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#![allow(clippy::non_canonical_clone_impl, unused)]
#![warn(clippy::unnecessary_struct_initialization)]
struct S {
f: String,
}
#[derive(Clone, Copy)]
struct T {
f: u32,
}
struct U {
f: u32,
}
impl Clone for U {
fn clone(&self) -> Self {
// Do not lint: `Self` does not implement `Copy`
Self { ..*self }
}
}
#[derive(Copy)]
struct V {
f: u32,
}
struct W {
f1: u32,
f2: u32,
}
impl Clone for V {
fn clone(&self) -> Self {
// Lint: `Self` implements `Copy`
*self
//~^ unnecessary_struct_initialization
}
}
fn main() {
// Should lint: `a` would be consumed anyway
let a = S { f: String::from("foo") };
let mut b = a;
//~^ unnecessary_struct_initialization
// Should lint: `b` would be consumed, and is mutable
let c = &mut b;
//~^ unnecessary_struct_initialization
// Should not lint as `d` is not mutable
let d = S { f: String::from("foo") };
let e = &mut S { ..d };
// Should lint as `f` would be consumed anyway
let f = S { f: String::from("foo") };
let g = &f;
//~^ unnecessary_struct_initialization
// Should lint: the result of an expression is mutable
let h = &mut *Box::new(S { f: String::from("foo") });
// Should not lint: `m` would be both alive and borrowed
let m = T { f: 17 };
let n = &T { ..m };
// Should not lint: `m` should not be modified
let o = &mut T { ..m };
o.f = 32;
assert_eq!(m.f, 17);
// Should not lint: `m` should not be modified
let o = &mut T { ..m } as *mut T;
unsafe { &mut *o }.f = 32;
assert_eq!(m.f, 17);
// Should lint: the result of an expression is mutable and temporary
let p = &mut *Box::new(T { f: 5 });
// Should lint: all fields of `q` would be consumed anyway
let q = W { f1: 42, f2: 1337 };
let r = q;
//~^ unnecessary_struct_initialization
// Should not lint: not all fields of `t` from same source
let s = W { f1: 1337, f2: 42 };
let t = W { f1: s.f1, f2: r.f2 };
// Should not lint: different fields of `s` assigned
let u = W { f1: s.f2, f2: s.f1 };
// Should lint: all fields of `v` would be consumed anyway
let v = W { f1: 42, f2: 1337 };
let w = v;
//~^ unnecessary_struct_initialization
// Should not lint: source differs between fields and base
let x = W { f1: 42, f2: 1337 };
let y = W { f1: w.f1, ..x };
// Should lint: range desugars to struct
let r1 = 0..5;
let r2 = r1;
//~^ unnecessary_struct_initialization
references();
shorthand();
}
fn references() {
// Should not lint as `a` is not mutable
let a = W { f1: 42, f2: 1337 };
let b = &mut W { f1: a.f1, f2: a.f2 };
// Should lint as `d` is a shared reference
let c = W { f1: 42, f2: 1337 };
let d = &c;
//~^ unnecessary_struct_initialization
// Should not lint as `e` is not mutable
let e = W { f1: 42, f2: 1337 };
let f = &mut W { f1: e.f1, ..e };
// Should lint as `h` is a shared reference
let g = W { f1: 42, f2: 1337 };
let h = &g;
//~^ unnecessary_struct_initialization
// Should not lint as `j` is copy
let i = V { f: 0x1701d };
let j = &V { ..i };
// Should not lint as `k` is copy
let k = V { f: 0x1701d };
let l = &V { f: k.f };
}
fn shorthand() {
struct S1 {
a: i32,
b: i32,
}
let a = 42;
let s = S1 { a: 3, b: 4 };
// Should not lint: `a` is not from `s`
let s = S1 { a, b: s.b };
}
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