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, sync::Arc};
   5
   6 use either::Either;
   7 use hir_expand::{
   8     ast_id_map::{AstIdMap, FileAstId},
   9     hygiene::Hygiene,
  10     name::{name, AsName, Name},
  11     ExpandError, HirFileId, InFile,
  12 };
  13 use la_arena::Arena;
  14 use profile::Count;
  15 use syntax::{
  16     ast::{
  17         self, ArrayExprKind, AstChildren, HasArgList, HasLoopBody, HasName, LiteralKind,
  18         SlicePatComponents,
  19     },
  20     AstNode, AstPtr, SyntaxNodePtr,
  21 };
  22
  23 use crate::{
  24     adt::StructKind,
  25     body::{Body, BodySourceMap, Expander, LabelSource, PatPtr, SyntheticSyntax},
  26     body::{BodyDiagnostic, ExprSource, PatSource},
  27     builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint},
  28     db::DefDatabase,
  29     expr::{
  30         dummy_expr_id, Array, BindingAnnotation, Expr, ExprId, Label, LabelId, Literal, MatchArm,
  31         Pat, PatId, RecordFieldPat, RecordLitField, Statement,
  32     },
  33     intern::Interned,
  34     item_scope::BuiltinShadowMode,
  35     path::{GenericArgs, Path},
  36     type_ref::{Mutability, Rawness, TypeRef},
  37     AdtId, BlockLoc, ModuleDefId, UnresolvedMacro,
  38 };
  39
  40 pub struct LowerCtx<'a> {
  41     pub db: &'a dyn DefDatabase,
  42     hygiene: Hygiene,
  43     file_id: Option<HirFileId>,
  44     source_ast_id_map: Option<Arc<AstIdMap>>,
  45 }
  46
  47 impl<'a> LowerCtx<'a> {
  48     pub fn new(db: &'a dyn DefDatabase, file_id: HirFileId) -> Self {
  49         LowerCtx {
  50             db,
  51             hygiene: Hygiene::new(db.upcast(), file_id),
  52             file_id: Some(file_id),
  53             source_ast_id_map: Some(db.ast_id_map(file_id)),
  54         }
  55     }
  56
  57     pub fn with_hygiene(db: &'a dyn DefDatabase, hygiene: &Hygiene) -> Self {
  58         LowerCtx { db, hygiene: hygiene.clone(), file_id: None, source_ast_id_map: None }
  59     }
  60
  61     pub(crate) fn hygiene(&self) -> &Hygiene {
  62         &self.hygiene
  63     }
  64
  65     pub(crate) fn file_id(&self) -> HirFileId {
  66         self.file_id.unwrap()
  67     }
  68
  69     pub(crate) fn lower_path(&self, ast: ast::Path) -> Option<Path> {
  70         Path::from_src(ast, self)
  71     }
  72
  73     pub(crate) fn ast_id<N: AstNode>(&self, item: &N) -> Option<FileAstId<N>> {
  74         self.source_ast_id_map.as_ref().map(|ast_id_map| ast_id_map.ast_id(item))
  75     }
  76 }
  77
  78 pub(super) fn lower(
  79     db: &dyn DefDatabase,
  80     expander: Expander,
  81     params: Option<ast::ParamList>,
  82     body: Option<ast::Expr>,
  83 ) -> (Body, BodySourceMap) {
  84     ExprCollector {
  85         db,
  86         source_map: BodySourceMap::default(),
  87         body: Body {
  88             exprs: Arena::default(),
  89             pats: Arena::default(),
  90             labels: Arena::default(),
  91             params: Vec::new(),
  92             body_expr: dummy_expr_id(),
  93             block_scopes: Vec::new(),
  94             _c: Count::new(),
  95         },
  96         expander,
  97         statements_in_scope: Vec::new(),
  98     }
  99     .collect(params, body)
 100 }
 101
 102 struct ExprCollector<'a> {
 103     db: &'a dyn DefDatabase,
 104     expander: Expander,
 105     body: Body,
 106     source_map: BodySourceMap,
 107     statements_in_scope: Vec<Statement>,
 108 }
 109
 110 impl ExprCollector<'_> {
 111     fn collect(
 112         mut self,
 113         param_list: Option<ast::ParamList>,
 114         body: Option<ast::Expr>,
 115     ) -> (Body, BodySourceMap) {
 116         if let Some(param_list) = param_list {
 117             if let Some(self_param) = param_list.self_param() {
 118                 let ptr = AstPtr::new(&self_param);
 119                 let param_pat = self.alloc_pat(
 120                     Pat::Bind {
 121                         name: name![self],
 122                         mode: BindingAnnotation::new(
 123                             self_param.mut_token().is_some() && self_param.amp_token().is_none(),
 124                             false,
 125                         ),
 126                         subpat: None,
 127                     },
 128                     Either::Right(ptr),
 129                 );
 130                 self.body.params.push(param_pat);
 131             }
 132
 133             for pat in param_list.params().filter_map(|param| param.pat()) {
 134                 let param_pat = self.collect_pat(pat);
 135                 self.body.params.push(param_pat);
 136             }
 137         };
 138
 139         self.body.body_expr = self.collect_expr_opt(body);
 140         (self.body, self.source_map)
 141     }
 142
 143     fn ctx(&self) -> LowerCtx<'_> {
 144         LowerCtx::new(self.db, self.expander.current_file_id)
 145     }
 146
 147     fn alloc_expr(&mut self, expr: Expr, ptr: AstPtr<ast::Expr>) -> ExprId {
 148         let src = self.expander.to_source(ptr);
 149         let id = self.make_expr(expr, Ok(src.clone()));
 150         self.source_map.expr_map.insert(src, id);
 151         id
 152     }
 153     // desugared exprs don't have ptr, that's wrong and should be fixed
 154     // somehow.
