1use std::assert_matches::assert_matches;
2use std::ops::ControlFlow;
3use std::sync::Arc;
4
5use rustc_ast::ptr::P as AstP;
6use rustc_ast::*;
7use rustc_ast_pretty::pprust::expr_to_string;
8use rustc_data_structures::stack::ensure_sufficient_stack;
9use rustc_hir as hir;
10use rustc_hir::HirId;
11use rustc_hir::def::{DefKind, Res};
12use rustc_middle::span_bug;
13use rustc_middle::ty::TyCtxt;
14use rustc_session::errors::report_lit_error;
15use rustc_span::source_map::{Spanned, respan};
16use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
17use thin_vec::{ThinVec, thin_vec};
18use visit::{Visitor, walk_expr};
19
20use super::errors::{
21 AsyncCoroutinesNotSupported, AwaitOnlyInAsyncFnAndBlocks, ClosureCannotBeStatic,
22 CoroutineTooManyParameters, FunctionalRecordUpdateDestructuringAssignment,
23 InclusiveRangeWithNoEnd, MatchArmWithNoBody, NeverPatternWithBody, NeverPatternWithGuard,
24 UnderscoreExprLhsAssign,
25};
26use super::{
27 GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
28};
29use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
30use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, fluent_generated};
31
32struct WillCreateDefIdsVisitor {}
33
34impl<'v> rustc_ast::visit::Visitor<'v> for WillCreateDefIdsVisitor {
35 type Result = ControlFlow<Span>;
36
37 fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
38 ControlFlow::Break(c.value.span)
39 }
40
41 fn visit_item(&mut self, item: &'v Item) -> Self::Result {
42 ControlFlow::Break(item.span)
43 }
44
45 fn visit_expr(&mut self, ex: &'v Expr) -> Self::Result {
46 match ex.kind {
47 ExprKind::Gen(..) | ExprKind::ConstBlock(..) | ExprKind::Closure(..) => {
48 ControlFlow::Break(ex.span)
49 }
50 _ => walk_expr(self, ex),
51 }
52 }
53}
54
55impl<'hir> LoweringContext<'_, 'hir> {
56 fn lower_exprs(&mut self, exprs: &[AstP<Expr>]) -> &'hir [hir::Expr<'hir>] {
57 self.arena.alloc_from_iter(exprs.iter().map(|x| self.lower_expr_mut(x)))
58 }
59
60 pub(super) fn lower_expr(&mut self, e: &Expr) -> &'hir hir::Expr<'hir> {
61 self.arena.alloc(self.lower_expr_mut(e))
62 }
63
64 pub(super) fn lower_expr_mut(&mut self, e: &Expr) -> hir::Expr<'hir> {
65 ensure_sufficient_stack(|| {
66 match &e.kind {
67 ExprKind::Paren(ex) => {
69 let mut ex = self.lower_expr_mut(ex);
70 if e.span.contains(ex.span) {
72 ex.span = self.lower_span(e.span);
73 }
74 if !e.attrs.is_empty() {
76 let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
77 let attrs = &*self.arena.alloc_from_iter(
78 self.lower_attrs_vec(&e.attrs, e.span)
79 .into_iter()
80 .chain(old_attrs.iter().cloned()),
81 );
82 if attrs.is_empty() {
83 return ex;
84 }
85
86 self.attrs.insert(ex.hir_id.local_id, attrs);
87 }
88 return ex;
89 }
90 ExprKind::ForLoop { pat, iter, body, label, kind } => {
96 return self.lower_expr_for(e, pat, iter, body, *label, *kind);
97 }
98 _ => (),
99 }
100
101 let expr_hir_id = self.lower_node_id(e.id);
102 self.lower_attrs(expr_hir_id, &e.attrs, e.span);
103
104 let kind = match &e.kind {
105 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
106 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
107 ExprKind::Repeat(expr, count) => {
108 let expr = self.lower_expr(expr);
109 let count = self.lower_array_length_to_const_arg(count);
110 hir::ExprKind::Repeat(expr, count)
111 }
112 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
113 ExprKind::Call(f, args) => {
114 if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) {
115 self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
116 } else {
117 let f = self.lower_expr(f);
118 hir::ExprKind::Call(f, self.lower_exprs(args))
119 }
120 }
121 ExprKind::MethodCall(box MethodCall { seg, receiver, args, span }) => {
122 let hir_seg = self.arena.alloc(self.lower_path_segment(
123 e.span,
124 seg,
125 ParamMode::Optional,
126 GenericArgsMode::Err,
127 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
128 None,
130 ));
131 let receiver = self.lower_expr(receiver);
132 let args =
133 self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
134 hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(*span))
135 }
136 ExprKind::Binary(binop, lhs, rhs) => {
137 let binop = self.lower_binop(*binop);
138 let lhs = self.lower_expr(lhs);
139 let rhs = self.lower_expr(rhs);
140 hir::ExprKind::Binary(binop, lhs, rhs)
141 }
142 ExprKind::Unary(op, ohs) => {
143 let op = self.lower_unop(*op);
144 let ohs = self.lower_expr(ohs);
145 hir::ExprKind::Unary(op, ohs)
146 }
147 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
148 ExprKind::IncludedBytes(bytes) => {
149 let lit = self.arena.alloc(respan(
150 self.lower_span(e.span),
151 LitKind::ByteStr(Arc::clone(bytes), StrStyle::Cooked),
152 ));
153 hir::ExprKind::Lit(lit)
154 }
155 ExprKind::Cast(expr, ty) => {
156 let expr = self.lower_expr(expr);
157 let ty =
158 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
159 hir::ExprKind::Cast(expr, ty)
160 }
161 ExprKind::Type(expr, ty) => {
162 let expr = self.lower_expr(expr);
163 let ty =
164 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
165 hir::ExprKind::Type(expr, ty)
166 }
167 ExprKind::AddrOf(k, m, ohs) => {
168 let ohs = self.lower_expr(ohs);
169 hir::ExprKind::AddrOf(*k, *m, ohs)
170 }
171 ExprKind::Let(pat, scrutinee, span, recovered) => {
172 hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
173 span: self.lower_span(*span),
174 pat: self.lower_pat(pat),
175 ty: None,
176 init: self.lower_expr(scrutinee),
177 recovered: *recovered,
178 }))
179 }
180 ExprKind::If(cond, then, else_opt) => {
181 self.lower_expr_if(cond, then, else_opt.as_deref())
182 }
183 ExprKind::While(cond, body, opt_label) => {
184 self.with_loop_scope(expr_hir_id, |this| {
185 let span =
186 this.mark_span_with_reason(DesugaringKind::WhileLoop, e.span, None);
187 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
188 this.lower_expr_while_in_loop_scope(span, cond, body, opt_label)
189 })
190 }
191 ExprKind::Loop(body, opt_label, span) => {
192 self.with_loop_scope(expr_hir_id, |this| {
193 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
194 hir::ExprKind::Loop(
195 this.lower_block(body, false),
196 opt_label,
197 hir::LoopSource::Loop,
198 this.lower_span(*span),
199 )
200 })
201 }
202 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
203 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
204 self.lower_expr(expr),
205 self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
206 match kind {
207 MatchKind::Prefix => hir::MatchSource::Normal,
208 MatchKind::Postfix => hir::MatchSource::Postfix,
209 },
210 ),
211 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
212 ExprKind::Use(expr, use_kw_span) => self.lower_expr_use(*use_kw_span, expr),
213 ExprKind::Closure(box Closure {
214 binder,
215 capture_clause,
216 constness,
217 coroutine_kind,
218 movability,
219 fn_decl,
220 body,
221 fn_decl_span,
222 fn_arg_span,
223 }) => match coroutine_kind {
224 Some(coroutine_kind) => self.lower_expr_coroutine_closure(
225 binder,
226 *capture_clause,
227 e.id,
228 expr_hir_id,
229 *coroutine_kind,
230 fn_decl,
231 body,
232 *fn_decl_span,
233 *fn_arg_span,
234 ),
235 None => self.lower_expr_closure(
236 binder,
237 *capture_clause,
238 e.id,
239 expr_hir_id,
240 *constness,
241 *movability,
242 fn_decl,
243 body,
244 *fn_decl_span,
245 *fn_arg_span,
246 ),
247 },
248 ExprKind::Gen(capture_clause, block, genblock_kind, decl_span) => {
249 let desugaring_kind = match genblock_kind {
250 GenBlockKind::Async => hir::CoroutineDesugaring::Async,
251 GenBlockKind::Gen => hir::CoroutineDesugaring::Gen,
252 GenBlockKind::AsyncGen => hir::CoroutineDesugaring::AsyncGen,
253 };
254 self.make_desugared_coroutine_expr(
