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# Error code E0130

A pattern was declared as an argument in a foreign function declaration.

Erroneous code example:

    #![allow(unused)]
    fn main() {
    extern "C" {
        fn foo((a, b): (u32, u32)); // error: patterns aren't allowed in foreign
                                    //        function declarations
    }
    }

To fix this error, replace the pattern argument with a regular one. Example:

    #![allow(unused)]
    fn main() {
    struct SomeStruct {
        a: u32,
        b: u32,
    }

    extern "C" {
        fn foo(s: SomeStruct); // ok!
    }
    }

Or:

    #![allow(unused)]
    fn main() {
    extern "C" {
        fn foo(a: (u32, u32)); // ok!
    }
    }