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(bytes) => {
148 let lit = self.arena.alloc(respan(
149 self.lower_span(e.span),
150 LitKind::ByteStr(Arc::clone(bytes), 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(
425 &mut self,
426 token_lit: &token::Lit,
427 span: Span,
428 ) -> &'hir Spanned<LitKind> {
429 let lit_kind = match LitKind::from_token_lit(*token_lit) {
430 Ok(lit_kind) => lit_kind,
431 Err(err) => {
432 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
433 LitKind::Err(guar)
434 }
435 };
436 self.arena.alloc(respan(self.lower_span(span), lit_kind))
437 }
438
439 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
440 match u {
441 UnOp::Deref => hir::UnOp::Deref,
442 UnOp::Not => hir::UnOp::Not,
443 UnOp::Neg => hir::UnOp::Neg,
444 }
445 }
446
447 fn lower_binop(&mut self, b: BinOp) -> BinOp {
448 Spanned { node: b.node, span: self.lower_span(b.span) }
449 }
450
451 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
452 Spanned { node: a.node, span: self.lower_span(a.span) }
453 }
454
455 fn lower_legacy_const_generics(
456 &mut self,
457 mut f: Expr,
458 args: ThinVec<AstP<Expr>>,
459 legacy_args_idx: &[usize],
460 ) -> hir::ExprKind<'hir> {
461 let ExprKind::Path(None, path) = &mut f.kind else {
462 unreachable!();
463 };
464
465 let mut error = None;
466 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
467 if error.is_none() {
469 let mut const_args = vec![];
470 let mut other_args = vec![];
471 for (idx, arg) in args.iter().enumerate() {
472 if legacy_args_idx.contains(&idx) {
473 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
474 } else {
475 other_args.push(expr_to_string(arg));
476 }
477 }
478 let suggestion = UseConstGenericArg {
479 end_of_fn: f.span.shrink_to_hi(),
480 const_args: const_args.join(", "),
481 other_args: other_args.join(", "),
482 call_args: args[0].span.to(args.last().unwrap().span),
483 };
484 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
485 }
486 error.unwrap()
487 };
488
489 let mut real_args = vec![];
491 let mut generic_args = ThinVec::new();
492 for (idx, arg) in args.iter().cloned().enumerate() {
493 if legacy_args_idx.contains(&idx) {
494 let node_id = self.next_node_id();
495 self.create_def(node_id, None, DefKind::AnonConst, f.span);
496 let mut visitor = WillCreateDefIdsVisitor {};
497 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
498 AstP(Expr {
499 id: self.next_node_id(),
500 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
501 span: f.span,
502 attrs: [].into(),
503 tokens: None,
504 })
505 } else {
506 arg
507 };
508
509 let anon_const = AnonConst { id: node_id, value: const_value };
510 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
511 } else {
512 real_args.push(arg);
513 }
514 }
515
516 let last_segment = path.segments.last_mut().unwrap();
518 assert!(last_segment.args.is_none());
519 last_segment.args = Some(AstP(GenericArgs::AngleBracketed(AngleBracketedArgs {
520 span: DUMMY_SP,
521 args: generic_args,
522 })));
523
524 let f = self.lower_expr(&f);
526 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
527 }
528
529 fn lower_expr_if(
530 &mut self,
531 cond: &Expr,
532 then: &Block,
533 else_opt: Option<&Expr>,
534 ) -> hir::ExprKind<'hir> {
535 let lowered_cond = self.lower_cond(cond);
536 let then_expr = self.lower_block_expr(then);
537 if let Some(rslt) = else_opt {
538 hir::ExprKind::If(
539 lowered_cond,
540 self.arena.alloc(then_expr),
541 Some(self.lower_expr(rslt)),
542 )
543 } else {
544 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
545 }
546 }
547
548 fn lower_cond(&mut self, cond: &Expr) -> &'hir hir::Expr<'hir> {
551 fn has_let_expr(expr: &Expr) -> bool {
552 match &expr.kind {
553 ExprKind::Binary(_, lhs, rhs) => has_let_expr(lhs) || has_let_expr(rhs),
554 ExprKind::Let(..) => true,
555 _ => false,
556 }
557 }
558
559 match &cond.kind {
567 ExprKind::Binary(op @ Spanned { node: ast::BinOpKind::And, .. }, lhs, rhs)
568 if has_let_expr(cond) =>
569 {
570 let op = self.lower_binop(*op);
571 let lhs = self.lower_cond(lhs);
572 let rhs = self.lower_cond(rhs);
573
574 self.arena.alloc(self.expr(cond.span, hir::ExprKind::Binary(op, lhs, rhs)))
575 }
576 ExprKind::Let(..) => self.lower_expr(cond),
577 _ => {
578 let cond = self.lower_expr(cond);
579 let reason = DesugaringKind::CondTemporary;