255 *capture_clause,
256 e.id,
257 None,
258 *decl_span,
259 e.span,
260 desugaring_kind,
261 hir::CoroutineSource::Block,
262 |this| this.with_new_scopes(e.span, |this| this.lower_block_expr(block)),
263 )
264 }
265 ExprKind::Block(blk, opt_label) => {
266 let block_hir_id = self.lower_node_id(blk.id);
269 let opt_label = self.lower_label(*opt_label, blk.id, block_hir_id);
270 let hir_block = self.arena.alloc(self.lower_block_noalloc(
271 block_hir_id,
272 blk,
273 opt_label.is_some(),
274 ));
275 hir::ExprKind::Block(hir_block, opt_label)
276 }
277 ExprKind::Assign(el, er, span) => self.lower_expr_assign(el, er, *span, e.span),
278 ExprKind::AssignOp(op, el, er) => hir::ExprKind::AssignOp(
279 self.lower_assign_op(*op),
280 self.lower_expr(el),
281 self.lower_expr(er),
282 ),
283 ExprKind::Field(el, ident) => {
284 hir::ExprKind::Field(self.lower_expr(el), self.lower_ident(*ident))
285 }
286 ExprKind::Index(el, er, brackets_span) => {
287 hir::ExprKind::Index(self.lower_expr(el), self.lower_expr(er), *brackets_span)
288 }
289 ExprKind::Range(e1, e2, lims) => {
290 self.lower_expr_range(e.span, e1.as_deref(), e2.as_deref(), *lims)
291 }
292 ExprKind::Underscore => {
293 let guar = self.dcx().emit_err(UnderscoreExprLhsAssign { span: e.span });
294 hir::ExprKind::Err(guar)
295 }
296 ExprKind::Path(qself, path) => {
297 let qpath = self.lower_qpath(
298 e.id,
299 qself,
300 path,
301 ParamMode::Optional,
302 AllowReturnTypeNotation::No,
303 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
304 None,
305 );
306 hir::ExprKind::Path(qpath)
307 }
308 ExprKind::Break(opt_label, opt_expr) => {
309 let opt_expr = opt_expr.as_ref().map(|x| self.lower_expr(x));
310 hir::ExprKind::Break(self.lower_jump_destination(e.id, *opt_label), opt_expr)
311 }
312 ExprKind::Continue(opt_label) => {
313 hir::ExprKind::Continue(self.lower_jump_destination(e.id, *opt_label))
314 }
315 ExprKind::Ret(e) => {
316 let expr = e.as_ref().map(|x| self.lower_expr(x));
317 self.checked_return(expr)
318 }
319 ExprKind::Yeet(sub_expr) => self.lower_expr_yeet(e.span, sub_expr.as_deref()),
320 ExprKind::Become(sub_expr) => {
321 let sub_expr = self.lower_expr(sub_expr);
322 hir::ExprKind::Become(sub_expr)
323 }
324 ExprKind::InlineAsm(asm) => {
325 hir::ExprKind::InlineAsm(self.lower_inline_asm(e.span, asm))
326 }
327 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
328 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
329 self.lower_ty(
330 container,
331 ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
332 ),
333 self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
334 ),
335 ExprKind::Struct(se) => {
336 let rest = match &se.rest {
337 StructRest::Base(e) => hir::StructTailExpr::Base(self.lower_expr(e)),
338 StructRest::Rest(sp) => hir::StructTailExpr::DefaultFields(*sp),
339 StructRest::None => hir::StructTailExpr::None,
340 };
341 hir::ExprKind::Struct(
342 self.arena.alloc(self.lower_qpath(
343 e.id,
344 &se.qself,
345 &se.path,
346 ParamMode::Optional,
347 AllowReturnTypeNotation::No,
348 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
349 None,
350 )),
351 self.arena
352 .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
353 rest,
354 )
355 }
356 ExprKind::Yield(kind) => self.lower_expr_yield(e.span, kind.expr().map(|x| &**x)),
357 ExprKind::Err(guar) => hir::ExprKind::Err(*guar),
358
359 ExprKind::UnsafeBinderCast(kind, expr, ty) => hir::ExprKind::UnsafeBinderCast(
360 *kind,
361 self.lower_expr(expr),
362 ty.as_ref().map(|ty| {
363 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
364 }),
365 ),
366
367 ExprKind::Dummy => {
368 span_bug!(e.span, "lowered ExprKind::Dummy")
369 }
370
371 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
372
373 ExprKind::Paren(_) | ExprKind::ForLoop { .. } => {
374 unreachable!("already handled")
375 }
376
377 ExprKind::MacCall(_) => panic!("{:?} shouldn't exist here", e.span),
378 };
379
380 hir::Expr { hir_id: expr_hir_id, kind, span: self.lower_span(e.span) }
381 })
382 }
383
384 fn checked_return(&mut self, opt_expr: Option<&'hir hir::Expr<'hir>>) -> hir::ExprKind<'hir> {
387 let checked_ret =
388 if let Some((check_span, check_ident, check_hir_id)) = self.contract_ensures {
389 let expr = opt_expr.unwrap_or_else(|| self.expr_unit(check_span));
390 Some(self.inject_ensures_check(expr, check_span, check_ident, check_hir_id))
391 } else {
392 opt_expr
393 };
394 hir::ExprKind::Ret(checked_ret)
395 }
396
397 pub(crate) fn inject_ensures_check(
399 &mut self,
400 expr: &'hir hir::Expr<'hir>,
401 span: Span,
402 cond_ident: Ident,
403 cond_hir_id: HirId,
404 ) -> &'hir hir::Expr<'hir> {
405 let cond_fn = self.expr_ident(span, cond_ident, cond_hir_id);
406 let call_expr = self.expr_call_lang_item_fn_mut(
407 span,
408 hir::LangItem::ContractCheckEnsures,
409 arena_vec![self; *cond_fn, *expr],
410 );
411 self.arena.alloc(call_expr)
412 }
413
414 pub(crate) fn lower_const_block(&mut self, c: &AnonConst) -> hir::ConstBlock {
415 self.with_new_scopes(c.value.span, |this| {
416 let def_id = this.local_def_id(c.id);
417 hir::ConstBlock {
418 def_id,
419 hir_id: this.lower_node_id(c.id),
420 body: this.lower_const_body(c.value.span, Some(&c.value)),
421 }
422 })
423 }
424
425 pub(crate) fn lower_lit(
426 &mut self,
427 token_lit: &token::Lit,
428 span: Span,
429 ) -> &'hir Spanned<LitKind> {
430 let lit_kind = match LitKind::from_token_lit(*token_lit) {
431 Ok(lit_kind) => lit_kind,
432 Err(err) => {
433 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
434 LitKind::Err(guar)
435 }
436 };
437 self.arena.alloc(respan(self.lower_span(span), lit_kind))
438 }
439
440 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
441 match u {
442 UnOp::Deref => hir::UnOp::Deref,
443 UnOp::Not => hir::UnOp::Not,
444 UnOp::Neg => hir::UnOp::Neg,
445 }
446 }
447
448 fn lower_binop(&mut self, b: BinOp) -> BinOp {
449 Spanned { node: b.node, span: self.lower_span(b.span) }
450 }
451
452 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
453 Spanned { node: a.node, span: self.lower_span(a.span) }
454 }
455
456 fn lower_legacy_const_generics(
457 &mut self,
458 mut f: Expr,
459 args: ThinVec<AstP<Expr>>,
460 legacy_args_idx: &[usize],
461 ) -> hir::ExprKind<'hir> {
462 let ExprKind::Path(None, path) = &mut f.kind else {
463 unreachable!();
464 };
465
466 let mut error = None;
467 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
468 if error.is_none() {
470 let mut const_args = vec![];
471 let mut other_args = vec![];
472 for (idx, arg) in args.iter().enumerate() {
473 if legacy_args_idx.contains(&idx) {
474 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
475 } else {
476 other_args.push(expr_to_string(arg));
477 }
478 }
479 let suggestion = UseConstGenericArg {
480 end_of_fn: f.span.shrink_to_hi(),
481 const_args: const_args.join(", "),
482 other_args: other_args.join(", "),
483 call_args: args[0].span.to(args.last().unwrap().span),
484 };
485 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
486 }
487 error.unwrap()
488 };
489
490 let mut real_args = vec![];
492 let mut generic_args = ThinVec::new();
493 for (idx, arg) in args.iter().cloned().enumerate() {
494 if legacy_args_idx.contains(&idx) {
495 let node_id = self.next_node_id();
496 self.create_def(node_id, None, DefKind::AnonConst, f.span);
497 let mut visitor = WillCreateDefIdsVisitor {};
498 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
499 AstP(Expr {
500 id: self.next_node_id(),
501 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
502 span: f.span,
503 attrs: [].into(),
504 tokens: None,
505 })
506 } else {
507 arg
508 };
509
510 let anon_const = AnonConst { id: node_id, value: const_value };
