Allow abstract type members in objects. #2044
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Contributor
| why? |
Contributor Author
| Because Furthermore it is already possible to have abstract types in objects by defining it in a trait trait A { type T <: Any } object B extends A // B has the abstract type TIn this case it would be simpler to define it as object B { type T <: Any } |
Contributor
| Do we have a test that checks that bounds of abstract type members are non-empty, i.e. lower bound <: upper bound? In that case, LGTM |
nicolasstucki commented Mar 2, 2017
| val v = new V {} // error: cannot be instantiated | ||
| v.brand("boom!") | ||
| } | ||
| object V { // error: cannot be instantiated |
Contributor Author
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The error of the bound >: Any <: Nothing is the reason for the cannot be instantiated error, the full message is quite clear on the source of the issue.
odersky approved these changes Mar 2, 2017
Member
| See here for a concrete use case: https://github.com/sjrd/scala-unboxed-option/blob/4222ec1d95982ac7a5912c1d06eacb8f7b09554f/src/main/scala/uoption/package.scala#L23 |
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