An intrinsic was declared without being a function.
Erroneous code example:
#![feature(intrinsics)] extern "rust-intrinsic" { pub static breakpoint : unsafe extern "rust-intrinsic" fn(); // error: intrinsic must be a function } fn main() { unsafe { breakpoint(); } }
An intrinsic is a function available for use in a given programming language whose implementation is handled specially by the compiler. In order to fix this error, just declare a function.