rust/tests/ui/polymorphization/closure_in_upvar/fnmut.rs

35 lines
722 B
Rust

//@ build-pass
//@ compile-flags:-Zpolymorphize=on -Csymbol-mangling-version=v0
fn foo(f: impl Fn()) {
// Mutate an upvar from `x` so that it implements `FnMut`.
let mut outer = 3;
let mut x = |_: ()| {
outer = 4;
()
};
// Don't use `f` in `y`, but refer to `x` so that the closure substs contain a reference to
// `x` that will differ for each instantiation despite polymorphisation of the varying
// argument.
let mut y = || x(());
// Consider `f` used in `foo`.
f();
// Use `y` so that it is visited in monomorphisation collection.
y();
}
fn entry_a() {
foo(|| ());
}
fn entry_b() {
foo(|| ());
}
fn main() {
entry_a();
entry_b();
}