511 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
512 } else {
513 real_args.push(arg);
514 }
515 }
516
517 let last_segment = path.segments.last_mut().unwrap();
519 assert!(last_segment.args.is_none());
520 last_segment.args = Some(AstP(GenericArgs::AngleBracketed(AngleBracketedArgs {
521 span: DUMMY_SP,
522 args: generic_args,
523 })));
524
525 let f = self.lower_expr(&f);
527 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
528 }
529
530 fn lower_expr_if(
531 &mut self,
532 cond: &Expr,
533 then: &Block,
534 else_opt: Option<&Expr>,
535 ) -> hir::ExprKind<'hir> {
536 let lowered_cond = self.lower_cond(cond);
537 let then_expr = self.lower_block_expr(then);
538 if let Some(rslt) = else_opt {
539 hir::ExprKind::If(
540 lowered_cond,
541 self.arena.alloc(then_expr),
542 Some(self.lower_expr(rslt)),
543 )
544 } else {
545 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
546 }
547 }
548
549 fn lower_cond(&mut self, cond: &Expr) -> &'hir hir::Expr<'hir> {
552 fn has_let_expr(expr: &Expr) -> bool {
553 match &expr.kind {
554 ExprKind::Binary(_, lhs, rhs) => has_let_expr(lhs) || has_let_expr(rhs),
555 ExprKind::Let(..) => true,
556 _ => false,
557 }
558 }
559
560 match &cond.kind {
568 ExprKind::Binary(op @ Spanned { node: ast::BinOpKind::And, .. }, lhs, rhs)
569 if has_let_expr(cond) =>
570 {
571 let op = self.lower_binop(*op);
572 let lhs = self.lower_cond(lhs);
573 let rhs = self.lower_cond(rhs);
574
575 self.arena.alloc(self.expr(cond.span, hir::ExprKind::Binary(op, lhs, rhs)))
576 }
577 ExprKind::Let(..) => self.lower_expr(cond),
578 _ => {
579 let cond = self.lower_expr(cond);
580 let reason = DesugaringKind::CondTemporary;
581 let span_block = self.mark_span_with_reason(reason, cond.span, None);
582 self.expr_drop_temps(span_block, cond)
583 }
584 }
585 }
586
587 fn lower_expr_while_in_loop_scope(
604 &mut self,
605 span: Span,
606 cond: &Expr,
607 body: &Block,
608 opt_label: Option<Label>,
609 ) -> hir::ExprKind<'hir> {
610 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_cond(cond));
611 let then = self.lower_block_expr(body);
612 let expr_break = self.expr_break(span);
613 let stmt_break = self.stmt_expr(span, expr_break);
614 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
615 let else_expr = self.arena.alloc(self.expr_block(else_blk));
616 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
617 let if_expr = self.expr(span, if_kind);
618 let block = self.block_expr(self.arena.alloc(if_expr));
619 let span = self.lower_span(span.with_hi(cond.span.hi()));
620 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
621 }
622
623 fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
627 let body_hir_id = self.lower_node_id(body.id);
628 self.with_catch_scope(body_hir_id, |this| {
629 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
630
631 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
633 (
634 this.mark_span_with_reason(
635 DesugaringKind::TryBlock,
636 expr.span,
637 Some(Arc::clone(&this.allow_try_trait)),
638 ),
639 expr,
640 )
641 } else {
642 let try_span = this.mark_span_with_reason(
643 DesugaringKind::TryBlock,
644 this.tcx.sess.source_map().end_point(body.span),
645 Some(Arc::clone(&this.allow_try_trait)),
646 );
647
648 (try_span, this.expr_unit(try_span))
649 };
650
651 let ok_wrapped_span =
652 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
653
654 block.expr = Some(this.wrap_in_try_constructor(
656 hir::LangItem::TryTraitFromOutput,
657 try_span,
658 tail_expr,
659 ok_wrapped_span,
660 ));
661
662 hir::ExprKind::Block(this.arena.alloc(block), None)
663 })
664 }
665
666 fn wrap_in_try_constructor(
667 &mut self,
668 lang_item: hir::LangItem,
669 method_span: Span,
670 expr: &'hir hir::Expr<'hir>,
671 overall_span: Span,
672 ) -> &'hir hir::Expr<'hir> {
673 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
674 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
675 }
676
677 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
678 let pat = self.lower_pat(&arm.pat);
679 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
680 let hir_id = self.next_id();
681 let span = self.lower_span(arm.span);
682 self.lower_attrs(hir_id, &arm.attrs, arm.span);
683 let is_never_pattern = pat.is_never_pattern();
684 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
687 let body = if let Some(body) = body
688 && !is_never_pattern
689 {
690 body
691 } else {
692 if !is_never_pattern {
694 if self.tcx.features().never_patterns() {
695 let suggestion = span.shrink_to_hi();
697 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
698 }
699 } else if let Some(body) = &arm.body {
700 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
701 } else if let Some(g) = &arm.guard {
702 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
703 }
704
705 let block = self.arena.alloc(hir::Block {
708 stmts: &[],
709 expr: None,
710 hir_id: self.next_id(),
711 rules: hir::BlockCheckMode::DefaultBlock,
712 span,
713 targeted_by_break: false,
714 });
715 self.arena.alloc(hir::Expr {
716 hir_id: self.next_id(),
717 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
718 span,
719 })
720 };
721 hir::Arm { hir_id, pat, guard, body, span }
722 }
723
724 pub(super) fn make_desugared_coroutine_expr(
736 &mut self,
737 capture_clause: CaptureBy,
738 closure_node_id: NodeId,
739 return_ty: Option<hir::FnRetTy<'hir>>,
740 fn_decl_span: Span,
741 span: Span,
742 desugaring_kind: hir::CoroutineDesugaring,
743 coroutine_source: hir::CoroutineSource,
744 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
745 ) -> hir::ExprKind<'hir> {
746 let closure_def_id = self.local_def_id(closure_node_id);
747 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
748
749 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
752 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
753 let unstable_span = self.mark_span_with_reason(
755 DesugaringKind::Async,
756 self.lower_span(span),
757 Some(Arc::clone(&self.allow_gen_future)),
758 );
759 let resume_ty =
760 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
761 let input_ty = hir::Ty {
762 hir_id: self.next_id(),
763 kind: hir::TyKind::Path(resume_ty),
764 span: unstable_span,
765 };
766 let inputs = arena_vec![self; input_ty];
767
768 let (pat, task_context_hid) = self.pat_ident_binding_mode(
770 span,
771 Ident::with_dummy_span(sym::_task_context),
772 hir::BindingMode::MUT,
773 );
774 let param = hir::Param {
775 hir_id: self.next_id(),
776 pat,
777 ty_span: self.lower_span(span),
778 span: self.lower_span(span),
779 };
780 let params = arena_vec![self; param];
781
782 (inputs, params, Some(task_context_hid))
783 }
784 hir::CoroutineDesugaring::Gen => (&[], &[], None),
785 };
786
787 let output =
788 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
789
790 let fn_decl = self.arena.alloc(hir::FnDecl {
791 inputs,
792 output,
793 c_variadic: false,
794 implicit_self: hir::ImplicitSelfKind::None,
795 lifetime_elision_allowed: false,
796 });
797
798 let body = self.lower_body(move |this| {
799 this.coroutine_kind = Some(coroutine_kind);
800
801 let old_ctx = this.task_context;
802 if task_context.is_some() {
803 this.task_context = task_context;
804 }
805 let res = body(this);
806 this.task_context = old_ctx;
807
808 (params, res)
809 });
810
811 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
813 def_id: closure_def_id,
814 binder: hir::ClosureBinder::Default,
815 capture_clause,
816 bound_generic_params: &[],
817 fn_decl,
818 body,
819 fn_decl_span: self.lower_span(fn_decl_span),
820 fn_arg_span: None,
821 kind: hir::ClosureKind::Coroutine(coroutine_kind),
822 constness: hir::Constness::NotConst,
823 }))
824 }
825
