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https://issues.apache.org/jira/browse/GROOVY-10844?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17635489#comment-17635489
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Eric Milles edited comment on GROOVY-10844 at 12/27/22 3:48 PM:
----------------------------------------------------------------
Please provide a complete script (preferable) or project to demonstrate the
issue.
Update: I had to make some guesses here. I added a cast to the result of
{{convertToRef}} and 3.0.14 STC is happy. Otherwise, it does not like
{{recover}} producing {{Ref.Uri}}. 4.0.7 runs fine without the cast.
{code:groovy}
@Grab('io.vavr:vavr:0.10.4')
import io.vavr.control.Try
interface Attachment {}
abstract class Ref {
static class File extends Ref {
}
static class Uri extends Ref {
}
}
class Spec {
Attachment toAttachment(Ref ref) {
println ref
return null
}
}
Map process(value) {
return [foo:'bar']
}
// Is the return type here Ref or Ref.File?
Ref.File convertToRef(Map map) {
return new Ref.File()
}
@groovy.transform.TypeChecked
def test(initialValue) {
Spec spec = []
Try.success(initialValue)
.mapTry { process(it) }
.map { (Ref) convertToRef(it) } // Ref.File extends Ref
.recover { new Ref.Uri(/*it.href*/) } // Ref.Uri extends Ref -- "it" is
Throwable
.map(spec::toAttachment)
}
print test(null)
{code}
was (Author: emilles):
Please provide a complete script (preferable) or project to demonstrate the
issue.
Update: I had to make some guesses here. I added a cast to the result of
{{convertToRef}} and STC is happy. Otherwise, it does not like {{recover}}
producing {{Ref.Uri}}.
{code:groovy}
@Grab('io.vavr:vavr:0.10.4')
import io.vavr.control.Try
interface Attachment {}
abstract class Ref {
static class File extends Ref {
}
static class Uri extends Ref {
}
}
class Spec {
Attachment toAttachment(Ref ref) {
println ref
return null
}
}
Map process(value) {
return [foo:'bar']
}
// Is the return type here Ref or Ref.File?
Ref.File convertToRef(Map map) {
return new Ref.File()
}
@groovy.transform.TypeChecked
def test(initialValue) {
Spec spec = []
Try.success(initialValue)
.mapTry { process(it) }
.map { (Ref) convertToRef(it) } // Ref.File extends Ref
.recover { new Ref.Uri(/*it.href*/) } // Ref.Uri extends Ref -- "it" is
Throwable
.map(spec::toAttachment)
}
print test(null)
{code}
> STC mis-tracks generics in type hierarchy
> -----------------------------------------
>
> Key: GROOVY-10844
> URL: https://issues.apache.org/jira/browse/GROOVY-10844
> Project: Groovy
> Issue Type: Bug
> Components: Static compilation, Static Type Checker
> Affects Versions: 4.0.6
> Reporter: Christopher Smith
> Assignee: Eric Milles
> Priority: Critical
>
> I have a Vavr {{Try}} pipeline of this form:
> {code:groovy}
> class AttachmentSpec {
> // fields
> Attachment toAttachment(Ref ref) { ... }
> }
> Try.success(initialValue)
> .mapTry { process(it) } // returns a Map
> .map { convertToRef(it) } // returns a Ref.File extends Ref
> .recover { new Ref.Uri(it.href) } // Ref.Uri extends Ref
> .map(spec::toAttachment)
> {code}
> On a failure in {{process}}, this pipeline should enter {{recover}} and
> supply a {{Ref.Uri}}, then do the final {{map}}. However, this fails with a
> {{ClassCastException: cannot convert Ref.Uri to Ref.File}}. Apparently, the
> compiler infers {{Ref.Uri}} as the return value from the first {{map}} (which
> is legitimate), but then it fails to produce a compile-time error when
> {{recover}} presents a then-incompatible {{Ref.File}}. The compiler should
> either (ideally) recognize that the desired type is superclass {{Ref}} or,
> more simply but at least correctly, produce a compile-time error until a type
> witness is inserted (and observed).
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