580 let span_block = self.mark_span_with_reason(reason, cond.span, None);
581 self.expr_drop_temps(span_block, cond)
582 }
583 }
584 }
585
586 fn lower_expr_while_in_loop_scope(
603 &mut self,
604 span: Span,
605 cond: &Expr,
606 body: &Block,
607 opt_label: Option<Label>,
608 ) -> hir::ExprKind<'hir> {
609 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_cond(cond));
610 let then = self.lower_block_expr(body);
611 let expr_break = self.expr_break(span);
612 let stmt_break = self.stmt_expr(span, expr_break);
613 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
614 let else_expr = self.arena.alloc(self.expr_block(else_blk));
615 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
616 let if_expr = self.expr(span, if_kind);
617 let block = self.block_expr(self.arena.alloc(if_expr));
618 let span = self.lower_span(span.with_hi(cond.span.hi()));
619 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
620 }
621
622 fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
626 let body_hir_id = self.lower_node_id(body.id);
627 self.with_catch_scope(body_hir_id, |this| {
628 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
629
630 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
632 (
633 this.mark_span_with_reason(
634 DesugaringKind::TryBlock,
635 expr.span,
636 Some(Arc::clone(&this.allow_try_trait)),
637 ),
638 expr,
639 )
640 } else {
641 let try_span = this.mark_span_with_reason(
642 DesugaringKind::TryBlock,
643 this.tcx.sess.source_map().end_point(body.span),
644 Some(Arc::clone(&this.allow_try_trait)),
645 );
646
647 (try_span, this.expr_unit(try_span))
648 };
649
650 let ok_wrapped_span =
651 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
652
653 block.expr = Some(this.wrap_in_try_constructor(
655 hir::LangItem::TryTraitFromOutput,
656 try_span,
657 tail_expr,
658 ok_wrapped_span,
659 ));
660
661 hir::ExprKind::Block(this.arena.alloc(block), None)
662 })
663 }
664
665 fn wrap_in_try_constructor(
666 &mut self,
667 lang_item: hir::LangItem,
668 method_span: Span,
669 expr: &'hir hir::Expr<'hir>,
670 overall_span: Span,
671 ) -> &'hir hir::Expr<'hir> {
672 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
673 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
674 }
675
676 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
677 let pat = self.lower_pat(&arm.pat);
678 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
679 let hir_id = self.next_id();
680 let span = self.lower_span(arm.span);
681 self.lower_attrs(hir_id, &arm.attrs, arm.span);
682 let is_never_pattern = pat.is_never_pattern();
683 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
686 let body = if let Some(body) = body
687 && !is_never_pattern
688 {
689 body
690 } else {
691 if !is_never_pattern {
693 if self.tcx.features().never_patterns() {
694 let suggestion = span.shrink_to_hi();
696 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
697 }
698 } else if let Some(body) = &arm.body {
699 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
700 } else if let Some(g) = &arm.guard {
701 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
702 }
703
704 let block = self.arena.alloc(hir::Block {
707 stmts: &[],
708 expr: None,
709 hir_id: self.next_id(),
710 rules: hir::BlockCheckMode::DefaultBlock,
711 span,
712 targeted_by_break: false,
713 });
714 self.arena.alloc(hir::Expr {
715 hir_id: self.next_id(),
716 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
717 span,
718 })
719 };
720 hir::Arm { hir_id, pat, guard, body, span }
721 }
722
723 pub(super) fn make_desugared_coroutine_expr(
735 &mut self,
736 capture_clause: CaptureBy,
737 closure_node_id: NodeId,
738 return_ty: Option<hir::FnRetTy<'hir>>,
739 fn_decl_span: Span,
740 span: Span,
741 desugaring_kind: hir::CoroutineDesugaring,
742 coroutine_source: hir::CoroutineSource,
743 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
744 ) -> hir::ExprKind<'hir> {
745 let closure_def_id = self.local_def_id(closure_node_id);
746 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
747
748 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
751 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
752 let unstable_span = self.mark_span_with_reason(
754 DesugaringKind::Async,
755 self.lower_span(span),
756 Some(Arc::clone(&self.allow_gen_future)),
757 );
758 let resume_ty =
759 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