826 pub(super) fn maybe_forward_track_caller(
829 &mut self,
830 span: Span,
831 outer_hir_id: HirId,
832 inner_hir_id: HirId,
833 ) {
834 if self.tcx.features().async_fn_track_caller()
835 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
836 && attrs.into_iter().any(|attr| attr.has_name(sym::track_caller))
837 {
838 let unstable_span = self.mark_span_with_reason(
839 DesugaringKind::Async,
840 span,
841 Some(Arc::clone(&self.allow_gen_future)),
842 );
843 self.lower_attrs(
844 inner_hir_id,
845 &[Attribute {
846 kind: AttrKind::Normal(ptr::P(NormalAttr::from_ident(Ident::new(
847 sym::track_caller,
848 span,
849 )))),
850 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
851 style: AttrStyle::Outer,
852 span: unstable_span,
853 }],
854 span,
855 );
856 }
857 }
858
859 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
875 let expr = self.arena.alloc(self.lower_expr_mut(expr));
876 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
877 }
878
879 fn make_lowered_await(
881 &mut self,
882 await_kw_span: Span,
883 expr: &'hir hir::Expr<'hir>,
884 await_kind: FutureKind,
885 ) -> hir::ExprKind<'hir> {
886 let full_span = expr.span.to(await_kw_span);
887
888 let is_async_gen = match self.coroutine_kind {
889 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
890 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
891 Some(hir::CoroutineKind::Coroutine(_))
892 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
893 | None => {
894 let stmt_id = self.next_id();
897 let expr_err = self.expr(
898 expr.span,
899 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
900 await_kw_span,
901 item_span: self.current_item,
902 })),
903 );
904 return hir::ExprKind::Block(
905 self.block_all(
906 expr.span,
907 arena_vec![self; hir::Stmt {
908 hir_id: stmt_id,
909 kind: hir::StmtKind::Semi(expr),
910 span: expr.span,
911 }],
912 Some(self.arena.alloc(expr_err)),
913 ),
914 None,
915 );
916 }
917 };
918
919 let features = match await_kind {
920 FutureKind::Future => None,
921 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
922 };
923 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
924 let gen_future_span = self.mark_span_with_reason(
925 DesugaringKind::Await,
926 full_span,
927 Some(Arc::clone(&self.allow_gen_future)),
928 );
929 let expr_hir_id = expr.hir_id;
930
931 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
935 let (awaitee_pat, awaitee_pat_hid) =
936 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
937
938 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
939
940 let poll_expr = {
947 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
948 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
949
950 let Some(task_context_hid) = self.task_context else {
951 unreachable!("use of `await` outside of an async context.");
952 };
953
954 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
955
956 let new_unchecked = self.expr_call_lang_item_fn_mut(
957 span,
958 hir::LangItem::PinNewUnchecked,
959 arena_vec![self; ref_mut_awaitee],
960 );
961 let get_context = self.expr_call_lang_item_fn_mut(
962 gen_future_span,
963 hir::LangItem::GetContext,
964 arena_vec![self; task_context],
965 );
966 let call = match await_kind {
967 FutureKind::Future => self.expr_call_lang_item_fn(
968 span,
969 hir::LangItem::FuturePoll,
970 arena_vec![self; new_unchecked, get_context],
971 ),
972 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
973 span,
974 hir::LangItem::AsyncIteratorPollNext,
975 arena_vec![self; new_unchecked, get_context],
976 ),
977 };
978 self.arena.alloc(self.expr_unsafe(call))
979 };
980
981 let loop_node_id = self.next_node_id();
983 let loop_hir_id = self.lower_node_id(loop_node_id);
984 let ready_arm = {
985 let x_ident = Ident::with_dummy_span(sym::result);
986 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
987 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
988 let ready_field = self.single_pat_field(gen_future_span, x_pat);
989 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
990 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
991 let expr_break =
992 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
993 this.arena.alloc(this.expr(gen_future_span, expr_break))
994 });
995 self.arm(ready_pat, break_x)
996 };
997
998 let pending_arm = {
1000 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
1001 let empty_block = self.expr_block_empty(span);
1002 self.arm(pending_pat, empty_block)
1003 };
1004
1005 let inner_match_stmt = {
1006 let match_expr = self.expr_match(
1007 span,
1008 poll_expr,
1009 arena_vec![self; ready_arm, pending_arm],
1010 hir::MatchSource::AwaitDesugar,
1011 );
1012 self.stmt_expr(span, match_expr)
1013 };
1014
1015 let yield_stmt = {
1019 let yielded = if is_async_gen {
1020 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
1021 } else {
1022 self.expr_unit(span)
1023 };
1024
1025 let yield_expr = self.expr(
1026 span,
1027 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
1028 );
1029 let yield_expr = self.arena.alloc(yield_expr);
1030
1031 let Some(task_context_hid) = self.task_context else {
1032 unreachable!("use of `await` outside of an async context.");
1033 };
1034
1035 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1036 let assign =
1037 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
1038 self.stmt_expr(span, assign)
1039 };
1040
1041 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
1042
1043 let loop_expr = self.arena.alloc(hir::Expr {
1045 hir_id: loop_hir_id,
1046 kind: hir::ExprKind::Loop(
1047 loop_block,
1048 None,
1049 hir::LoopSource::Loop,
1050 self.lower_span(span),
1051 ),
1052 span: self.lower_span(span),
1053 });
1054
1055 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1057
1058 let into_future_expr = match await_kind {
1060 FutureKind::Future => self.expr_call_lang_item_fn(
1061 span,
1062 hir::LangItem::IntoFutureIntoFuture,
1063 arena_vec![self; *expr],
1064 ),
1065 FutureKind::AsyncIterator => expr,
1068 };
1069
1070 hir::ExprKind::Match(
1074 into_future_expr,
1075 arena_vec![self; awaitee_arm],
1076 hir::MatchSource::AwaitDesugar,
1077 )
1078 }
1079
1080 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1081 hir::ExprKind::Use(self.lower_expr(expr), use_kw_span)
1082 }
1083
1084 fn lower_expr_closure(
1085 &mut self,
1086 binder: &ClosureBinder,
1087 capture_clause: CaptureBy,
1088 closure_id: NodeId,
1089 closure_hir_id: hir::HirId,
1090 constness: Const,
1091 movability: Movability,
1092 decl: &FnDecl,
1093 body: &Expr,
1094 fn_decl_span: Span,
1095 fn_arg_span: Span,
1096 ) -> hir::ExprKind<'hir> {
1097 let closure_def_id = self.local_def_id(closure_id);
1098 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1099
1100 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1101 let mut coroutine_kind = if this
1102 .attrs
1103 .get(&closure_hir_id.local_id)
1104 .is_some_and(|attrs| attrs.iter().any(|attr| attr.has_name(sym::coroutine)))
1105 {
1106 Some(hir::CoroutineKind::Coroutine(Movability::Movable))
1107 } else {
1108 None
1109 };
1110 let body_id = this.lower_fn_body(decl, None, |this| {
1112 this.coroutine_kind = coroutine_kind;
1113 let e = this.lower_expr_mut(body);
1114 coroutine_kind = this.coroutine_kind;
1115 e
1116 });
1117 let coroutine_option =
1118 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1119 (body_id, coroutine_option)
1120 });
1121
1122 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1123 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1125
1126 let c = self.arena.alloc(hir::Closure {
1127 def_id: closure_def_id,
1128 binder: binder_clause,
1129 capture_clause,
1130 bound_generic_params,
1131 fn_decl,
