1use std::ops::ControlFlow;
2use std::sync::Arc;
3
4use rustc_ast::ptr::P as AstP;
5use rustc_ast::*;
6use rustc_ast_pretty::pprust::expr_to_string;
7use rustc_attr_data_structures::{AttributeKind, find_attr};
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 new_attrs = self
78 .lower_attrs_vec(&e.attrs, e.span, ex.hir_id)
79 .into_iter()
80 .chain(old_attrs.iter().cloned());
81 let new_attrs = &*self.arena.alloc_from_iter(new_attrs);
82 if new_attrs.is_empty() {
83 return ex;
84 }
85 self.attrs.insert(ex.hir_id.local_id, new_attrs);
86 }
87 return ex;
88 }
89 ExprKind::ForLoop { pat, iter, body, label, kind } => {
95 return self.lower_expr_for(e, pat, iter, body, *label, *kind);
96 }
97 _ => (),
98 }
99
100 let expr_hir_id = self.lower_node_id(e.id);
101 self.lower_attrs(expr_hir_id, &e.attrs, e.span);
102
103 let kind = match &e.kind {
104 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
105 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
106 ExprKind::Repeat(expr, count) => {
107 let expr = self.lower_expr(expr);
108 let count = self.lower_array_length_to_const_arg(count);
109 hir::ExprKind::Repeat(expr, count)
110 }
111 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
112 ExprKind::Call(f, args) => {
113 if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) {
114 self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
115 } else {
116 let f = self.lower_expr(f);
117 hir::ExprKind::Call(f, self.lower_exprs(args))
118 }
119 }
120 ExprKind::MethodCall(box MethodCall { seg, receiver, args, span }) => {
121 let hir_seg = self.arena.alloc(self.lower_path_segment(
122 e.span,
123 seg,
124 ParamMode::Optional,
125 GenericArgsMode::Err,
126 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
127 None,
129 ));
130 let receiver = self.lower_expr(receiver);
131 let args =
132 self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
133 hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(*span))
134 }
135 ExprKind::Binary(binop, lhs, rhs) => {
136 let binop = self.lower_binop(*binop);
137 let lhs = self.lower_expr(lhs);
138 let rhs = self.lower_expr(rhs);
139 hir::ExprKind::Binary(binop, lhs, rhs)
140 }
141 ExprKind::Unary(op, ohs) => {
142 let op = self.lower_unop(*op);
143 let ohs = self.lower_expr(ohs);
144 hir::ExprKind::Unary(op, ohs)
145 }
146 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
147 ExprKind::IncludedBytes(byte_sym) => {
148 let lit = respan(
149 self.lower_span(e.span),
150 LitKind::ByteStr(*byte_sym, StrStyle::Cooked),
151 );
152 hir::ExprKind::Lit(lit)
153 }
154 ExprKind::Cast(expr, ty) => {
155 let expr = self.lower_expr(expr);
156 let ty =
157 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
158 hir::ExprKind::Cast(expr, ty)
159 }
160 ExprKind::Type(expr, ty) => {
161 let expr = self.lower_expr(expr);
162 let ty =
163 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
164 hir::ExprKind::Type(expr, ty)
165 }
166 ExprKind::AddrOf(k, m, ohs) => {
167 let ohs = self.lower_expr(ohs);
168 hir::ExprKind::AddrOf(*k, *m, ohs)
169 }
170 ExprKind::Let(pat, scrutinee, span, recovered) => {
171 hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
172 span: self.lower_span(*span),
173 pat: self.lower_pat(pat),
174 ty: None,
175 init: self.lower_expr(scrutinee),
176 recovered: *recovered,
177 }))
178 }
179 ExprKind::If(cond, then, else_opt) => {
180 self.lower_expr_if(cond, then, else_opt.as_deref())
181 }
182 ExprKind::While(cond, body, opt_label) => {
183 self.with_loop_scope(expr_hir_id, |this| {
184 let span =
185 this.mark_span_with_reason(DesugaringKind::WhileLoop, e.span, None);
186 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
187 this.lower_expr_while_in_loop_scope(span, cond, body, opt_label)
188 })
189 }
190 ExprKind::Loop(body, opt_label, span) => {
191 self.with_loop_scope(expr_hir_id, |this| {
192 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
193 hir::ExprKind::Loop(
194 this.lower_block(body, false),
195 opt_label,
196 hir::LoopSource::Loop,
197 this.lower_span(*span),
198 )
199 })
200 }
201 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
202 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
203 self.lower_expr(expr),
204 self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
205 match kind {
206 MatchKind::Prefix => hir::MatchSource::Normal,
207 MatchKind::Postfix => hir::MatchSource::Postfix,
208 },
209 ),
210 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
211 ExprKind::Use(expr, use_kw_span) => self.lower_expr_use(*use_kw_span, expr),
212 ExprKind::Closure(box Closure {
213 binder,
214 capture_clause,
215 constness,
216 coroutine_kind,
217 movability,
218 fn_decl,
219 body,
220 fn_decl_span,
221 fn_arg_span,
222 }) => match coroutine_kind {
223 Some(coroutine_kind) => self.lower_expr_coroutine_closure(
224 binder,
225 *capture_clause,
226 e.id,
227 expr_hir_id,
228 *coroutine_kind,
229 fn_decl,
230 body,
231 *fn_decl_span,
232 *fn_arg_span,
233 ),
234 None => self.lower_expr_closure(
235 binder,
236 *capture_clause,
237 e.id,
238 expr_hir_id,
239 *constness,
240 *movability,
241 fn_decl,
242 body,
243 *fn_decl_span,
244 *fn_arg_span,
245 ),
246 },
247 ExprKind::Gen(capture_clause, block, genblock_kind, decl_span) => {
248 let desugaring_kind = match genblock_kind {
249 GenBlockKind::Async => hir::CoroutineDesugaring::Async,
250 GenBlockKind::Gen => hir::CoroutineDesugaring::Gen,
251 GenBlockKind::AsyncGen => hir::CoroutineDesugaring::AsyncGen,
252 };
253 self.make_desugared_coroutine_expr(
254 *capture_clause,
255 e.id,
256 None,
257 *decl_span,
258 e.span,
259 desugaring_kind,
260 hir::CoroutineSource::Block,
261 |this| this.with_new_scopes(e.span, |this| this.lower_block_expr(block)),
262 )
263 }
264 ExprKind::Block(blk, opt_label) => {
265 let block_hir_id = self.lower_node_id(blk.id);
268 let opt_label = self.lower_label(*opt_label, blk.id, block_hir_id);
269 let hir_block = self.arena.alloc(self.lower_block_noalloc(
270 block_hir_id,
271 blk,
272 opt_label.is_some(),
273 ));
274 hir::ExprKind::Block(hir_block, opt_label)
275 }
276 ExprKind::Assign(el, er, span) => self.lower_expr_assign(el, er, *span, e.span),
277 ExprKind::AssignOp(op, el, er) => hir::ExprKind::AssignOp(
278 self.lower_assign_op(*op),
279 self.lower_expr(el),
280 self.lower_expr(er),
281 ),
282 ExprKind::Field(el, ident) => {
283 hir::ExprKind::Field(self.lower_expr(el), self.lower_ident(*ident))
284 }
285 ExprKind::Index(el, er, brackets_span) => {
286 hir::ExprKind::Index(self.lower_expr(el), self.lower_expr(er), *brackets_span)
287 }
288 ExprKind::Range(e1, e2, lims) => {
289 self.lower_expr_range(e.span, e1.as_deref(), e2.as_deref(), *lims)
290 }
291 ExprKind::Underscore => {
292 let guar = self.dcx().emit_err(UnderscoreExprLhsAssign { span: e.span });
293 hir::ExprKind::Err(guar)
294 }
295 ExprKind::Path(qself, path) => {
296 let qpath = self.lower_qpath(
297 e.id,
298 qself,
299 path,
300 ParamMode::Optional,
301 AllowReturnTypeNotation::No,
302 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
303 None,
304 );
305 hir::ExprKind::Path(qpath)
306 }
307 ExprKind::Break(opt_label, opt_expr) => {
308 let opt_expr = opt_expr.as_ref().map(|x| self.lower_expr(x));
309 hir::ExprKind::Break(self.lower_jump_destination(e.id, *opt_label), opt_expr)
310 }
311 ExprKind::Continue(opt_label) => {
312 hir::ExprKind::Continue(self.lower_jump_destination(e.id, *opt_label))
313 }
