crates/ide_assists/src/handlers/replace_derive_with_manual_impl.rs

   1 use hir::ModuleDef;
   2 use ide_db::helpers::{import_assets::NameToImport, mod_path_to_ast};
   3 use ide_db::items_locator;
   4 use itertools::Itertools;
   5 use syntax::{
   6     ast::{self, make, AstNode, NameOwner},
   7     SyntaxKind::{IDENT, WHITESPACE},
   8 };
   9
  10 use crate::{
  11     assist_context::{AssistBuilder, AssistContext, Assists},
  12     utils::{
  13         add_trait_assoc_items_to_impl, filter_assoc_items, gen_trait_fn_body,
  14         generate_trait_impl_text, render_snippet, Cursor, DefaultMethods,
  15     },
  16     AssistId, AssistKind,
  17 };
  18
  19 // Assist: replace_derive_with_manual_impl
  20 //
  21 // Converts a `derive` impl into a manual one.
  22 //
  23 // ```
  24 // # trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
  25 // #[derive(Deb$0ug, Display)]
  26 // struct S;
  27 // ```
  28 // ->
  29 // ```
  30 // # trait Debug { fn fmt(&self, f: &mut Formatter) -> Result<()>; }
  31 // #[derive(Display)]
  32 // struct S;
  33 //
  34 // impl Debug for S {
  35 //     $0fn fmt(&self, f: &mut Formatter) -> Result<()> {
  36 //         f.debug_struct("S").finish()
  37 //     }
  38 // }
  39 // ```
  40 pub(crate) fn replace_derive_with_manual_impl(
  41     acc: &mut Assists,
  42     ctx: &AssistContext,
  43 ) -> Option<()> {
  44     let attr = ctx.find_node_at_offset::<ast::Attr>()?;
  45     let (name, args) = attr.as_simple_call()?;
  46     if name != "derive" {
  47         return None;
  48     }
  49
  50     if !args.syntax().text_range().contains(ctx.offset()) {
  51         cov_mark::hit!(outside_of_attr_args);
  52         return None;
  53     }
  54
  55     let trait_token = args.syntax().token_at_offset(ctx.offset()).find(|t| t.kind() == IDENT)?;
  56     let trait_name = trait_token.text();
  57
  58     let adt = attr.syntax().parent().and_then(ast::Adt::cast)?;
  59
  60     let current_module = ctx.sema.scope(adt.syntax()).module()?;
  61     let current_crate = current_module.krate();
  62
  63     let found_traits = items_locator::items_with_name(
  64         &ctx.sema,
  65         current_crate,
  66         NameToImport::Exact(trait_name.to_string()),
  67         items_locator::AssocItemSearch::Exclude,
  68         Some(items_locator::DEFAULT_QUERY_SEARCH_LIMIT.inner()),
  69     )
  70     .filter_map(|item| match item.as_module_def()? {
  71         ModuleDef::Trait(trait_) => Some(trait_),
  72         _ => None,
  73     })
  74     .flat_map(|trait_| {
  75         current_module
  76             .find_use_path(ctx.sema.db, hir::ModuleDef::Trait(trait_))
  77             .as_ref()
  78             .map(mod_path_to_ast)
  79             .zip(Some(trait_))
  80     });
  81
  82     let mut no_traits_found = true;
  83     for (trait_path, trait_) in found_traits.inspect(|_| no_traits_found = false) {
  84         add_assist(acc, ctx, &attr, &args, &trait_path, Some(trait_), &adt)?;
  85     }
  86     if no_traits_found {
  87         let trait_path = make::ext::ident_path(trait_name);
  88         add_assist(acc, ctx, &attr, &args, &trait_path, None, &adt)?;
  89     }
  90     Some(())
  91 }
  92
  93 fn add_assist(
  94     acc: &mut Assists,
  95     ctx: &AssistContext,
  96     attr: &ast::Attr,