 155     fn alloc_expr_desugared(&mut self, expr: Expr) -> ExprId {
 156         self.make_expr(expr, Err(SyntheticSyntax))
 157     }
 158     fn missing_expr(&mut self) -> ExprId {
 159         self.alloc_expr_desugared(Expr::Missing)
 160     }
 161     fn make_expr(&mut self, expr: Expr, src: Result<ExprSource, SyntheticSyntax>) -> ExprId {
 162         let id = self.body.exprs.alloc(expr);
 163         self.source_map.expr_map_back.insert(id, src);
 164         id
 165     }
 166
 167     fn alloc_pat(&mut self, pat: Pat, ptr: PatPtr) -> PatId {
 168         let src = self.expander.to_source(ptr);
 169         let id = self.make_pat(pat, Ok(src.clone()));
 170         self.source_map.pat_map.insert(src, id);
 171         id
 172     }
 173     fn missing_pat(&mut self) -> PatId {
 174         self.make_pat(Pat::Missing, Err(SyntheticSyntax))
 175     }
 176     fn make_pat(&mut self, pat: Pat, src: Result<PatSource, SyntheticSyntax>) -> PatId {
 177         let id = self.body.pats.alloc(pat);
 178         self.source_map.pat_map_back.insert(id, src);
 179         id
 180     }
 181
 182     fn alloc_label(&mut self, label: Label, ptr: AstPtr<ast::Label>) -> LabelId {
 183         let src = self.expander.to_source(ptr);
 184         let id = self.make_label(label, src.clone());
 185         self.source_map.label_map.insert(src, id);
 186         id
 187     }
 188     fn make_label(&mut self, label: Label, src: LabelSource) -> LabelId {
 189         let id = self.body.labels.alloc(label);
 190         self.source_map.label_map_back.insert(id, src);
 191         id
 192     }
 193
 194     fn collect_expr(&mut self, expr: ast::Expr) -> ExprId {
 195         self.maybe_collect_expr(expr).unwrap_or_else(|| self.missing_expr())
 196     }
 197
 198     /// Returns `None` if and only if the expression is `#[cfg]`d out.
 199     fn maybe_collect_expr(&mut self, expr: ast::Expr) -> Option<ExprId> {
 200         let syntax_ptr = AstPtr::new(&expr);
 201         self.check_cfg(&expr)?;
 202
 203         Some(match expr {
 204             ast::Expr::IfExpr(e) => {
 205                 let then_branch = self.collect_block_opt(e.then_branch());
 206
 207                 let else_branch = e.else_branch().map(|b| match b {
 208                     ast::ElseBranch::Block(it) => self.collect_block(it),
 209                     ast::ElseBranch::IfExpr(elif) => {
 210                         let expr: ast::Expr = ast::Expr::cast(elif.syntax().clone()).unwrap();
 211                         self.collect_expr(expr)
 212                     }
 213                 });
 214
 215                 let condition = self.collect_expr_opt(e.condition());
 216
 217                 self.alloc_expr(Expr::If { condition, then_branch, else_branch }, syntax_ptr)
 218             }
 219             ast::Expr::LetExpr(e) => {
 220                 let pat = self.collect_pat_opt(e.pat());
 221                 let expr = self.collect_expr_opt(e.expr());
 222                 self.alloc_expr(Expr::Let { pat, expr }, syntax_ptr)
 223             }
 224             ast::Expr::BlockExpr(e) => match e.modifier() {
 225                 Some(ast::BlockModifier::Try(_)) => {
 226                     let body = self.collect_block(e);
 227                     self.alloc_expr(Expr::TryBlock { body }, syntax_ptr)
 228                 }
 229                 Some(ast::BlockModifier::Unsafe(_)) => {
 230                     let body = self.collect_block(e);
 231                     self.alloc_expr(Expr::Unsafe { body }, syntax_ptr)
 232                 }
 233                 // FIXME: we need to record these effects somewhere...