314 ExprKind::Ret(e) => {
315 let expr = e.as_ref().map(|x| self.lower_expr(x));
316 self.checked_return(expr)
317 }
318 ExprKind::Yeet(sub_expr) => self.lower_expr_yeet(e.span, sub_expr.as_deref()),
319 ExprKind::Become(sub_expr) => {
320 let sub_expr = self.lower_expr(sub_expr);
321 hir::ExprKind::Become(sub_expr)
322 }
323 ExprKind::InlineAsm(asm) => {
324 hir::ExprKind::InlineAsm(self.lower_inline_asm(e.span, asm))
325 }
326 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
327 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
328 self.lower_ty(
329 container,
330 ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
331 ),
332 self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
333 ),
334 ExprKind::Struct(se) => {
335 let rest = match &se.rest {
336 StructRest::Base(e) => hir::StructTailExpr::Base(self.lower_expr(e)),
337 StructRest::Rest(sp) => hir::StructTailExpr::DefaultFields(*sp),
338 StructRest::None => hir::StructTailExpr::None,
339 };
340 hir::ExprKind::Struct(
341 self.arena.alloc(self.lower_qpath(
342 e.id,
343 &se.qself,
344 &se.path,
345 ParamMode::Optional,
346 AllowReturnTypeNotation::No,
347 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
348 None,
349 )),
350 self.arena
351 .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
352 rest,
353 )
354 }
355 ExprKind::Yield(kind) => self.lower_expr_yield(e.span, kind.expr().map(|x| &**x)),
356 ExprKind::Err(guar) => hir::ExprKind::Err(*guar),
357
358 ExprKind::UnsafeBinderCast(kind, expr, ty) => hir::ExprKind::UnsafeBinderCast(
359 *kind,
360 self.lower_expr(expr),
361 ty.as_ref().map(|ty| {
362 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
363 }),
364 ),
365
366 ExprKind::Dummy => {
367 span_bug!(e.span, "lowered ExprKind::Dummy")
368 }
369
370 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
371
372 ExprKind::Paren(_) | ExprKind::ForLoop { .. } => {
373 unreachable!("already handled")
374 }
375
376 ExprKind::MacCall(_) => panic!("{:?} shouldn't exist here", e.span),
377 };
378
379 hir::Expr { hir_id: expr_hir_id, kind, span: self.lower_span(e.span) }
380 })
381 }
382
383 fn checked_return(&mut self, opt_expr: Option<&'hir hir::Expr<'hir>>) -> hir::ExprKind<'hir> {
386 let checked_ret =
387 if let Some((check_span, check_ident, check_hir_id)) = self.contract_ensures {
388 let expr = opt_expr.unwrap_or_else(|| self.expr_unit(check_span));
389 Some(self.inject_ensures_check(expr, check_span, check_ident, check_hir_id))
390 } else {
391 opt_expr
392 };
393 hir::ExprKind::Ret(checked_ret)
394 }
395
396 pub(crate) fn inject_ensures_check(
398 &mut self,
399 expr: &'hir hir::Expr<'hir>,
400 span: Span,
401 cond_ident: Ident,
402 cond_hir_id: HirId,
403 ) -> &'hir hir::Expr<'hir> {
404 let cond_fn = self.expr_ident(span, cond_ident, cond_hir_id);
405 let call_expr = self.expr_call_lang_item_fn_mut(
406 span,
407 hir::LangItem::ContractCheckEnsures,
408 arena_vec![self; *cond_fn, *expr],
409 );
410 self.arena.alloc(call_expr)
411 }
412
413 pub(crate) fn lower_const_block(&mut self, c: &AnonConst) -> hir::ConstBlock {
414 self.with_new_scopes(c.value.span, |this| {
415 let def_id = this.local_def_id(c.id);
416 hir::ConstBlock {
417 def_id,
418 hir_id: this.lower_node_id(c.id),
419 body: this.lower_const_body(c.value.span, Some(&c.value)),
420 }
421 })
422 }
423
424 pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
425 let lit_kind = match LitKind::from_token_lit(*token_lit) {
426 Ok(lit_kind) => lit_kind,
427 Err(err) => {
428 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
429 LitKind::Err(guar)
430 }
431 };
432 respan(self.lower_span(span), lit_kind)
433 }
434
435 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
436 match u {
437 UnOp::Deref => hir::UnOp::Deref,
438 UnOp::Not => hir::UnOp::Not,
439 UnOp::Neg => hir::UnOp::Neg,
440 }
441 }
442
443 fn lower_binop(&mut self, b: BinOp) -> BinOp {
444 Spanned { node: b.node, span: self.lower_span(b.span) }
445 }
446
447 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
448 Spanned { node: a.node, span: self.lower_span(a.span) }
449 }
450
451 fn lower_legacy_const_generics(
452 &mut self,
453 mut f: Expr,
454 args: ThinVec<AstP<Expr>>,
455 legacy_args_idx: &[usize],
456 ) -> hir::ExprKind<'hir> {
457 let ExprKind::Path(None, path) = &mut f.kind else {
458 unreachable!();
459 };
460
461 let mut error = None;
462 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
463 if error.is_none() {
465 let mut const_args = vec![];
466 let mut other_args = vec![];
467 for (idx, arg) in args.iter().enumerate() {
468 if legacy_args_idx.contains(&idx) {
469 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
470 } else {
471 other_args.push(expr_to_string(arg));
472 }
473 }
474 let suggestion = UseConstGenericArg {
475 end_of_fn: f.span.shrink_to_hi(),
476 const_args: const_args.join(", "),
477 other_args: other_args.join(", "),
478 call_args: args[0].span.to(args.last().unwrap().span),
479 };
480 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
481 }
482 error.unwrap()
483 };
484
485 let mut real_args = vec![];
487 let mut generic_args = ThinVec::new();
488 for (idx, arg) in args.iter().cloned().enumerate() {
489 if legacy_args_idx.contains(&idx) {
490 let node_id = self.next_node_id();
491 self.create_def(node_id, None, DefKind::AnonConst, f.span);
492 let mut visitor = WillCreateDefIdsVisitor {};
493 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
494 AstP(Expr {
495 id: self.next_node_id(),
496 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
497 span: f.span,
498 attrs: [].into(),
499 tokens: None,
500 })
501 } else {
502 arg
503 };
504
505 let anon_const = AnonConst { id: node_id, value: const_value };
506 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
507 } else {
508 real_args.push(arg);
509 }
510 }
511
512 let last_segment = path.segments.last_mut().unwrap();
514 assert!(last_segment.args.is_none());
515 last_segment.args = Some(AstP(GenericArgs::AngleBracketed(AngleBracketedArgs {
516 span: DUMMY_SP,
517 args: generic_args,
518 })));
519
520 let f = self.lower_expr(&f);
522 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
523 }
524
525 fn lower_expr_if(
526 &mut self,
527 cond: &Expr,
528 then: &Block,
529 else_opt: Option<&Expr>,
530 ) -> hir::ExprKind<'hir> {
531 let lowered_cond = self.lower_cond(cond);
532 let then_expr = self.lower_block_expr(then);
533 if let Some(rslt) = else_opt {
534 hir::ExprKind::If(
535 lowered_cond,
536 self.arena.alloc(then_expr),
537 Some(self.lower_expr(rslt)),
538 )
539 } else {
540 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
541 }
542 }
543
544 fn lower_cond(&mut self, cond: &Expr) -> &'hir hir::Expr<'hir> {
547 fn has_let_expr(expr: &Expr) -> bool {
548 match &expr.kind {
549 ExprKind::Binary(_, lhs, rhs) => has_let_expr(lhs) || has_let_expr(rhs),
550 ExprKind::Let(..) => true,
551 _ => false,
552 }
553 }
554
555 match &cond.kind {
563 ExprKind::Binary(op @ Spanned { node: ast::BinOpKind::And, .. }, lhs, rhs)
564 if has_let_expr(cond) =>
565 {
566 let op = self.lower_binop(*op);
567 let lhs = self.lower_cond(lhs);
568 let rhs = self.lower_cond(rhs);
569
570 self.arena.alloc(self.expr(cond.span, hir::ExprKind::Binary(op, lhs, rhs)))
571 }
572 ExprKind::Let(..) => self.lower_expr(cond),
573 _ => {
574 let cond = self.lower_expr(cond);
575 let reason = DesugaringKind::CondTemporary;
576 let span_block = self.mark_span_with_reason(reason, cond.span, None);
577 self.expr_drop_temps(span_block, cond)
578 }
579 }
580 }
581
582 fn lower_expr_while_in_loop_scope(
599 &mut self,
600 span: Span,
601 cond: &Expr,
602 body: &Block,
603 opt_label: Option<Label>,
604 ) -> hir::ExprKind<'hir> {
605 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_cond(cond));
606 let then = self.lower_block_expr(body);
607 let expr_break = self.expr_break(span);
608 let stmt_break = self.stmt_expr(span, expr_break);
609 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
610 let else_expr = self.arena.alloc(self.expr_block(else_blk));
611 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
612 let if_expr = self.expr(span, if_kind);
613 let block = self.block_expr(self.arena.alloc(if_expr));
614 let span = self.lower_span(span.with_hi(cond.span.hi()));
615 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
616 }
617
618 fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
622 let body_hir_id = self.lower_node_id(body.id);
623 self.with_catch_scope(body_hir_id, |this| {
624 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
625
626 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
628 (
629 this.mark_span_with_reason(
630 DesugaringKind::TryBlock,
631 expr.span,
632 Some(Arc::clone(&this.allow_try_trait)),
633 ),
634 expr,
635 )
636 } else {
637 let try_span = this.mark_span_with_reason(
638 DesugaringKind::TryBlock,
639 this.tcx.sess.source_map().end_point(body.span),
640 Some(Arc::clone(&this.allow_try_trait)),
641 );
642
643 (try_span, this.expr_unit(try_span))
644 };
645
646 let ok_wrapped_span =
647 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
648
649 block.expr = Some(this.wrap_in_try_constructor(
651 hir::LangItem::TryTraitFromOutput,
652 try_span,
653 tail_expr,
654 ok_wrapped_span,
655 ));
656
657 hir::ExprKind::Block(this.arena.alloc(block), None)
658 })
659 }
660
661 fn wrap_in_try_constructor(
662 &mut self,
663 lang_item: hir::LangItem,
664 method_span: Span,
665 expr: &'hir hir::Expr<'hir>,
666 overall_span: Span,
667 ) -> &'hir hir::Expr<'hir> {
668 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
669 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
670 }
671
672 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
673 let pat = self.lower_pat(&arm.pat);
674 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
675 let hir_id = self.next_id();
676 let span = self.lower_span(arm.span);
677 self.lower_attrs(hir_id, &arm.attrs, arm.span);
678 let is_never_pattern = pat.is_never_pattern();
679 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
682 let body = if let Some(body) = body
683 && !is_never_pattern
684 {
685 body
686 } else {
687 if !is_never_pattern {
689 if self.tcx.features().never_patterns() {
690 let suggestion = span.shrink_to_hi();
692 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
693 }
694 } else if let Some(body) = &arm.body {
695 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
696 } else if let Some(g) = &arm.guard {
697 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
698 }
699
700 let block = self.arena.alloc(hir::Block {
703 stmts: &[],
704 expr: None,
705 hir_id: self.next_id(),
706 rules: hir::BlockCheckMode::DefaultBlock,
707 span,
708 targeted_by_break: false,
709 });
710 self.arena.alloc(hir::Expr {
711 hir_id: self.next_id(),
712 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
713 span,
714 })
715 };
716 hir::Arm { hir_id, pat, guard, body, span }
717 }
718
719 pub(super) fn make_desugared_coroutine_expr(
731 &mut self,
732 capture_clause: CaptureBy,
733 closure_node_id: NodeId,
734 return_ty: Option<hir::FnRetTy<'hir>>,
735 fn_decl_span: Span,
736 span: Span,
737 desugaring_kind: hir::CoroutineDesugaring,
738 coroutine_source: hir::CoroutineSource,
739 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
740 ) -> hir::ExprKind<'hir> {
741 let closure_def_id = self.local_def_id(closure_node_id);
742 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
743
744 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
747 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
748 let unstable_span = self.mark_span_with_reason(
750 DesugaringKind::Async,
751 self.lower_span(span),
752 Some(Arc::clone(&self.allow_gen_future)),
753 );
754 let resume_ty =
755 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
756 let input_ty = hir::Ty {
757 hir_id: self.next_id(),
758 kind: hir::TyKind::Path(resume_ty),
759 span: unstable_span,
760 };
761 let inputs = arena_vec![self; input_ty];
762
763 let (pat, task_context_hid) = self.pat_ident_binding_mode(
765 span,
766 Ident::with_dummy_span(sym::_task_context),
767 hir::BindingMode::MUT,
768 );
769 let param = hir::Param {
770 hir_id: self.next_id(),
771 pat,
772 ty_span: self.lower_span(span),
773 span: self.lower_span(span),
774 };
775 let params = arena_vec![self; param];
776
777 (inputs, params, Some(task_context_hid))
778 }
779 hir::CoroutineDesugaring::Gen => (&[], &[], None),
780 };
781
782 let output =
783 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
784
785 let fn_decl = self.arena.alloc(hir::FnDecl {
786 inputs,
787 output,
788 c_variadic: false,
789 implicit_self: hir::ImplicitSelfKind::None,
790 lifetime_elision_allowed: false,
791 });
792
793 let body = self.lower_body(move |this| {
794 this.coroutine_kind = Some(coroutine_kind);
795
796 let old_ctx = this.task_context;
797 if task_context.is_some() {
798 this.task_context = task_context;
799 }
800 let res = body(this);
801 this.task_context = old_ctx;
802
803 (params, res)
804 });
805
806 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
808 def_id: closure_def_id,
809 binder: hir::ClosureBinder::Default,
810 capture_clause,
811 bound_generic_params: &[],
812 fn_decl,
813 body,
814 fn_decl_span: self.lower_span(fn_decl_span),
815 fn_arg_span: None,
816 kind: hir::ClosureKind::Coroutine(coroutine_kind),
817 constness: hir::Constness::NotConst,
818 }))
819 }
820
821 pub(super) fn maybe_forward_track_caller(
824 &mut self,
825 span: Span,
826 outer_hir_id: HirId,
827 inner_hir_id: HirId,
828 ) {
829 if self.tcx.features().async_fn_track_caller()
830 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
831 && find_attr!(*attrs, AttributeKind::TrackCaller(_))
832 {
833 let unstable_span = self.mark_span_with_reason(
834 DesugaringKind::Async,
835 span,
836 Some(Arc::clone(&self.allow_gen_future)),
837 );
838 self.lower_attrs(
839 inner_hir_id,
840 &[Attribute {
841 kind: AttrKind::Normal(ptr::P(NormalAttr::from_ident(Ident::new(
842 sym::track_caller,
843 span,
844 )))),
845 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
846 style: AttrStyle::Outer,
847 span: unstable_span,
848 }],
849 span,
850 );
851 }
852 }
853
854 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
870 let expr = self.arena.alloc(self.lower_expr_mut(expr));
871 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
872 }
873
874 fn make_lowered_await(
876 &mut self,
877 await_kw_span: Span,
878 expr: &'hir hir::Expr<'hir>,
879 await_kind: FutureKind,
880 ) -> hir::ExprKind<'hir> {
881 let full_span = expr.span.to(await_kw_span);
882
883 let is_async_gen = match self.coroutine_kind {
884 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
885 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
886 Some(hir::CoroutineKind::Coroutine(_))
887 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
888 | None => {
889 let stmt_id = self.next_id();
892 let expr_err = self.expr(
893 expr.span,
894 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
895 await_kw_span,
896 item_span: self.current_item,
897 })),
898 );
899 return hir::ExprKind::Block(
900 self.block_all(
901 expr.span,
902 arena_vec![self; hir::Stmt {
903 hir_id: stmt_id,
904 kind: hir::StmtKind::Semi(expr),
905 span: expr.span,
906 }],
907 Some(self.arena.alloc(expr_err)),
908 ),
909 None,
910 );
911 }
912 };
913
914 let features = match await_kind {
915 FutureKind::Future => None,
916 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
917 };
918 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
919 let gen_future_span = self.mark_span_with_reason(
920 DesugaringKind::Await,
921 full_span,
922 Some(Arc::clone(&self.allow_gen_future)),
923 );
924 let expr_hir_id = expr.hir_id;
925
926 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
930 let (awaitee_pat, awaitee_pat_hid) =
931 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
932
933 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
934
935 let poll_expr = {
942 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
943 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
944
945 let Some(task_context_hid) = self.task_context else {
946 unreachable!("use of `await` outside of an async context.");
947 };
948
949 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
950
951 let new_unchecked = self.expr_call_lang_item_fn_mut(
952 span,
953 hir::LangItem::PinNewUnchecked,
954 arena_vec![self; ref_mut_awaitee],
955 );
956 let get_context = self.expr_call_lang_item_fn_mut(
957 gen_future_span,
958 hir::LangItem::GetContext,
959 arena_vec![self; task_context],
960 );
961 let call = match await_kind {
962 FutureKind::Future => self.expr_call_lang_item_fn(
963 span,
964 hir::LangItem::FuturePoll,
965 arena_vec![self; new_unchecked, get_context],
966 ),
967 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
968 span,
969 hir::LangItem::AsyncIteratorPollNext,
970 arena_vec![self; new_unchecked, get_context],
971 ),
972 };
973 self.arena.alloc(self.expr_unsafe(call))
974 };
975
976 let loop_node_id = self.next_node_id();
978 let loop_hir_id = self.lower_node_id(loop_node_id);
979 let ready_arm = {
980 let x_ident = Ident::with_dummy_span(sym::result);
981 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
982 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
983 let ready_field = self.single_pat_field(gen_future_span, x_pat);
984 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
985 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
986 let expr_break =
987 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
988 this.arena.alloc(this.expr(gen_future_span, expr_break))
989 });
990 self.arm(ready_pat, break_x)
991 };
992
993 let pending_arm = {
995 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
996 let empty_block = self.expr_block_empty(span);
997 self.arm(pending_pat, empty_block)
998 };
999
1000 let inner_match_stmt = {
1001 let match_expr = self.expr_match(
1002 span,
1003 poll_expr,
1004 arena_vec![self; ready_arm, pending_arm],
1005 hir::MatchSource::AwaitDesugar,
1006 );
1007 self.stmt_expr(span, match_expr)
1008 };
1009
1010 let yield_stmt = {
1014 let yielded = if is_async_gen {
1015 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
1016 } else {
1017 self.expr_unit(span)
1018 };
1019
1020 let yield_expr = self.expr(
1021 span,
1022 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
1023 );
1024 let yield_expr = self.arena.alloc(yield_expr);
1025
1026 let Some(task_context_hid) = self.task_context else {
1027 unreachable!("use of `await` outside of an async context.");
1028 };
1029
1030 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1031 let assign =
1032 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
1033 self.stmt_expr(span, assign)
1034 };
1035
1036 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
1037
1038 let loop_expr = self.arena.alloc(hir::Expr {
1040 hir_id: loop_hir_id,
1041 kind: hir::ExprKind::Loop(
1042 loop_block,
1043 None,
1044 hir::LoopSource::Loop,
1045 self.lower_span(span),
1046 ),
1047 span: self.lower_span(span),
1048 });
1049
1050 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1052
1053 let into_future_expr = match await_kind {
1055 FutureKind::Future => self.expr_call_lang_item_fn(
1056 span,
1057 hir::LangItem::IntoFutureIntoFuture,
1058 arena_vec![self; *expr],
1059 ),
1060 FutureKind::AsyncIterator => expr,
1063 };
1064
1065 hir::ExprKind::Match(
1069 into_future_expr,
1070 arena_vec![self; awaitee_arm],
1071 hir::MatchSource::AwaitDesugar,
1072 )
1073 }
1074
1075 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1076 hir::ExprKind::Use(self.lower_expr(expr), use_kw_span)
1077 }
1078
1079 fn lower_expr_closure(
1080 &mut self,
1081 binder: &ClosureBinder,
1082 capture_clause: CaptureBy,
1083 closure_id: NodeId,
1084 closure_hir_id: hir::HirId,
1085 constness: Const,
1086 movability: Movability,
1087 decl: &FnDecl,
1088 body: &Expr,
1089 fn_decl_span: Span,
1090 fn_arg_span: Span,
1091 ) -> hir::ExprKind<'hir> {
1092 let closure_def_id = self.local_def_id(closure_id);
1093 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1094
1095 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1096 let mut coroutine_kind = if this
1097 .attrs
1098 .get(&closure_hir_id.local_id)
1099 .is_some_and(|attrs| attrs.iter().any(|attr| attr.has_name(sym::coroutine)))
1100 {
1101 Some(hir::CoroutineKind::Coroutine(Movability::Movable))
1102 } else {
1103 None
1104 };
1105 let body_id = this.lower_fn_body(decl, None, |this| {
1107 this.coroutine_kind = coroutine_kind;
1108 let e = this.lower_expr_mut(body);
1109 coroutine_kind = this.coroutine_kind;
1110 e
1111 });
1112 let coroutine_option =
1113 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1114 (body_id, coroutine_option)
1115 });
1116
1117 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1118 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1120
1121 let c = self.arena.alloc(hir::Closure {
1122 def_id: closure_def_id,
1123 binder: binder_clause,
1124 capture_clause,
1125 bound_generic_params,
1126 fn_decl,
1127 body: body_id,
1128 fn_decl_span: self.lower_span(fn_decl_span),
1129 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1130 kind: closure_kind,
1131 constness: self.lower_constness(constness),
1132 });
1133
1134 hir::ExprKind::Closure(c)
1135 }
1136
1137 fn closure_movability_for_fn(
1138 &mut self,
1139 decl: &FnDecl,
1140 fn_decl_span: Span,
1141 coroutine_kind: Option<hir::CoroutineKind>,
1142 movability: Movability,
1143 ) -> hir::ClosureKind {
1144 match coroutine_kind {
1145 Some(hir::CoroutineKind::Coroutine(_)) => {
1146 if decl.inputs.len() > 1 {
1147 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1148 }
1149 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1150 }
1151 Some(
1152 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1153 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1154 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1155 ) => {
1156 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1157 }
1158 None => {
1159 if movability == Movability::Static {
1160 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1161 }
1162 hir::ClosureKind::Closure
1163 }
1164 }
1165 }
1166
1167 fn lower_closure_binder<'c>(
1168 &mut self,
1169 binder: &'c ClosureBinder,
1170 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1171 let (binder, params) = match binder {
1172 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1173 ClosureBinder::For { span, generic_params } => {
1174 let span = self.lower_span(*span);
1175 (hir::ClosureBinder::For { span }, &**generic_params)
1176 }
1177 };
1178
1179 (binder, params)
1180 }
1181
1182 fn lower_expr_coroutine_closure(
1183 &mut self,
1184 binder: &ClosureBinder,
1185 capture_clause: CaptureBy,
1186 closure_id: NodeId,
1187 closure_hir_id: HirId,
1188 coroutine_kind: CoroutineKind,
1189 decl: &FnDecl,
1190 body: &Expr,
1191 fn_decl_span: Span,
1192 fn_arg_span: Span,
1193 ) -> hir::ExprKind<'hir> {
1194 let closure_def_id = self.local_def_id(closure_id);
1195 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1196
1197 let coroutine_desugaring = match coroutine_kind {
1198 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1199 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1200 CoroutineKind::AsyncGen { span, .. } => {
1201 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1202 }
1203 };
1204
1205 let body = self.with_new_scopes(fn_decl_span, |this| {
1206 let inner_decl =
1207 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1208
1209 let body_id = this.lower_body(|this| {
1212 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1213 &inner_decl,
1214 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1215 fn_decl_span,
1216 body.span,
1217 coroutine_kind,
1218 hir::CoroutineSource::Closure,
1219 );
1220
1221 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1222
1223 (parameters, expr)
1224 });
1225 body_id
1226 });
1227
1228 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1229 let fn_decl =
1233 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1234
1235 let c = self.arena.alloc(hir::Closure {
1236 def_id: closure_def_id,
1237 binder: binder_clause,
1238 capture_clause,
1239 bound_generic_params,
1240 fn_decl,
1241 body,
1242 fn_decl_span: self.lower_span(fn_decl_span),
1243 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1244 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1248 constness: hir::Constness::NotConst,
1249 });
1250 hir::ExprKind::Closure(c)
1251 }
1252
1253 fn lower_expr_assign(
1256 &mut self,
1257 lhs: &Expr,
1258 rhs: &Expr,
1259 eq_sign_span: Span,
1260 whole_span: Span,
1261 ) -> hir::ExprKind<'hir> {
1262 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1264 match &lhs.kind {
1265 ExprKind::Array(..)
1266 | ExprKind::Struct(..)
1267 | ExprKind::Tup(..)
1268 | ExprKind::Underscore => false,
1269 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1271 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1273 ExprKind::Paren(e) => {
1274 match e.kind {
1275 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1277 _ => is_ordinary(lower_ctx, e),
1278 }
1279 }
1280 _ => true,
1281 }
1282 }
1283 if is_ordinary(self, lhs) {
1284 return hir::ExprKind::Assign(
1285 self.lower_expr(lhs),
1286 self.lower_expr(rhs),
1287 self.lower_span(eq_sign_span),
1288 );
1289 }
1290
1291 let mut assignments = vec![];
1292
1293 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1295 let rhs = self.lower_expr(rhs);
1296
1297 let destructure_let = self.stmt_let_pat(
1299 None,
1300 whole_span,
1301 Some(rhs),
1302 pat,
1303 hir::LocalSource::AssignDesugar(self.lower_span(eq_sign_span)),
1304 );
1305
1306 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1308
1309 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1311 }
1312
1313 fn extract_tuple_struct_path<'a>(
1318 &mut self,
1319 expr: &'a Expr,
1320 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1321 if let ExprKind::Path(qself, path) = &expr.kind {
1322 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1324 if let Some(res) = partial_res.full_res()
1325 && !res.expected_in_tuple_struct_pat()
1326 {
1327 return None;
1328 }
1329 }
1330 return Some((qself, path));
1331 }
1332 None
1333 }
1334
1335 fn extract_unit_struct_path<'a>(
1340 &mut self,
1341 expr: &'a Expr,
1342 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1343 if let ExprKind::Path(qself, path) = &expr.kind {
1344 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1346 if let Some(res) = partial_res.full_res()
1347 && !res.expected_in_unit_struct_pat()
1348 {
1349 return None;
1350 }
1351 }
1352 return Some((qself, path));
1353 }
1354 None
1355 }
1356
1357 fn destructure_assign(
1360 &mut self,
1361 lhs: &Expr,
1362 eq_sign_span: Span,
1363 assignments: &mut Vec<hir::Stmt<'hir>>,
1364 ) -> &'hir hir::Pat<'hir> {
1365 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1366 }
1367
1368 fn destructure_assign_mut(
1369 &mut self,
1370 lhs: &Expr,
1371 eq_sign_span: Span,
1372 assignments: &mut Vec<hir::Stmt<'hir>>,
1373 ) -> hir::Pat<'hir> {
1374 match &lhs.kind {
1375 ExprKind::Underscore => {
1377 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1378 }
1379 ExprKind::Array(elements) => {
1381 let (pats, rest) =
1382 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1383 let slice_pat = if let Some((i, span)) = rest {
1384 let (before, after) = pats.split_at(i);
1385 hir::PatKind::Slice(
1386 before,
1387 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1388 after,
1389 )
1390 } else {
1391 hir::PatKind::Slice(pats, None, &[])
1392 };
1393 return self.pat_without_dbm(lhs.span, slice_pat);
1394 }
1395 ExprKind::Call(callee, args) => {
1397 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1398 let (pats, rest) = self.destructure_sequence(
1399 args,
1400 "tuple struct or variant",
1401 eq_sign_span,
1402 assignments,
1403 );
1404 let qpath = self.lower_qpath(
1405 callee.id,
1406 qself,
1407 path,
1408 ParamMode::Optional,
1409 AllowReturnTypeNotation::No,
1410 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1411 None,
1412 );
1413 let tuple_struct_pat = hir::PatKind::TupleStruct(
1415 qpath,
1416 pats,
1417 hir::DotDotPos::new(rest.map(|r| r.0)),
1418 );
1419 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1420 }
1421 }
1422 ExprKind::Path(..) => {
1424 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1425 let qpath = self.lower_qpath(
1426 lhs.id,
1427 qself,
1428 path,
1429 ParamMode::Optional,
1430 AllowReturnTypeNotation::No,
1431 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1432 None,
1433 );
1434 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1436 kind: hir::PatExprKind::Path(qpath),
1437 hir_id: self.next_id(),
1438 span: self.lower_span(lhs.span),
1439 }));
1440 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1441 }
1442 }
1443 ExprKind::Struct(se) => {
1445 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1446 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1447 hir::PatField {
1448 hir_id: self.next_id(),
1449 ident: self.lower_ident(f.ident),
1450 pat,
1451 is_shorthand: f.is_shorthand,
1452 span: self.lower_span(f.span),
1453 }
1454 }));
1455 let qpath = self.lower_qpath(
1456 lhs.id,
1457 &se.qself,
1458 &se.path,
1459 ParamMode::Optional,
1460 AllowReturnTypeNotation::No,
1461 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1462 None,
1463 );
1464 let fields_omitted = match &se.rest {
1465 StructRest::Base(e) => {
1466 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1467 span: e.span,
1468 });
1469 true
1470 }
1471 StructRest::Rest(_) => true,
1472 StructRest::None => false,
