonoType & AnyRef^{p, this}
+  }
+
+  trait Singleton extends Product {
+    type MirroredMonoType = this.type
+    type MirroredType = this.type
+    type MirroredElemTypes = EmptyTuple
+    type MirroredElemLabels = EmptyTuple
+    def fromProduct(p: scala.Product^): this.type = this
+  }
+
+  /** A proxy for Scala 2 singletons, which do not inherit `Singleton` directly */
+  class SingletonProxy(val value: AnyRef^) extends Product {
+    type MirroredMonoType = value.type
+    type MirroredType = value.type
+    type MirroredElemTypes = EmptyTuple
+    type MirroredElemLabels = EmptyTuple
+    def fromProduct(p: scala.Product^): value.type = value
+  }
+
+  type Of[T] = Mirror { type MirroredType = T; type MirroredMonoType = T ; type MirroredElemTypes <: Tuple }
+  type ProductOf[T] = Mirror.Product { type MirroredType = T; type MirroredMonoType = T ; type MirroredElemTypes <: Tuple }
+  type SumOf[T] = Mirror.Sum { type MirroredType = T; type MirroredMonoType = T; type MirroredElemTypes <: Tuple }
+
+  extension [T](p: ProductOf[T]^)
+    /** Create a new instance of type `T` with elements taken from product `a`. */
+    def fromProductTyped[A <: scala.Product, Elems <: p.MirroredElemTypes](a: A)(using ProductOf[A] { type MirroredElemTypes = Elems }): T =
+      p.fromProduct(a)
+
+    /** Create a new instance of type `T` with elements taken from tuple `t`. */
+    def fromTuple(t: p.MirroredElemTypes): T =
+      p.fromProduct(t)
+}

library/src/scala/deriving/Mirror.scala renamed to library/src-non-bootstrapped/scala/deriving/Mirror.scala

@@ -1,5 +1,7 @@
 package scala.deriving
 
+import language.experimental.captureChecking
+
 /** Mirrors allows typelevel access to enums, case classes and objects, and their sealed parents.
  */
 sealed trait Mirror {
@@ -26,31 +28,31 @@ object Mirror {
   trait Product extends Mirror {
 
     /** Create a new instance of type `T` with elements taken from product `p`. */
-    def fromProduct(p: scala.Product): MirroredMonoType
+    def fromProduct(p: scala.Product): MirroredMonoType & AnyRef^{this}
   }
 
   trait Singleton extends Product {
     type MirroredMonoType = this.type
     type MirroredType = this.type
     type MirroredElemTypes = EmptyTuple
     type MirroredElemLabels = EmptyTuple
-    def fromProduct(p: scala.Product): MirroredMonoType = this
+    def fromProduct(p: scala.Product): this.type = this
   }
 
   /** A proxy for Scala 2 singletons, which do not inherit `Singleton` directly */
-  class SingletonProxy(val value: AnyRef) extends Product {
+  class SingletonProxy(val value: AnyRef^) extends Product {
     type MirroredMonoType = value.type
     type MirroredType = value.type
     type MirroredElemTypes = EmptyTuple
     type MirroredElemLabels = EmptyTuple
-    def fromProduct(p: scala.Product): MirroredMonoType = value
+    def fromProduct(p: scala.Product): value.type = value
   }
 
   type Of[T] = Mirror { type MirroredType = T; type MirroredMonoType = T ; type MirroredElemTypes <: Tuple }
   type ProductOf[T] = Mirror.Product { type MirroredType = T; type MirroredMonoType = T ; type MirroredElemTypes <: Tuple }
   type SumOf[T] = Mirror.Sum { type MirroredType = T; type MirroredMonoType = T; type MirroredElemTypes <: Tuple }
 
-  extension [T](p: ProductOf[T])
+  extension [T](p: ProductOf[T]^)
     /** Create a new instance of type `T` with elements taken from product `a`. */
     def fromProductTyped[A <: scala.Product, Elems <: p.MirroredElemTypes](a: A)(using ProductOf[A] { type MirroredElemTypes = Elems }): T =
       p.fromProduct(a)

library/src/scala/runtime/TupleMirror.scala

@@ -10,7 +10,7 @@ final class TupleMirror(arity: Int) extends scala.deriving.Mirror.Product with S
 
   override type MirroredMonoType <: Tuple
 
-  final def fromProduct(product: Product): MirroredMonoType =
+  final def fromProduct(product: Product^): MirroredMonoType^{product} =
     if product.productArity != arity then
       throw IllegalArgumentException(s"expected Product with $arity elements, got ${product.productArity}")
     runtime.Tuples.fromProduct(product).asInstanceOf[MirroredMonoType]

library/src/scala/runtime/Tuples.scala

@@ -59,7 +59,7 @@ object Tuples {
     if (xs.length <= 22) fromArray(xs.asInstanceOf[Array[Object]])
     else TupleXXL.fromIArray(xs).asInstanceOf[Tuple]
 
-  def fromProduct(xs: Product): Tuple = (xs.productArity match {
+  def fromProduct(xs: Product^): Tuple^{xs} = (xs.productArity match {
     case 0  => EmptyTuple
     case 1 =>
       xs match {

mk_todo.fish

@@ -0,0 +1,6 @@
+#!/usr/bin/env fish
+
+for file in (ls library/src/**.scala | sort)
+  set checkbox (if rg -Fq "import language.experimental.captureChecking" $file; echo "[x]"; else; echo "[ ]"; end)
+  printf "- %s %s\n" $checkbox $file
+end

project/Build.scala

@@ -1143,7 +1143,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/stableNull.scala"),
-        file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
+        file(s"${baseDirectory.value}/src-non-bootstrapped/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Varargs.scala"),
@@ -1281,7 +1281,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/stableNull.scala"),
-        file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
+        file(s"${baseDirectory.value}/src-bootstrapped/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Varargs.scala"),