src/tools/clippy/tests/ui/use_self.fixed

   1 // run-rustfix
   2 // aux-build:proc_macro_derive.rs
   3
   4 #![warn(clippy::use_self)]
   5 #![allow(dead_code, unreachable_code)]
   6 #![allow(
   7     clippy::should_implement_trait,
   8     clippy::upper_case_acronyms,
   9     clippy::from_over_into,
  10     clippy::self_named_constructors
  11 )]
  12
  13 #[macro_use]
  14 extern crate proc_macro_derive;
  15
  16 fn main() {}
  17
  18 mod use_self {
  19     struct Foo {}
  20
  21     impl Foo {
  22         fn new() -> Self {
  23             Self {}
  24         }
  25         fn test() -> Self {
  26             Self::new()
  27         }
  28     }
  29
  30     impl Default for Foo {
  31         fn default() -> Self {
  32             Self::new()
  33         }
  34     }
  35 }
  36
  37 mod better {
  38     struct Foo {}
  39
  40     impl Foo {
  41         fn new() -> Self {
  42             Self {}
  43         }
  44         fn test() -> Self {
  45             Self::new()
  46         }
  47     }
  48
  49     impl Default for Foo {
  50         fn default() -> Self {
  51             Self::new()
  52         }
  53     }
  54 }
  55
  56 mod lifetimes {
  57     struct Foo<'a> {
  58         foo_str: &'a str,
  59     }
  60
  61     impl<'a> Foo<'a> {
  62         // Cannot use `Self` as return type, because the function is actually `fn foo<'b>(s: &'b str) ->
  63         // Foo<'b>`
  64         fn foo(s: &str) -> Foo {
  65             Foo { foo_str: s }
  66         }
  67         // cannot replace with `Self`, because that's `Foo<'a>`
  68         fn bar() -> Foo<'static> {
  69             Foo { foo_str: "foo" }
  70         }
  71
  72         // FIXME: the lint does not handle lifetimed struct
  73         // `Self` should be applicable here
  74         fn clone(&self) -> Foo<'a> {
  75             Foo { foo_str: self.foo_str }
  76         }
  77     }
  78 }
  79
  80 mod issue2894 {
  81     trait IntoBytes {
  82         fn to_bytes(self) -> Vec<u8>;
  83     }
  84
  85     // This should not be linted
  86     impl IntoBytes for u8 {
  87         fn to_bytes(self) -> Vec<u8> {
  88             vec![self]
  89         }
  90     }
  91 }
  92
  93 mod existential {
  94     struct Foo;
  95
  96     impl Foo {
  97         fn bad(foos: &[Self]) -> impl Iterator<Item = &Self> {
  98             foos.iter()
  99         }
 100
 101         fn good(foos: &[Self]) -> impl Iterator<Item = &Self> {
 102             foos.iter()
 103         }
 104     }
 105 }
 106
 107 mod tuple_structs {
 108     pub struct TS(i32);
 109
 110     impl TS {
 111         pub fn ts() -> Self {
 112             Self(0)
 113         }
 114     }
 115 }
 116
 117 mod macros {
 118     macro_rules! use_self_expand {
 119         () => {
 120             fn new() -> Foo {
 121                 Foo {}
 122             }
 123         };
 124     }
 125
 126     struct Foo {}
 127
 128     impl Foo {
 129         use_self_expand!(); // Should not lint in local macros
 130     }
 131
 132     #[derive(StructAUseSelf)] // Should not lint in derives
 133     struct A;
 134 }
 135
 136 mod nesting {
 137     struct Foo {}
 138     impl Foo {
 139         fn foo() {
 140             #[allow(unused_imports)]
 141             use self::Foo; // Can't use Self here
 142             struct Bar {
 143                 foo: Foo, // Foo != Self
 144             }
 145
 146             impl Bar {
 147                 fn bar() -> Self {
 148                     Self { foo: Foo {} }
 149                 }
 150             }
 151
 152             // Can't use Self here
 153             fn baz() -> Foo {
 154                 Foo {}