1473 };
1474 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1475 return self.pat_without_dbm(lhs.span, struct_pat);
1476 }
1477 ExprKind::Tup(elements) => {
1479 let (pats, rest) =
1480 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1481 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1482 return self.pat_without_dbm(lhs.span, tuple_pat);
1483 }
1484 ExprKind::Paren(e) => {
1485 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1487 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1488 return self.pat_without_dbm(lhs.span, tuple_pat);
1489 } else {
1490 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1491 }
1492 }
1493 _ => {}
1494 }
1495 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1497 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1498 let ident = self.expr_ident(lhs.span, ident, binding);
1499 let assign =
1500 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1501 let expr = self.expr(lhs.span, assign);
1502 assignments.push(self.stmt_expr(lhs.span, expr));
1503 pat
1504 }
1505
1506 fn destructure_sequence(
1512 &mut self,
1513 elements: &[AstP<Expr>],
1514 ctx: &str,
1515 eq_sign_span: Span,
1516 assignments: &mut Vec<hir::Stmt<'hir>>,
1517 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1518 let mut rest = None;
1519 let elements =
1520 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1521 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1523 if let Some((_, prev_span)) = rest {
1524 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1525 } else {
1526 rest = Some((i, e.span));
1527 }
1528 None
1529 } else {
1530 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1531 }
1532 }));
1533 (elements, rest)
1534 }
1535
1536 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1538 let e1 = self.lower_expr_mut(e1);
1539 let e2 = self.lower_expr_mut(e2);
1540 let fn_path = hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, self.lower_span(span));
1541 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1542 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1543 }
1544
1545 fn lower_expr_range(
1546 &mut self,
1547 span: Span,
1548 e1: Option<&Expr>,
1549 e2: Option<&Expr>,
1550 lims: RangeLimits,
1551 ) -> hir::ExprKind<'hir> {
1552 use rustc_ast::RangeLimits::*;
1553
1554 let lang_item = match (e1, e2, lims) {
1555 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1556 (Some(..), None, HalfOpen) => {
1557 if self.tcx.features().new_range() {
1558 hir::LangItem::RangeFromCopy
1559 } else {
1560 hir::LangItem::RangeFrom
1561 }
1562 }
1563 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1564 (Some(..), Some(..), HalfOpen) => {
1565 if self.tcx.features().new_range() {
1566 hir::LangItem::RangeCopy
1567 } else {
1568 hir::LangItem::Range
1569 }
1570 }
1571 (None, Some(..), Closed) => hir::LangItem::RangeToInclusive,
1572 (Some(e1), Some(e2), Closed) => {
1573 if self.tcx.features().new_range() {
1574 hir::LangItem::RangeInclusiveCopy
1575 } else {
1576 return self.lower_expr_range_closed(span, e1, e2);
1577 }
1578 }
1579 (start, None, Closed) => {
1580 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1581 match start {
1582 Some(..) => {
1583 if self.tcx.features().new_range() {
1584 hir::LangItem::RangeFromCopy
1585 } else {
1586 hir::LangItem::RangeFrom
1587 }
1588 }
1589 None => hir::LangItem::RangeFull,
1590 }
1591 }
1592 };
1593
1594 let fields = self.arena.alloc_from_iter(
1595 e1.iter().map(|e| (sym::start, e)).chain(e2.iter().map(|e| (sym::end, e))).map(
1596 |(s, e)| {
1597 let expr = self.lower_expr(e);
1598 let ident = Ident::new(s, self.lower_span(e.span));
1599 self.expr_field(ident, expr, e.span)
1600 },
1601 ),
1602 );
1603
1604 hir::ExprKind::Struct(
1605 self.arena.alloc(hir::QPath::LangItem(lang_item, self.lower_span(span))),
1606 fields,
1607 hir::StructTailExpr::None,
1608 )
1609 }
1610
1611 fn lower_label(
1614 &mut self,
1615 opt_label: Option<Label>,
1616 dest_id: NodeId,
1617 dest_hir_id: hir::HirId,
1618 ) -> Option<Label> {
1619 let label = opt_label?;
1620 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1621 Some(Label { ident: self.lower_ident(label.ident) })
1622 }
1623
1624 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1625 let target_id = match destination {
1626 Some((id, _)) => {
1627 if let Some(loop_id) = self.resolver.get_label_res(id) {
1628 let local_id = self.ident_and_label_to_local_id[&loop_id];
1629 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1630 Ok(loop_hir_id)
1631 } else {
1632 Err(hir::LoopIdError::UnresolvedLabel)
1633 }
1634 }
1635 None => {
1636 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1637 }
1638 };
1639 let label = destination
1640 .map(|(_, label)| label)
1641 .map(|label| Label { ident: self.lower_ident(label.ident) });
1642 hir::Destination { label, target_id }
1643 }
1644
1645 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1646 if self.is_in_loop_condition && opt_label.is_none() {
1647 hir::Destination {
1648 label: None,
1649 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1650 }
1651 } else {
1652 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1653 }
1654 }
1655
1656 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1657 let old_scope = self.catch_scope.replace(catch_id);
1658 let result = f(self);
1659 self.catch_scope = old_scope;
1660 result
1661 }
1662
1663 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1664 let was_in_loop_condition = self.is_in_loop_condition;
1666 self.is_in_loop_condition = false;
1667
1668 let old_scope = self.loop_scope.replace(loop_id);
1669 let result = f(self);
1670 self.loop_scope = old_scope;
1671
1672 self.is_in_loop_condition = was_in_loop_condition;
1673
1674 result
1675 }
1676
1677 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1678 let was_in_loop_condition = self.is_in_loop_condition;
1679 self.is_in_loop_condition = true;
1680
1681 let result = f(self);
1682
1683 self.is_in_loop_condition = was_in_loop_condition;
1684
1685 result
1686 }
1687
1688 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1689 let hir_id = self.lower_node_id(f.id);
1690 self.lower_attrs(hir_id, &f.attrs, f.span);
1691 hir::ExprField {
1692 hir_id,
1693 ident: self.lower_ident(f.ident),
1694 expr: self.lower_expr(&f.expr),
1695 span: self.lower_span(f.span),
1696 is_shorthand: f.is_shorthand,
1697 }
1698 }
1699
1700 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1701 let yielded =
1702 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1703
1704 if !self.tcx.features().yield_expr()
1705 && !self.tcx.features().coroutines()
1706 && !self.tcx.features().gen_blocks()
1707 {
1708 rustc_session::parse::feature_err(
1709 &self.tcx.sess,
1710 sym::yield_expr,
1711 span,
1712 fluent_generated::ast_lowering_yield,
1713 )
1714 .emit();
1715 }
1716
1717 let is_async_gen = match self.coroutine_kind {
1718 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1719 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1720 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1721 let stmt_id = self.next_id();
1724 let expr_err = self.expr(
1725 yielded.span,
1726 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1727 );
1728 return hir::ExprKind::Block(
1729 self.block_all(
1730 yielded.span,
1731 arena_vec![self; hir::Stmt {
1732 hir_id: stmt_id,
1733 kind: hir::StmtKind::Semi(yielded),
1734 span: yielded.span,
1735 }],