760 let input_ty = hir::Ty {
761 hir_id: self.next_id(),
762 kind: hir::TyKind::Path(resume_ty),
763 span: unstable_span,
764 };
765 let inputs = arena_vec![self; input_ty];
766
767 let (pat, task_context_hid) = self.pat_ident_binding_mode(
769 span,
770 Ident::with_dummy_span(sym::_task_context),
771 hir::BindingMode::MUT,
772 );
773 let param = hir::Param {
774 hir_id: self.next_id(),
775 pat,
776 ty_span: self.lower_span(span),
777 span: self.lower_span(span),
778 };
779 let params = arena_vec![self; param];
780
781 (inputs, params, Some(task_context_hid))
782 }
783 hir::CoroutineDesugaring::Gen => (&[], &[], None),
784 };
785
786 let output =
787 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
788
789 let fn_decl = self.arena.alloc(hir::FnDecl {
790 inputs,
791 output,
792 c_variadic: false,
793 implicit_self: hir::ImplicitSelfKind::None,
794 lifetime_elision_allowed: false,
795 });
796
797 let body = self.lower_body(move |this| {
798 this.coroutine_kind = Some(coroutine_kind);
799
800 let old_ctx = this.task_context;
801 if task_context.is_some() {
802 this.task_context = task_context;
803 }
804 let res = body(this);
805 this.task_context = old_ctx;
806
807 (params, res)
808 });
809
810 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
812 def_id: closure_def_id,
813 binder: hir::ClosureBinder::Default,
814 capture_clause,
815 bound_generic_params: &[],
816 fn_decl,
817 body,
818 fn_decl_span: self.lower_span(fn_decl_span),
819 fn_arg_span: None,
820 kind: hir::ClosureKind::Coroutine(coroutine_kind),
821 constness: hir::Constness::NotConst,
822 }))
823 }
824
825 pub(super) fn maybe_forward_track_caller(
828 &mut self,
829 span: Span,
830 outer_hir_id: HirId,
831 inner_hir_id: HirId,
832 ) {
833 if self.tcx.features().async_fn_track_caller()
834 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
835 && find_attr!(*attrs, AttributeKind::TrackCaller(_))
836 {
837 let unstable_span = self.mark_span_with_reason(
838 DesugaringKind::Async,
839 span,
840 Some(Arc::clone(&self.allow_gen_future)),
841 );
842 self.lower_attrs(
843 inner_hir_id,
844 &[Attribute {
845 kind: AttrKind::Normal(ptr::P(NormalAttr::from_ident(Ident::new(
846 sym::track_caller,
847 span,
848 )))),
849 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
850 style: AttrStyle::Outer,
851 span: unstable_span,
852 }],
853 span,
854 );
855 }
856 }
857
858 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
874 let expr = self.arena.alloc(self.lower_expr_mut(expr));
875 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
876 }
877
878 fn make_lowered_await(
880 &mut self,
881 await_kw_span: Span,
882 expr: &'hir hir::Expr<'hir>,
883 await_kind: FutureKind,
884 ) -> hir::ExprKind<'hir> {
885 let full_span = expr.span.to(await_kw_span);
886
887 let is_async_gen = match self.coroutine_kind {
888 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
889 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
890 Some(hir::CoroutineKind::Coroutine(_))
891 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
892 | None => {
893 let stmt_id = self.next_id();
896 let expr_err = self.expr(
897 expr.span,
898 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
899 await_kw_span,
900 item_span: self.current_item,
901 })),
902 );
903 return hir::ExprKind::Block(
904 self.block_all(
905 expr.span,
906 arena_vec![self; hir::Stmt {
907 hir_id: stmt_id,
908 kind: hir::StmtKind::Semi(expr),
909 span: expr.span,
910 }],
911 Some(self.arena.alloc(expr_err)),
912 ),
913 None,
914 );
915 }
916 };
917
918 let features = match await_kind {
919 FutureKind::Future => None,
920 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
921 };
922 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
923 let gen_future_span = self.mark_span_with_reason(
924 DesugaringKind::Await,
925 full_span,
926 Some(Arc::clone(&self.allow_gen_future)),
927 );
928 let expr_hir_id = expr.hir_id;
929
930 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
934 let (awaitee_pat, awaitee_pat_hid) =
935 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
936
937 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
938
939 let poll_expr = {
946 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
947 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
948
949 let Some(task_context_hid) = self.task_context else {
