rust/src/test/compile-fail/mutable-huh-variance-vec4.rs

47 lines
1.0 KiB
Rust

fn main() {
// Note: here we do not have any type annotations
// but we do express conflicting requirements:
let v = [mut [0]];
let w = [mut [mut 0]];
let x = [mut [mut 0]];
fn f(&&v: [mut [int]]) {
v[0] = [3]
}
fn g(&&v: [const [const int]]) {
}
fn h(&&v: [mut [mut int]]) {
v[0] = [mut 3]
}
fn i(&&v: [mut [const int]]) {
v[0] = [mut 3]
}
fn j(&&v: [[const int]]) {
}
f(v);
g(v);
h(v); //! ERROR (values differ in mutability)
i(v); //! ERROR (values differ in mutability)
j(v); //! ERROR (values differ in mutability)
f(w); //! ERROR (values differ in mutability)
g(w);
h(w);
i(w); //! ERROR (values differ in mutability)
j(w); //! ERROR (values differ in mutability)
// Note that without adding f() or h() to the mix, it is valid for
// x to have the type [mut [const int]], and thus we can safely
// call g() and i() but not j():
g(x);
i(x);
j(x); //! ERROR (values differ in mutability)
}