crates/hir/src/display.rs

   1 //! HirDisplay implementations for various hir types.
   2 use hir_def::{
   3     adt::VariantData,
   4     generics::{
   5         TypeOrConstParamData, TypeParamProvenance, WherePredicate, WherePredicateTypeTarget,
   6     },
   7     type_ref::{TypeBound, TypeRef},
   8     AdtId, GenericDefId,
   9 };
  10 use hir_ty::{
  11     display::{
  12         write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
  13         HirFormatter, SizedByDefault,
  14     },
  15     Interner, TraitRefExt, WhereClause,
  16 };
  17 use syntax::SmolStr;
  18
  19 use crate::{
  20     Adt, Const, ConstParam, Enum, Field, Function, GenericParam, HasCrate, HasVisibility,
  21     LifetimeParam, Macro, Module, Static, Struct, Trait, TyBuilder, Type, TypeAlias,
  22     TypeOrConstParam, TypeParam, Union, Variant,
  23 };
  24
  25 impl HirDisplay for Function {
  26     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
  27         let data = f.db.function_data(self.id);
  28         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
  29         if data.has_default_kw() {
  30             f.write_str("default ")?;
  31         }
  32         if data.has_const_kw() {
  33             f.write_str("const ")?;
  34         }
  35         if data.has_async_kw() {
  36             f.write_str("async ")?;
  37         }
  38         if self.is_unsafe_to_call(f.db) {
  39             f.write_str("unsafe ")?;
  40         }
  41         if let Some(abi) = &data.abi {
  42             // FIXME: String escape?
  43             write!(f, "extern \"{}\" ", &**abi)?;
  44         }
  45         write!(f, "fn {}", data.name)?;
  46
  47         write_generic_params(GenericDefId::FunctionId(self.id), f)?;
  48
  49         f.write_char('(')?;
  50
  51         let write_self_param = |ty: &TypeRef, f: &mut HirFormatter<'_>| match ty {
  52             TypeRef::Path(p) if p.is_self_type() => f.write_str("self"),
  53             TypeRef::Reference(inner, lifetime, mut_) if matches!(&**inner,TypeRef::Path(p) if p.is_self_type()) =>
  54             {
  55                 f.write_char('&')?;
  56                 if let Some(lifetime) = lifetime {
  57                     write!(f, "{} ", lifetime.name)?;
  58                 }
  59                 if let hir_def::type_ref::Mutability::Mut = mut_ {
  60                     f.write_str("mut ")?;
  61                 }
  62                 f.write_str("self")
  63             }
  64             _ => {
  65                 f.write_str("self: ")?;
  66                 ty.hir_fmt(f)
  67             }
  68         };
  69
  70         let mut first = true;
  71         for (name, type_ref) in &data.params {
  72             if !first {
  73                 f.write_str(", ")?;
  74             } else {
  75                 first = false;
  76                 if data.has_self_param() {
  77                     write_self_param(type_ref, f)?;
  78                     continue;
  79                 }
  80             }
  81             match name {
  82                 Some(name) => write!(f, "{}: ", name)?,
  83                 None => f.write_str("_: ")?,
  84             }
  85             // FIXME: Use resolved `param.ty` or raw `type_ref`?
  86             // The former will ignore lifetime arguments currently.
  87             type_ref.hir_fmt(f)?;
  88         }
  89
  90         if data.is_varargs() {
  91             f.write_str(", ...")?;
  92         }
  93
  94         f.write_char(')')?;
  95
  96         // `FunctionData::ret_type` will be `::core::future::Future<Output = ...>` for async fns.
  97         // Use ugly pattern match to strip the Future trait.
  98         // Better way?
