crates/hir_def/src/body/lower.rs

   1 //! Transforms `ast::Expr` into an equivalent `hir_def::expr::Expr`
   2 //! representation.
   3
   4 use std::mem;
   5
   6 use either::Either;
   7 use hir_expand::{
   8     hygiene::Hygiene,
   9     name::{name, AsName, Name},
  10     ExpandError, HirFileId,
  11 };
  12 use la_arena::Arena;
  13 use profile::Count;
  14 use syntax::{
  15     ast::{
  16         self, ArgListOwner, ArrayExprKind, AstChildren, LiteralKind, LoopBodyOwner, NameOwner,
  17         SlicePatComponents,
  18     },
  19     AstNode, AstPtr, SyntaxNodePtr,
  20 };
  21
  22 use crate::{
  23     adt::StructKind,
  24     body::{Body, BodySourceMap, Expander, LabelSource, PatPtr, SyntheticSyntax},
  25     builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint},
  26     db::DefDatabase,
  27     diagnostics::{InactiveCode, MacroError, UnresolvedProcMacro},
  28     expr::{
  29         dummy_expr_id, ArithOp, Array, BinaryOp, BindingAnnotation, CmpOp, Expr, ExprId, Label,
  30         LabelId, Literal, LogicOp, MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField,
  31         Statement,
  32     },
  33     item_scope::BuiltinShadowMode,
  34     path::{GenericArgs, Path},
  35     type_ref::{Mutability, Rawness, TypeRef},
  36     AdtId, BlockLoc, ModuleDefId,
  37 };
  38
  39 use super::{diagnostics::BodyDiagnostic, ExprSource, PatSource};
  40
  41 pub(crate) struct LowerCtx {
  42     hygiene: Hygiene,
  43 }
  44
  45 impl LowerCtx {
  46     pub(crate) fn new(db: &dyn DefDatabase, file_id: HirFileId) -> Self {
  47         LowerCtx { hygiene: Hygiene::new(db.upcast(), file_id) }
  48     }
  49     pub(crate) fn with_hygiene(hygiene: &Hygiene) -> Self {
  50         LowerCtx { hygiene: hygiene.clone() }
  51     }
  52
  53     pub(crate) fn lower_path(&self, ast: ast::Path) -> Option<Path> {
  54         Path::from_src(ast, &self.hygiene)
  55     }
  56 }
  57
  58 pub(super) fn lower(
  59     db: &dyn DefDatabase,
  60     expander: Expander,
  61     params: Option<ast::ParamList>,
  62     body: Option<ast::Expr>,
  63 ) -> (Body, BodySourceMap) {
  64     ExprCollector {
  65         db,
  66         source_map: BodySourceMap::default(),
  67         body: Body {
  68             exprs: Arena::default(),
  69             pats: Arena::default(),
  70             labels: Arena::default(),
  71             params: Vec::new(),
  72             body_expr: dummy_expr_id(),
  73             block_scopes: Vec::new(),
  74             _c: Count::new(),
  75         },
  76         expander,
  77     }
  78     .collect(params, body)
  79 }
  80
  81 struct ExprCollector<'a> {
  82     db: &'a dyn DefDatabase,
  83     expander: Expander,
  84     body: Body,
  85     source_map: BodySourceMap,
  86 }
  87
  88 impl ExprCollector<'_> {
  89     fn collect(
  90         mut self,
  91         param_list: Option<ast::ParamList>,
  92         body: Option<ast::Expr>,
  93     ) -> (Body, BodySourceMap) {
  94         if let Some(param_list) = param_list {
  95             if let Some(self_param) = param_list.self_param() {
  96                 let ptr = AstPtr::new(&self_param);
  97                 let param_pat = self.alloc_pat(
  98                     Pat::Bind {
  99                         name: name![self],
 100                         mode: BindingAnnotation::new(
 101                             self_param.mut_token().is_some() && self_param.amp_token().is_none(),
 102                             false,
 103                         ),
 104                         subpat: None,
 105                     },
 106                     Either::Right(ptr),
 107                 );
 108                 self.body.params.push(param_pat);
 109             }
 110
 111             for param in param_list.params() {
 112                 let pat = match param.pat() {
 113                     None => continue,
 114                     Some(pat) => pat,
 115                 };
 116                 let param_pat = self.collect_pat(pat);
 117                 self.body.params.push(param_pat);
 118             }
 119         };
 120
 121         self.body.body_expr = self.collect_expr_opt(body);
 122         (self.body, self.source_map)
 123     }
 124
 125     fn ctx(&self) -> LowerCtx {
 126         LowerCtx::new(self.db, self.expander.current_file_id)
 127     }
 128
 129     fn alloc_expr(&mut self, expr: Expr, ptr: AstPtr<ast::Expr>) -> ExprId {
 130         let src = self.expander.to_source(ptr);
 131         let id = self.make_expr(expr, Ok(src.clone()));
 132         self.source_map.expr_map.insert(src, id);
 133         id
 134     }
 135     // desugared exprs don't have ptr, that's wrong and should be fixed
 136     // somehow.