1132 body: body_id,
1133 fn_decl_span: self.lower_span(fn_decl_span),
1134 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1135 kind: closure_kind,
1136 constness: self.lower_constness(constness),
1137 });
1138
1139 hir::ExprKind::Closure(c)
1140 }
1141
1142 fn closure_movability_for_fn(
1143 &mut self,
1144 decl: &FnDecl,
1145 fn_decl_span: Span,
1146 coroutine_kind: Option<hir::CoroutineKind>,
1147 movability: Movability,
1148 ) -> hir::ClosureKind {
1149 match coroutine_kind {
1150 Some(hir::CoroutineKind::Coroutine(_)) => {
1151 if decl.inputs.len() > 1 {
1152 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1153 }
1154 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1155 }
1156 Some(
1157 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1158 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1159 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1160 ) => {
1161 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1162 }
1163 None => {
1164 if movability == Movability::Static {
1165 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1166 }
1167 hir::ClosureKind::Closure
1168 }
1169 }
1170 }
1171
1172 fn lower_closure_binder<'c>(
1173 &mut self,
1174 binder: &'c ClosureBinder,
1175 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1176 let (binder, params) = match binder {
1177 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1178 ClosureBinder::For { span, generic_params } => {
1179 let span = self.lower_span(*span);
1180 (hir::ClosureBinder::For { span }, &**generic_params)
1181 }
1182 };
1183
1184 (binder, params)
1185 }
1186
1187 fn lower_expr_coroutine_closure(
1188 &mut self,
1189 binder: &ClosureBinder,
1190 capture_clause: CaptureBy,
1191 closure_id: NodeId,
1192 closure_hir_id: HirId,
1193 coroutine_kind: CoroutineKind,
1194 decl: &FnDecl,
1195 body: &Expr,
1196 fn_decl_span: Span,
1197 fn_arg_span: Span,
1198 ) -> hir::ExprKind<'hir> {
1199 let closure_def_id = self.local_def_id(closure_id);
1200 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1201
1202 assert_matches!(
1203 coroutine_kind,
1204 CoroutineKind::Async { .. },
1205 "only async closures are supported currently"
1206 );
1207
1208 let body = self.with_new_scopes(fn_decl_span, |this| {
1209 let inner_decl =
1210 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1211
1212 let body_id = this.lower_body(|this| {
1215 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1216 &inner_decl,
1217 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1218 fn_decl_span,
1219 body.span,
1220 coroutine_kind,
1221 hir::CoroutineSource::Closure,
1222 );
1223
1224 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1225
1226 (parameters, expr)
1227 });
1228 body_id
1229 });
1230
1231 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1232 let fn_decl =
1236 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1237
1238 let c = self.arena.alloc(hir::Closure {
1239 def_id: closure_def_id,
1240 binder: binder_clause,
1241 capture_clause,
1242 bound_generic_params,
1243 fn_decl,
1244 body,
1245 fn_decl_span: self.lower_span(fn_decl_span),
1246 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1247 kind: hir::ClosureKind::CoroutineClosure(hir::CoroutineDesugaring::Async),
1251 constness: hir::Constness::NotConst,
1252 });
1253 hir::ExprKind::Closure(c)
1254 }
1255
1256 fn lower_expr_assign(
1259 &mut self,
1260 lhs: &Expr,
1261 rhs: &Expr,
1262 eq_sign_span: Span,
1263 whole_span: Span,
1264 ) -> hir::ExprKind<'hir> {
1265 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1267 match &lhs.kind {
1268 ExprKind::Array(..)
1269 | ExprKind::Struct(..)
1270 | ExprKind::Tup(..)
1271 | ExprKind::Underscore => false,
1272 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1274 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1276 ExprKind::Paren(e) => {
1277 match e.kind {
1278 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1280 _ => is_ordinary(lower_ctx, e),
1281 }
1282 }
1283 _ => true,
1284 }
1285 }
1286 if is_ordinary(self, lhs) {
1287 return hir::ExprKind::Assign(
1288 self.lower_expr(lhs),
1289 self.lower_expr(rhs),
1290 self.lower_span(eq_sign_span),
1291 );
1292 }
1293
1294 let mut assignments = vec![];
1295
1296 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1298 let rhs = self.lower_expr(rhs);
1299
1300 let destructure_let = self.stmt_let_pat(
1302 None,
1303 whole_span,
1304 Some(rhs),
1305 pat,
1306 hir::LocalSource::AssignDesugar(self.lower_span(eq_sign_span)),
1307 );
1308
1309 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1311
1312 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1314 }
1315
1316 fn extract_tuple_struct_path<'a>(
1321 &mut self,
1322 expr: &'a Expr,
1323 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1324 if let ExprKind::Path(qself, path) = &expr.kind {
1325 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1327 if let Some(res) = partial_res.full_res()
1328 && !res.expected_in_tuple_struct_pat()
1329 {
1330 return None;
1331 }
1332 }
1333 return Some((qself, path));
1334 }
1335 None
1336 }
1337
1338 fn extract_unit_struct_path<'a>(
1343 &mut self,
1344 expr: &'a Expr,
1345 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1346 if let ExprKind::Path(qself, path) = &expr.kind {
1347 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1349 if let Some(res) = partial_res.full_res()
1350 && !res.expected_in_unit_struct_pat()
1351 {
1352 return None;
1353 }
1354 }
1355 return Some((qself, path));
1356 }
1357 None
1358 }
1359
1360 fn destructure_assign(
1363 &mut self,
1364 lhs: &Expr,
1365 eq_sign_span: Span,
1366 assignments: &mut Vec<hir::Stmt<'hir>>,
1367 ) -> &'hir hir::Pat<'hir> {
1368 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1369 }
1370
1371 fn destructure_assign_mut(
1372 &mut self,
1373 lhs: &Expr,
1374 eq_sign_span: Span,
1375 assignments: &mut Vec<hir::Stmt<'hir>>,
1376 ) -> hir::Pat<'hir> {
1377 match &lhs.kind {
1378 ExprKind::Underscore => {
1380 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1381 }
1382 ExprKind::Array(elements) => {
1384 let (pats, rest) =
1385 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1386 let slice_pat = if let Some((i, span)) = rest {
1387 let (before, after) = pats.split_at(i);
1388 hir::PatKind::Slice(
1389 before,
1390 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1391 after,
1392 )
1393 } else {
1394 hir::PatKind::Slice(pats, None, &[])
1395 };
1396 return self.pat_without_dbm(lhs.span, slice_pat);
1397 }
1398 ExprKind::Call(callee, args) => {
1400 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1401 let (pats, rest) = self.destructure_sequence(
1402 args,
1403 "tuple struct or variant",
1404 eq_sign_span,
1405 assignments,
1406 );
1407 let qpath = self.lower_qpath(
1408 callee.id,
1409 qself,
1410 path,
1411 ParamMode::Optional,
1412 AllowReturnTypeNotation::No,
1413 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1414 None,
1415 );
1416 let tuple_struct_pat = hir::PatKind::TupleStruct(
1418 qpath,
1419 pats,
1420 hir::DotDotPos::new(rest.map(|r| r.0)),
1421 );
1422 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1423 }
1424 }
1425 ExprKind::Path(..) => {
1427 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1428 let qpath = self.lower_qpath(
1429 lhs.id,
1430 qself,
1431 path,
1432 ParamMode::Optional,
1433 AllowReturnTypeNotation::No,
1434 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1435 None,
1436 );
1437 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1439 kind: hir::PatExprKind::Path(qpath),
1440 hir_id: self.next_id(),
1441 span: self.lower_span(lhs.span),
1442 }));
1443 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1444 }
1445 }