  99         let ret_type = if !data.has_async_kw() {
 100             &data.ret_type
 101         } else {
 102             match &*data.ret_type {
 103                 TypeRef::ImplTrait(bounds) => match bounds[0].as_ref() {
 104                     TypeBound::Path(path, _) => {
 105                         path.segments().iter().last().unwrap().args_and_bindings.unwrap().bindings
 106                             [0]
 107                         .type_ref
 108                         .as_ref()
 109                         .unwrap()
 110                     }
 111                     _ => panic!("Async fn ret_type should be impl Future"),
 112                 },
 113                 _ => panic!("Async fn ret_type should be impl Future"),
 114             }
 115         };
 116
 117         match ret_type {
 118             TypeRef::Tuple(tup) if tup.is_empty() => {}
 119             ty => {
 120                 f.write_str(" -> ")?;
 121                 ty.hir_fmt(f)?;
 122             }
 123         }
 124
 125         write_where_clause(GenericDefId::FunctionId(self.id), f)?;
 126
 127         Ok(())
 128     }
 129 }
 130
 131 impl HirDisplay for Adt {
 132     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 133         match self {
 134             Adt::Struct(it) => it.hir_fmt(f),
 135             Adt::Union(it) => it.hir_fmt(f),
 136             Adt::Enum(it) => it.hir_fmt(f),
 137         }
 138     }
 139 }
 140
 141 impl HirDisplay for Struct {
 142     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 143         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 144         f.write_str("struct ")?;
 145         write!(f, "{}", self.name(f.db))?;
 146         let def_id = GenericDefId::AdtId(AdtId::StructId(self.id));
 147         write_generic_params(def_id, f)?;
 148         write_where_clause(def_id, f)?;
 149         Ok(())
 150     }
 151 }
 152
 153 impl HirDisplay for Enum {
 154     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 155         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 156         f.write_str("enum ")?;
 157         write!(f, "{}", self.name(f.db))?;
 158         let def_id = GenericDefId::AdtId(AdtId::EnumId(self.id));
 159         write_generic_params(def_id, f)?;
 160         write_where_clause(def_id, f)?;
 161         Ok(())
 162     }
 163 }
 164
 165 impl HirDisplay for Union {
 166     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 167         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 168         f.write_str("union ")?;
 169         write!(f, "{}", self.name(f.db))?;
 170         let def_id = GenericDefId::AdtId(AdtId::UnionId(self.id));
 171         write_generic_params(def_id, f)?;
 172         write_where_clause(def_id, f)?;
 173         Ok(())
 174     }
 175 }
 176
 177 impl HirDisplay for Field {
 178     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 179         write_visibility(self.parent.module(f.db).id, self.visibility(f.db), f)?;
 180         write!(f, "{}: ", self.name(f.db))?;
 181         self.ty(f.db).hir_fmt(f)
 182     }
 183 }
 184
 185 impl HirDisplay for Variant {
 186     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 187         write!(f, "{}", self.name(f.db))?;
 188         let data = self.variant_data(f.db);
 189         match &*data {
 190             VariantData::Unit => {}
 191             VariantData::Tuple(fields) => {
 192                 f.write_char('(')?;
 193                 let mut first = true;
 194                 for (_, field) in fields.iter() {
 195                     if first {
 196                         first = false;
 197                     } else {
 198                         f.write_str(", ")?;
 199                     }
 200                     // Enum variant fields must be pub.
 201                     field.type_ref.hir_fmt(f)?;
 202                 }
 203                 f.write_char(')')?;
 204             }
 205             VariantData::Record(fields) => {
 206                 f.write_str(" {")?;
 207                 let mut first = true;
 208                 for (_, field) in fields.iter() {
 209                     if first {
 210                         first = false;
 211                         f.write_char(' ')?;
 212                     } else {
 213                         f.write_str(", ")?;
 214                     }
 215                     // Enum variant fields must be pub.
 216                     write!(f, "{}: ", field.name)?;
 217                     field.type_ref.hir_fmt(f)?;
 218                 }
 219                 f.write_str(" }")?;
 220             }
 221         }
 222         Ok(())
 223     }
 224 }
 225
 226 impl HirDisplay for Type {
 227     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 228         self.ty.hir_fmt(f)
 229     }
 230 }
 231
 232 impl HirDisplay for GenericParam {
 233     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 234         match self {
 235             GenericParam::TypeParam(it) => it.hir_fmt(f),
 236             GenericParam::ConstParam(it) => it.hir_fmt(f),
 237             GenericParam::LifetimeParam(it) => it.hir_fmt(f),
 238         }
 239     }
 240 }
 241
 242 impl HirDisplay for TypeOrConstParam {
 243     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 244         match self.split(f.db) {
 245             either::Either::Left(x) => x.hir_fmt(f),
 246             either::Either::Right(x) => x.hir_fmt(f),
 247         }
 248     }
 249 }
 250
 251 impl HirDisplay for TypeParam {