 137     fn alloc_expr_desugared(&mut self, expr: Expr) -> ExprId {
 138         self.make_expr(expr, Err(SyntheticSyntax))
 139     }
 140     fn unit(&mut self) -> ExprId {
 141         self.alloc_expr_desugared(Expr::Tuple { exprs: Vec::new() })
 142     }
 143     fn missing_expr(&mut self) -> ExprId {
 144         self.alloc_expr_desugared(Expr::Missing)
 145     }
 146     fn make_expr(&mut self, expr: Expr, src: Result<ExprSource, SyntheticSyntax>) -> ExprId {
 147         let id = self.body.exprs.alloc(expr);
 148         self.source_map.expr_map_back.insert(id, src);
 149         id
 150     }
 151
 152     fn alloc_pat(&mut self, pat: Pat, ptr: PatPtr) -> PatId {
 153         let src = self.expander.to_source(ptr);
 154         let id = self.make_pat(pat, Ok(src.clone()));
 155         self.source_map.pat_map.insert(src, id);
 156         id
 157     }
 158     fn missing_pat(&mut self) -> PatId {
 159         self.make_pat(Pat::Missing, Err(SyntheticSyntax))
 160     }
 161     fn make_pat(&mut self, pat: Pat, src: Result<PatSource, SyntheticSyntax>) -> PatId {
 162         let id = self.body.pats.alloc(pat);
 163         self.source_map.pat_map_back.insert(id, src);
 164         id
 165     }
 166
 167     fn alloc_label(&mut self, label: Label, ptr: AstPtr<ast::Label>) -> LabelId {
 168         let src = self.expander.to_source(ptr);
 169         let id = self.make_label(label, src.clone());
 170         self.source_map.label_map.insert(src, id);
 171         id
 172     }
 173     fn make_label(&mut self, label: Label, src: LabelSource) -> LabelId {
 174         let id = self.body.labels.alloc(label);
 175         self.source_map.label_map_back.insert(id, src);
 176         id
 177     }
 178
 179     fn collect_expr(&mut self, expr: ast::Expr) -> ExprId {
 180         let syntax_ptr = AstPtr::new(&expr);
 181         if self.check_cfg(&expr).is_none() {
 182             return self.missing_expr();
 183         }
 184
 185         match expr {
 186             ast::Expr::IfExpr(e) => {
 187                 let then_branch = self.collect_block_opt(e.then_branch());
 188
 189                 let else_branch = e.else_branch().map(|b| match b {
 190                     ast::ElseBranch::Block(it) => self.collect_block(it),
 191                     ast::ElseBranch::IfExpr(elif) => {
 192                         let expr: ast::Expr = ast::Expr::cast(elif.syntax().clone()).unwrap();
 193                         self.collect_expr(expr)
 194                     }
 195                 });
 196
 197                 let condition = match e.condition() {
 198                     None => self.missing_expr(),
 199                     Some(condition) => match condition.pat() {
 200                         None => self.collect_expr_opt(condition.expr()),
 201                         // if let -- desugar to match
 202                         Some(pat) => {
 203                             let pat = self.collect_pat(pat);
 204                             let match_expr = self.collect_expr_opt(condition.expr());
 205                             let placeholder_pat = self.missing_pat();
 206                             let arms = vec![
 207                                 MatchArm { pat, expr: then_branch, guard: None },
 208                                 MatchArm {
 209                                     pat: placeholder_pat,
 210                                     expr: else_branch.unwrap_or_else(|| self.unit()),
 211                                     guard: None,
 212                                 },
 213                             ];
 214                             return self
 215                                 .alloc_expr(Expr::Match { expr: match_expr, arms }, syntax_ptr);
 216                         }
 217                     },
 218                 };
 219
 220                 self.alloc_expr(Expr::If { condition, then_branch, else_branch }, syntax_ptr)
 221             }
 222             ast::Expr::EffectExpr(e) => match e.effect() {
 223                 ast::Effect::Try(_) => {
 224                     let body = self.collect_block_opt(e.block_expr());
 225                     self.alloc_expr(Expr::TryBlock { body }, syntax_ptr)
 226                 }
 227                 ast::Effect::Unsafe(_) => {
 228                     let body = self.collect_block_opt(e.block_expr());
 229                     self.alloc_expr(Expr::Unsafe { body }, syntax_ptr)
 230                 }
 231                 // FIXME: we need to record these effects somewhere...
 232                 ast::Effect::Label(label) => {
 233                     let label = self.collect_label(label);
 234                     match e.block_expr() {
 235                         Some(block) => {
 236                             let res = self.collect_block(block);
 237                             match &mut self.body.exprs[res] {
 238                                 Expr::Block { label: block_label, .. } => {
 239                                     *block_label = Some(label);
 240                                 }
 241                                 _ => unreachable!(),
 242                             }
 243                             res
 244                         }
 245                         None => self.missing_expr(),
 246                     }
 247                 }
 248                 // FIXME: we need to record these effects somewhere...
 249                 ast::Effect::Async(_) => {
 250                     let body = self.collect_block_opt(e.block_expr());
 251                     self.alloc_expr(Expr::Async { body }, syntax_ptr)
 252                 }
 253                 ast::Effect::Const(_) => {
 254                     let body = self.collect_block_opt(e.block_expr());
 255                     self.alloc_expr(Expr::Const { body }, syntax_ptr)
 256                 }
 257             },
 258             ast::Expr::BlockExpr(e) => self.collect_block(e),
 259             ast::Expr::LoopExpr(e) => {
 260                 let label = e.label().map(|label| self.collect_label(label));
 261                 let body = self.collect_block_opt(e.loop_body());
 262                 self.alloc_expr(Expr::Loop { body, label }, syntax_ptr)
 263             }
 264             ast::Expr::WhileExpr(e) => {
 265                 let label = e.label().map(|label| self.collect_label(label));
 266                 let body = self.collect_block_opt(e.loop_body());
 267
 268                 let condition = match e.condition() {
 269                     None => self.missing_expr(),
 270                     Some(condition) => match condition.pat() {
 271                         None => self.collect_expr_opt(condition.expr()),
 272                         // if let -- desugar to match
 273                         Some(pat) => {
 274                             cov_mark::hit!(infer_resolve_while_let);
 275                             let pat = self.collect_pat(pat);
 276                             let match_expr = self.collect_expr_opt(condition.expr());
 277                             let placeholder_pat = self.missing_pat();
 278                             let break_ =
 279                                 self.alloc_expr_desugared(Expr::Break { expr: None, label: None });
 280                             let arms = vec![
 281                                 MatchArm { pat, expr: body, guard: None },
 282                                 MatchArm { pat: placeholder_pat, expr: break_, guard: None },
 283                             ];
 284                             let match_expr =
 285                                 self.alloc_expr_desugared(Expr::Match { expr: match_expr, arms });
 286                             return self
 287                                 .alloc_expr(Expr::Loop { body: match_expr, label }, syntax_ptr);
 288                         }
 289                     },
 290                 };
 291
 292                 self.alloc_expr(Expr::While { condition, body, label }, syntax_ptr)
 293             }
 294             ast::Expr::ForExpr(e) => {
 295                 let label = e.label().map(|label| self.collect_label(label));
 296                 let iterable = self.collect_expr_opt(e.iterable());
 297                 let pat = self.collect_pat_opt(e.pat());
 298                 let body = self.collect_block_opt(e.loop_body());
 299                 self.alloc_expr(Expr::For { iterable, pat, body, label }, syntax_ptr)
 300             }
 301             ast::Expr::CallExpr(e) => {
 302                 let callee = self.collect_expr_opt(e.expr());
 303                 let args = if let Some(arg_list) = e.arg_list() {
 304                     arg_list.args().map(|e| self.collect_expr(e)).collect()
 305                 } else {
 306                     Vec::new()
 307                 };
 308                 self.alloc_expr(Expr::Call { callee, args }, syntax_ptr)
 309             }
 310             ast::Expr::MethodCallExpr(e) => {
 311                 let receiver = self.collect_expr_opt(e.receiver());
 312                 let args = if let Some(arg_list) = e.arg_list() {
 313                     arg_list.args().map(|e| self.collect_expr(e)).collect()
 314                 } else {
 315                     Vec::new()
 316                 };
 317                 let method_name = e.name_ref().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
 318                 let generic_args =
 319                     e.generic_arg_list().and_then(|it| GenericArgs::from_ast(&self.ctx(), it));
 320                 self.alloc_expr(
 321                     Expr::MethodCall { receiver, method_name, args, generic_args },
 322                     syntax_ptr,
 323                 )
 324             }
 325             ast::Expr::MatchExpr(e) => {
 326                 let expr = self.collect_expr_opt(e.expr());
 327                 let arms = if let Some(match_arm_list) = e.match_arm_list() {
 328                     match_arm_list
 329                         .arms()
 330                         .filter_map(|arm| {
 331                             self.check_cfg(&arm).map(|()| MatchArm {
 332                                 pat: self.collect_pat_opt(arm.pat()),
 333                                 expr: self.collect_expr_opt(arm.expr()),
 334                                 guard: arm
 335                                     .guard()
 336                                     .and_then(|guard| guard.expr())
 337                                     .map(|e| self.collect_expr(e)),
 338                             })
 339                         })
 340                         .collect()
 341                 } else {
 342                     Vec::new()
 343                 };
 344                 self.alloc_expr(Expr::Match { expr, arms }, syntax_ptr)
 345             }
 346             ast::Expr::PathExpr(e) => {
 347                 let path = e
 348                     .path()