950 unreachable!("use of `await` outside of an async context.");
951 };
952
953 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
954
955 let new_unchecked = self.expr_call_lang_item_fn_mut(
956 span,
957 hir::LangItem::PinNewUnchecked,
958 arena_vec![self; ref_mut_awaitee],
959 );
960 let get_context = self.expr_call_lang_item_fn_mut(
961 gen_future_span,
962 hir::LangItem::GetContext,
963 arena_vec![self; task_context],
964 );
965 let call = match await_kind {
966 FutureKind::Future => self.expr_call_lang_item_fn(
967 span,
968 hir::LangItem::FuturePoll,
969 arena_vec![self; new_unchecked, get_context],
970 ),
971 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
972 span,
973 hir::LangItem::AsyncIteratorPollNext,
974 arena_vec![self; new_unchecked, get_context],
975 ),
976 };
977 self.arena.alloc(self.expr_unsafe(call))
978 };
979
980 let loop_node_id = self.next_node_id();
982 let loop_hir_id = self.lower_node_id(loop_node_id);
983 let ready_arm = {
984 let x_ident = Ident::with_dummy_span(sym::result);
985 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
986 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
987 let ready_field = self.single_pat_field(gen_future_span, x_pat);
988 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
989 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
990 let expr_break =
991 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
992 this.arena.alloc(this.expr(gen_future_span, expr_break))
993 });
994 self.arm(ready_pat, break_x)
995 };
996
997 let pending_arm = {
999 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
1000 let empty_block = self.expr_block_empty(span);
1001 self.arm(pending_pat, empty_block)
1002 };
1003
1004 let inner_match_stmt = {
1005 let match_expr = self.expr_match(
1006 span,
1007 poll_expr,
1008 arena_vec![self; ready_arm, pending_arm],
1009 hir::MatchSource::AwaitDesugar,
1010 );
1011 self.stmt_expr(span, match_expr)
1012 };
1013
1014 let yield_stmt = {
1018 let yielded = if is_async_gen {
1019 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
1020 } else {
1021 self.expr_unit(span)
1022 };
1023
1024 let yield_expr = self.expr(
1025 span,
1026 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
1027 );
1028 let yield_expr = self.arena.alloc(yield_expr);
1029
1030 let Some(task_context_hid) = self.task_context else {
1031 unreachable!("use of `await` outside of an async context.");
1032 };
1033
1034 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1035 let assign =
1036 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
1037 self.stmt_expr(span, assign)
1038 };
1039
1040 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
1041
1042 let loop_expr = self.arena.alloc(hir::Expr {
1044 hir_id: loop_hir_id,
1045 kind: hir::ExprKind::Loop(
1046 loop_block,
1047 None,
1048 hir::LoopSource::Loop,
1049 self.lower_span(span),
1050 ),
1051 span: self.lower_span(span),
1052 });
1053
1054 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1056
1057 let into_future_expr = match await_kind {
1059 FutureKind::Future => self.expr_call_lang_item_fn(
1060 span,
1061 hir::LangItem::IntoFutureIntoFuture,
1062 arena_vec![self; *expr],
1063 ),
1064 FutureKind::AsyncIterator => expr,
1067 };
1068
1069 hir::ExprKind::Match(
1073 into_future_expr,
1074 arena_vec![self; awaitee_arm],
1075 hir::MatchSource::AwaitDesugar,
1076 )
1077 }
1078
1079 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1080 hir::ExprKind::Use(self.lower_expr(expr), use_kw_span)
1081 }
1082
1083 fn lower_expr_closure(
1084 &mut self,
1085 binder: &ClosureBinder,
1086 capture_clause: CaptureBy,
1087 closure_id: NodeId,
1088 closure_hir_id: hir::HirId,
1089 constness: Const,
1090 movability: Movability,
1091 decl: &FnDecl,
1092 body: &Expr,
1093 fn_decl_span: Span,
1094 fn_arg_span: Span,
1095 ) -> hir::ExprKind<'hir> {
1096 let closure_def_id = self.local_def_id(closure_id);
1097 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1098
1099 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1100 let mut coroutine_kind = if this
1101 .attrs
1102 .get(&closure_hir_id.local_id)
1103 .is_some_and(|attrs| attrs.iter().any(|attr| attr.has_name(sym::coroutine)))
1104 {
1105 Some(hir::CoroutineKind::Coroutine(Movability::Movable))
1106 } else {
1107 None
1108 };
1109 let body_id = this.lower_fn_body(decl, None, |this| {