 155             }
 156         }
 157
 158         // Should lint here
 159         fn baz() -> Self {
 160             Self {}
 161         }
 162     }
 163
 164     enum Enum {
 165         A,
 166         B(u64),
 167         C { field: bool },
 168     }
 169     impl Enum {
 170         fn method() {
 171             #[allow(unused_imports)]
 172             use self::Enum::*; // Issue 3425
 173             static STATIC: Enum = Enum::A; // Can't use Self as type
 174         }
 175
 176         fn method2() {
 177             let _ = Self::B(42);
 178             let _ = Self::C { field: true };
 179             let _ = Self::A;
 180         }
 181     }
 182 }
 183
 184 mod issue3410 {
 185
 186     struct A;
 187     struct B;
 188
 189     trait Trait<T> {
 190         fn a(v: T) -> Self;
 191     }
 192
 193     impl Trait<Vec<A>> for Vec<B> {
 194         fn a(_: Vec<A>) -> Self {
 195             unimplemented!()
 196         }
 197     }
 198
 199     impl<T> Trait<Vec<A>> for Vec<T>
 200     where
 201         T: Trait<B>,
 202     {
 203         fn a(v: Vec<A>) -> Self {
 204             <Vec<B>>::a(v).into_iter().map(Trait::a).collect()
 205         }
 206     }
 207 }
 208
 209 #[allow(clippy::no_effect, path_statements)]
 210 mod rustfix {
 211     mod nested {
 212         pub struct A {}
 213     }
 214
 215     impl nested::A {
 216         const A: bool = true;
 217
 218         fn fun_1() {}
 219
 220         fn fun_2() {
 221             Self::fun_1();
 222             Self::A;
 223
 224             Self {};
 225         }
 226     }
 227 }
 228
 229 mod issue3567 {
 230     struct TestStruct {}
 231     impl TestStruct {
 232         fn from_something() -> Self {
 233             Self {}
 234         }
 235     }
 236
 237     trait Test {
 238         fn test() -> TestStruct;
 239     }
 240
 241     impl Test for TestStruct {
 242         fn test() -> TestStruct {
 243             Self::from_something()
 244         }
 245     }
 246 }
 247
 248 mod paths_created_by_lowering {
 249     use std::ops::Range;
 250
 251     struct S {}
 252
 253     impl S {
 254         const A: usize = 0;
 255         const B: usize = 1;
 256
 257         async fn g() -> Self {
 258             Self {}
 259         }
 260
 261         fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
 262             &p[Self::A..Self::B]
 263         }
 264     }
 265
 266     trait T {
 267         fn f<'a>(&self, p: &'a [u8]) -> &'a [u8];
 268     }
 269
 270     impl T for Range<u8> {
 271         fn f<'a>(&self, p: &'a [u8]) -> &'a [u8] {
 272             &p[0..1]
 273         }
 274     }
 275 }
 276
 277 // reused from #1997
 278 mod generics {
 279     struct Foo<T> {
 280         value: T,
 281     }
 282
 283     impl<T> Foo<T> {
 284         // `Self` is applicable here
 285         fn foo(value: T) -> Self {
 286             Self { value }
 287         }
 288
 289         // `Cannot` use `Self` as a return type as the generic types are different
 290         fn bar(value: i32) -> Foo<i32> {
 291             Foo { value }
 292         }
 293     }
 294 }
 295
 296 mod issue4140 {
 297     pub struct Error<From, To> {
 298         _from: From,
 299         _too: To,
 300     }
 301
 302     pub trait From<T> {
 303         type From;
 304         type To;
 305
 306         fn from(value: T) -> Self;
 307     }
 308
 309     pub trait TryFrom<T>
 310     where
 311         Self: Sized,
 312     {
 313         type From;
 314         type To;
 315
 316         fn try_from(value: T) -> Result<Self, Error<Self::From, Self::To>>;
 317     }
 318
 319     // FIXME: Suggested fix results in infinite recursion.