  97     input: &ast::TokenTree,
  98     trait_path: &ast::Path,
  99     trait_: Option<hir::Trait>,
 100     adt: &ast::Adt,
 101 ) -> Option<()> {
 102     let target = attr.syntax().text_range();
 103     let annotated_name = adt.name()?;
 104     let label = format!("Convert to manual `impl {} for {}`", trait_path, annotated_name);
 105     let trait_name = trait_path.segment().and_then(|seg| seg.name_ref())?;
 106
 107     acc.add(
 108         AssistId("replace_derive_with_manual_impl", AssistKind::Refactor),
 109         label,
 110         target,
 111         |builder| {
 112             let insert_pos = adt.syntax().text_range().end();
 113             let impl_def_with_items =
 114                 impl_def_from_trait(&ctx.sema, adt, &annotated_name, trait_, trait_path);
 115             update_attribute(builder, input, &trait_name, attr);
 116             let trait_path = format!("{}", trait_path);
 117             match (ctx.config.snippet_cap, impl_def_with_items) {
 118                 (None, _) => {
 119                     builder.insert(insert_pos, generate_trait_impl_text(adt, &trait_path, ""))
 120                 }
 121                 (Some(cap), None) => builder.insert_snippet(
 122                     cap,
 123                     insert_pos,
 124                     generate_trait_impl_text(adt, &trait_path, "    $0"),
 125                 ),
 126                 (Some(cap), Some((impl_def, first_assoc_item))) => {
 127                     let mut cursor = Cursor::Before(first_assoc_item.syntax());
 128                     let placeholder;
 129                     if let ast::AssocItem::Fn(ref func) = first_assoc_item {
 130                         if let Some(m) = func.syntax().descendants().find_map(ast::MacroCall::cast)
 131                         {
 132                             if m.syntax().text() == "todo!()" {
 133                                 placeholder = m;
 134                                 cursor = Cursor::Replace(placeholder.syntax());
 135                             }
 136                         }
 137                     }
 138
 139                     builder.insert_snippet(
 140                         cap,
 141                         insert_pos,
 142                         format!("\n\n{}", render_snippet(cap, impl_def.syntax(), cursor)),
 143                     )
 144                 }
 145             };
 146         },
 147     )
 148 }
 149
 150 fn impl_def_from_trait(
 151     sema: &hir::Semantics<ide_db::RootDatabase>,
 152     adt: &ast::Adt,
 153     annotated_name: &ast::Name,
 154     trait_: Option<hir::Trait>,
 155     trait_path: &ast::Path,
 156 ) -> Option<(ast::Impl, ast::AssocItem)> {
 157     let trait_ = trait_?;
 158     let target_scope = sema.scope(annotated_name.syntax());
 159     let trait_items = filter_assoc_items(sema.db, &trait_.items(sema.db), DefaultMethods::No);
 160     if trait_items.is_empty() {
 161         return None;
 162     }
 163     let impl_def =
 164         make::impl_trait(trait_path.clone(), make::ext::ident_path(&annotated_name.text()));
 165     let (impl_def, first_assoc_item) =
 166         add_trait_assoc_items_to_impl(sema, trait_items, trait_, impl_def, target_scope);
 167
 168     // Generate a default `impl` function body for the derived trait.
