/
constrained-types.check
151 lines (109 loc) · 3.51 KB
/
constrained-types.check
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Type in expressions to have them evaluated.
Type :help for more information.
scala> class Annot(obj: Any) extends annotation.Annotation with annotation.TypeConstraint
defined class Annot
scala>
scala> class A {
val x = "hello"
val y: Int @Annot(x) = 10
override def toString = "an A"
}
defined class A
scala>
scala> val a = new A
a: A = an A
scala> val y = a.y // should rewrite "this.x" to "a.x"
y: Int @Annot(a.x) = 10
scala> var a2 = new A
a2: A = an A
scala> val y2 = a2.y // should drop the annotation
y2: Int = 10
scala>
scala> object Stuff {
val x = "hello"
val y : Int @Annot(x) = 10
}
defined object Stuff
scala>
scala> val y = Stuff.y // should rewrite the annotation
y: Int @Annot(Stuff.x) = 10
scala>
scala> class B {
val y: Int @Annot(Stuff.x) = 10
override def toString = "a B"
}
defined class B
scala>
scala> val b = new B
b: B = a B
scala> val y = b.y // should keep the annotation
y: Int @Annot(Stuff.x) = 10
scala> def m(x: String): String @Annot(x) = x
m: (x: String)String @Annot(x)
scala>
scala> val three = "three"
three: String = three
scala> val three2 = m(three:three.type) // should change x to three
three2: String @Annot(three) = three
scala> var four = "four"
four: String = four
scala> val four2 = m(four) // should have an existential bound
warning: there was one feature warning; re-run with -feature for details
four2: String @Annot(x) forSome { val x: String } = four
scala> val four3 = four2 // should have the same type as four2
warning: there was one feature warning; re-run with -feature for details
four3: String @Annot(x) forSome { val x: String } = four
scala> val stuff = m("stuff") // should not crash
stuff: String @Annot("stuff") = stuff
scala>
scala> class peer extends annotation.Annotation // should not crash
defined class peer
scala>
scala> class NPE[T <: NPE[T] @peer] // should not crash
defined class NPE
scala>
scala> def m = {
val x = "three"
val y : String @Annot(x) = x
y
} // x should not escape the local scope with a narrow type
warning: there was one feature warning; re-run with -feature for details
m: String @Annot(x) forSome { val x: String }
scala>
scala> def n(y: String) = {
def m(x: String) : String @Annot(x) = {
(if (x == "")
m("default")
else
x)
}
m("stuff".stripMargin)
} // x should be existentially bound
warning: there was one feature warning; re-run with -feature for details
n: (y: String)String @Annot(x) forSome { val x: String }
scala>
scala> class rep extends annotation.Annotation { }
defined class rep
scala>
scala> object A { val x = "hello" : String @ rep }
defined object A
warning: previously defined class A is not a companion to object A.
Companions must be defined together; you may wish to use :paste mode for this.
scala>
scala> val y = a.x // should drop the annotation
y: String = hello
scala>
scala> val x = 3 : Int @Annot(e+f+g+h) // should have a graceful error message
<console>:8: error: not found: value e
val x = 3 : Int @Annot(e+f+g+h) // should have a graceful error message
^
<console>:8: error: not found: value f
val x = 3 : Int @Annot(e+f+g+h) // should have a graceful error message
^
<console>:8: error: not found: value g
val x = 3 : Int @Annot(e+f+g+h) // should have a graceful error message
^
<console>:8: error: not found: value h
val x = 3 : Int @Annot(e+f+g+h) // should have a graceful error message
^
scala>