 252     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 253         write!(f, "{}", self.name(f.db))?;
 254         if f.omit_verbose_types() {
 255             return Ok(());
 256         }
 257
 258         let bounds = f.db.generic_predicates_for_param(self.id.parent(), self.id.into(), None);
 259         let substs = TyBuilder::placeholder_subst(f.db, self.id.parent());
 260         let predicates: Vec<_> =
 261             bounds.iter().cloned().map(|b| b.substitute(Interner, &substs)).collect();
 262         let krate = self.id.parent().krate(f.db).id;
 263         let sized_trait =
 264             f.db.lang_item(krate, SmolStr::new_inline("sized"))
 265                 .and_then(|lang_item| lang_item.as_trait());
 266         let has_only_sized_bound = predicates.iter().all(move |pred| match pred.skip_binders() {
 267             WhereClause::Implemented(it) => Some(it.hir_trait_id()) == sized_trait,
 268             _ => false,
 269         });
 270         let has_only_not_sized_bound = predicates.is_empty();
 271         if !has_only_sized_bound || has_only_not_sized_bound {
 272             let default_sized = SizedByDefault::Sized { anchor: krate };
 273             write_bounds_like_dyn_trait_with_prefix(":", &predicates, default_sized, f)?;
 274         }
 275         Ok(())
 276     }
 277 }
 278
 279 impl HirDisplay for LifetimeParam {
 280     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 281         write!(f, "{}", self.name(f.db))
 282     }
 283 }
 284
 285 impl HirDisplay for ConstParam {
 286     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 287         write!(f, "const {}: ", self.name(f.db))?;
 288         self.ty(f.db).hir_fmt(f)
 289     }
 290 }
 291
 292 fn write_generic_params(
 293     def: GenericDefId,
 294     f: &mut HirFormatter<'_>,
 295 ) -> Result<(), HirDisplayError> {
 296     let params = f.db.generic_params(def);
 297     if params.lifetimes.is_empty()
 298         && params.type_or_consts.iter().all(|x| x.1.const_param().is_none())
 299         && params
 300             .type_or_consts
 301             .iter()
 302             .filter_map(|x| x.1.type_param())
 303             .all(|param| !matches!(param.provenance, TypeParamProvenance::TypeParamList))
 304     {
 305         return Ok(());
 306     }
 307     f.write_char('<')?;
 308
 309     let mut first = true;
 310     let mut delim = |f: &mut HirFormatter<'_>| {
 311         if first {
 312             first = false;
 313             Ok(())
 314         } else {
 315             f.write_str(", ")
 316         }
 317     };
 318     for (_, lifetime) in params.lifetimes.iter() {
 319         delim(f)?;
 320         write!(f, "{}", lifetime.name)?;
 321     }
 322     for (_, ty) in params.type_or_consts.iter() {
 323         if let Some(name) = &ty.name() {
 324             match ty {
 325                 TypeOrConstParamData::TypeParamData(ty) => {
 326                     if ty.provenance != TypeParamProvenance::TypeParamList {
 327                         continue;
 328                     }
 329                     delim(f)?;
 330                     write!(f, "{}", name)?;
 331                     if let Some(default) = &ty.default {
 332                         f.write_str(" = ")?;
 333                         default.hir_fmt(f)?;
 334                     }
 335                 }
 336                 TypeOrConstParamData::ConstParamData(c) => {
 337                     delim(f)?;
 338                     write!(f, "const {}: ", name)?;
 339                     c.ty.hir_fmt(f)?;
 340                 }
 341             }
 342         }
 343     }
 344
 345     f.write_char('>')?;
 346     Ok(())
 347 }
 348
 349 fn write_where_clause(def: GenericDefId, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 350     let params = f.db.generic_params(def);
 351
 352     // unnamed type targets are displayed inline with the argument itself, e.g. `f: impl Y`.
 353     let is_unnamed_type_target = |target: &WherePredicateTypeTarget| match target {
 354         WherePredicateTypeTarget::TypeRef(_) => false,
 355         WherePredicateTypeTarget::TypeOrConstParam(id) => {
 356             params.type_or_consts[*id].name().is_none()
 357         }
 358     };
 359
 360     let has_displayable_predicate = params
 361         .where_predicates
 362         .iter()
 363         .any(|pred| {
 364             !matches!(pred, WherePredicate::TypeBound { target, .. } if is_unnamed_type_target(target))
 365         });
 366
 367     if !has_displayable_predicate {
 368         return Ok(());
 369     }
 370
 371     let write_target = |target: &WherePredicateTypeTarget, f: &mut HirFormatter<'_>| match target {
 372         WherePredicateTypeTarget::TypeRef(ty) => ty.hir_fmt(f),
 373         WherePredicateTypeTarget::TypeOrConstParam(id) => {
 374             match &params.type_or_consts[*id].name() {
 375                 Some(name) => write!(f, "{}", name),
 376                 None => f.write_str("{unnamed}"),
 377             }
 378         }
 379     };
 380
 381     f.write_str("\nwhere")?;
 382
 383     for (pred_idx, pred) in params.where_predicates.iter().enumerate() {
 384         let prev_pred =
 385             if pred_idx == 0 { None } else { Some(&params.where_predicates[pred_idx - 1]) };
 386
 387         let new_predicate = |f: &mut HirFormatter<'_>| {
 388             f.write_str(if pred_idx == 0 { "\n    " } else { ",\n    " })
 389         };
 390
 391         match pred {
