[jira] [Updated] (GROOVY-10324) STC is unable to infer type variable when combining parameterized types and the diamond operator

["Eric Milles (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-10324?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eric Milles updated GROOVY-10324:
---------------------------------
    Fix Version/s: 3.0.11

> STC is unable to infer type variable when combining parameterized types and the diamond operator
> ------------------------------------------------------------------------------------------------
>
>                 Key: GROOVY-10324
>                 URL: https://issues.apache.org/jira/browse/GROOVY-10324
>             Project: Groovy
>          Issue Type: Bug
>            Reporter: Thodoris Sotiropoulos
>            Assignee: Eric Milles
>            Priority: Major
>             Fix For: 4.0.0-beta-2, 3.0.11
>
>
> I have the following program
> {code:java}
> class A {
>   <T> T foo(C<T> t) { return null; }
> }
> class C<T> {}
> class B {
>   void test() {
>     C<String> x = (new A()).foo(new C<>());
>   }
> }
> {code}
> h3. Actual behaviour
> {code}
> org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
> test.groovy: 12: [Static type checking] - Cannot assign value of type java.lang.Object to variable of type C<java.lang.String>
>  @ line 12, column 19.
>        C<String> x = (new A()).foo(new C<>());
>                      ^
> 1 error
> {code}
> h3. Expected behaviour
> Compile successfully
> Note that compilation fails only if the expected return type is parameterized (i.e., `D<String>`). If I replace the declared type of `x` with a regular type (i.e., `String`), the code compiles fine.
> Tested against master.



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