Thodoris Sotiropoulos created GROOVY-11470:
----------------------------------------------
Summary: 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
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.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
