Frank Pavageau created GROOVY-7691:
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Summary: Type checking error on generic property with covariant
type in subclass
Key: GROOVY-7691
URL: https://issues.apache.org/jira/browse/GROOVY-7691
Project: Groovy
Issue Type: Bug
Components: Static Type Checker
Affects Versions: 2.4.5
Reporter: Frank Pavageau
Assignee: Cédric Champeau
A property declared with a generic type in a superclass is not seen with the
correct covariant type in a subclass narrowing the type:
{code}
abstract class AbstractNumberWrapper<S extends Number> {
protected final S number;
AbstractNumberWrapper(S number) {
this.number = number
}
}
class LongWrapper<S extends Long> extends AbstractNumberWrapper<S> {
LongWrapper(S longNumber) {
super(longNumber)
}
S getValue() {
return number;
}
}
assert new LongWrapper<Long>(42L).value == 42
{code}
raises the following error when type checked:
{noformat}
[Static type checking] - Cannot return value of type java.lang.Number on method
returning type S
@ line 15, column 28.
return number;
^
1 error{noformat}
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