1111 this.coroutine_kind = coroutine_kind;
1112 let e = this.lower_expr_mut(body);
1113 coroutine_kind = this.coroutine_kind;
1114 e
1115 });
1116 let coroutine_option =
1117 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1118 (body_id, coroutine_option)
1119 });
1120
1121 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1122 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1124
1125 let c = self.arena.alloc(hir::Closure {
1126 def_id: closure_def_id,
1127 binder: binder_clause,
1128 capture_clause,
1129 bound_generic_params,
1130 fn_decl,
1131 body: body_id,
1132 fn_decl_span: self.lower_span(fn_decl_span),
1133 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1134 kind: closure_kind,
1135 constness: self.lower_constness(constness),
1136 });
1137
1138 hir::ExprKind::Closure(c)
1139 }
1140
1141 fn closure_movability_for_fn(
1142 &mut self,
1143 decl: &FnDecl,
1144 fn_decl_span: Span,
1145 coroutine_kind: Option<hir::CoroutineKind>,
1146 movability: Movability,
1147 ) -> hir::ClosureKind {
1148 match coroutine_kind {
1149 Some(hir::CoroutineKind::Coroutine(_)) => {
1150 if decl.inputs.len() > 1 {
1151 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1152 }
1153 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1154 }
1155 Some(
1156 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1157 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1158 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1159 ) => {
1160 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1161 }
1162 None => {
1163 if movability == Movability::Static {
1164 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1165 }
1166 hir::ClosureKind::Closure
1167 }
1168 }
1169 }
1170
1171 fn lower_closure_binder<'c>(
1172 &mut self,
1173 binder: &'c ClosureBinder,
1174 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1175 let (binder, params) = match binder {
1176 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1177 ClosureBinder::For { span, generic_params } => {
1178 let span = self.lower_span(*span);
1179 (hir::ClosureBinder::For { span }, &**generic_params)
1180 }
1181 };
1182
1183 (binder, params)
1184 }
1185
1186 fn lower_expr_coroutine_closure(
1187 &mut self,
1188 binder: &ClosureBinder,
1189 capture_clause: CaptureBy,
1190 closure_id: NodeId,
1191 closure_hir_id: HirId,
1192 coroutine_kind: CoroutineKind,
1193 decl: &FnDecl,
1194 body: &Expr,
1195 fn_decl_span: Span,
1196 fn_arg_span: Span,
1197 ) -> hir::ExprKind<'hir> {
1198 let closure_def_id = self.local_def_id(closure_id);
1199 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1200
1201 let coroutine_desugaring = match coroutine_kind {
1202 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1203 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1204 CoroutineKind::AsyncGen { span, .. } => {
1205 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1206 }
1207 };
1208
1209 let body = self.with_new_scopes(fn_decl_span, |this| {
1210 let inner_decl =
1211 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1212
1213 let body_id = this.lower_body(|this| {
1216 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1217 &inner_decl,
1218 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1219 fn_decl_span,
1220 body.span,
1221 coroutine_kind,
1222 hir::CoroutineSource::Closure,
1223 );
1224
1225 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1226
1227 (parameters, expr)
1228 });
1229 body_id
1230 });
1231
1232 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1233 let fn_decl =
1237 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1238
1239 let c = self.arena.alloc(hir::Closure {
1240 def_id: closure_def_id,
1241 binder: binder_clause,
1242 capture_clause,
1243 bound_generic_params,
1244 fn_decl,
1245 body,
1246 fn_decl_span: self.lower_span(fn_decl_span),
1247 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1248 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1252 constness: hir::Constness::NotConst,
1253 });
1254 hir::ExprKind::Closure(c)
1255 }
1256
1257 fn lower_expr_assign(
1260 &mut self,
1261 lhs: &Expr,
1262 rhs: &Expr,
1263 eq_sign_span: Span,
1264 whole_span: Span,
1265 ) -> hir::ExprKind<'hir> {
1266 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1268 match &lhs.kind {
1269 ExprKind::Array(..)
1270 | ExprKind::Struct(..)
1271 | ExprKind::Tup(..)
