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  1. JDK
  2. JDK-8063052

Inference chokes on wildcard derived from method reference

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      Description

        This will not compile:

            void test(Box<? extends Box<? extends Number>> b) {
                Number n = b.map(Box::get).get();
            }

            interface Func<S,T> { T apply(S arg); }

            interface Box<T> {
                T get();
                <R> Box<R> map(Func<T,R> f);
            }

        error: incompatible types: inferred type does not conform to upper bound(s)
                Number n = b.map(Box::get).get();
                                ^
            inferred: ? extends Number
            upper bound(s): Object

        If I remove the wildcards, there is no error.

        Perhaps javac is failing to capture the return type of Box.get?

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            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8065407 Inference chokes on wildcard derived from method reference

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8067612 Inference chokes on wildcard derived from method reference

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8070293 Inference chokes on wildcard derived from method reference

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8085273 Inference chokes on wildcard derived from method reference

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            relates to

            Bug - A problem which impairs or prevents the functions of the product. JDK-8063054 Incorrect raw type warning for method reference

            • P5 - Cosmetic problem like misspelt words or misaligned text.
            • Resolved

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                vromero Vicente Arturo Romero Zaldivar
                dlsmith Dan Smith
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                  Updated:
                  Resolved: