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# Error code E0703

Invalid ABI (Application Binary Interface) used in the code.

Erroneous code example:

    extern "invalid" fn foo() {} // error!
    fn main() {}

At present few predefined ABI’s (like Rust, C, system, etc.) can be used in Rust. Verify that the ABI is predefined. For example you can replace the given ABI from ‘Rust’.

    extern "Rust" fn foo() {} // ok!
    fn main() { }