 234                 Some(ast::BlockModifier::Label(label)) => {
 235                     let label = self.collect_label(label);
 236                     let res = self.collect_block(e);
 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                 Some(ast::BlockModifier::Async(_)) => {
 246                     let body = self.collect_block(e);
 247                     self.alloc_expr(Expr::Async { body }, syntax_ptr)
 248                 }
 249                 Some(ast::BlockModifier::Const(_)) => {
 250                     let body = self.collect_block(e);
 251                     self.alloc_expr(Expr::Const { body }, syntax_ptr)
 252                 }
 253                 None => self.collect_block(e),
 254             },
 255             ast::Expr::LoopExpr(e) => {
 256                 let label = e.label().map(|label| self.collect_label(label));
 257                 let body = self.collect_block_opt(e.loop_body());
 258                 self.alloc_expr(Expr::Loop { body, label }, syntax_ptr)
 259             }
 260             ast::Expr::WhileExpr(e) => {
 261                 let label = e.label().map(|label| self.collect_label(label));
 262                 let body = self.collect_block_opt(e.loop_body());
 263
 264                 let condition = self.collect_expr_opt(e.condition());
 265
 266                 self.alloc_expr(Expr::While { condition, body, label }, syntax_ptr)
 267             }
 268             ast::Expr::ForExpr(e) => {
 269                 let label = e.label().map(|label| self.collect_label(label));
 270                 let iterable = self.collect_expr_opt(e.iterable());
 271                 let pat = self.collect_pat_opt(e.pat());
 272                 let body = self.collect_block_opt(e.loop_body());
 273                 self.alloc_expr(Expr::For { iterable, pat, body, label }, syntax_ptr)
 274             }
 275             ast::Expr::CallExpr(e) => {
 276                 let callee = self.collect_expr_opt(e.expr());
 277                 let args = if let Some(arg_list) = e.arg_list() {
 278                     arg_list.args().filter_map(|e| self.maybe_collect_expr(e)).collect()
 279                 } else {
 280                     Box::default()
 281                 };
 282                 self.alloc_expr(Expr::Call { callee, args }, syntax_ptr)
 283             }
 284             ast::Expr::MethodCallExpr(e) => {
 285                 let receiver = self.collect_expr_opt(e.receiver());
 286                 let args = if let Some(arg_list) = e.arg_list() {
 287                     arg_list.args().filter_map(|e| self.maybe_collect_expr(e)).collect()
 288                 } else {
 289                     Box::default()
 290                 };
 291                 let method_name = e.name_ref().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
 292                 let generic_args = e
 293                     .generic_arg_list()
 294                     .and_then(|it| GenericArgs::from_ast(&self.ctx(), it))
 295                     .map(Box::new);
 296                 self.alloc_expr(
 297                     Expr::MethodCall { receiver, method_name, args, generic_args },
 298                     syntax_ptr,
 299                 )
 300             }
 301             ast::Expr::MatchExpr(e) => {
 302                 let expr = self.collect_expr_opt(e.expr());
 303                 let arms = if let Some(match_arm_list) = e.match_arm_list() {
 304                     match_arm_list
 305                         .arms()
 306                         .filter_map(|arm| {
 307                             self.check_cfg(&arm).map(|()| MatchArm {
 308                                 pat: self.collect_pat_opt(arm.pat()),
 309                                 expr: self.collect_expr_opt(arm.expr()),
 310                                 guard: arm
 311                                     .guard()
 312                                     .map(|guard| self.collect_expr_opt(guard.condition())),
 313                             })
 314                         })
 315                         .collect()
 316                 } else {
 317                     Box::default()
 318                 };
 319                 self.alloc_expr(Expr::Match { expr, arms }, syntax_ptr)
 320             }
 321             ast::Expr::PathExpr(e) => {
 322                 let path = e
 323                     .path()
 324                     .and_then(|path| self.expander.parse_path(self.db, path))
 325                     .map(Expr::Path)
 326                     .unwrap_or(Expr::Missing);
 327                 self.alloc_expr(path, syntax_ptr)
 328             }
 329             ast::Expr::ContinueExpr(e) => self.alloc_expr(
 330                 Expr::Continue { label: e.lifetime().map(|l| Name::new_lifetime(&l)) },
 331                 syntax_ptr,
 332             ),
 333             ast::Expr::BreakExpr(e) => {
 334                 let expr = e.expr().map(|e| self.collect_expr(e));
 335                 self.alloc_expr(
 336                     Expr::Break { expr, label: e.lifetime().map(|l| Name::new_lifetime(&l)) },
 337                     syntax_ptr,
 338                 )
 339             }
 340             ast::Expr::ParenExpr(e) => {
 341                 let inner = self.collect_expr_opt(e.expr());
 342                 // make the paren expr point to the inner expression as well
 343                 let src = self.expander.to_source(syntax_ptr);
 344                 self.source_map.expr_map.insert(src, inner);
 345                 inner
 346             }
 347             ast::Expr::ReturnExpr(e) => {
 348                 let expr = e.expr().map(|e| self.collect_expr(e));
 349                 self.alloc_expr(Expr::Return { expr }, syntax_ptr)
 350             }
 351             ast::Expr::YieldExpr(e) => {