 349                     .and_then(|path| self.expander.parse_path(path))
 350                     .map(Expr::Path)
 351                     .unwrap_or(Expr::Missing);
 352                 self.alloc_expr(path, syntax_ptr)
 353             }
 354             ast::Expr::ContinueExpr(e) => self.alloc_expr(
 355                 Expr::Continue { label: e.lifetime().map(|l| Name::new_lifetime(&l)) },
 356                 syntax_ptr,
 357             ),
 358             ast::Expr::BreakExpr(e) => {
 359                 let expr = e.expr().map(|e| self.collect_expr(e));
 360                 self.alloc_expr(
 361                     Expr::Break { expr, label: e.lifetime().map(|l| Name::new_lifetime(&l)) },
 362                     syntax_ptr,
 363                 )
 364             }
 365             ast::Expr::ParenExpr(e) => {
 366                 let inner = self.collect_expr_opt(e.expr());
 367                 // make the paren expr point to the inner expression as well
 368                 let src = self.expander.to_source(syntax_ptr);
 369                 self.source_map.expr_map.insert(src, inner);
 370                 inner
 371             }
 372             ast::Expr::ReturnExpr(e) => {
 373                 let expr = e.expr().map(|e| self.collect_expr(e));
 374                 self.alloc_expr(Expr::Return { expr }, syntax_ptr)
 375             }
 376             ast::Expr::YieldExpr(e) => {
 377                 let expr = e.expr().map(|e| self.collect_expr(e));
 378                 self.alloc_expr(Expr::Yield { expr }, syntax_ptr)
 379             }
 380             ast::Expr::RecordExpr(e) => {
 381                 let path = e.path().and_then(|path| self.expander.parse_path(path));
 382                 let record_lit = if let Some(nfl) = e.record_expr_field_list() {
 383                     let fields = nfl
 384                         .fields()
 385                         .filter_map(|field| {
 386                             self.check_cfg(&field)?;
 387
 388                             let name = field.field_name()?.as_name();
 389
 390                             let expr = match field.expr() {
 391                                 Some(e) => self.collect_expr(e),
 392                                 None => self.missing_expr(),
 393                             };
 394                             let src = self.expander.to_source(AstPtr::new(&field));
 395                             self.source_map.field_map.insert(src.clone(), expr);
 396                             self.source_map.field_map_back.insert(expr, src);
 397                             Some(RecordLitField { name, expr })
 398                         })
 399                         .collect();
 400                     let spread = nfl.spread().map(|s| self.collect_expr(s));
 401                     Expr::RecordLit { path, fields, spread }
 402                 } else {
 403                     Expr::RecordLit { path, fields: Vec::new(), spread: None }
 404                 };
 405
 406                 self.alloc_expr(record_lit, syntax_ptr)
 407             }
 408             ast::Expr::FieldExpr(e) => {
 409                 let expr = self.collect_expr_opt(e.expr());
 410                 let name = match e.field_access() {
 411                     Some(kind) => kind.as_name(),
 412                     _ => Name::missing(),
 413                 };
 414                 self.alloc_expr(Expr::Field { expr, name }, syntax_ptr)
 415             }
 416             ast::Expr::AwaitExpr(e) => {
 417                 let expr = self.collect_expr_opt(e.expr());
 418                 self.alloc_expr(Expr::Await { expr }, syntax_ptr)
 419             }
 420             ast::Expr::TryExpr(e) => {
 421                 let expr = self.collect_expr_opt(e.expr());
 422                 self.alloc_expr(Expr::Try { expr }, syntax_ptr)
 423             }
 424             ast::Expr::CastExpr(e) => {
 425                 let expr = self.collect_expr_opt(e.expr());
 426                 let type_ref = TypeRef::from_ast_opt(&self.ctx(), e.ty());
 427                 self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
 428             }
 429             ast::Expr::RefExpr(e) => {
 430                 let expr = self.collect_expr_opt(e.expr());
 431                 let raw_tok = e.raw_token().is_some();
 432                 let mutability = if raw_tok {
 433                     if e.mut_token().is_some() {
 434                         Mutability::Mut
 435                     } else if e.const_token().is_some() {
 436                         Mutability::Shared
 437                     } else {
 438                         unreachable!("parser only remaps to raw_token() if matching mutability token follows")
 439                     }
 440                 } else {
 441                     Mutability::from_mutable(e.mut_token().is_some())
 442                 };
 443                 let rawness = Rawness::from_raw(raw_tok);
 444                 self.alloc_expr(Expr::Ref { expr, rawness, mutability }, syntax_ptr)
 445             }
 446             ast::Expr::PrefixExpr(e) => {
 447                 let expr = self.collect_expr_opt(e.expr());
 448                 if let Some(op) = e.op_kind() {
 449                     self.alloc_expr(Expr::UnaryOp { expr, op }, syntax_ptr)
 450                 } else {
 451                     self.alloc_expr(Expr::Missing, syntax_ptr)
 452                 }
 453             }
 454             ast::Expr::ClosureExpr(e) => {
 455                 let mut args = Vec::new();
 456                 let mut arg_types = Vec::new();
 457                 if let Some(pl) = e.param_list() {
 458                     for param in pl.params() {
 459                         let pat = self.collect_pat_opt(param.pat());
 460                         let type_ref = param.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
 461                         args.push(pat);
 462                         arg_types.push(type_ref);
 463                     }
 464                 }
 465                 let ret_type =
 466                     e.ret_type().and_then(|r| r.ty()).map(|it| TypeRef::from_ast(&self.ctx(), it));
 467                 let body = self.collect_expr_opt(e.body());
 468                 self.alloc_expr(Expr::Lambda { args, arg_types, ret_type, body }, syntax_ptr)
 469             }
 470             ast::Expr::BinExpr(e) => {
 471                 let lhs = self.collect_expr_opt(e.lhs());
 472                 let rhs = self.collect_expr_opt(e.rhs());
 473                 let op = e.op_kind().map(BinaryOp::from);
 474                 self.alloc_expr(Expr::BinaryOp { lhs, rhs, op }, syntax_ptr)
 475             }
 476             ast::Expr::TupleExpr(e) => {
 477                 let exprs = e.fields().map(|expr| self.collect_expr(expr)).collect();
 478                 self.alloc_expr(Expr::Tuple { exprs }, syntax_ptr)
 479             }
 480             ast::Expr::BoxExpr(e) => {
 481                 let expr = self.collect_expr_opt(e.expr());
 482                 self.alloc_expr(Expr::Box { expr }, syntax_ptr)
 483             }
 484
 485             ast::Expr::ArrayExpr(e) => {
 486                 let kind = e.kind();
 487
 488                 match kind {
 489                     ArrayExprKind::ElementList(e) => {
 490                         let exprs = e.map(|expr| self.collect_expr(expr)).collect();
 491                         self.alloc_expr(Expr::Array(Array::ElementList(exprs)), syntax_ptr)
 492                     }
 493                     ArrayExprKind::Repeat { initializer, repeat } => {
 494                         let initializer = self.collect_expr_opt(initializer);
 495                         let repeat = self.collect_expr_opt(repeat);
 496                         self.alloc_expr(
 497                             Expr::Array(Array::Repeat { initializer, repeat }),
 498                             syntax_ptr,
 499                         )
 500                     }
 501                 }
 502             }
 503
 504             ast::Expr::Literal(e) => self.alloc_expr(Expr::Literal(e.kind().into()), syntax_ptr),
 505             ast::Expr::IndexExpr(e) => {
 506                 let base = self.collect_expr_opt(e.base());
 507                 let index = self.collect_expr_opt(e.index());
 508                 self.alloc_expr(Expr::Index { base, index }, syntax_ptr)
 509             }
 510             ast::Expr::RangeExpr(e) => {
 511                 let lhs = e.start().map(|lhs| self.collect_expr(lhs));
 512                 let rhs = e.end().map(|rhs| self.collect_expr(rhs));
 513                 match e.op_kind() {
 514                     Some(range_type) => {
 515                         self.alloc_expr(Expr::Range { lhs, rhs, range_type }, syntax_ptr)
 516                     }
 517                     None => self.alloc_expr(Expr::Missing, syntax_ptr),
 518                 }
 519             }
 520             ast::Expr::MacroCall(e) => {
 521                 let mut ids = vec![];
 522                 self.collect_macro_call(e, syntax_ptr.clone(), |this, expansion| {
 523                     ids.push(match expansion {
 524                         Some(it) => this.collect_expr(it),
 525                         None => this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
 526                     })
 527                 });
 528                 ids[0]
 529             }
 530         }
 531     }
 532
 533     fn collect_macro_call<F: FnMut(&mut Self, Option<T>), T: ast::AstNode>(
 534         &mut self,
 535         e: ast::MacroCall,
 536         syntax_ptr: AstPtr<ast::Expr>,
 537         mut collector: F,
 538     ) {
 539         // File containing the macro call. Expansion errors will be attached here.
 540         let outer_file = self.expander.current_file_id;
 541
 542         let macro_call = self.expander.to_source(AstPtr::new(&e));
 543         let res = self.expander.enter_expand(self.db, e);
 544
 545         match &res.err {
 546             Some(ExpandError::UnresolvedProcMacro) => {
 547                 self.source_map.diagnostics.push(BodyDiagnostic::UnresolvedProcMacro(
 548                     UnresolvedProcMacro {
 549                         file: outer_file,
 550                         node: syntax_ptr.into(),
 551                         precise_location: None,
 552                         macro_name: None,
 553                     },
 554                 ));
 555             }
 556             Some(err) => {
 557                 self.source_map.diagnostics.push(BodyDiagnostic::MacroError(MacroError {
 558                     file: outer_file,
 559                     node: syntax_ptr.into(),
 560                     message: err.to_string(),
 561                 }));
 562             }
 563             None => {}
 564         }
 565
 566         match res.value {
 567             Some((mark, expansion)) => {
 568                 // FIXME: Statements are too complicated to recover from error for now.
 569                 // It is because we don't have any hygiene for local variable expansion right now.
 570                 if T::can_cast(syntax::SyntaxKind::MACRO_STMTS) && res.err.is_some() {
 571                     self.expander.exit(self.db, mark);
 572                     collector(self, None);
 573                 } else {
 574                     self.source_map.expansions.insert(macro_call, self.expander.current_file_id);
 575
 576                     let id = collector(self, Some(expansion));
 577                     self.expander.exit(self.db, mark);
 578                     id
 579                 }
 580             }
 581             None => collector(self, None),
 582         }
 583     }
 584
 585     fn collect_expr_opt(&mut self, expr: Option<ast::Expr>) -> ExprId {
 586         if let Some(expr) = expr {
 587             self.collect_expr(expr)
 588         } else {
 589             self.missing_expr()
 590         }
 591     }
 592
 593     fn collect_stmt(&mut self, s: ast::Stmt) -> Option<Vec<Statement>> {
 594         let stmt =
 595             match s {
 596                 ast::Stmt::LetStmt(stmt) => {
 597                     self.check_cfg(&stmt)?;
 598
 599                     let pat = self.collect_pat_opt(stmt.pat());
 600                     let type_ref = stmt.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
 601                     let initializer = stmt.initializer().map(|e| self.collect_expr(e));
 602                     vec![Statement::Let { pat, type_ref, initializer }]
 603                 }
 604                 ast::Stmt::ExprStmt(stmt) => {
 605                     self.check_cfg(&stmt)?;
 606
 607                     // Note that macro could be expended to multiple statements
 608                     if let Some(ast::Expr::MacroCall(m)) = stmt.expr() {
 609                         let syntax_ptr = AstPtr::new(&stmt.expr().unwrap());
 610                         let mut stmts = vec![];
 611
 612                         self.collect_macro_call(m, syntax_ptr.clone(), |this, expansion| {
 613                             match expansion {
 614                                 Some(expansion) => {
 615                                     let statements: ast::MacroStmts = expansion;
 616
 617                                     statements.statements().for_each(|stmt| {
 618                                         if let Some(mut r) = this.collect_stmt(stmt) {
 619                                             stmts.append(&mut r);
 620                                         }
 621                                     });
 622                                     if let Some(expr) = statements.expr() {
 623                                         stmts.push(Statement::Expr(this.collect_expr(expr)));
 624                                     }
 625                                 }
 626                                 None => {
 627                                     stmts.push(Statement::Expr(
 628                                         this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
 629                                     ));
 630                                 }
 631                             }
 632                         });
 633                         stmts
 634                     } else {
 635                         vec![Statement::Expr(self.collect_expr_opt(stmt.expr()))]
 636                     }
 637                 }
 638                 ast::Stmt::Item(item) => {
 639                     self.check_cfg(&item)?;
 640
 641                     return None;
 642                 }
 643             };
 644
 645         Some(stmt)
 646     }
 647
 648     fn collect_block(&mut self, block: ast::BlockExpr) -> ExprId {
 649         let ast_id = self.expander.ast_id(&block);
 650         let block_loc =
 651             BlockLoc { ast_id, module: self.expander.def_map.module_id(self.expander.module) };
 652         let block_id = self.db.intern_block(block_loc);
 653         self.body.block_scopes.push(block_id);
 654
 655         let opt_def_map = self.db.block_def_map(block_id);
 656         let has_def_map = opt_def_map.is_some();
 657         let def_map = opt_def_map.unwrap_or_else(|| self.expander.def_map.clone());
 658         let module = if has_def_map { def_map.root() } else { self.expander.module };
 659         let prev_def_map = mem::replace(&mut self.expander.def_map, def_map);
 660         let prev_local_module = mem::replace(&mut self.expander.module, module);
 661
 662         let statements =
 663             block.statements().filter_map(|s| self.collect_stmt(s)).flatten().collect();
 664         let tail = block.tail_expr().map(|e| self.collect_expr(e));
 665         let syntax_node_ptr = AstPtr::new(&block.into());
 666         let expr_id = self.alloc_expr(
 667             Expr::Block { id: block_id, statements, tail, label: None },
 668             syntax_node_ptr,
 669         );
 670
 671         self.expander.def_map = prev_def_map;
 672         self.expander.module = prev_local_module;
 673         expr_id
 674     }
 675
 676     fn collect_block_opt(&mut self, expr: Option<ast::BlockExpr>) -> ExprId {
 677         if let Some(block) = expr {
 678             self.collect_block(block)
 679         } else {
 680             self.missing_expr()
 681         }
 682     }
 683
 684     fn collect_label(&mut self, ast_label: ast::Label) -> LabelId {
 685         let label = Label {
 686             name: ast_label.lifetime().as_ref().map_or_else(Name::missing, Name::new_lifetime),
 687         };
 688         self.alloc_label(label, AstPtr::new(&ast_label))
 689     }
 690
 691     fn collect_pat(&mut self, pat: ast::Pat) -> PatId {
 692         let pattern = match &pat {
 693             ast::Pat::IdentPat(bp) => {
 694                 let name = bp.name().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
 695                 let annotation =
 696                     BindingAnnotation::new(bp.mut_token().is_some(), bp.ref_token().is_some());
 697                 let subpat = bp.pat().map(|subpat| self.collect_pat(subpat));
 698                 if annotation == BindingAnnotation::Unannotated && subpat.is_none() {
 699                     // This could also be a single-segment path pattern. To
 700                     // decide that, we need to try resolving the name.
 701                     let (resolved, _) = self.expander.def_map.resolve_path(
 702                         self.db,
 703                         self.expander.module,
 704                         &name.clone().into(),
 705                         BuiltinShadowMode::Other,
 706                     );
 707                     match resolved.take_values() {
 708                         Some(ModuleDefId::ConstId(_)) => Pat::Path(name.into()),
 709                         Some(ModuleDefId::EnumVariantId(_)) => {
 710                             // this is only really valid for unit variants, but
 711                             // shadowing other enum variants with a pattern is
 712                             // an error anyway
 713                             Pat::Path(name.into())
 714                         }
 715                         Some(ModuleDefId::AdtId(AdtId::StructId(s)))
 716                             if self.db.struct_data(s).variant_data.kind() != StructKind::Record =>
 717                         {
 718                             // Funnily enough, record structs *can* be shadowed
 719                             // by pattern bindings (but unit or tuple structs
 720                             // can't).