 392             WherePredicate::TypeBound { target, .. } if is_unnamed_type_target(target) => {}
 393             WherePredicate::TypeBound { target, bound } => {
 394                 if matches!(prev_pred, Some(WherePredicate::TypeBound { target: target_, .. }) if target_ == target)
 395                 {
 396                     f.write_str(" + ")?;
 397                 } else {
 398                     new_predicate(f)?;
 399                     write_target(target, f)?;
 400                     f.write_str(": ")?;
 401                 }
 402                 bound.hir_fmt(f)?;
 403             }
 404             WherePredicate::Lifetime { target, bound } => {
 405                 if matches!(prev_pred, Some(WherePredicate::Lifetime { target: target_, .. }) if target_ == target)
 406                 {
 407                     write!(f, " + {}", bound.name)?;
 408                 } else {
 409                     new_predicate(f)?;
 410                     write!(f, "{}: {}", target.name, bound.name)?;
 411                 }
 412             }
 413             WherePredicate::ForLifetime { lifetimes, target, bound } => {
 414                 if matches!(
 415                     prev_pred,
 416                     Some(WherePredicate::ForLifetime { lifetimes: lifetimes_, target: target_, .. })
 417                     if lifetimes_ == lifetimes && target_ == target,
 418                 ) {
 419                     f.write_str(" + ")?;
 420                 } else {
 421                     new_predicate(f)?;
 422                     f.write_str("for<")?;
 423                     for (idx, lifetime) in lifetimes.iter().enumerate() {
 424                         if idx != 0 {
 425                             f.write_str(", ")?;
 426                         }
 427                         write!(f, "{}", lifetime)?;
 428                     }
 429                     f.write_str("> ")?;
 430                     write_target(target, f)?;
 431                     f.write_str(": ")?;
 432                 }
 433                 bound.hir_fmt(f)?;
 434             }
 435         }
 436     }
 437
 438     // End of final predicate. There must be at least one predicate here.
 439     f.write_char(',')?;
 440
 441     Ok(())
 442 }
 443
 444 impl HirDisplay for Const {
 445     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 446         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 447         let data = f.db.const_data(self.id);
 448         f.write_str("const ")?;
 449         match &data.name {
 450             Some(name) => write!(f, "{}: ", name)?,
 451             None => f.write_str("_: ")?,
 452         }
 453         data.type_ref.hir_fmt(f)?;
 454         Ok(())
 455     }
 456 }
 457
 458 impl HirDisplay for Static {
 459     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 460         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 461         let data = f.db.static_data(self.id);
 462         f.write_str("static ")?;
 463         if data.mutable {
 464             f.write_str("mut ")?;
 465         }
 466         write!(f, "{}: ", &data.name)?;
 467         data.type_ref.hir_fmt(f)?;
 468         Ok(())
 469     }
 470 }
 471
 472 impl HirDisplay for Trait {
 473     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 474         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 475         let data = f.db.trait_data(self.id);
 476         if data.is_unsafe {
 477             f.write_str("unsafe ")?;
 478         }
 479         if data.is_auto {
 480             f.write_str("auto ")?;
 481         }
 482         write!(f, "trait {}", data.name)?;
 483         let def_id = GenericDefId::TraitId(self.id);
 484         write_generic_params(def_id, f)?;
 485         write_where_clause(def_id, f)?;
 486         Ok(())
 487     }
 488 }
 489
 490 impl HirDisplay for TypeAlias {
 491     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 492         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
 493         let data = f.db.type_alias_data(self.id);
 494         write!(f, "type {}", data.name)?;
 495         if !data.bounds.is_empty() {
 496             f.write_str(": ")?;
 497             f.write_joined(&data.bounds, " + ")?;
 498         }
 499         if let Some(ty) = &data.type_ref {
 500             f.write_str(" = ")?;
 501             ty.hir_fmt(f)?;
 502         }
 503         Ok(())
 504     }
 505 }
 506
 507 impl HirDisplay for Module {
 508     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 509         // FIXME: Module doesn't have visibility saved in data.
 510         match self.name(f.db) {
 511             Some(name) => write!(f, "mod {}", name),
 512             None if self.is_crate_root(f.db) => match self.krate(f.db).display_name(f.db) {
 513                 Some(name) => write!(f, "extern crate {}", name),
 514                 None => f.write_str("extern crate {unknown}"),
 515             },
 516             None => f.write_str("mod {unnamed}"),
 517         }
 518     }
 519 }
 520
 521 impl HirDisplay for Macro {
 522     fn hir_fmt(&self, f: &mut HirFormatter<'_>) -> Result<(), HirDisplayError> {
 523         match self.id {
 524             hir_def::MacroId::Macro2Id(_) => f.write_str("macro"),
 525             hir_def::MacroId::MacroRulesId(_) => f.write_str("macro_rules!"),
 526             hir_def::MacroId::ProcMacroId(_) => f.write_str("proc_macro"),
 527         }?;
 528         write!(f, " {}", self.name(f.db))
 529     }
 530 }