1446 ExprKind::Struct(se) => {
1448 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1449 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1450 hir::PatField {
1451 hir_id: self.next_id(),
1452 ident: self.lower_ident(f.ident),
1453 pat,
1454 is_shorthand: f.is_shorthand,
1455 span: self.lower_span(f.span),
1456 }
1457 }));
1458 let qpath = self.lower_qpath(
1459 lhs.id,
1460 &se.qself,
1461 &se.path,
1462 ParamMode::Optional,
1463 AllowReturnTypeNotation::No,
1464 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1465 None,
1466 );
1467 let fields_omitted = match &se.rest {
1468 StructRest::Base(e) => {
1469 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1470 span: e.span,
1471 });
1472 true
1473 }
1474 StructRest::Rest(_) => true,
1475 StructRest::None => false,
1476 };
1477 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1478 return self.pat_without_dbm(lhs.span, struct_pat);
1479 }
1480 ExprKind::Tup(elements) => {
1482 let (pats, rest) =
1483 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1484 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1485 return self.pat_without_dbm(lhs.span, tuple_pat);
1486 }
1487 ExprKind::Paren(e) => {
1488 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1490 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1491 return self.pat_without_dbm(lhs.span, tuple_pat);
1492 } else {
1493 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1494 }
1495 }
1496 _ => {}
1497 }
1498 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1500 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1501 let ident = self.expr_ident(lhs.span, ident, binding);
1502 let assign =
1503 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1504 let expr = self.expr(lhs.span, assign);
1505 assignments.push(self.stmt_expr(lhs.span, expr));
1506 pat
1507 }
1508
1509 fn destructure_sequence(
1515 &mut self,
1516 elements: &[AstP<Expr>],
1517 ctx: &str,
1518 eq_sign_span: Span,
1519 assignments: &mut Vec<hir::Stmt<'hir>>,
1520 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1521 let mut rest = None;
1522 let elements =
1523 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1524 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1526 if let Some((_, prev_span)) = rest {
1527 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1528 } else {
1529 rest = Some((i, e.span));
1530 }
1531 None
1532 } else {
1533 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1534 }
1535 }));
1536 (elements, rest)
1537 }
1538
1539 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1541 let e1 = self.lower_expr_mut(e1);
1542 let e2 = self.lower_expr_mut(e2);
1543 let fn_path = hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, self.lower_span(span));
1544 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1545 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1546 }
1547
1548 fn lower_expr_range(
1549 &mut self,
1550 span: Span,
1551 e1: Option<&Expr>,
1552 e2: Option<&Expr>,
1553 lims: RangeLimits,
1554 ) -> hir::ExprKind<'hir> {
1555 use rustc_ast::RangeLimits::*;
1556
1557 let lang_item = match (e1, e2, lims) {
1558 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1559 (Some(..), None, HalfOpen) => {
1560 if self.tcx.features().new_range() {
1561 hir::LangItem::RangeFromCopy
1562 } else {
1563 hir::LangItem::RangeFrom
1564 }
1565 }
1566 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1567 (Some(..), Some(..), HalfOpen) => {
1568 if self.tcx.features().new_range() {
1569 hir::LangItem::RangeCopy
1570 } else {
1571 hir::LangItem::Range
1572 }
1573 }
1574 (None, Some(..), Closed) => hir::LangItem::RangeToInclusive,
1575 (Some(e1), Some(e2), Closed) => {
1576 if self.tcx.features().new_range() {
1577 hir::LangItem::RangeInclusiveCopy
1578 } else {
1579 return self.lower_expr_range_closed(span, e1, e2);
1580 }
1581 }
1582 (start, None, Closed) => {
1583 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1584 match start {
1585 Some(..) => {
1586 if self.tcx.features().new_range() {
1587 hir::LangItem::RangeFromCopy
1588 } else {
1589 hir::LangItem::RangeFrom
1590 }
1591 }
1592 None => hir::LangItem::RangeFull,
1593 }
1594 }
1595 };
1596
1597 let fields = self.arena.alloc_from_iter(
1598 e1.iter().map(|e| (sym::start, e)).chain(e2.iter().map(|e| (sym::end, e))).map(
1599 |(s, e)| {
1600 let expr = self.lower_expr(e);
1601 let ident = Ident::new(s, self.lower_span(e.span));
1602 self.expr_field(ident, expr, e.span)
1603 },
1604 ),
1605 );
1606
1607 hir::ExprKind::Struct(
1608 self.arena.alloc(hir::QPath::LangItem(lang_item, self.lower_span(span))),
1609 fields,
1610 hir::StructTailExpr::None,
1611 )
1612 }
1613
1614 fn lower_label(
1617 &mut self,
1618 opt_label: Option<Label>,
1619 dest_id: NodeId,
1620 dest_hir_id: hir::HirId,
1621 ) -> Option<Label> {
1622 let label = opt_label?;
1623 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1624 Some(Label { ident: self.lower_ident(label.ident) })
1625 }
1626
1627 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1628 let target_id = match destination {
1629 Some((id, _)) => {
1630 if let Some(loop_id) = self.resolver.get_label_res(id) {
1631 let local_id = self.ident_and_label_to_local_id[&loop_id];
1632 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1633 Ok(loop_hir_id)
1634 } else {
1635 Err(hir::LoopIdError::UnresolvedLabel)
1636 }
1637 }
1638 None => {
1639 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1640 }
1641 };
1642 let label = destination
1643 .map(|(_, label)| label)
1644 .map(|label| Label { ident: self.lower_ident(label.ident) });
1645 hir::Destination { label, target_id }
1646 }
1647
1648 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1649 if self.is_in_loop_condition && opt_label.is_none() {
1650 hir::Destination {
1651 label: None,
1652 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1653 }
1654 } else {
1655 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1656 }
1657 }
1658
1659 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1660 let old_scope = self.catch_scope.replace(catch_id);
1661 let result = f(self);
1662 self.catch_scope = old_scope;
1663 result
1664 }
1665
1666 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1667 let was_in_loop_condition = self.is_in_loop_condition;
1669 self.is_in_loop_condition = false;
1670
1671 let old_scope = self.loop_scope.replace(loop_id);
1672 let result = f(self);
1673 self.loop_scope = old_scope;
1674
1675 self.is_in_loop_condition = was_in_loop_condition;
1676
1677 result
1678 }
1679
1680 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1681 let was_in_loop_condition = self.is_in_loop_condition;
1682 self.is_in_loop_condition = true;
1683
1684 let result = f(self);
1685
1686 self.is_in_loop_condition = was_in_loop_condition;
1687
1688 result
1689 }
1690
1691 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1692 let hir_id = self.lower_node_id(f.id);
1693 self.lower_attrs(hir_id, &f.attrs, f.span);
1694 hir::ExprField {
1695 hir_id,
1696 ident: self.lower_ident(f.ident),
1697 expr: self.lower_expr(&f.expr),
1698 span: self.lower_span(f.span),
1699 is_shorthand: f.is_shorthand,
1700 }
1701 }
1702
1703 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1704 let yielded =
1705 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1706
1707 if !self.tcx.features().yield_expr()
1708 && !self.tcx.features().coroutines()
1709 && !self.tcx.features().gen_blocks()
1710 {
1711 rustc_session::parse::feature_err(
1712 &self.tcx.sess,
1713 sym::yield_expr,
1714 span,
1715 fluent_generated::ast_lowering_yield,
1716 )
1717 .emit();
1718 }
1719
1720 let is_async_gen = match self.coroutine_kind {