 721                             Pat::Path(name.into())
 722                         }
 723                         // shadowing statics is an error as well, so we just ignore that case here
 724                         _ => Pat::Bind { name, mode: annotation, subpat },
 725                     }
 726                 } else {
 727                     Pat::Bind { name, mode: annotation, subpat }
 728                 }
 729             }
 730             ast::Pat::TupleStructPat(p) => {
 731                 let path = p.path().and_then(|path| self.expander.parse_path(path));
 732                 let (args, ellipsis) = self.collect_tuple_pat(p.fields());
 733                 Pat::TupleStruct { path, args, ellipsis }
 734             }
 735             ast::Pat::RefPat(p) => {
 736                 let pat = self.collect_pat_opt(p.pat());
 737                 let mutability = Mutability::from_mutable(p.mut_token().is_some());
 738                 Pat::Ref { pat, mutability }
 739             }
 740             ast::Pat::PathPat(p) => {
 741                 let path = p.path().and_then(|path| self.expander.parse_path(path));
 742                 path.map(Pat::Path).unwrap_or(Pat::Missing)
 743             }
 744             ast::Pat::OrPat(p) => {
 745                 let pats = p.pats().map(|p| self.collect_pat(p)).collect();
 746                 Pat::Or(pats)
 747             }
 748             ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat()),
 749             ast::Pat::TuplePat(p) => {
 750                 let (args, ellipsis) = self.collect_tuple_pat(p.fields());
 751                 Pat::Tuple { args, ellipsis }
 752             }
 753             ast::Pat::WildcardPat(_) => Pat::Wild,
 754             ast::Pat::RecordPat(p) => {
 755                 let path = p.path().and_then(|path| self.expander.parse_path(path));
 756                 let args: Vec<_> = p
 757                     .record_pat_field_list()
 758                     .expect("every struct should have a field list")
 759                     .fields()
 760                     .filter_map(|f| {
 761                         let ast_pat = f.pat()?;
 762                         let pat = self.collect_pat(ast_pat);
 763                         let name = f.field_name()?.as_name();
 764                         Some(RecordFieldPat { name, pat })
 765                     })
 766                     .collect();
 767
 768                 let ellipsis = p
 769                     .record_pat_field_list()
 770                     .expect("every struct should have a field list")
 771                     .dotdot_token()
 772                     .is_some();
 773
 774                 Pat::Record { path, args, ellipsis }
 775             }
 776             ast::Pat::SlicePat(p) => {
 777                 let SlicePatComponents { prefix, slice, suffix } = p.components();
 778
 779                 // FIXME properly handle `RestPat`
 780                 Pat::Slice {
 781                     prefix: prefix.into_iter().map(|p| self.collect_pat(p)).collect(),
 782                     slice: slice.map(|p| self.collect_pat(p)),
 783                     suffix: suffix.into_iter().map(|p| self.collect_pat(p)).collect(),
 784                 }
 785             }
 786             ast::Pat::LiteralPat(lit) => {
 787                 if let Some(ast_lit) = lit.literal() {
 788                     let expr = Expr::Literal(ast_lit.kind().into());
 789                     let expr_ptr = AstPtr::new(&ast::Expr::Literal(ast_lit));
 790                     let expr_id = self.alloc_expr(expr, expr_ptr);
 791                     Pat::Lit(expr_id)
 792                 } else {
 793                     Pat::Missing
 794                 }
 795             }
 796             ast::Pat::RestPat(_) => {
 797                 // `RestPat` requires special handling and should not be mapped
 798                 // to a Pat. Here we are using `Pat::Missing` as a fallback for
 799                 // when `RestPat` is mapped to `Pat`, which can easily happen
 800                 // when the source code being analyzed has a malformed pattern
 801                 // which includes `..` in a place where it isn't valid.
 802
 803                 Pat::Missing
 804             }
 805             ast::Pat::BoxPat(boxpat) => {
 806                 let inner = self.collect_pat_opt(boxpat.pat());
 807                 Pat::Box { inner }
 808             }
 809             ast::Pat::ConstBlockPat(const_block_pat) => {
 810                 if let Some(expr) = const_block_pat.block_expr() {
 811                     let expr_id = self.collect_block(expr);
 812                     Pat::ConstBlock(expr_id)
 813                 } else {
 814                     Pat::Missing
 815                 }
 816             }
 817             // FIXME: implement
 818             ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
 819         };
 820         let ptr = AstPtr::new(&pat);
 821         self.alloc_pat(pattern, Either::Left(ptr))
 822     }
 823
 824     fn collect_pat_opt(&mut self, pat: Option<ast::Pat>) -> PatId {
 825         if let Some(pat) = pat {
 826             self.collect_pat(pat)
 827         } else {
 828             self.missing_pat()
 829         }
 830     }
 831
 832     fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Vec<PatId>, Option<usize>) {
 833         // Find the location of the `..`, if there is one. Note that we do not
 834         // consider the possibility of there being multiple `..` here.
 835         let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::RestPat(_)));
 836         // We want to skip the `..` pattern here, since we account for it above.
 837         let args = args
 838             .filter(|p| !matches!(p, ast::Pat::RestPat(_)))
 839             .map(|p| self.collect_pat(p))
 840             .collect();
 841
 842         (args, ellipsis)
 843     }
 844
 845     /// Returns `None` (and emits diagnostics) when `owner` if `#[cfg]`d out, and `Some(())` when
 846     /// not.
