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|
// aux-build:proc_macro_derive.rs
// aux-build:macro_rules.rs
#![warn(clippy::field_reassign_with_default)]
#[macro_use]
extern crate proc_macro_derive;
#[macro_use]
extern crate macro_rules;
// Don't lint on derives that derive `Default`
// See https://github.com/rust-lang/rust-clippy/issues/6545
#[derive(FieldReassignWithDefault)]
struct DerivedStruct;
#[derive(Default)]
struct A {
i: i32,
j: i64,
}
struct B {
i: i32,
j: i64,
}
#[derive(Default)]
struct C {
i: Vec<i32>,
j: i64,
}
#[derive(Default)]
struct D {
a: Option<i32>,
b: Option<i32>,
}
macro_rules! m {
($key:ident: $value:tt) => {{
let mut data = $crate::D::default();
data.$key = Some($value);
data
}};
}
/// Implements .next() that returns a different number each time.
struct SideEffect(i32);
impl SideEffect {
fn new() -> SideEffect {
SideEffect(0)
}
fn next(&mut self) -> i32 {
self.0 += 1;
self.0
}
}
fn main() {
// wrong, produces first error in stderr
let mut a: A = Default::default();
a.i = 42;
// right
let mut a: A = Default::default();
// right
let a = A {
i: 42,
..Default::default()
};
// right
let mut a: A = Default::default();
if a.i == 0 {
a.j = 12;
}
// right
let mut a: A = Default::default();
let b = 5;
// right
let mut b = 32;
let mut a: A = Default::default();
b = 2;
// right
let b: B = B { i: 42, j: 24 };
// right
let mut b: B = B { i: 42, j: 24 };
b.i = 52;
// right
let mut b = B { i: 15, j: 16 };
let mut a: A = Default::default();
b.i = 2;
// wrong, produces second error in stderr
let mut a: A = Default::default();
a.j = 43;
a.i = 42;
// wrong, produces third error in stderr
let mut a: A = Default::default();
a.i = 42;
a.j = 43;
a.j = 44;
// wrong, produces fourth error in stderr
let mut a = A::default();
a.i = 42;
// wrong, but does not produce an error in stderr, because we can't produce a correct kind of
// suggestion with current implementation
let mut c: (i32, i32) = Default::default();
c.0 = 42;
c.1 = 21;
// wrong, produces the fifth error in stderr
let mut a: A = Default::default();
a.i = Default::default();
// wrong, produces the sixth error in stderr
let mut a: A = Default::default();
a.i = Default::default();
a.j = 45;
// right, because an assignment refers to another field
let mut x = A::default();
x.i = 42;
x.j = 21 + x.i as i64;
// right, we bail out if there's a reassignment to the same variable, since there is a risk of
// side-effects affecting the outcome
let mut x = A::default();
let mut side_effect = SideEffect::new();
x.i = side_effect.next();
x.j = 2;
x.i = side_effect.next();
// don't lint - some private fields
let mut x = m::F::default();
x.a = 1;
// don't expand macros in the suggestion (#6522)
let mut a: C = C::default();
a.i = vec![1];
// Don't lint in external macros
field_reassign_with_default!();
// be sure suggestion is correct with generics
let mut a: Wrapper<bool> = Default::default();
a.i = true;
let mut a: WrapperMulti<i32, i64> = Default::default();
a.i = 42;
// Don't lint in macros
m! {
a: 42
};
}
mod m {
#[derive(Default)]
pub struct F {
pub a: u64,
b: u64,
}
}
#[derive(Default)]
struct Wrapper<T> {
i: T,
}
#[derive(Default)]
struct WrapperMulti<T, U> {
i: T,
j: U,
}
mod issue6312 {
use std::sync::atomic::AtomicBool;
use std::sync::Arc;
// do not lint: type implements `Drop` but not all fields are `Copy`
#[derive(Clone, Default)]
pub struct ImplDropNotAllCopy {
name: String,
delay_data_sync: Arc<AtomicBool>,
}
impl Drop for ImplDropNotAllCopy {
fn drop(&mut self) {
self.close()
}
}
impl ImplDropNotAllCopy {
fn new(name: &str) -> Self {
let mut f = ImplDropNotAllCopy::default();
f.name = name.to_owned();
f
}
fn close(&self) {}
}
// lint: type implements `Drop` and all fields are `Copy`
#[derive(Clone, Default)]
pub struct ImplDropAllCopy {
name: usize,
delay_data_sync: bool,
}
impl Drop for ImplDropAllCopy {
fn drop(&mut self) {
self.close()
}
}
impl ImplDropAllCopy {
fn new(name: &str) -> Self {
let mut f = ImplDropAllCopy::default();
f.name = name.len();
f
}
fn close(&self) {}
}
// lint: type does not implement `Drop` though all fields are `Copy`
#[derive(Clone, Default)]
pub struct NoDropAllCopy {
name: usize,
delay_data_sync: bool,
}
impl NoDropAllCopy {
fn new(name: &str) -> Self {
let mut f = NoDropAllCopy::default();
f.name = name.len();
f
}
}
}
|