 320     // impl<F, T> TryFrom<F> for T
 321     // where
 322     //     T: From<F>,
 323     // {
 324     //     type From = Self::From;
 325     //     type To = Self::To;
 326
 327     //     fn try_from(value: F) -> Result<Self, Error<Self::From, Self::To>> {
 328     //         Ok(From::from(value))
 329     //     }
 330     // }
 331
 332     impl From<bool> for i64 {
 333         type From = bool;
 334         type To = Self;
 335
 336         fn from(value: bool) -> Self {
 337             if value { 100 } else { 0 }
 338         }
 339     }
 340 }
 341
 342 mod issue2843 {
 343     trait Foo {
 344         type Bar;
 345     }
 346
 347     impl Foo for usize {
 348         type Bar = u8;
 349     }
 350
 351     impl<T: Foo> Foo for Option<T> {
 352         type Bar = Option<T::Bar>;
 353     }
 354 }
 355
 356 mod issue3859 {
 357     pub struct Foo;
 358     pub struct Bar([usize; 3]);
 359
 360     impl Foo {
 361         pub const BAR: usize = 3;
 362
 363         pub fn foo() {
 364             const _X: usize = Foo::BAR;
 365             // const _Y: usize = Self::BAR;
 366         }
 367     }
 368 }
 369
 370 mod issue4305 {
 371     trait Foo: 'static {}
 372
 373     struct Bar;
 374
 375     impl Foo for Bar {}
 376
 377     impl<T: Foo> From<T> for Box<dyn Foo> {
 378         fn from(t: T) -> Self {
 379             Box::new(t)
 380         }
 381     }
 382 }
 383
 384 mod lint_at_item_level {
 385     struct Foo {}
 386
 387     #[allow(clippy::use_self)]
 388     impl Foo {
 389         fn new() -> Foo {
 390             Foo {}
 391         }
 392     }
 393
 394     #[allow(clippy::use_self)]
 395     impl Default for Foo {
 396         fn default() -> Foo {
 397             Foo::new()
 398         }
 399     }
 400 }
 401
 402 mod lint_at_impl_item_level {
 403     struct Foo {}
 404
 405     impl Foo {
 406         #[allow(clippy::use_self)]
 407         fn new() -> Foo {
 408             Foo {}
 409         }
 410     }
 411
 412     impl Default for Foo {
 413         #[allow(clippy::use_self)]
 414         fn default() -> Foo {
 415             Foo::new()
 416         }
 417     }
 418 }
 419
 420 mod issue4734 {
 421     #[repr(C, packed)]
 422     pub struct X {
 423         pub x: u32,
 424     }
 425
 426     impl From<X> for u32 {
 427         fn from(c: X) -> Self {
 428             unsafe { core::mem::transmute(c) }
 429         }
 430     }
 431 }
 432
 433 mod nested_paths {
 434     use std::convert::Into;
 435     mod submod {
 436         pub struct B {}
 437         pub struct C {}
 438
 439         impl Into<C> for B {
 440             fn into(self) -> C {
 441                 C {}
 442             }
 443         }
 444     }
 445
 446     struct A<T> {
 447         t: T,
 448     }
 449
 450     impl<T> A<T> {
 451         fn new<V: Into<T>>(v: V) -> Self {
 452             Self { t: Into::into(v) }
 453         }
 454     }
 455
 456     impl A<submod::C> {
 457         fn test() -> Self {
 458             Self::new::<submod::B>(submod::B {})
 459         }
 460     }
 461 }
 462
 463 mod issue6818 {
 464     #[derive(serde::Deserialize)]
 465     struct A {
 466         a: i32,
 467     }
 468 }
 469
 470 mod issue7206 {
 471     struct MyStruct<const C: char>;
 472     impl From<MyStruct<'a'>> for MyStruct<'b'> {
 473         fn from(_s: MyStruct<'a'>) -> Self {
 474             Self
 475         }
 476     }
 477
 478     // keep linting non-`Const` generic args
 479     struct S<'a> {
 480         inner: &'a str,
 481     }
 482
 483     struct S2<T> {
 484         inner: T,
 485     }
 486
 487     impl<T> S2<T> {
 488         fn new() -> Self {
 489             unimplemented!();
 490         }
 491     }
 492
 493     impl<'a> S2<S<'a>> {
 494         fn new_again() -> Self {
 495             Self::new()
 496         }
 497     }
 498 }
 499
 500 mod self_is_ty_param {
 501     trait Trait {
 502         type Type;
 503         type Hi;
 504
 505         fn test();
 506     }
 507
 508     impl<I> Trait for I
 509     where
 510         I: Iterator,
 511         I::Item: Trait, // changing this to Self would require <Self as Iterator>
 512     {
 513         type Type = I;
 514         type Hi = I::Item;
 515
 516         fn test() {
 517             let _: I::Item;
 518             let _: I; // this could lint, but is questionable
 519         }
 520     }
 521 }
 522
 523 mod use_self_in_pat {
 524     enum Foo {
 525         Bar,
 526         Baz,
 527     }
 528
 529     impl Foo {
 530         fn do_stuff(self) {
 531             match self {
 532                 Self::Bar => unimplemented!(),
 533                 Self::Baz => unimplemented!(),
 534             }
 535             match Some(1) {
 536                 Some(_) => unimplemented!(),
 537                 None => unimplemented!(),
 538             }
 539             if let Self::Bar = self {
 540                 unimplemented!()
 541             }
 542         }
 543     }
 544 }