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https://issues.apache.org/jira/browse/GROOVY-12649?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18139160#comment-18139160
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ASF GitHub Bot commented on GROOVY-12649:
-----------------------------------------
paulk-asert merged PR #3222:
URL: https://github.com/apache/groovy/pull/3222
> SC: explicit spread over a Set or other non-List Iterable that declares the
> property casts each element to the receiver type
> ----------------------------------------------------------------------------------------------------------------------------
>
> Key: GROOVY-12649
> URL: https://issues.apache.org/jira/browse/GROOVY-12649
> Project: Groovy
> Issue Type: Bug
> Components: Static compilation
> Affects Versions: 4.0.33, 5.1.3, 6.0.0
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
> Description:
> Under {{@CompileStatic}}, an explicit spread {{coll*.prop}} over a {{Set}}
> subclass, or over any other non-List {{Iterable}}, fails at runtime if the
> receiver's own class declares {{prop}} (as a field or a getter). The compiled
> code reads the receiver's property from each element instead, casting the
> element to the receiver type:
> {code:groovy}
> class Person { String name; Person(String n) { name = n } }
> class PeopleSet extends LinkedHashSet<Person> { String name = 'the set' }
> @groovy.transform.CompileStatic
> def test() {
> def s = new PeopleSet()
> s << new Person('Alice') << new Person('Bob')
> assert s.name == 'the set' // ok
> assert s*.name == ['Alice', 'Bob'] // GroovyCastException: Cannot cast
> object 'Person@...' with class 'Person' to class 'PeopleSet'
> }
> test()
> {code}
> Dynamic Groovy and {{@TypeChecked}} return {{[Alice, Bob]}}: an explicit
> spread always reads the elements.
> ||Receiver ({{x*.name}})||dynamic||CS ≤ 4.0.5||CS 4.0.24 → master||
> |{{Set}} subclass declaring field {{name}}|[Alice, Bob]|[Alice,
> Bob]|GroovyCastException|
> |{{Set}} subclass declaring {{getName()}}|[Alice, Bob]|[Alice,
> Bob]|GroovyCastException|
> |{{Iterable}} (not a Collection) declaring field {{name}}|[Alice,
> Bob]|[Alice, Bob]|GroovyCastException|
> |plain {{Set<Person>}}|[Alice, Bob]|[Alice, Bob]|[Alice, Bob]|
> Seen on JDK 17 with 4.0.24, 4.0.33, 5.0.8, 5.1.3, 6.0.0 and master. It works
> on 3.0.25 and 4.0.5, so this is a regression within the 4.0.x line. I haven't
> bisected it; 9e2ed767e3 (GROOVY-5568, GROOVY-10815, "SC: groovy method as
> property", first in 4.0.7) changed how SC compiles property access and is a
> likely candidate.
> The {{List}} form of this ({{people*.name}} where a List subclass declares
> {{name}}, or gets it from an extension method) is addressed by GROOVY-12534
> (PR #3058). Its spread skip in {{StaticTypeCheckingVisitor.existsProperty}}
> is limited to receivers implementing {{List}}, so the cases above still fail
> with that change applied. Widening that check to any receiver of an explicit
> spread may be enough, but I haven't tested it.
> Related: GROOVY-6311 (resolved), where CS rejected spread over a {{Set}} at
> compile time.
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