 169     if let ast::AssocItem::Fn(ref func) = first_assoc_item {
 170         let _ = gen_trait_fn_body(func, trait_path, adt);
 171     };
 172
 173     Some((impl_def, first_assoc_item))
 174 }
 175
 176 fn update_attribute(
 177     builder: &mut AssistBuilder,
 178     input: &ast::TokenTree,
 179     trait_name: &ast::NameRef,
 180     attr: &ast::Attr,
 181 ) {
 182     let trait_name = trait_name.text();
 183     let new_attr_input = input
 184         .syntax()
 185         .descendants_with_tokens()
 186         .filter(|t| t.kind() == IDENT)
 187         .filter_map(|t| t.into_token().map(|t| t.text().to_string()))
 188         .filter(|t| t != &trait_name)
 189         .collect::<Vec<_>>();
 190     let has_more_derives = !new_attr_input.is_empty();
 191
 192     if has_more_derives {
 193         let new_attr_input = format!("({})", new_attr_input.iter().format(", "));
 194         builder.replace(input.syntax().text_range(), new_attr_input);
 195     } else {
 196         let attr_range = attr.syntax().text_range();
 197         builder.delete(attr_range);
 198
 199         if let Some(line_break_range) = attr
 200             .syntax()
 201             .next_sibling_or_token()
 202             .filter(|t| t.kind() == WHITESPACE)
 203             .map(|t| t.text_range())
 204         {
 205             builder.delete(line_break_range);
 206         }
 207     }
 208 }
 209
 210 #[cfg(test)]
 211 mod tests {
 212     use crate::tests::{check_assist, check_assist_not_applicable};
 213
 214     use super::*;
 215
 216     #[test]
 217     fn add_custom_impl_debug_record_struct() {
 218         check_assist(
 219             replace_derive_with_manual_impl,
 220             r#"
 221 //- minicore: fmt
 222 #[derive(Debu$0g)]
 223 struct Foo {
 224     bar: String,
 225 }
 226 "#,
 227             r#"
 228 struct Foo {
 229     bar: String,
 230 }
 231
 232 impl core::fmt::Debug for Foo {
 233     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 234         f.debug_struct("Foo").field("bar", &self.bar).finish()
 235     }
 236 }
 237 "#,
 238         )
 239     }
 240     #[test]
 241     fn add_custom_impl_debug_tuple_struct() {
 242         check_assist(
 243             replace_derive_with_manual_impl,
 244             r#"
 245 //- minicore: fmt
 246 #[derive(Debu$0g)]
 247 struct Foo(String, usize);
 248 "#,
 249             r#"struct Foo(String, usize);
 250
 251 impl core::fmt::Debug for Foo {
 252     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 253         f.debug_tuple("Foo").field(&self.0).field(&self.1).finish()
 254     }
 255 }
 256 "#,
 257         )
 258     }
 259     #[test]
 260     fn add_custom_impl_debug_empty_struct() {
 261         check_assist(
 262             replace_derive_with_manual_impl,
 263             r#"
 264 //- minicore: fmt
 265 #[derive(Debu$0g)]
 266 struct Foo;
 267 "#,
 268             r#"
 269 struct Foo;
 270
 271 impl core::fmt::Debug for Foo {
 272     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 273         f.debug_struct("Foo").finish()
 274     }
 275 }
 276 "#,
 277         )
 278     }
 279     #[test]
 280     fn add_custom_impl_debug_enum() {
 281         check_assist(
 282             replace_derive_with_manual_impl,
 283             r#"
 284 //- minicore: fmt
 285 #[derive(Debu$0g)]
 286 enum Foo {
 287     Bar,
 288     Baz,
 289 }
 290 "#,
 291             r#"
 292 enum Foo {
 293     Bar,
 294     Baz,
 295 }
 296
 297 impl core::fmt::Debug for Foo {
 298     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 299         match self {
 300             Self::Bar => write!(f, "Bar"),
 301             Self::Baz => write!(f, "Baz"),
 302         }
 303     }
 304 }
 305 "#,
 306         )
 307     }
 308
 309     #[test]
 310     fn add_custom_impl_debug_tuple_enum() {
 311         check_assist(
