[GROOVY-6729] FirstParam.FirstGenericType don't works whe the method returns generic type

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.1, 2.3.0-rc-1
• Fix Version/s: 2.3.0-rc-2
• Component/s: Compiler
• Environment: Groovy Version: 2.3.0-rc-1 JVM: 1.7.0_10 Vendor: Oracle Corporation OS: Mac OS X 10.9.2
• Assignee: Cédric Champeau
• Reporter: UEHARA Junji
• Created: 26/Apr/14 15:38
• Updated: 28/Apr/14 19:31
• Resolved: 27/Apr/14 10:02

Description

Following code fails. The method which using FirstParam.FirstGeneics and returns generic type (where List<T>), it have no effect for closure parameter inference. FirstParam.ToString also didn't works.

fails:

    // NG. FirstParams.FirstGenericType looks don't works.
    static <T> List<T> callee01(List<T>self, @ClosureParams(FirstParam.FirstGenericType) Closure c) {
        self.each {
            c.call(it)
        }
        return self
    }
    // NG
    @TypeChecked
    void caller01() {
        callee01(["a","b","c"]) { a ->
            println(a.toUpperCase()) // [Static type checking] - Cannot find matching method java.lang.Object#toUpperCase(). Please check if the declared type is right and if the method exists.
        }
    }

if the return type is void, it works.

    // OK
    static <T> void callee02(List<T>self, @ClosureParams(FirstParam.FirstGenericType) Closure c) {
        self.each {
            c.call(it)
        }
    }
    @TypeChecked
    void caller02() {
        callee02(["a","b","c"]) { a ->
            println(a.toUpperCase())
        }
    }
    

and if the return type is monomorphic type, its also ok(following case, it's String)

    static <T> String callee03(List<T>self, @ClosureParams(FirstParam.FirstGenericType) Closure c) {
        self.each {
            c.call(it)
        }
        return "foo"
    }

    @TypeChecked
    void caller03() {
        callee03(["a","b","c"]) { a ->
            println(a.toUpperCase())
        }
    }