 352                 let expr = e.expr().map(|e| self.collect_expr(e));
 353                 self.alloc_expr(Expr::Yield { expr }, syntax_ptr)
 354             }
 355             ast::Expr::RecordExpr(e) => {
 356                 let path =
 357                     e.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
 358                 let record_lit = if let Some(nfl) = e.record_expr_field_list() {
 359                     let fields = nfl
 360                         .fields()
 361                         .filter_map(|field| {
 362                             self.check_cfg(&field)?;
 363
 364                             let name = field.field_name()?.as_name();
 365
 366                             let expr = match field.expr() {
 367                                 Some(e) => self.collect_expr(e),
 368                                 None => self.missing_expr(),
 369                             };
 370                             let src = self.expander.to_source(AstPtr::new(&field));
 371                             self.source_map.field_map.insert(src.clone(), expr);
 372                             self.source_map.field_map_back.insert(expr, src);
 373                             Some(RecordLitField { name, expr })
 374                         })
 375                         .collect();
 376                     let spread = nfl.spread().map(|s| self.collect_expr(s));
 377                     Expr::RecordLit { path, fields, spread }
 378                 } else {
 379                     Expr::RecordLit { path, fields: Box::default(), spread: None }
 380                 };
 381
 382                 self.alloc_expr(record_lit, syntax_ptr)
 383             }
 384             ast::Expr::FieldExpr(e) => {
 385                 let expr = self.collect_expr_opt(e.expr());
 386                 let name = match e.field_access() {
 387                     Some(kind) => kind.as_name(),
 388                     _ => Name::missing(),
 389                 };
 390                 self.alloc_expr(Expr::Field { expr, name }, syntax_ptr)
 391             }
 392             ast::Expr::AwaitExpr(e) => {
 393                 let expr = self.collect_expr_opt(e.expr());
 394                 self.alloc_expr(Expr::Await { expr }, syntax_ptr)
 395             }
 396             ast::Expr::TryExpr(e) => {
 397                 let expr = self.collect_expr_opt(e.expr());
 398                 self.alloc_expr(Expr::Try { expr }, syntax_ptr)
 399             }
 400             ast::Expr::CastExpr(e) => {
 401                 let expr = self.collect_expr_opt(e.expr());
 402                 let type_ref = Interned::new(TypeRef::from_ast_opt(&self.ctx(), e.ty()));
 403                 self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
 404             }
 405             ast::Expr::RefExpr(e) => {
 406                 let expr = self.collect_expr_opt(e.expr());
 407                 let raw_tok = e.raw_token().is_some();
 408                 let mutability = if raw_tok {
 409                     if e.mut_token().is_some() {
 410                         Mutability::Mut
 411                     } else if e.const_token().is_some() {
 412                         Mutability::Shared
 413                     } else {
 414                         unreachable!("parser only remaps to raw_token() if matching mutability token follows")
 415                     }
 416                 } else {
 417                     Mutability::from_mutable(e.mut_token().is_some())
 418                 };
 419                 let rawness = Rawness::from_raw(raw_tok);
 420                 self.alloc_expr(Expr::Ref { expr, rawness, mutability }, syntax_ptr)
 421             }
 422             ast::Expr::PrefixExpr(e) => {
 423                 let expr = self.collect_expr_opt(e.expr());
 424                 match e.op_kind() {
 425                     Some(op) => self.alloc_expr(Expr::UnaryOp { expr, op }, syntax_ptr),
 426                     None => self.alloc_expr(Expr::Missing, syntax_ptr),
 427                 }
 428             }
 429             ast::Expr::ClosureExpr(e) => {
 430                 let mut args = Vec::new();
 431                 let mut arg_types = Vec::new();
 432                 if let Some(pl) = e.param_list() {
 433                     for param in pl.params() {
 434                         let pat = self.collect_pat_opt(param.pat());
 435                         let type_ref =
 436                             param.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
 437                         args.push(pat);
 438                         arg_types.push(type_ref);
 439                     }
 440                 }
 441                 let ret_type = e
 442                     .ret_type()
 443                     .and_then(|r| r.ty())
 444                     .map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
 445                 let body = self.collect_expr_opt(e.body());
 446                 self.alloc_expr(
 447                     Expr::Lambda { args: args.into(), arg_types: arg_types.into(), ret_type, body },
 448                     syntax_ptr,
 449                 )
 450             }
 451             ast::Expr::BinExpr(e) => {
 452                 let lhs = self.collect_expr_opt(e.lhs());
 453                 let rhs = self.collect_expr_opt(e.rhs());
 454                 let op = e.op_kind();
 455                 self.alloc_expr(Expr::BinaryOp { lhs, rhs, op }, syntax_ptr)
 456             }
 457             ast::Expr::TupleExpr(e) => {
 458                 let exprs = e.fields().map(|expr| self.collect_expr(expr)).collect();
 459                 self.alloc_expr(Expr::Tuple { exprs }, syntax_ptr)
 460             }
 461             ast::Expr::BoxExpr(e) => {
 462                 let expr = self.collect_expr_opt(e.expr());
 463                 self.alloc_expr(Expr::Box { expr }, syntax_ptr)
 464             }
 465
 466             ast::Expr::ArrayExpr(e) => {
 467                 let kind = e.kind();
 468
 469                 match kind {
 470                     ArrayExprKind::ElementList(e) => {
 471                         let exprs = e.map(|expr| self.collect_expr(expr)).collect();
 472                         self.alloc_expr(Expr::Array(Array::ElementList(exprs)), syntax_ptr)
 473                     }
 474                     ArrayExprKind::Repeat { initializer, repeat } => {
 475                         let initializer = self.collect_expr_opt(initializer);
 476                         let repeat = self.collect_expr_opt(repeat);
 477                         self.alloc_expr(
 478                             Expr::Array(Array::Repeat { initializer, repeat }),
 479                             syntax_ptr,
 480                         )
 481                     }
 482                 }
 483             }
 484
 485             ast::Expr::Literal(e) => self.alloc_expr(Expr::Literal(e.kind().into()), syntax_ptr),
 486             ast::Expr::IndexExpr(e) => {
 487                 let base = self.collect_expr_opt(e.base());
 488                 let index = self.collect_expr_opt(e.index());
 489                 self.alloc_expr(Expr::Index { base, index }, syntax_ptr)
 490             }
 491             ast::Expr::RangeExpr(e) => {
 492                 let lhs = e.start().map(|lhs| self.collect_expr(lhs));
 493                 let rhs = e.end().map(|rhs| self.collect_expr(rhs));
 494                 match e.op_kind() {
 495                     Some(range_type) => {
 496                         self.alloc_expr(Expr::Range { lhs, rhs, range_type }, syntax_ptr)
 497                     }
 498                     None => self.alloc_expr(Expr::Missing, syntax_ptr),
 499                 }
 500             }
 501             ast::Expr::MacroCall(e) => {
 502                 let macro_ptr = AstPtr::new(&e);
 503                 let mut ids = vec![];
 504                 self.collect_macro_call(e, macro_ptr, true, |this, expansion| {
 505                     ids.push(match expansion {
 506                         Some(it) => this.collect_expr(it),
 507                         None => this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
 508                     })
 509                 });
 510                 ids[0]
 511             }
 512             ast::Expr::MacroStmts(e) => {
 513                 e.statements().for_each(|s| self.collect_stmt(s));
 514                 let tail = e
 515                     .expr()
 516                     .map(|e| self.collect_expr(e))
 517                     .unwrap_or_else(|| self.alloc_expr(Expr::Missing, syntax_ptr.clone()));
 518
 519                 self.alloc_expr(Expr::MacroStmts { tail }, syntax_ptr)
 520             }
 521         })
 522     }
 523
 524     fn collect_macro_call<F: FnMut(&mut Self, Option<T>), T: ast::AstNode>(
 525         &mut self,
 526         e: ast::MacroCall,
 527         syntax_ptr: AstPtr<ast::MacroCall>,
 528         record_diagnostics: bool,
 529         mut collector: F,
 530     ) {
 531         // File containing the macro call. Expansion errors will be attached here.
 532         let outer_file = self.expander.current_file_id;
 533
 534         let macro_call = self.expander.to_source(AstPtr::new(&e));
 535         let res = self.expander.enter_expand(self.db, e);
 536
 537         let res = match res {
 538             Ok(res) => res,
 539             Err(UnresolvedMacro { path }) => {
 540                 if record_diagnostics {
 541                     self.source_map.diagnostics.push(BodyDiagnostic::UnresolvedMacroCall {
 542                         node: InFile::new(outer_file, syntax_ptr),
 543                         path,
 544                     });
 545                 }
 546                 collector(self, None);
 547                 return;
 548             }
 549         };
 550
 551         if record_diagnostics {
 552             match &res.err {
 553                 Some(ExpandError::UnresolvedProcMacro) => {
 554                     self.source_map.diagnostics.push(BodyDiagnostic::UnresolvedProcMacro {
 555                         node: InFile::new(outer_file, syntax_ptr),
 556                     });
 557                 }
 558                 Some(err) => {
 559                     self.source_map.diagnostics.push(BodyDiagnostic::MacroError {
 560                         node: InFile::new(outer_file, syntax_ptr),
 561                         message: err.to_string(),
 562                     });
 563                 }
 564                 None => {}
 565             }
 566         }
 567
 568         match res.value {
 569             Some((mark, expansion)) => {
 570                 self.source_map.expansions.insert(macro_call, self.expander.current_file_id);
 571
 572                 let id = collector(self, Some(expansion));
 573                 self.expander.exit(self.db, mark);
 574                 id
 575             }
 576             None => collector(self, None),
 577         }
 578     }
 579
 580     fn collect_expr_opt(&mut self, expr: Option<ast::Expr>) -> ExprId {
 581         match expr {
 582             Some(expr) => self.collect_expr(expr),
 583             None => self.missing_expr(),
 584         }
 585     }
 586
 587     fn collect_stmt(&mut self, s: ast::Stmt) {
 588         match s {
 589             ast::Stmt::LetStmt(stmt) => {
 590                 if self.check_cfg(&stmt).is_none() {
 591                     return;
 592                 }
 593                 let pat = self.collect_pat_opt(stmt.pat());
 594                 let type_ref =
 595                     stmt.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
 596                 let initializer = stmt.initializer().map(|e| self.collect_expr(e));
 597                 let else_branch = stmt
 598                     .let_else()
 599                     .and_then(|let_else| let_else.block_expr())
 600                     .map(|block| self.collect_block(block));
 601                 self.statements_in_scope.push(Statement::Let {
 602                     pat,
 603                     type_ref,
 604                     initializer,
 605                     else_branch,
 606                 });
 607             }
 608             ast::Stmt::ExprStmt(stmt) => {
 609                 if let Some(expr) = stmt.expr() {
 610                     if self.check_cfg(&expr).is_none() {
 611                         return;
 612                     }
 613                 }
 614                 let has_semi = stmt.semicolon_token().is_some();
 615                 // Note that macro could be expended to multiple statements
 616                 if let Some(ast::Expr::MacroCall(m)) = stmt.expr() {
 617                     let macro_ptr = AstPtr::new(&m);
 618                     let syntax_ptr = AstPtr::new(&stmt.expr().unwrap());
 619
 620                     self.collect_macro_call(
 621                         m,
 622                         macro_ptr,
 623                         false,
 624                         |this, expansion| match expansion {
 625                             Some(expansion) => {
 626                                 let statements: ast::MacroStmts = expansion;
 627
 628                                 statements.statements().for_each(|stmt| this.collect_stmt(stmt));
 629                                 if let Some(expr) = statements.expr() {
 630                                     let expr = this.collect_expr(expr);
 631                                     this.statements_in_scope
 632                                         .push(Statement::Expr { expr, has_semi });
 633                                 }
 634                             }
 635                             None => {
 636                                 let expr = this.alloc_expr(Expr::Missing, syntax_ptr.clone());
 637                                 this.statements_in_scope.push(Statement::Expr { expr, has_semi });
 638                             }
 639                         },
 640                     );
 641                 } else {
 642                     let expr = self.collect_expr_opt(stmt.expr());
 643                     self.statements_in_scope.push(Statement::Expr { expr, has_semi });
 644                 }
 645             }
 646             ast::Stmt::Item(_item) => {}
 647         }
 648     }
 649
 650     fn collect_block(&mut self, block: ast::BlockExpr) -> ExprId {
 651         let ast_id = self.expander.ast_id(&block);
 652         let block_loc =
 653             BlockLoc { ast_id, module: self.expander.def_map.module_id(self.expander.module) };
 654         let block_id = self.db.intern_block(block_loc);
 655
 656         let (module, def_map) = match self.db.block_def_map(block_id) {
 657             Some(def_map) => {
 658                 self.body.block_scopes.push(block_id);
 659                 (def_map.root(), def_map)
 660             }
 661             None => (self.expander.module, self.expander.def_map.clone()),
 662         };
 663         let prev_def_map = mem::replace(&mut self.expander.def_map, def_map);
 664         let prev_local_module = mem::replace(&mut self.expander.module, module);
 665         let prev_statements = std::mem::take(&mut self.statements_in_scope);
 666
 667         block.statements().for_each(|s| self.collect_stmt(s));
 668         block.tail_expr().and_then(|e| {
 669             let expr = self.maybe_collect_expr(e)?;
 670             self.statements_in_scope.push(Statement::Expr { expr, has_semi: false });
 671             Some(())
 672         });
 673
 674         let mut tail = None;
 675         if let Some(Statement::Expr { expr, has_semi: false }) = self.statements_in_scope.last() {
 676             tail = Some(*expr);
 677             self.statements_in_scope.pop();
 678         }
 679         let tail = tail;
 680         let statements = std::mem::replace(&mut self.statements_in_scope, prev_statements).into();
 681         let syntax_node_ptr = AstPtr::new(&block.into());
 682         let expr_id = self.alloc_expr(
 683             Expr::Block { id: block_id, statements, tail, label: None },
 684             syntax_node_ptr,
 685         );
 686
 687         self.expander.def_map = prev_def_map;
 688         self.expander.module = prev_local_module;
 689         expr_id
 690     }
 691
 692     fn collect_block_opt(&mut self, expr: Option<ast::BlockExpr>) -> ExprId {
 693         match expr {
 694             Some(block) => self.collect_block(block),
 695             None => self.missing_expr(),
 696         }
 697     }
 698
 699     fn collect_label(&mut self, ast_label: ast::Label) -> LabelId {
 700         let label = Label {
 701             name: ast_label.lifetime().as_ref().map_or_else(Name::missing, Name::new_lifetime),
 702         };
 703         self.alloc_label(label, AstPtr::new(&ast_label))
 704     }
 705
 706     fn collect_pat(&mut self, pat: ast::Pat) -> PatId {
 707         let pattern = match &pat {
 708             ast::Pat::IdentPat(bp) => {
 709                 let name = bp.name().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
 710                 let annotation =
 711                     BindingAnnotation::new(bp.mut_token().is_some(), bp.ref_token().is_some());
 712                 let subpat = bp.pat().map(|subpat| self.collect_pat(subpat));
 713                 if annotation == BindingAnnotation::Unannotated && subpat.is_none() {
 714                     // This could also be a single-segment path pattern. To
 715                     // decide that, we need to try resolving the name.