 312             replace_derive_with_manual_impl,
 313             r#"
 314 //- minicore: fmt
 315 #[derive(Debu$0g)]
 316 enum Foo {
 317     Bar(usize, usize),
 318     Baz,
 319 }
 320 "#,
 321             r#"
 322 enum Foo {
 323     Bar(usize, usize),
 324     Baz,
 325 }
 326
 327 impl core::fmt::Debug for Foo {
 328     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 329         match self {
 330             Self::Bar(arg0, arg1) => f.debug_tuple("Bar").field(arg0).field(arg1).finish(),
 331             Self::Baz => write!(f, "Baz"),
 332         }
 333     }
 334 }
 335 "#,
 336         )
 337     }
 338     #[test]
 339     fn add_custom_impl_debug_record_enum() {
 340         check_assist(
 341             replace_derive_with_manual_impl,
 342             r#"
 343 //- minicore: fmt
 344 #[derive(Debu$0g)]
 345 enum Foo {
 346     Bar {
 347         baz: usize,
 348         qux: usize,
 349     },
 350     Baz,
 351 }
 352 "#,
 353             r#"
 354 enum Foo {
 355     Bar {
 356         baz: usize,
 357         qux: usize,
 358     },
 359     Baz,
 360 }
 361
 362 impl core::fmt::Debug for Foo {
 363     $0fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 364         match self {
 365             Self::Bar { baz, qux } => f.debug_struct("Bar").field("baz", baz).field("qux", qux).finish(),
 366             Self::Baz => write!(f, "Baz"),
 367         }
 368     }
 369 }
 370 "#,
 371         )
 372     }
 373     #[test]
 374     fn add_custom_impl_default_record_struct() {
 375         check_assist(
 376             replace_derive_with_manual_impl,
 377             r#"
 378 //- minicore: default
 379 #[derive(Defau$0lt)]
 380 struct Foo {
 381     foo: usize,
 382 }
 383 "#,
 384             r#"
 385 struct Foo {
 386     foo: usize,
 387 }
 388
 389 impl Default for Foo {
 390     $0fn default() -> Self {
 391         Self { foo: Default::default() }
 392     }
 393 }
 394 "#,
 395         )
 396     }
 397     #[test]
 398     fn add_custom_impl_default_tuple_struct() {
 399         check_assist(
 400             replace_derive_with_manual_impl,
 401             r#"
 402 //- minicore: default
 403 #[derive(Defau$0lt)]
 404 struct Foo(usize);
 405 "#,
 406             r#"
 407 struct Foo(usize);
 408
 409 impl Default for Foo {
 410     $0fn default() -> Self {
 411         Self(Default::default())
 412     }
 413 }
 414 "#,
 415         )
 416     }
 417     #[test]
 418     fn add_custom_impl_default_empty_struct() {
 419         check_assist(
 420             replace_derive_with_manual_impl,
 421             r#"
 422 //- minicore: default
 423 #[derive(Defau$0lt)]
 424 struct Foo;
 425 "#,
 426             r#"
 427 struct Foo;
 428
 429 impl Default for Foo {
 430     $0fn default() -> Self {
 431         Self {  }
 432     }
 433 }
 434 "#,
 435         )
 436     }
 437
 438     #[test]
 439     fn add_custom_impl_hash_record_struct() {
 440         check_assist(
 441             replace_derive_with_manual_impl,
 442             r#"
 443 //- minicore: hash
 444 #[derive(Has$0h)]
 445 struct Foo {
 446     bin: usize,
 447     bar: usize,
 448 }
 449 "#,
 450             r#"
 451 struct Foo {
 452     bin: usize,
 453     bar: usize,
 454 }
 455
 456 impl core::hash::Hash for Foo {
 457     $0fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
 458         self.bin.hash(state);
 459         self.bar.hash(state);
 460     }
 461 }
 462 "#,
 463         )
 464     }
 465
 466     #[test]
 467     fn add_custom_impl_hash_tuple_struct() {
 468         check_assist(
 469             replace_derive_with_manual_impl,
 470             r#"
 471 //- minicore: hash
 472 #[derive(Has$0h)]
 473 struct Foo(usize, usize);
 474 "#,
 475             r#"
 476 struct Foo(usize, usize);
 477
 478 impl core::hash::Hash for Foo {
 479     $0fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
