rust-clippy/tests/ui/escape_analysis.rs
Michael Wright 9d6ecc7485 Fix boxed_local suggestion
Don't warn about an argument that is moved into a closure.

ExprUseVisitor doesn't walk into nested bodies so use a new
visitor that collects the variables that are moved into closures.

Fixes #3739
2019-02-21 06:59:10 +02:00

170 lines
2.7 KiB
Rust

#![feature(box_syntax)]
#![allow(clippy::borrowed_box, clippy::needless_pass_by_value, clippy::unused_unit)]
#![warn(clippy::boxed_local)]
#[derive(Clone)]
struct A;
impl A {
fn foo(&self) {}
}
trait Z {
fn bar(&self);
}
impl Z for A {
fn bar(&self) {
//nothing
}
}
fn main() {}
fn ok_box_trait(boxed_trait: &Box<Z>) {
let boxed_local = boxed_trait;
// done
}
fn warn_call() {
let x = box A;
x.foo();
}
fn warn_arg(x: Box<A>) {
x.foo();
}
fn nowarn_closure_arg() {
let x = Some(box A);
x.map_or((), |x| take_ref(&x));
}
fn warn_rename_call() {
let x = box A;
let y = x;
y.foo(); // via autoderef
}
fn warn_notuse() {
let bz = box A;
}
fn warn_pass() {
let bz = box A;
take_ref(&bz); // via deref coercion
}
fn nowarn_return() -> Box<A> {
box A // moved out, "escapes"
}
fn nowarn_move() {
let bx = box A;
drop(bx) // moved in, "escapes"
}
fn nowarn_call() {
let bx = box A;
bx.clone(); // method only available to Box, not via autoderef
}
fn nowarn_pass() {
let bx = box A;
take_box(&bx); // fn needs &Box
}
fn take_box(x: &Box<A>) {}
fn take_ref(x: &A) {}
fn nowarn_ref_take() {
// false positive, should actually warn
let x = box A;
let y = &x;
take_box(y);
}
fn nowarn_match() {
let x = box A; // moved into a match
match x {
y => drop(y),
}
}
fn warn_match() {
let x = box A;
match &x {
// not moved
ref y => (),
}
}
fn nowarn_large_array() {
// should not warn, is large array
// and should not be on stack
let x = box [1; 10000];
match &x {
// not moved
ref y => (),
}
}
/// ICE regression test
pub trait Foo {
type Item;
}
impl<'a> Foo for &'a () {
type Item = ();
}
pub struct PeekableSeekable<I: Foo> {
_peeked: I::Item,
}
pub fn new(_needs_name: Box<PeekableSeekable<&()>>) -> () {}
/// Regression for #916, #1123
///
/// This shouldn't warn for `boxed_local`as the implementation of a trait
/// can't change much about the trait definition.
trait BoxedAction {
fn do_sth(self: Box<Self>);
}
impl BoxedAction for u64 {
fn do_sth(self: Box<Self>) {
println!("{}", *self)
}
}
/// Regression for #1478
///
/// This shouldn't warn for `boxed_local`as self itself is a box type.
trait MyTrait {
fn do_sth(self);
}
impl<T> MyTrait for Box<T> {
fn do_sth(self) {}
}
// Issue #3739 - capture in closures
mod issue_3739 {
use super::A;
fn consume<T>(_: T) {}
fn borrow<T>(_: &T) {}
fn closure_consume(x: Box<A>) {
let _ = move || {
consume(x);
};
}
fn closure_borrow(x: Box<A>) {
let _ = || {
borrow(&x);
};
}
}