1272 | ExprKind::Underscore => false,
1273 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1275 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1277 ExprKind::Paren(e) => {
1278 match e.kind {
1279 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1281 _ => is_ordinary(lower_ctx, e),
1282 }
1283 }
1284 _ => true,
1285 }
1286 }
1287 if is_ordinary(self, lhs) {
1288 return hir::ExprKind::Assign(
1289 self.lower_expr(lhs),
1290 self.lower_expr(rhs),
1291 self.lower_span(eq_sign_span),
1292 );
1293 }
1294
1295 let mut assignments = vec![];
1296
1297 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1299 let rhs = self.lower_expr(rhs);
1300
1301 let destructure_let = self.stmt_let_pat(
1303 None,
1304 whole_span,
1305 Some(rhs),
1306 pat,
1307 hir::LocalSource::AssignDesugar(self.lower_span(eq_sign_span)),
1308 );
1309
1310 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1312
1313 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1315 }
1316
1317 fn extract_tuple_struct_path<'a>(
1322 &mut self,
1323 expr: &'a Expr,
1324 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1325 if let ExprKind::Path(qself, path) = &expr.kind {
1326 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1328 if let Some(res) = partial_res.full_res()
1329 && !res.expected_in_tuple_struct_pat()
1330 {
1331 return None;
1332 }
1333 }
1334 return Some((qself, path));
1335 }
1336 None
1337 }
1338
1339 fn extract_unit_struct_path<'a>(
1344 &mut self,
1345 expr: &'a Expr,
1346 ) -> Option<(&'a Option<AstP<QSelf>>, &'a Path)> {
1347 if let ExprKind::Path(qself, path) = &expr.kind {
1348 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1350 if let Some(res) = partial_res.full_res()
1351 && !res.expected_in_unit_struct_pat()
1352 {
1353 return None;
1354 }
1355 }
1356 return Some((qself, path));
1357 }
1358 None
1359 }
1360
1361 fn destructure_assign(
1364 &mut self,
1365 lhs: &Expr,
1366 eq_sign_span: Span,
1367 assignments: &mut Vec<hir::Stmt<'hir>>,
1368 ) -> &'hir hir::Pat<'hir> {
1369 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1370 }
1371
1372 fn destructure_assign_mut(
1373 &mut self,
1374 lhs: &Expr,
1375 eq_sign_span: Span,
1376 assignments: &mut Vec<hir::Stmt<'hir>>,
1377 ) -> hir::Pat<'hir> {
1378 match &lhs.kind {
1379 ExprKind::Underscore => {
1381 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1382 }
1383 ExprKind::Array(elements) => {
1385 let (pats, rest) =
1386 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1387 let slice_pat = if let Some((i, span)) = rest {
1388 let (before, after) = pats.split_at(i);
1389 hir::PatKind::Slice(
1390 before,
1391 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1392 after,
1393 )
1394 } else {
1395 hir::PatKind::Slice(pats, None, &[])
1396 };
1397 return self.pat_without_dbm(lhs.span, slice_pat);
1398 }
1399 ExprKind::Call(callee, args) => {
1401 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1402 let (pats, rest) = self.destructure_sequence(
1403 args,
1404 "tuple struct or variant",
1405 eq_sign_span,
1406 assignments,
1407 );
1408 let qpath = self.lower_qpath(
1409 callee.id,
1410 qself,
1411 path,
1412 ParamMode::Optional,
1413 AllowReturnTypeNotation::No,
1414 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1415 None,
1416 );
1417 let tuple_struct_pat = hir::PatKind::TupleStruct(
1419 qpath,
1420 pats,
1421 hir::DotDotPos::new(rest.map(|r| r.0)),
1422 );
1423 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1424 }
1425 }
1426 ExprKind::Path(..) => {
1428 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1429 let qpath = self.lower_qpath(
1430 lhs.id,
1431 qself,
1432 path,
1433 ParamMode::Optional,
1434 AllowReturnTypeNotation::No,
1435 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1436 None,
1437 );
1438 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1440 kind: hir::PatExprKind::Path(qpath),
1441 hir_id: self.next_id(),
1442 span: self.lower_span(lhs.span),
1443 }));
1444 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1445 }
1446 }
1447 ExprKind::Struct(se) => {
1449 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1450 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1451 hir::PatField {
1452 hir_id: self.next_id(),
1453 ident: self.lower_ident(f.ident),
1454 pat,
1455 is_shorthand: f.is_shorthand,
1456 span: self.lower_span(f.span),
1457 }
1458 }));
1459 let qpath = self.lower_qpath(
1460 lhs.id,
1461 &se.qself,
1462 &se.path,
1463 ParamMode::Optional,
1464 AllowReturnTypeNotation::No,
1465 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1466 None,
1467 );
1468 let fields_omitted = match &se.rest {
1469 StructRest::Base(e) => {
1470 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1471 span: e.span,
1472 });
1473 true
1474 }
1475 StructRest::Rest(_) => true,
1476 StructRest::None => false,
1477 };
1478 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1479 return self.pat_without_dbm(lhs.span, struct_pat);
1480 }
