enable -Yexplicit-nulls for scala3-library #13729
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| true | ||
| } | ||
| } | ||
| .map(_.get(null).asInstanceOf[sun.misc.Unsafe]) | ||
| .map(_.nn.get(null).asInstanceOf[sun.misc.Unsafe]) |
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.nn.get(null) reads strange to me - it looks redundant contradictory?
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Here classOf[sun.misc.Unsafe].getDeclaredFields.nn is an Array[Field | Null] and then after calling find is an Option[Field | Null], so calling map would require asserting the inner value is also not null
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.map is being called on Option[Field | Null].
The type of _ is thus Field | Null.
The type of _.nn is thus java.lang.reflect.Field. This type has a get(Object) method to read the value of the field. The API of this method says that for a static field, the parameter of type Object is ignored and should be null.
| if (x == null) throw new NullPointerException("tried to cast away nullability, but value is null") | ||
| val isNull = x == null | ||
| if (isNull) throw new NullPointerException("tried to cast away nullability, but value is null") |
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What is the benefit of this change?
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A workaround for #7882
| @@ -328,54 +328,59 @@ object IArray: | |||
| extension [T, U >: T: ClassTag](x: T) | |||
| def +:(arr: IArray[U]): IArray[U] = genericArrayOps(arr).prepended(x) | |||
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| // For backwards compatibility with code compiled without -Yexplicit-nulls | |||
| private def mapNull[A, B](a: A, f: =>B): B = | |||
| if((a: A|Null) == null) null.asInstanceOf[B] else f | |||
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We can't use eq for nulls anymore?
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Apparently not. The motivation comes from:
https://contributors.scala-lang.org/t/wip-scala-with-explicit-nulls/2761/4
I don't think this was discussed widely so if people feel strongly about it, we can discuss it.
Co-authored-by: Nicolas Stucki <nicolas.stucki@gmail.com>
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| @@ -328,54 +328,59 @@ object IArray: | |||
| extension [T, U >: T: ClassTag](x: T) | |||
| def +:(arr: IArray[U]): IArray[U] = genericArrayOps(arr).prepended(x) | |||
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| // For backwards compatibility with code compiled without -Yexplicit-nulls | |||
| private inline def mapNull[A, B](a: A, inline f: B): B = | |||
| if((a: A|Null) == null) null.asInstanceOf[B] else f | |||
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What happens if A = X | Null (for some type X)?
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That shouldn't be a problem: an expression of type X | Null | Null is still allowed to be compared with null.
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
- This was caused by changes in issue scala#13729
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