 716                     let (resolved, _) = self.expander.def_map.resolve_path(
 717                         self.db,
 718                         self.expander.module,
 719                         &name.clone().into(),
 720                         BuiltinShadowMode::Other,
 721                     );
 722                     match resolved.take_values() {
 723                         Some(ModuleDefId::ConstId(_)) => Pat::Path(name.into()),
 724                         Some(ModuleDefId::EnumVariantId(_)) => {
 725                             // this is only really valid for unit variants, but
 726                             // shadowing other enum variants with a pattern is
 727                             // an error anyway
 728                             Pat::Path(name.into())
 729                         }
 730                         Some(ModuleDefId::AdtId(AdtId::StructId(s)))
 731                             if self.db.struct_data(s).variant_data.kind() != StructKind::Record =>
 732                         {
 733                             // Funnily enough, record structs *can* be shadowed
 734                             // by pattern bindings (but unit or tuple structs
 735                             // can't).
 736                             Pat::Path(name.into())
 737                         }
 738                         // shadowing statics is an error as well, so we just ignore that case here
 739                         _ => Pat::Bind { name, mode: annotation, subpat },
 740                     }
 741                 } else {
 742                     Pat::Bind { name, mode: annotation, subpat }
 743                 }
 744             }
 745             ast::Pat::TupleStructPat(p) => {
 746                 let path =
 747                     p.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
 748                 let (args, ellipsis) = self.collect_tuple_pat(p.fields());
 749                 Pat::TupleStruct { path, args, ellipsis }
 750             }
 751             ast::Pat::RefPat(p) => {
 752                 let pat = self.collect_pat_opt(p.pat());
 753                 let mutability = Mutability::from_mutable(p.mut_token().is_some());
 754                 Pat::Ref { pat, mutability }
 755             }
 756             ast::Pat::PathPat(p) => {
 757                 let path =
 758                     p.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
 759                 path.map(Pat::Path).unwrap_or(Pat::Missing)
 760             }
 761             ast::Pat::OrPat(p) => {
 762                 let pats = p.pats().map(|p| self.collect_pat(p)).collect();
 763                 Pat::Or(pats)
 764             }
 765             ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat()),
 766             ast::Pat::TuplePat(p) => {
 767                 let (args, ellipsis) = self.collect_tuple_pat(p.fields());
 768                 Pat::Tuple { args, ellipsis }
 769             }
 770             ast::Pat::WildcardPat(_) => Pat::Wild,
 771             ast::Pat::RecordPat(p) => {
 772                 let path =
 773                     p.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
 774                 let args = p
 775                     .record_pat_field_list()
 776                     .expect("every struct should have a field list")
 777                     .fields()
 778                     .filter_map(|f| {
 779                         let ast_pat = f.pat()?;
 780                         let pat = self.collect_pat(ast_pat);
 781                         let name = f.field_name()?.as_name();
 782                         Some(RecordFieldPat { name, pat })
 783                     })
 784                     .collect();
 785
 786                 let ellipsis = p
 787                     .record_pat_field_list()
 788                     .expect("every struct should have a field list")
 789                     .rest_pat()
 790                     .is_some();
 791
 792                 Pat::Record { path, args, ellipsis }
 793             }
 794             ast::Pat::SlicePat(p) => {
 795                 let SlicePatComponents { prefix, slice, suffix } = p.components();
 796
 797                 // FIXME properly handle `RestPat`
 798                 Pat::Slice {
 799                     prefix: prefix.into_iter().map(|p| self.collect_pat(p)).collect(),
 800                     slice: slice.map(|p| self.collect_pat(p)),
 801                     suffix: suffix.into_iter().map(|p| self.collect_pat(p)).collect(),
 802                 }
 803             }
 804             ast::Pat::LiteralPat(lit) => {
 805                 if let Some(ast_lit) = lit.literal() {
 806                     let expr = Expr::Literal(ast_lit.kind().into());
 807                     let expr_ptr = AstPtr::new(&ast::Expr::Literal(ast_lit));
 808                     let expr_id = self.alloc_expr(expr, expr_ptr);
 809                     Pat::Lit(expr_id)
 810                 } else {
 811                     Pat::Missing
 812                 }
 813             }
 814             ast::Pat::RestPat(_) => {
 815                 // `RestPat` requires special handling and should not be mapped
 816                 // to a Pat. Here we are using `Pat::Missing` as a fallback for
 817                 // when `RestPat` is mapped to `Pat`, which can easily happen
 818                 // when the source code being analyzed has a malformed pattern
 819                 // which includes `..` in a place where it isn't valid.