1481 ExprKind::Tup(elements) => {
1483 let (pats, rest) =
1484 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1485 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1486 return self.pat_without_dbm(lhs.span, tuple_pat);
1487 }
1488 ExprKind::Paren(e) => {
1489 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1491 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1492 return self.pat_without_dbm(lhs.span, tuple_pat);
1493 } else {
1494 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1495 }
1496 }
1497 _ => {}
1498 }
1499 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1501 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1502 let ident = self.expr_ident(lhs.span, ident, binding);
1503 let assign =
1504 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1505 let expr = self.expr(lhs.span, assign);
1506 assignments.push(self.stmt_expr(lhs.span, expr));
1507 pat
1508 }
1509
1510 fn destructure_sequence(
1516 &mut self,
1517 elements: &[AstP<Expr>],
1518 ctx: &str,
1519 eq_sign_span: Span,
1520 assignments: &mut Vec<hir::Stmt<'hir>>,
1521 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1522 let mut rest = None;
1523 let elements =
1524 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1525 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1527 if let Some((_, prev_span)) = rest {
1528 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1529 } else {
1530 rest = Some((i, e.span));
1531 }
1532 None
1533 } else {
1534 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1535 }
1536 }));
1537 (elements, rest)
1538 }
1539
1540 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1542 let e1 = self.lower_expr_mut(e1);
1543 let e2 = self.lower_expr_mut(e2);
1544 let fn_path = hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, self.lower_span(span));
1545 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1546 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1547 }
1548
1549 fn lower_expr_range(
1550 &mut self,
1551 span: Span,
1552 e1: Option<&Expr>,
1553 e2: Option<&Expr>,
1554 lims: RangeLimits,
1555 ) -> hir::ExprKind<'hir> {
1556 use rustc_ast::RangeLimits::*;
1557
1558 let lang_item = match (e1, e2, lims) {
1559 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1560 (Some(..), None, HalfOpen) => {
1561 if self.tcx.features().new_range() {
1562 hir::LangItem::RangeFromCopy
1563 } else {
1564 hir::LangItem::RangeFrom
1565 }
1566 }
1567 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1568 (Some(..), Some(..), HalfOpen) => {
1569 if self.tcx.features().new_range() {
1570 hir::LangItem::RangeCopy
1571 } else {
1572 hir::LangItem::Range
1573 }
1574 }
1575 (None, Some(..), Closed) => hir::LangItem::RangeToInclusive,
1576 (Some(e1), Some(e2), Closed) => {
1577 if self.tcx.features().new_range() {
1578 hir::LangItem::RangeInclusiveCopy
1579 } else {
1580 return self.lower_expr_range_closed(span, e1, e2);
1581 }
1582 }
1583 (start, None, Closed) => {
1584 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1585 match start {
1586 Some(..) => {
1587 if self.tcx.features().new_range() {
1588 hir::LangItem::RangeFromCopy
1589 } else {
1590 hir::LangItem::RangeFrom
1591 }
1592 }
1593 None => hir::LangItem::RangeFull,
1594 }
1595 }
1596 };
1597
1598 let fields = self.arena.alloc_from_iter(
1599 e1.iter().map(|e| (sym::start, e)).chain(e2.iter().map(|e| (sym::end, e))).map(
1600 |(s, e)| {
1601 let expr = self.lower_expr(e);
1602 let ident = Ident::new(s, self.lower_span(e.span));
1603 self.expr_field(ident, expr, e.span)
1604 },
1605 ),
1606 );
1607
1608 hir::ExprKind::Struct(
1609 self.arena.alloc(hir::QPath::LangItem(lang_item, self.lower_span(span))),
1610 fields,
1611 hir::StructTailExpr::None,
1612 )
1613 }
1614
1615 fn lower_label(
1618 &mut self,
1619 opt_label: Option<Label>,
1620 dest_id: NodeId,
1621 dest_hir_id: hir::HirId,
1622 ) -> Option<Label> {
1623 let label = opt_label?;
1624 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1625 Some(Label { ident: self.lower_ident(label.ident) })
1626 }
1627
1628 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1629 let target_id = match destination {
1630 Some((id, _)) => {
1631 if let Some(loop_id) = self.resolver.get_label_res(id) {
1632 let local_id = self.ident_and_label_to_local_id[&loop_id];
1633 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1634 Ok(loop_hir_id)
1635 } else {
1636 Err(hir::LoopIdError::UnresolvedLabel)
1637 }
1638 }
1639 None => {
1640 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1641 }
1642 };
1643 let label = destination
1644 .map(|(_, label)| label)
1645 .map(|label| Label { ident: self.lower_ident(label.ident) });
1646 hir::Destination { label, target_id }
1647 }
1648
1649 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1650 if self.is_in_loop_condition && opt_label.is_none() {
1651 hir::Destination {
1652 label: None,
1653 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1654 }
1655 } else {
