Description
I extracted it from the #21693 comments
Compiler version
Scala 3.7.0-RC4
I played around the with the @unroll annotation and I find the error message ranges confusing
Example 0
"Cannot unroll method foo in class Example at line 5 because parameter z needs a default value"
The error is specific to a single parameter.
The whole parameter range is highlighted - OK, seems no issue.
import scala.annotation.unroll
class Example {
final def foo(x: Int, y: Int, @unroll z: Int): Int = x + y + z
}
Example 1
"Cannot unroll parameters of method foo: it is not final"
The error is specific to the whole function and the @unroll annotation usage fact.
However, the range here is the parameter name identifier, which looks strange.
Nothing in the parameter z is special here, so I suppose the better range to highlight here would be just @unroll annotation
import scala.annotation.unroll
class Example {
def foo(x: Int, y: Int, @unroll z: Int): Int = x + y + z
}
Example 2
"@unroll is only allowed on a method parameter"
It's shown on the name identifier foo.
To me it seems the @unroll annotation itself would be a better fit here as well - it's the annotation to blame, not the definition name identifier.
import scala.annotation.unroll
class Example {
@unroll def foo(x: Int, y: Int, z: Int): Int = x + y + z
}
Note that the error at @unroll is different:
