A TypeTest[S, T] contains the logic needed to know at runtime if a value of
type S can be downcasted to T.
A TypeTest[S, T] contains the logic needed to know at runtime if a value of
type S can be downcasted to T.
If a pattern match is performed on a term of type s: S that is uncheckable with s.isInstanceOf[T] and
the pattern are of the form:
t: Tt @ X()where theX.unapplyhas takes an argument of typeTthen a given instance ofTypeTest[S, T]is summoned and used to perform the test.
- Companion
- object
Value members
Abstract methods
A TypeTest[S, T] can serve as an extractor that matches only S of type T.
A TypeTest[S, T] can serve as an extractor that matches only S of type T.
The compiler tries to turn unchecked type tests in pattern matches into checked ones
by wrapping a (_: T) type pattern as tt(_: T), where tt is the TypeTest[S, T] instance.
Type tests necessary before calling other extractors are treated similarly.
SomeExtractor(...) is turned into tt(SomeExtractor(...)) if T in SomeExtractor.unapply(x: T)
is uncheckable, but we have an instance of TypeTest[S, T].