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https://issues.apache.org/jira/browse/GROOVY-11470?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17879639#comment-17879639
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Jochen Theodorou commented on GROOVY-11470:
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yes, that should be a problem of intersection. the type in the if and outside
need to be interjected after the if-block, so I guess something like
Comparable<? super Serializable> should have been the type for x at the point
of assignent to p, which is obviously not compatible
> type unsafety when using flow typing and wildcard
> -------------------------------------------------
>
> Key: GROOVY-11470
> URL: https://issues.apache.org/jira/browse/GROOVY-11470
> Project: Groovy
> Issue Type: Bug
> Components: Static Type Checker
> Reporter: Thodoris Sotiropoulos
> Priority: Minor
>
> I have the following program
> {code:java}
> class Test {
> public static Comparable<Integer> m() {
> return 1;
> }
> public static void main(String[] args) {
> def x = m()
> if (true) {
> x = ""
> }
> Comparable<? super Integer> p = x
> p.compareTo(1)
> }
> } {code}
> h3. Actual behavior
> The code compiles, but I receive a ClassCastException at runtime
> {code:java}
> Exception in thread "main" java.lang.ClassCastException: class
> java.lang.Integer cannot be cast to class java.lang.String (java.lang.Integer
> and java.lang.String are in module java.base of loader 'bootstrap')
> at java.base/java.lang.String.compareTo(String.java:144)
> at Test.main(test.groovy:16)
> {code}
> h3. Expected behavior
> The code should have been rejected, as the type of variable x is not
> Comparable<? super Integer>.
> I suppose that the problem lies in the implementation of intersection types,
> and not in the implementation of flow-sensitive analysis.
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