 480         self.0.hash(state);
 481         self.1.hash(state);
 482     }
 483 }
 484 "#,
 485         )
 486     }
 487
 488     #[test]
 489     fn add_custom_impl_hash_enum() {
 490         check_assist(
 491             replace_derive_with_manual_impl,
 492             r#"
 493 //- minicore: hash
 494 #[derive(Has$0h)]
 495 enum Foo {
 496     Bar,
 497     Baz,
 498 }
 499 "#,
 500             r#"
 501 enum Foo {
 502     Bar,
 503     Baz,
 504 }
 505
 506 impl core::hash::Hash for Foo {
 507     $0fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
 508         core::mem::discriminant(self).hash(state);
 509     }
 510 }
 511 "#,
 512         )
 513     }
 514
 515     #[test]
 516     fn add_custom_impl_clone_record_struct() {
 517         check_assist(
 518             replace_derive_with_manual_impl,
 519             r#"
 520 //- minicore: clone
 521 #[derive(Clo$0ne)]
 522 struct Foo {
 523     bin: usize,
 524     bar: usize,
 525 }
 526 "#,
 527             r#"
 528 struct Foo {
 529     bin: usize,
 530     bar: usize,
 531 }
 532
 533 impl Clone for Foo {
 534     $0fn clone(&self) -> Self {
 535         Self { bin: self.bin.clone(), bar: self.bar.clone() }
 536     }
 537 }
 538 "#,
 539         )
 540     }
 541
 542     #[test]
 543     fn add_custom_impl_clone_tuple_struct() {
 544         check_assist(
 545             replace_derive_with_manual_impl,
 546             r#"
 547 //- minicore: clone
 548 #[derive(Clo$0ne)]
 549 struct Foo(usize, usize);
 550 "#,
 551             r#"
 552 struct Foo(usize, usize);
 553
 554 impl Clone for Foo {
 555     $0fn clone(&self) -> Self {
 556         Self(self.0.clone(), self.1.clone())
 557     }
 558 }
 559 "#,
 560         )
 561     }
 562
 563     #[test]
 564     fn add_custom_impl_clone_empty_struct() {
 565         check_assist(
 566             replace_derive_with_manual_impl,
 567             r#"
 568 //- minicore: clone
 569 #[derive(Clo$0ne)]
 570 struct Foo;
 571 "#,
 572             r#"
 573 struct Foo;
 574
 575 impl Clone for Foo {
 576     $0fn clone(&self) -> Self {
 577         Self {  }
 578     }
 579 }
 580 "#,
 581         )
 582     }
 583
 584     #[test]
 585     fn add_custom_impl_clone_enum() {
 586         check_assist(
 587             replace_derive_with_manual_impl,
 588             r#"
 589 //- minicore: clone
 590 #[derive(Clo$0ne)]
 591 enum Foo {
 592     Bar,
 593     Baz,
 594 }
 595 "#,
 596             r#"
 597 enum Foo {
 598     Bar,
 599     Baz,
 600 }
 601
 602 impl Clone for Foo {
 603     $0fn clone(&self) -> Self {
 604         match self {
 605             Self::Bar => Self::Bar,
 606             Self::Baz => Self::Baz,
 607         }
 608     }
 609 }
 610 "#,
 611         )
 612     }
 613
 614     #[test]
 615     fn add_custom_impl_clone_tuple_enum() {
 616         check_assist(
 617             replace_derive_with_manual_impl,
 618             r#"
 619 //- minicore: clone
 620 #[derive(Clo$0ne)]
 621 enum Foo {
 622     Bar(String),
 623     Baz,
 624 }
 625 "#,
 626             r#"
 627 enum Foo {
 628     Bar(String),
 629     Baz,
 630 }
 631
 632 impl Clone for Foo {
 633     $0fn clone(&self) -> Self {
 634         match self {
 635             Self::Bar(arg0) => Self::Bar(arg0.clone()),
 636             Self::Baz => Self::Baz,
 637         }
 638     }
 639 }
 640 "#,
 641         )
 642     }
 643
 644     #[test]
 645     fn add_custom_impl_clone_record_enum() {
 646         check_assist(
 647             replace_derive_with_manual_impl,
 648             r#"
 649 //- minicore: clone
 650 #[derive(Clo$0ne)]
 651 enum Foo {
 652     Bar {
 653         bin: String,
 654     },
 655     Baz,
 656 }
 657 "#,
 658             r#"
 659 enum Foo {
 660     Bar {
 661         bin: String,
 662     },
 663     Baz,
 664 }
 665
 666 impl Clone for Foo {