 820
 821                 Pat::Missing
 822             }
 823             ast::Pat::BoxPat(boxpat) => {
 824                 let inner = self.collect_pat_opt(boxpat.pat());
 825                 Pat::Box { inner }
 826             }
 827             ast::Pat::ConstBlockPat(const_block_pat) => {
 828                 if let Some(expr) = const_block_pat.block_expr() {
 829                     let expr_id = self.collect_block(expr);
 830                     Pat::ConstBlock(expr_id)
 831                 } else {
 832                     Pat::Missing
 833                 }
 834             }
 835             ast::Pat::MacroPat(mac) => match mac.macro_call() {
 836                 Some(call) => {
 837                     let macro_ptr = AstPtr::new(&call);
 838                     let mut pat = None;
 839                     self.collect_macro_call(call, macro_ptr, true, |this, expanded_pat| {
 840                         pat = Some(this.collect_pat_opt(expanded_pat));
 841                     });
 842
 843                     match pat {
 844                         Some(pat) => return pat,
 845                         None => Pat::Missing,
 846                     }
 847                 }
 848                 None => Pat::Missing,
 849             },
 850             // FIXME: implement
 851             ast::Pat::RangePat(_) => Pat::Missing,
 852         };
 853         let ptr = AstPtr::new(&pat);
 854         self.alloc_pat(pattern, Either::Left(ptr))
 855     }
 856
 857     fn collect_pat_opt(&mut self, pat: Option<ast::Pat>) -> PatId {
 858         match pat {
 859             Some(pat) => self.collect_pat(pat),
 860             None => self.missing_pat(),
 861         }
 862     }
 863
 864     fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Box<[PatId]>, Option<usize>) {
 865         // Find the location of the `..`, if there is one. Note that we do not
 866         // consider the possibility of there being multiple `..` here.
 867         let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::RestPat(_)));
 868         // We want to skip the `..` pattern here, since we account for it above.
 869         let args = args
 870             .filter(|p| !matches!(p, ast::Pat::RestPat(_)))
 871             .map(|p| self.collect_pat(p))
 872             .collect();
 873
 874         (args, ellipsis)
 875     }
 876
 877     /// Returns `None` (and emits diagnostics) when `owner` if `#[cfg]`d out, and `Some(())` when
 878     /// not.
 879     fn check_cfg(&mut self, owner: &dyn ast::HasAttrs) -> Option<()> {
 880         match self.expander.parse_attrs(self.db, owner).cfg() {
 881             Some(cfg) => {
 882                 if self.expander.cfg_options().check(&cfg) != Some(false) {
 883                     return Some(());
 884                 }
 885
 886                 self.source_map.diagnostics.push(BodyDiagnostic::InactiveCode {
 887                     node: InFile::new(
 888                         self.expander.current_file_id,
 889                         SyntaxNodePtr::new(owner.syntax()),
 890                     ),
 891                     cfg,
 892                     opts: self.expander.cfg_options().clone(),
 893                 });
 894
 895                 None
 896             }
 897             None => Some(()),
 898         }
 899     }
 900 }
 901
 902 impl From<ast::LiteralKind> for Literal {
 903     fn from(ast_lit_kind: ast::LiteralKind) -> Self {
 904         match ast_lit_kind {
 905             // FIXME: these should have actual values filled in, but unsure on perf impact
 906             LiteralKind::IntNumber(lit) => {
 907                 if let builtin @ Some(_) = lit.suffix().and_then(BuiltinFloat::from_suffix) {
 908                     Literal::Float(Default::default(), builtin)
 909                 } else if let builtin @ Some(_) =
 910                     lit.suffix().and_then(|it| BuiltinInt::from_suffix(it))
 911                 {
 912                     Literal::Int(lit.value().unwrap_or(0) as i128, builtin)
 913                 } else {
 914                     let builtin = lit.suffix().and_then(|it| BuiltinUint::from_suffix(it));
 915                     Literal::Uint(lit.value().unwrap_or(0), builtin)
 916                 }
 917             }
 918             LiteralKind::FloatNumber(lit) => {
 919                 let ty = lit.suffix().and_then(|it| BuiltinFloat::from_suffix(it));
 920                 Literal::Float(Default::default(), ty)
 921             }
 922             LiteralKind::ByteString(bs) => {
 923                 let text = bs.value().map(Box::from).unwrap_or_else(Default::default);
 924                 Literal::ByteString(text)
 925             }
 926             LiteralKind::String(_) => Literal::String(Default::default()),
 927             LiteralKind::Byte => Literal::Uint(Default::default(), Some(BuiltinUint::U8)),
 928             LiteralKind::Bool(val) => Literal::Bool(val),
 929             LiteralKind::Char => Literal::Char(Default::default()),
 930         }
 931     }
 932 }