 847     fn check_cfg(&mut self, owner: &dyn ast::AttrsOwner) -> Option<()> {
 848         match self.expander.parse_attrs(self.db, owner).cfg() {
 849             Some(cfg) => {
 850                 if self.expander.cfg_options().check(&cfg) != Some(false) {
 851                     return Some(());
 852                 }
 853
 854                 self.source_map.diagnostics.push(BodyDiagnostic::InactiveCode(InactiveCode {
 855                     file: self.expander.current_file_id,
 856                     node: SyntaxNodePtr::new(owner.syntax()),
 857                     cfg,
 858                     opts: self.expander.cfg_options().clone(),
 859                 }));
 860
 861                 None
 862             }
 863             None => Some(()),
 864         }
 865     }
 866 }
 867
 868 impl From<ast::BinOp> for BinaryOp {
 869     fn from(ast_op: ast::BinOp) -> Self {
 870         match ast_op {
 871             ast::BinOp::BooleanOr => BinaryOp::LogicOp(LogicOp::Or),
 872             ast::BinOp::BooleanAnd => BinaryOp::LogicOp(LogicOp::And),
 873             ast::BinOp::EqualityTest => BinaryOp::CmpOp(CmpOp::Eq { negated: false }),
 874             ast::BinOp::NegatedEqualityTest => BinaryOp::CmpOp(CmpOp::Eq { negated: true }),
 875             ast::BinOp::LesserEqualTest => {
 876                 BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Less, strict: false })
 877             }
 878             ast::BinOp::GreaterEqualTest => {
 879                 BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Greater, strict: false })
 880             }
 881             ast::BinOp::LesserTest => {
 882                 BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Less, strict: true })
 883             }
 884             ast::BinOp::GreaterTest => {
 885                 BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Greater, strict: true })
 886             }
 887             ast::BinOp::Addition => BinaryOp::ArithOp(ArithOp::Add),
 888             ast::BinOp::Multiplication => BinaryOp::ArithOp(ArithOp::Mul),
 889             ast::BinOp::Subtraction => BinaryOp::ArithOp(ArithOp::Sub),
 890             ast::BinOp::Division => BinaryOp::ArithOp(ArithOp::Div),
 891             ast::BinOp::Remainder => BinaryOp::ArithOp(ArithOp::Rem),
 892             ast::BinOp::LeftShift => BinaryOp::ArithOp(ArithOp::Shl),
 893             ast::BinOp::RightShift => BinaryOp::ArithOp(ArithOp::Shr),
 894             ast::BinOp::BitwiseXor => BinaryOp::ArithOp(ArithOp::BitXor),
 895             ast::BinOp::BitwiseOr => BinaryOp::ArithOp(ArithOp::BitOr),
 896             ast::BinOp::BitwiseAnd => BinaryOp::ArithOp(ArithOp::BitAnd),
 897             ast::BinOp::Assignment => BinaryOp::Assignment { op: None },
 898             ast::BinOp::AddAssign => BinaryOp::Assignment { op: Some(ArithOp::Add) },
 899             ast::BinOp::DivAssign => BinaryOp::Assignment { op: Some(ArithOp::Div) },
 900             ast::BinOp::MulAssign => BinaryOp::Assignment { op: Some(ArithOp::Mul) },
 901             ast::BinOp::RemAssign => BinaryOp::Assignment { op: Some(ArithOp::Rem) },
 902             ast::BinOp::ShlAssign => BinaryOp::Assignment { op: Some(ArithOp::Shl) },
 903             ast::BinOp::ShrAssign => BinaryOp::Assignment { op: Some(ArithOp::Shr) },
 904             ast::BinOp::SubAssign => BinaryOp::Assignment { op: Some(ArithOp::Sub) },
 905             ast::BinOp::BitOrAssign => BinaryOp::Assignment { op: Some(ArithOp::BitOr) },
 906             ast::BinOp::BitAndAssign => BinaryOp::Assignment { op: Some(ArithOp::BitAnd) },
 907             ast::BinOp::BitXorAssign => BinaryOp::Assignment { op: Some(ArithOp::BitXor) },
 908         }
 909     }
 910 }
 911
 912 impl From<ast::LiteralKind> for Literal {
 913     fn from(ast_lit_kind: ast::LiteralKind) -> Self {
 914         match ast_lit_kind {
 915             LiteralKind::IntNumber(lit) => {
 916                 if let builtin @ Some(_) = lit.suffix().and_then(BuiltinFloat::from_suffix) {
 917                     return Literal::Float(Default::default(), builtin);
 918                 } else if let builtin @ Some(_) =
 919                     lit.suffix().and_then(|it| BuiltinInt::from_suffix(&it))
 920                 {
 921                     Literal::Int(Default::default(), builtin)
 922                 } else {
 923                     let builtin = lit.suffix().and_then(|it| BuiltinUint::from_suffix(&it));
 924                     Literal::Uint(Default::default(), builtin)
 925                 }
 926             }
 927             LiteralKind::FloatNumber(lit) => {
 928                 let ty = lit.suffix().and_then(|it| BuiltinFloat::from_suffix(&it));
 929                 Literal::Float(Default::default(), ty)
 930             }
 931             LiteralKind::ByteString(_) => Literal::ByteString(Default::default()),
 932             LiteralKind::String(_) => Literal::String(Default::default()),
 933             LiteralKind::Byte => Literal::Uint(Default::default(), Some(BuiltinUint::U8)),
 934             LiteralKind::Bool(val) => Literal::Bool(val),
 935             LiteralKind::Char => Literal::Char(Default::default()),
 936         }
 937     }
 938 }