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(Scala 2.11.8)
Consider the following snippet:
class Case2 {
trait Container[+A] {
def addAll[B >: A, T2 <: Container[B]](that: T2): Boolean
}
def t1: Container[String] = ???
def t2: Container[Int] = ???
// Works
t1.addAll[Any, Container[Any]](t2)
// Errors:
//* type mismatch; found : Case2.this.Descendant[Int] required: T2
//* inferred type arguments [String,Case2.this.Descendant[Int]] do not conform to method addAll's type parameter bounds [B >: String,T2 <: Case2.this.Ancestor[B]]
t1.addAll(t2)
}
Why can't last addAll
call inference the proper least common denominator?
asked 40 secs ago
Higher-kinder types inference
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