1736 Some(self.arena.alloc(expr_err)),
1737 ),
1738 None,
1739 );
1740 }
1741 Some(hir::CoroutineKind::Coroutine(_)) => false,
1742 None => {
1743 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1744 self.dcx().emit_err(YieldInClosure { span, suggestion });
1745 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1746
1747 false
1748 }
1749 };
1750
1751 if is_async_gen {
1752 let wrapped_yielded = self.expr_call_lang_item_fn(
1756 span,
1757 hir::LangItem::AsyncGenReady,
1758 std::slice::from_ref(yielded),
1759 );
1760 let yield_expr = self.arena.alloc(
1761 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1762 );
1763
1764 let Some(task_context_hid) = self.task_context else {
1765 unreachable!("use of `await` outside of an async context.");
1766 };
1767 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1768 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1769
1770 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1771 } else {
1772 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1773 }
1774 }
1775
1776 fn lower_expr_for(
1793 &mut self,
1794 e: &Expr,
1795 pat: &Pat,
1796 head: &Expr,
1797 body: &Block,
1798 opt_label: Option<Label>,
1799 loop_kind: ForLoopKind,
1800 ) -> hir::Expr<'hir> {
1801 let head = self.lower_expr_mut(head);
1802 let pat = self.lower_pat(pat);
1803 let for_span =
1804 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1805 let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
1806 let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
1807
1808 let loop_hir_id = self.lower_node_id(e.id);
1809 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1810
1811 let none_arm = {
1813 let break_expr =
1814 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1815 let pat = self.pat_none(for_span);
1816 self.arm(pat, break_expr)
1817 };
1818
1819 let some_arm = {
1821 let some_pat = self.pat_some(pat_span, pat);
1822 let body_block =
1823 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1824 let body_expr = self.arena.alloc(self.expr_block(body_block));
1825 self.arm(some_pat, body_expr)
1826 };
1827
1828 let iter = Ident::with_dummy_span(sym::iter);
1830 let (iter_pat, iter_pat_nid) =
1831 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1832
1833 let match_expr = {
1834 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1835 let next_expr = match loop_kind {
1836 ForLoopKind::For => {
1837 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1839 self.expr_call_lang_item_fn(
1840 head_span,
1841 hir::LangItem::IteratorNext,
1842 arena_vec![self; ref_mut_iter],
1843 )
1844 }
1845 ForLoopKind::ForAwait => {
1846 let iter = self.expr_mut_addr_of(head_span, iter);
1853 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1855 head_span,
1856 hir::LangItem::PinNewUnchecked,
1857 arena_vec![self; iter],
1858 ));
1859 let iter = self.arena.alloc(self.expr_unsafe(iter));
1861 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1862 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1863 }
1864 };
1865 let arms = arena_vec![self; none_arm, some_arm];
1866
1867 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1869 };
1870 let match_stmt = self.stmt_expr(for_span, match_expr);
1871
1872 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1873
1874 let kind = hir::ExprKind::Loop(
1876 loop_block,
1877 label,
1878 hir::LoopSource::ForLoop,
1879 self.lower_span(for_span.with_hi(head.span.hi())),
1880 );
1881 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1882
1883 let iter_arm = self.arm(iter_pat, loop_expr);
1885
1886 let match_expr = match loop_kind {
1887 ForLoopKind::For => {
1888 let into_iter_expr = self.expr_call_lang_item_fn(
1890 head_span,
1891 hir::LangItem::IntoIterIntoIter,
1892 arena_vec![self; head],
1893 );
1894
1895 self.arena.alloc(self.expr_match(
1896 for_span,
1897 into_iter_expr,
1898 arena_vec![self; iter_arm],
1899 hir::MatchSource::ForLoopDesugar,
1900 ))
1901 }
1902 ForLoopKind::ForAwait => {
1904 let iter_ident = iter;
1905 let (async_iter_pat, async_iter_pat_id) =
1906 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1907 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1908 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1910 head_span,
1911 hir::LangItem::PinNewUnchecked,
1912 arena_vec![self; iter],
1913 ));
1914 let iter = self.arena.alloc(self.expr_unsafe(iter));
1916 let inner_match_expr = self.arena.alloc(self.expr_match(
1917 for_span,
1918 iter,
1919 arena_vec![self; iter_arm],
1920 hir::MatchSource::ForLoopDesugar,
1921 ));
1922
1923 let iter = self.expr_call_lang_item_fn(
1925 head_span,
1926 hir::LangItem::IntoAsyncIterIntoIter,
1927 arena_vec![self; head],
1928 );
1929 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1930 self.arena.alloc(self.expr_match(
1931 for_span,
1932 iter,
1933 arena_vec![self; iter_arm],
1934 hir::MatchSource::ForLoopDesugar,
1935 ))
1936 }
1937 };
1938
1939 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1946 self.lower_attrs(expr.hir_id, &e.attrs, e.span);
1947 expr
1948 }
1949
1950 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1963 let unstable_span = self.mark_span_with_reason(
1964 DesugaringKind::QuestionMark,
1965 span,
1966 Some(Arc::clone(&self.allow_try_trait)),
1967 );
1968 let try_span = self.tcx.sess.source_map().end_point(span);
1969 let try_span = self.mark_span_with_reason(
1970 DesugaringKind::QuestionMark,
1971 try_span,
1972 Some(Arc::clone(&self.allow_try_trait)),
1973 );
1974
1975 let scrutinee = {
1977 let sub_expr = self.lower_expr_mut(sub_expr);
1979
1980 self.expr_call_lang_item_fn(
1981 unstable_span,
1982 hir::LangItem::TryTraitBranch,
1983 arena_vec![self; sub_expr],
1984 )
1985 };
1986
1987 let attr = attr::mk_attr_nested_word(
1989 &self.tcx.sess.psess.attr_id_generator,
1990 AttrStyle::Outer,
1991 Safety::Default,
1992 sym::allow,
1993 sym::unreachable_code,
1994 try_span,
1995 );
1996 let attrs: AttrVec = thin_vec![attr];
1997
1998 let continue_arm = {
2000 let val_ident = Ident::with_dummy_span(sym::val);
2001 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
2002 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
2003 self.lower_attrs(val_expr.hir_id, &attrs, span);
2004 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
2005 self.arm(continue_pat, val_expr)
2006 };
2007
2008 let break_arm = {
2012 let residual_ident = Ident::with_dummy_span(sym::residual);
2013 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
2014 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
2015 let from_residual_expr = self.wrap_in_try_constructor(
2016 hir::LangItem::TryTraitFromResidual,
2017 try_span,
2018 self.arena.alloc(residual_expr),
2019 unstable_span,
2020 );
2021 let ret_expr = if let Some(catch_id) = self.catch_scope {
2022 let target_id = Ok(catch_id);
2023 self.arena.alloc(self.expr(
2024 try_span,
2025 hir::ExprKind::Break(
2026 hir::Destination { label: None, target_id },
2027 Some(from_residual_expr),
2028 ),
2029 ))
2030 } else {
2031 let ret_expr = self.checked_return(Some(from_residual_expr));
2032 self.arena.alloc(self.expr(try_span, ret_expr))
2033 };
2034 self.lower_attrs(ret_expr.hir_id, &attrs, span);
2035
2036 let break_pat = self.pat_cf_break(try_span, residual_local);
2037 self.arm(break_pat, ret_expr)
2038 };
2039
2040 hir::ExprKind::Match(
2041 scrutinee,
2042 arena_vec![self; break_arm, continue_arm],
2043 hir::MatchSource::TryDesugar(scrutinee.hir_id),
