Open
Description
Compiler version
3.1.1
Minimized code
package p
class C(private[p] c: Int)
object X:
trait T(private[X] i: Int)
class C(n: Int) extends T(n)
def x = C(42).i
@main def test() = println {
C(42).c
}Output
-- [E008] Not Found Error: param-access.scala:9:16 ---------------------------------------------------------------------
9 | def x = C(42).i
| ^^^^^^^
| value i is not a member of p.X.C
-- Error: param-access.scala:12:8 --------------------------------------------------------------------------------------
12 | C(42).c
| ^^^^^^^
| value c cannot be accessed as a member of p.C from module class param-access$package$.Compilation output
[[syntax trees at end of typer]] // param-access.scala
package p {
class C(private[p] c: Int) extends Object() {
private[this] private[this] val c: Int
}
final lazy module val X: p.X = new p.X()
final module class X() extends Object() { this: p.X.type =>
trait T(private[X] i: Int) extends Object {
private[this] private[this] val i: Int
}
class C(n: Int) extends Object(), p.X.T(C.this.n) {
private[this] val n: Int
}
def x: <error value i is not a member of p.X.C> = new p.X.C(42).i
}
final lazy module val param-access$package: p.param-access$package = new p.param-access$package()
final module class param-access$package() extends Object() { this: p.param-access$package.type =>
@main def test(): Unit =
println(
{
new p.C(42).c
}
)
}
}Expectation
Probably no one is confused by scala/bug#12562 unless they read the spec, which says that when there is an access modifier on a class (or trait) param, val is assumed.
That specified behavior makes sense because "whether there is a member field" for "private" is inferred.
Actually I also expected "assumed val" for param access equivalent to private or private[C].
scala> class C(c: Int) { def ok(other: C) = other.c == c }
-- Error: --------------------------------------------------------------------------------------------------------------
1 |class C(c: Int) { def ok(other: C) = other.c == c }
| ^^^^^^^
| value c cannot be accessed as a member of (other : C) from class C.
1 error found
Probably during the long pandemic, in my imagination, private[this] inference took on additional powers.
For clarification, I would expect either the spec behavior or just reject the meaningless modifier, if it is meaningless.