 667     $0fn clone(&self) -> Self {
 668         match self {
 669             Self::Bar { bin } => Self::Bar { bin: bin.clone() },
 670             Self::Baz => Self::Baz,
 671         }
 672     }
 673 }
 674 "#,
 675         )
 676     }
 677
 678     #[test]
 679     fn add_custom_impl_partial_eq_record_struct() {
 680         check_assist(
 681             replace_derive_with_manual_impl,
 682             r#"
 683 //- minicore: eq
 684 #[derive(Partial$0Eq)]
 685 struct Foo {
 686     bin: usize,
 687     bar: usize,
 688 }
 689 "#,
 690             r#"
 691 struct Foo {
 692     bin: usize,
 693     bar: usize,
 694 }
 695
 696 impl PartialEq for Foo {
 697     $0fn eq(&self, other: &Self) -> bool {
 698         self.bin == other.bin && self.bar == other.bar
 699     }
 700 }
 701 "#,
 702         )
 703     }
 704
 705     #[test]
 706     fn add_custom_impl_partial_eq_tuple_struct() {
 707         check_assist(
 708             replace_derive_with_manual_impl,
 709             r#"
 710 //- minicore: eq
 711 #[derive(Partial$0Eq)]
 712 struct Foo(usize, usize);
 713 "#,
 714             r#"
 715 struct Foo(usize, usize);
 716
 717 impl PartialEq for Foo {
 718     $0fn eq(&self, other: &Self) -> bool {
 719         self.0 == other.0 && self.1 == other.1
 720     }
 721 }
 722 "#,
 723         )
 724     }
 725
 726     #[test]
 727     fn add_custom_impl_partial_eq_empty_struct() {
 728         check_assist(
 729             replace_derive_with_manual_impl,
 730             r#"
 731 //- minicore: eq
 732 #[derive(Partial$0Eq)]
 733 struct Foo;
 734 "#,
 735             r#"
 736 struct Foo;
 737
 738 impl PartialEq for Foo {
 739     $0fn eq(&self, other: &Self) -> bool {
 740         true
 741     }
 742 }
 743 "#,
 744         )
 745     }
 746
 747     #[test]
 748     fn add_custom_impl_partial_eq_enum() {
 749         check_assist(
 750             replace_derive_with_manual_impl,
 751             r#"
 752 //- minicore: eq
 753 #[derive(Partial$0Eq)]
 754 enum Foo {
 755     Bar,
 756     Baz,
 757 }
 758 "#,
 759             r#"
 760 enum Foo {
 761     Bar,
 762     Baz,
 763 }
 764
 765 impl PartialEq for Foo {
 766     $0fn eq(&self, other: &Self) -> bool {
 767         core::mem::discriminant(self) == core::mem::discriminant(other)
 768     }
 769 }
 770 "#,
 771         )
 772     }
 773
 774     #[test]
 775     fn add_custom_impl_partial_eq_tuple_enum() {
 776         check_assist(
 777             replace_derive_with_manual_impl,
 778             r#"
 779 //- minicore: eq
 780 #[derive(Partial$0Eq)]
 781 enum Foo {
 782     Bar(String),
 783     Baz,
 784 }
 785 "#,
 786             r#"
 787 enum Foo {
 788     Bar(String),
 789     Baz,
 790 }
 791
 792 impl PartialEq for Foo {
 793     $0fn eq(&self, other: &Self) -> bool {
 794         match (self, other) {
 795             (Self::Bar(l0), Self::Bar(r0)) => l0 == r0,
 796             _ => core::mem::discriminant(self) == core::mem::discriminant(other),
 797         }
 798     }
 799 }
 800 "#,
 801         )
 802     }
 803
 804     #[test]
 805     fn add_custom_impl_partial_eq_record_enum() {
 806         check_assist(
 807             replace_derive_with_manual_impl,
 808             r#"
 809 //- minicore: eq
 810 #[derive(Partial$0Eq)]
 811 enum Foo {
 812     Bar {
 813         bin: String,
 814     },
 815     Baz {
 816         qux: String,
 817         fez: String,
 818     },
 819     Qux {},
 820     Bin,
 821 }
 822 "#,
 823             r#"
 824 enum Foo {
 825     Bar {
 826         bin: String,
 827     },
 828     Baz {
 829         qux: String,
 830         fez: String,
 831     },
 832     Qux {},
 833     Bin,
 834 }
 835
 836 impl PartialEq for Foo {
 837     $0fn eq(&self, other: &Self) -> bool {
 838         match (self, other) {
 839             (Self::Bar { bin: l_bin }, Self::Bar { bin: r_bin }) => l_bin == r_bin,