1721 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1722 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1723 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1724 let stmt_id = self.next_id();
1727 let expr_err = self.expr(
1728 yielded.span,
1729 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1730 );
1731 return hir::ExprKind::Block(
1732 self.block_all(
1733 yielded.span,
1734 arena_vec![self; hir::Stmt {
1735 hir_id: stmt_id,
1736 kind: hir::StmtKind::Semi(yielded),
1737 span: yielded.span,
1738 }],
1739 Some(self.arena.alloc(expr_err)),
1740 ),
1741 None,
1742 );
1743 }
1744 Some(hir::CoroutineKind::Coroutine(_)) => false,
1745 None => {
1746 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1747 self.dcx().emit_err(YieldInClosure { span, suggestion });
1748 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1749
1750 false
1751 }
1752 };
1753
1754 if is_async_gen {
1755 let wrapped_yielded = self.expr_call_lang_item_fn(
1759 span,
1760 hir::LangItem::AsyncGenReady,
1761 std::slice::from_ref(yielded),
1762 );
1763 let yield_expr = self.arena.alloc(
1764 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1765 );
1766
1767 let Some(task_context_hid) = self.task_context else {
1768 unreachable!("use of `await` outside of an async context.");
1769 };
1770 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1771 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1772
1773 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1774 } else {
1775 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1776 }
1777 }
1778
1779 fn lower_expr_for(
1796 &mut self,
1797 e: &Expr,
1798 pat: &Pat,
1799 head: &Expr,
1800 body: &Block,
1801 opt_label: Option<Label>,
1802 loop_kind: ForLoopKind,
1803 ) -> hir::Expr<'hir> {
1804 let head = self.lower_expr_mut(head);
1805 let pat = self.lower_pat(pat);
1806 let for_span =
1807 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1808 let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
1809 let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
1810
1811 let loop_hir_id = self.lower_node_id(e.id);
1812 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1813
1814 let none_arm = {
1816 let break_expr =
1817 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1818 let pat = self.pat_none(for_span);
1819 self.arm(pat, break_expr)
1820 };
1821
1822 let some_arm = {
1824 let some_pat = self.pat_some(pat_span, pat);
1825 let body_block =
1826 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1827 let body_expr = self.arena.alloc(self.expr_block(body_block));
1828 self.arm(some_pat, body_expr)
1829 };
1830
1831 let iter = Ident::with_dummy_span(sym::iter);
1833 let (iter_pat, iter_pat_nid) =
1834 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1835
1836 let match_expr = {
1837 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1838 let next_expr = match loop_kind {
1839 ForLoopKind::For => {
1840 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1842 self.expr_call_lang_item_fn(
1843 head_span,
1844 hir::LangItem::IteratorNext,
1845 arena_vec![self; ref_mut_iter],
1846 )
1847 }
1848 ForLoopKind::ForAwait => {
1849 let iter = self.expr_mut_addr_of(head_span, iter);
1856 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1858 head_span,
1859 hir::LangItem::PinNewUnchecked,
1860 arena_vec![self; iter],
1861 ));
1862 let iter = self.arena.alloc(self.expr_unsafe(iter));
1864 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1865 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1866 }
1867 };
1868 let arms = arena_vec![self; none_arm, some_arm];
1869
1870 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1872 };
1873 let match_stmt = self.stmt_expr(for_span, match_expr);
1874
1875 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1876
1877 let kind = hir::ExprKind::Loop(
1879 loop_block,
1880 label,
1881 hir::LoopSource::ForLoop,
1882 self.lower_span(for_span.with_hi(head.span.hi())),
1883 );
1884 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1885
1886 let iter_arm = self.arm(iter_pat, loop_expr);
1888
1889 let match_expr = match loop_kind {
1890 ForLoopKind::For => {
1891 let into_iter_expr = self.expr_call_lang_item_fn(
1893 head_span,
1894 hir::LangItem::IntoIterIntoIter,
1895 arena_vec![self; head],
1896 );
1897
1898 self.arena.alloc(self.expr_match(
1899 for_span,
1900 into_iter_expr,
1901 arena_vec![self; iter_arm],
1902 hir::MatchSource::ForLoopDesugar,
1903 ))
1904 }
1905 ForLoopKind::ForAwait => {
1907 let iter_ident = iter;
1908 let (async_iter_pat, async_iter_pat_id) =
1909 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1910 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1911 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1913 head_span,
1914 hir::LangItem::PinNewUnchecked,
1915 arena_vec![self; iter],
1916 ));
1917 let iter = self.arena.alloc(self.expr_unsafe(iter));
1919 let inner_match_expr = self.arena.alloc(self.expr_match(
1920 for_span,
1921 iter,
1922 arena_vec![self; iter_arm],
1923 hir::MatchSource::ForLoopDesugar,
1924 ));
1925
1926 let iter = self.expr_call_lang_item_fn(
1928 head_span,
1929 hir::LangItem::IntoAsyncIterIntoIter,
1930 arena_vec![self; head],
1931 );
1932 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1933 self.arena.alloc(self.expr_match(
1934 for_span,
1935 iter,
1936 arena_vec![self; iter_arm],
1937 hir::MatchSource::ForLoopDesugar,
1938 ))
1939 }
1940 };
1941
1942 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1949 self.lower_attrs(expr.hir_id, &e.attrs, e.span);
1950 expr
1951 }
1952
1953 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1966 let unstable_span = self.mark_span_with_reason(
1967 DesugaringKind::QuestionMark,
1968 span,
1969 Some(Arc::clone(&self.allow_try_trait)),
1970 );
1971 let try_span = self.tcx.sess.source_map().end_point(span);
1972 let try_span = self.mark_span_with_reason(
1973 DesugaringKind::QuestionMark,
1974 try_span,
1975 Some(Arc::clone(&self.allow_try_trait)),
1976 );
1977
1978 let scrutinee = {
1980 let sub_expr = self.lower_expr_mut(sub_expr);
1982
1983 self.expr_call_lang_item_fn(
1984 unstable_span,
1985 hir::LangItem::TryTraitBranch,
1986 arena_vec![self; sub_expr],
1987 )
1988 };
1989
1990 let attr = attr::mk_attr_nested_word(
1992 &self.tcx.sess.psess.attr_id_generator,
1993 AttrStyle::Outer,
1994 Safety::Default,
1995 sym::allow,
1996 sym::unreachable_code,
1997 try_span,
1998 );
1999 let attrs: AttrVec = thin_vec![attr];
2000
2001 let continue_arm = {
2003 let val_ident = Ident::with_dummy_span(sym::val);
2004 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
2005 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
2006 self.lower_attrs(val_expr.hir_id, &attrs, span);
2007 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
2008 self.arm(continue_pat, val_expr)
2009 };
2010
2011 let break_arm = {
2015 let residual_ident = Ident::with_dummy_span(sym::residual);
2016 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
2017 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
2018 let from_residual_expr = self.wrap_in_try_constructor(
2019 hir::LangItem::TryTraitFromResidual,
2020 try_span,
2021 self.arena.alloc(residual_expr),
2022 unstable_span,
2023 );
2024 let ret_expr = if let Some(catch_id) = self.catch_scope {
2025 let target_id = Ok(catch_id);
2026 self.arena.alloc(self.expr(
2027 try_span,
2028 hir::ExprKind::Break(
2029 hir::Destination { label: None, target_id },
2030 Some(from_residual_expr),
2031 ),
2032 ))
2033 } else {
2034 let ret_expr = self.checked_return(Some(from_residual_expr));
2035 self.arena.alloc(self.expr(try_span, ret_expr))
2036 };
2037 self.lower_attrs(ret_expr.hir_id, &attrs, ret_expr.span);