2044 )
2045 }
2046
2047 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2057 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2059 (sub_expr.span, self.lower_expr(sub_expr))
2060 } else {
2061 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2062 };
2063
2064 let unstable_span = self.mark_span_with_reason(
2065 DesugaringKind::YeetExpr,
2066 span,
2067 Some(Arc::clone(&self.allow_try_trait)),
2068 );
2069
2070 let from_yeet_expr = self.wrap_in_try_constructor(
2071 hir::LangItem::TryTraitFromYeet,
2072 unstable_span,
2073 yeeted_expr,
2074 yeeted_span,
2075 );
2076
2077 if let Some(catch_id) = self.catch_scope {
2078 let target_id = Ok(catch_id);
2079 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2080 } else {
2081 self.checked_return(Some(from_yeet_expr))
2082 }
2083 }
2084
2085 pub(super) fn expr_drop_temps(
2096 &mut self,
2097 span: Span,
2098 expr: &'hir hir::Expr<'hir>,
2099 ) -> &'hir hir::Expr<'hir> {
2100 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2101 }
2102
2103 pub(super) fn expr_drop_temps_mut(
2104 &mut self,
2105 span: Span,
2106 expr: &'hir hir::Expr<'hir>,
2107 ) -> hir::Expr<'hir> {
2108 self.expr(span, hir::ExprKind::DropTemps(expr))
2109 }
2110
2111 pub(super) fn expr_match(
2112 &mut self,
2113 span: Span,
2114 arg: &'hir hir::Expr<'hir>,
2115 arms: &'hir [hir::Arm<'hir>],
2116 source: hir::MatchSource,
2117 ) -> hir::Expr<'hir> {
2118 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2119 }
2120
2121 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2122 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2123 self.expr(span, expr_break)
2124 }
2125
2126 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2127 let expr_break = self.expr_break(span);
2128 self.arena.alloc(expr_break)
2129 }
2130
2131 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2132 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2133 }
2134
2135 fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2136 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2137 }
2138
2139 fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
2140 let lit = hir::Lit {
2141 span: sp,
2142 node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
2143 };
2144 self.expr(sp, hir::ExprKind::Lit(lit))
2145 }
2146
2147 pub(super) fn expr_usize(&mut self, sp: Span, value: usize) -> hir::Expr<'hir> {
2148 self.expr_uint(sp, ast::UintTy::Usize, value as u128)
2149 }
2150
2151 pub(super) fn expr_u32(&mut self, sp: Span, value: u32) -> hir::Expr<'hir> {
2152 self.expr_uint(sp, ast::UintTy::U32, value as u128)
2153 }
2154
2155 pub(super) fn expr_u16(&mut self, sp: Span, value: u16) -> hir::Expr<'hir> {
2156 self.expr_uint(sp, ast::UintTy::U16, value as u128)
2157 }
2158
2159 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2160 let lit = hir::Lit { span: sp, node: ast::LitKind::Str(value, ast::StrStyle::Cooked) };
2161 self.expr(sp, hir::ExprKind::Lit(lit))
2162 }
2163
2164 pub(super) fn expr_call_mut(
2165 &mut self,
2166 span: Span,
2167 e: &'hir hir::Expr<'hir>,
2168 args: &'hir [hir::Expr<'hir>],
2169 ) -> hir::Expr<'hir> {
2170 self.expr(span, hir::ExprKind::Call(e, args))
2171 }
2172
2173 pub(super) fn expr_call(
2174 &mut self,
2175 span: Span,
2176 e: &'hir hir::Expr<'hir>,
2177 args: &'hir [hir::Expr<'hir>],
2178 ) -> &'hir hir::Expr<'hir> {
2179 self.arena.alloc(self.expr_call_mut(span, e, args))
2180 }
2181
2182 pub(super) fn expr_call_lang_item_fn_mut(
2183 &mut self,
2184 span: Span,
2185 lang_item: hir::LangItem,
2186 args: &'hir [hir::Expr<'hir>],
2187 ) -> hir::Expr<'hir> {
2188 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2189 self.expr_call_mut(span, path, args)
2190 }
2191
2192 pub(super) fn expr_call_lang_item_fn(
2193 &mut self,
2194 span: Span,
2195 lang_item: hir::LangItem,
2196 args: &'hir [hir::Expr<'hir>],
2197 ) -> &'hir hir::Expr<'hir> {
2198 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2199 }
2200
2201 fn expr_lang_item_path(&mut self, span: Span, lang_item: hir::LangItem) -> hir::Expr<'hir> {
2202 self.expr(span, hir::ExprKind::Path(hir::QPath::LangItem(lang_item, self.lower_span(span))))
2203 }
2204
2205 pub(super) fn expr_lang_item_type_relative(
2207 &mut self,
2208 span: Span,
2209 lang_item: hir::LangItem,
2210 name: Symbol,
2211 ) -> hir::Expr<'hir> {
2212 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2213 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2214 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2215 self.arena.alloc(hir::PathSegment::new(
2216 Ident::new(name, self.lower_span(span)),
2217 self.next_id(),
2218 Res::Err,
2219 )),
2220 ));
2221 self.expr(span, path)
2222 }
2223
2224 pub(super) fn expr_ident(
2225 &mut self,
2226 sp: Span,
2227 ident: Ident,
2228 binding: HirId,
2229 ) -> &'hir hir::Expr<'hir> {
2230 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2231 }
2232
2233 pub(super) fn expr_ident_mut(
2234 &mut self,
2235 span: Span,
2236 ident: Ident,
2237 binding: HirId,
2238 ) -> hir::Expr<'hir> {
2239 let hir_id = self.next_id();
2240 let res = Res::Local(binding);
2241 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2242 None,
2243 self.arena.alloc(hir::Path {
2244 span: self.lower_span(span),
2245 res,
2246 segments: arena_vec![self; hir::PathSegment::new(ident, hir_id, res)],
2247 }),
2248 ));
2249
2250 self.expr(span, expr_path)
2251 }
2252
2253 fn expr_unsafe(&mut self, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2254 let hir_id = self.next_id();
2255 let span = expr.span;
2256 self.expr(
2257 span,
2258 hir::ExprKind::Block(
2259 self.arena.alloc(hir::Block {
2260 stmts: &[],
2261 expr: Some(expr),
2262 hir_id,
2263 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2264 span: self.lower_span(span),
2265 targeted_by_break: false,
2266 }),
2267 None,
2268 ),
2269 )
2270 }
2271
2272 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2273 let blk = self.block_all(span, &[], None);
2274 let expr = self.expr_block(blk);
2275 self.arena.alloc(expr)
2276 }
2277
2278 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2279 self.expr(b.span, hir::ExprKind::Block(b, None))
2280 }
2281
2282 pub(super) fn expr_array_ref(
2283 &mut self,
2284 span: Span,
2285 elements: &'hir [hir::Expr<'hir>],
2286 ) -> hir::Expr<'hir> {
2287 let array = self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements)));
2288 self.expr_ref(span, array)
2289 }
2290
2291 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2292 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2293 }
2294
2295 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2296 let hir_id = self.next_id();
2297 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2298 }
2299
2300 pub(super) fn expr_field(
2301 &mut self,
2302 ident: Ident,
2303 expr: &'hir hir::Expr<'hir>,
2304 span: Span,
2305 ) -> hir::ExprField<'hir> {
2306 hir::ExprField {
2307 hir_id: self.next_id(),
2308 ident,
2309 span: self.lower_span(span),
2310 expr,
2311 is_shorthand: false,
2312 }
2313 }
2314
2315 pub(super) fn arm(
2316 &mut self,
2317 pat: &'hir hir::Pat<'hir>,
2318 expr: &'hir hir::Expr<'hir>,
2319 ) -> hir::Arm<'hir> {
2320 hir::Arm {
2321 hir_id: self.next_id(),
2322 pat,
2323 guard: None,
2324 span: self.lower_span(expr.span),
2325 body: expr,
2326 }
2327 }
2328}
2329
2330#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2333enum FutureKind {
2334 Future,
2336 AsyncIterator,
2339}