 840             (Self::Baz { qux: l_qux, fez: l_fez }, Self::Baz { qux: r_qux, fez: r_fez }) => l_qux == r_qux && l_fez == r_fez,
 841             _ => core::mem::discriminant(self) == core::mem::discriminant(other),
 842         }
 843     }
 844 }
 845 "#,
 846         )
 847     }
 848     #[test]
 849     fn add_custom_impl_all() {
 850         check_assist(
 851             replace_derive_with_manual_impl,
 852             r#"
 853 mod foo {
 854     pub trait Bar {
 855         type Qux;
 856         const Baz: usize = 42;
 857         const Fez: usize;
 858         fn foo();
 859         fn bar() {}
 860     }
 861 }
 862
 863 #[derive($0Bar)]
 864 struct Foo {
 865     bar: String,
 866 }
 867 "#,
 868             r#"
 869 mod foo {
 870     pub trait Bar {
 871         type Qux;
 872         const Baz: usize = 42;
 873         const Fez: usize;
 874         fn foo();
 875         fn bar() {}
 876     }
 877 }
 878
 879 struct Foo {
 880     bar: String,
 881 }
 882
 883 impl foo::Bar for Foo {
 884     $0type Qux;
 885
 886     const Baz: usize = 42;
 887
 888     const Fez: usize;
 889
 890     fn foo() {
 891         todo!()
 892     }
 893 }
 894 "#,
 895         )
 896     }
 897     #[test]
 898     fn add_custom_impl_for_unique_input() {
 899         check_assist(
 900             replace_derive_with_manual_impl,
 901             r#"
 902 #[derive(Debu$0g)]
 903 struct Foo {
 904     bar: String,
 905 }
 906             "#,
 907             r#"
 908 struct Foo {
 909     bar: String,
 910 }
 911
 912 impl Debug for Foo {
 913     $0
 914 }
 915             "#,
 916         )
 917     }
 918
 919     #[test]
 920     fn add_custom_impl_for_with_visibility_modifier() {
 921         check_assist(
 922             replace_derive_with_manual_impl,
 923             r#"
 924 #[derive(Debug$0)]
 925 pub struct Foo {
 926     bar: String,
 927 }
 928             "#,
 929             r#"
 930 pub struct Foo {
 931     bar: String,
 932 }
 933
 934 impl Debug for Foo {
 935     $0
 936 }
 937             "#,
 938         )
 939     }
 940
 941     #[test]
 942     fn add_custom_impl_when_multiple_inputs() {
 943         check_assist(
 944             replace_derive_with_manual_impl,
 945             r#"
 946 #[derive(Display, Debug$0, Serialize)]
 947 struct Foo {}
 948             "#,
 949             r#"
 950 #[derive(Display, Serialize)]
 951 struct Foo {}
 952
 953 impl Debug for Foo {
 954     $0
 955 }
 956             "#,
 957         )
 958     }
 959
 960     #[test]
 961     fn test_ignore_derive_macro_without_input() {
 962         check_assist_not_applicable(
 963             replace_derive_with_manual_impl,
 964             r#"
 965 #[derive($0)]
 966 struct Foo {}
 967             "#,
 968         )
 969     }
 970
 971     #[test]
 972     fn test_ignore_if_cursor_on_param() {
 973         check_assist_not_applicable(
 974             replace_derive_with_manual_impl,
 975             r#"
 976 #[derive$0(Debug)]
 977 struct Foo {}
 978             "#,
 979         );
 980
 981         check_assist_not_applicable(
 982             replace_derive_with_manual_impl,
 983             r#"
 984 #[derive(Debug)$0]
 985 struct Foo {}
 986             "#,
 987         )
 988     }
 989
 990     #[test]
 991     fn test_ignore_if_not_derive() {
 992         check_assist_not_applicable(
 993             replace_derive_with_manual_impl,
 994             r#"
 995 #[allow(non_camel_$0case_types)]
 996 struct Foo {}
 997             "#,
 998         )
 999     }
1000
1001     #[test]
1002     fn works_at_start_of_file() {
1003         cov_mark::check!(outside_of_attr_args);
1004         check_assist_not_applicable(
1005             replace_derive_with_manual_impl,
1006             r#"
1007 $0#[derive(Debug)]
1008 struct S;
1009             "#,
1010         );
1011     }
1012 }