2038
2039 let break_pat = self.pat_cf_break(try_span, residual_local);
2040 self.arm(break_pat, ret_expr)
2041 };
2042
2043 hir::ExprKind::Match(
2044 scrutinee,
2045 arena_vec![self; break_arm, continue_arm],
2046 hir::MatchSource::TryDesugar(scrutinee.hir_id),
2047 )
2048 }
2049
2050 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2060 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2062 (sub_expr.span, self.lower_expr(sub_expr))
2063 } else {
2064 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2065 };
2066
2067 let unstable_span = self.mark_span_with_reason(
2068 DesugaringKind::YeetExpr,
2069 span,
2070 Some(Arc::clone(&self.allow_try_trait)),
2071 );
2072
2073 let from_yeet_expr = self.wrap_in_try_constructor(
2074 hir::LangItem::TryTraitFromYeet,
2075 unstable_span,
2076 yeeted_expr,
2077 yeeted_span,
2078 );
2079
2080 if let Some(catch_id) = self.catch_scope {
2081 let target_id = Ok(catch_id);
2082 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2083 } else {
2084 self.checked_return(Some(from_yeet_expr))
2085 }
2086 }
2087
2088 pub(super) fn expr_drop_temps(
2099 &mut self,
2100 span: Span,
2101 expr: &'hir hir::Expr<'hir>,
2102 ) -> &'hir hir::Expr<'hir> {
2103 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2104 }
2105
2106 pub(super) fn expr_drop_temps_mut(
2107 &mut self,
2108 span: Span,
2109 expr: &'hir hir::Expr<'hir>,
2110 ) -> hir::Expr<'hir> {
2111 self.expr(span, hir::ExprKind::DropTemps(expr))
2112 }
2113
2114 pub(super) fn expr_match(
2115 &mut self,
2116 span: Span,
2117 arg: &'hir hir::Expr<'hir>,
2118 arms: &'hir [hir::Arm<'hir>],
2119 source: hir::MatchSource,
2120 ) -> hir::Expr<'hir> {
2121 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2122 }
2123
2124 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2125 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2126 self.expr(span, expr_break)
2127 }
2128
2129 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2130 let expr_break = self.expr_break(span);
2131 self.arena.alloc(expr_break)
2132 }
2133
2134 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2135 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2136 }
2137
2138 fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2139 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2140 }
2141
2142 fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
2143 let lit = self.arena.alloc(hir::Lit {
2144 span: sp,
2145 node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
2146 });
2147 self.expr(sp, hir::ExprKind::Lit(lit))
2148 }
2149
2150 pub(super) fn expr_usize(&mut self, sp: Span, value: usize) -> hir::Expr<'hir> {
2151 self.expr_uint(sp, ast::UintTy::Usize, value as u128)
2152 }
2153
2154 pub(super) fn expr_u32(&mut self, sp: Span, value: u32) -> hir::Expr<'hir> {
2155 self.expr_uint(sp, ast::UintTy::U32, value as u128)
2156 }
2157
2158 pub(super) fn expr_u16(&mut self, sp: Span, value: u16) -> hir::Expr<'hir> {
2159 self.expr_uint(sp, ast::UintTy::U16, value as u128)
2160 }
2161
2162 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2163 let lit = self
2164 .arena
2165 .alloc(hir::Lit { span: sp, node: ast::LitKind::Str(value, ast::StrStyle::Cooked) });
2166 self.expr(sp, hir::ExprKind::Lit(lit))
2167 }
2168
2169 pub(super) fn expr_call_mut(
2170 &mut self,
2171 span: Span,
2172 e: &'hir hir::Expr<'hir>,
2173 args: &'hir [hir::Expr<'hir>],
2174 ) -> hir::Expr<'hir> {
2175 self.expr(span, hir::ExprKind::Call(e, args))
2176 }
2177
2178 pub(super) fn expr_call(
2179 &mut self,
2180 span: Span,
2181 e: &'hir hir::Expr<'hir>,
2182 args: &'hir [hir::Expr<'hir>],
2183 ) -> &'hir hir::Expr<'hir> {
2184 self.arena.alloc(self.expr_call_mut(span, e, args))
2185 }
2186
2187 pub(super) fn expr_call_lang_item_fn_mut(
2188 &mut self,
2189 span: Span,
2190 lang_item: hir::LangItem,
2191 args: &'hir [hir::Expr<'hir>],
2192 ) -> hir::Expr<'hir> {
2193 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2194 self.expr_call_mut(span, path, args)
2195 }
2196
2197 pub(super) fn expr_call_lang_item_fn(
2198 &mut self,
2199 span: Span,
2200 lang_item: hir::LangItem,
2201 args: &'hir [hir::Expr<'hir>],
2202 ) -> &'hir hir::Expr<'hir> {
2203 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2204 }
2205
2206 fn expr_lang_item_path(&mut self, span: Span, lang_item: hir::LangItem) -> hir::Expr<'hir> {
2207 self.expr(span, hir::ExprKind::Path(hir::QPath::LangItem(lang_item, self.lower_span(span))))
2208 }
2209
2210 pub(super) fn expr_lang_item_type_relative(
2212 &mut self,
2213 span: Span,
2214 lang_item: hir::LangItem,
2215 name: Symbol,
2216 ) -> hir::Expr<'hir> {
2217 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2218 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2219 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2220 self.arena.alloc(hir::PathSegment::new(
2221 Ident::new(name, self.lower_span(span)),
2222 self.next_id(),
2223 Res::Err,
2224 )),
2225 ));
2226 self.expr(span, path)
2227 }
2228
2229 pub(super) fn expr_ident(
2230 &mut self,
2231 sp: Span,
2232 ident: Ident,
2233 binding: HirId,
2234 ) -> &'hir hir::Expr<'hir> {
2235 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2236 }
2237
2238 pub(super) fn expr_ident_mut(
2239 &mut self,
2240 span: Span,
2241 ident: Ident,
2242 binding: HirId,
2243 ) -> hir::Expr<'hir> {
2244 let hir_id = self.next_id();
2245 let res = Res::Local(binding);
2246 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2247 None,
2248 self.arena.alloc(hir::Path {
2249 span: self.lower_span(span),
2250 res,
2251 segments: arena_vec![self; hir::PathSegment::new(ident, hir_id, res)],
2252 }),
2253 ));
2254
2255 self.expr(span, expr_path)
2256 }
2257
2258 fn expr_unsafe(&mut self, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2259 let hir_id = self.next_id();
2260 let span = expr.span;
2261 self.expr(
2262 span,
2263 hir::ExprKind::Block(
2264 self.arena.alloc(hir::Block {
2265 stmts: &[],
2266 expr: Some(expr),
2267 hir_id,
2268 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2269 span: self.lower_span(span),
2270 targeted_by_break: false,
2271 }),
2272 None,
2273 ),
2274 )
2275 }
2276
2277 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2278 let blk = self.block_all(span, &[], None);
2279 let expr = self.expr_block(blk);
2280 self.arena.alloc(expr)
2281 }
2282
2283 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2284 self.expr(b.span, hir::ExprKind::Block(b, None))
2285 }
2286
2287 pub(super) fn expr_array_ref(
2288 &mut self,
2289 span: Span,
2290 elements: &'hir [hir::Expr<'hir>],
2291 ) -> hir::Expr<'hir> {
2292 let addrof = hir::ExprKind::AddrOf(
2293 hir::BorrowKind::Ref,
2294 hir::Mutability::Not,
2295 self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements))),
2296 );
2297 self.expr(span, addrof)
2298 }
2299
2300 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2301 let hir_id = self.next_id();
2302 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2303 }
2304
2305 pub(super) fn expr_field(
2306 &mut self,
2307 ident: Ident,
2308 expr: &'hir hir::Expr<'hir>,
2309 span: Span,
2310 ) -> hir::ExprField<'hir> {
2311 hir::ExprField {
2312 hir_id: self.next_id(),
2313 ident,
2314 span: self.lower_span(span),
2315 expr,
2316 is_shorthand: false,
2317 }
2318 }
2319
2320 pub(super) fn arm(
2321 &mut self,
2322 pat: &'hir hir::Pat<'hir>,
2323 expr: &'hir hir::Expr<'hir>,
2324 ) -> hir::Arm<'hir> {
2325 hir::Arm {
2326 hir_id: self.next_id(),
2327 pat,
2328 guard: None,
2329 span: self.lower_span(expr.span),
2330 body: expr,
2331 }
2332 }
2333}
2334
2335#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2338enum FutureKind {
2339 Future,
2341 AsyncIterator,
2344}