An invalid number of generic parameters was passed to an intrinsic function.

Erroneous code example:

#![feature(intrinsics)]
#![allow(internal_features)]

#[rustc_intrinsic]
#[rustc_intrinsic_must_be_overridden]
fn size_of<T, U>() -> usize // error: intrinsic has wrong number
                            //        of type parameters
{
    loop {}
}

Please check that you provided the right number of type parameters and verify with the function declaration in the Rust source code. Example:

#![feature(intrinsics)]
#![allow(internal_features)]

#[rustc_intrinsic]
#[rustc_intrinsic_must_be_overridden]
fn size_of<T>() -> usize // ok!
{
    loop {}
}