1656 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1657 }
1658 }
1659
1660 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1661 let old_scope = self.catch_scope.replace(catch_id);
1662 let result = f(self);
1663 self.catch_scope = old_scope;
1664 result
1665 }
1666
1667 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1668 let was_in_loop_condition = self.is_in_loop_condition;
1670 self.is_in_loop_condition = false;
1671
1672 let old_scope = self.loop_scope.replace(loop_id);
1673 let result = f(self);
1674 self.loop_scope = old_scope;
1675
1676 self.is_in_loop_condition = was_in_loop_condition;
1677
1678 result
1679 }
1680
1681 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1682 let was_in_loop_condition = self.is_in_loop_condition;
1683 self.is_in_loop_condition = true;
1684
1685 let result = f(self);
1686
1687 self.is_in_loop_condition = was_in_loop_condition;
1688
1689 result
1690 }
1691
1692 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1693 let hir_id = self.lower_node_id(f.id);
1694 self.lower_attrs(hir_id, &f.attrs, f.span);
1695 hir::ExprField {
1696 hir_id,
1697 ident: self.lower_ident(f.ident),
1698 expr: self.lower_expr(&f.expr),
1699 span: self.lower_span(f.span),
1700 is_shorthand: f.is_shorthand,
1701 }
1702 }
1703
1704 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1705 let yielded =
1706 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1707
1708 if !self.tcx.features().yield_expr()
1709 && !self.tcx.features().coroutines()
1710 && !self.tcx.features().gen_blocks()
1711 {
1712 rustc_session::parse::feature_err(
1713 &self.tcx.sess,
1714 sym::yield_expr,
1715 span,
1716 fluent_generated::ast_lowering_yield,
1717 )
1718 .emit();
1719 }
1720
1721 let is_async_gen = match self.coroutine_kind {
1722 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1723 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1724 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1725 let stmt_id = self.next_id();
1728 let expr_err = self.expr(
1729 yielded.span,
1730 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1731 );
1732 return hir::ExprKind::Block(
1733 self.block_all(
1734 yielded.span,
1735 arena_vec![self; hir::Stmt {
1736 hir_id: stmt_id,
1737 kind: hir::StmtKind::Semi(yielded),
1738 span: yielded.span,
1739 }],
1740 Some(self.arena.alloc(expr_err)),
1741 ),
1742 None,
1743 );
1744 }
1745 Some(hir::CoroutineKind::Coroutine(_)) => false,
1746 None => {
1747 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1748 self.dcx().emit_err(YieldInClosure { span, suggestion });
1749 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1750
1751 false
1752 }
1753 };
1754
1755 if is_async_gen {
1756 let wrapped_yielded = self.expr_call_lang_item_fn(
1760 span,
1761 hir::LangItem::AsyncGenReady,
1762 std::slice::from_ref(yielded),
1763 );
1764 let yield_expr = self.arena.alloc(
1765 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1766 );
1767
1768 let Some(task_context_hid) = self.task_context else {
1769 unreachable!("use of `await` outside of an async context.");
1770 };
1771 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1772 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1773
1774 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1775 } else {
1776 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1777 }
1778 }
1779
1780 fn lower_expr_for(
1797 &mut self,
1798 e: &Expr,
1799 pat: &Pat,
1800 head: &Expr,
1801 body: &Block,
1802 opt_label: Option<Label>,
1803 loop_kind: ForLoopKind,
1804 ) -> hir::Expr<'hir> {
1805 let head = self.lower_expr_mut(head);
1806 let pat = self.lower_pat(pat);
1807 let for_span =
1808 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1809 let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
1810 let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
1811
1812 let loop_hir_id = self.lower_node_id(e.id);
1813 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1814
1815 let none_arm = {
1817 let break_expr =
1818 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1819 let pat = self.pat_none(for_span);
1820 self.arm(pat, break_expr)
1821 };
1822
1823 let some_arm = {
1825 let some_pat = self.pat_some(pat_span, pat);
1826 let body_block =
1827 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1828 let body_expr = self.arena.alloc(self.expr_block(body_block));
1829 self.arm(some_pat, body_expr)
1830 };
1831
1832 let iter = Ident::with_dummy_span(sym::iter);
1834 let (iter_pat, iter_pat_nid) =
1835 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1836
1837 let match_expr = {
1838 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1839 let next_expr = match loop_kind {
1840 ForLoopKind::For => {
1841 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1843 self.expr_call_lang_item_fn(
1844 head_span,
1845 hir::LangItem::IteratorNext,
1846 arena_vec![self; ref_mut_iter],
1847 )
1848 }
1849 ForLoopKind::ForAwait => {
1850 let iter = self.expr_mut_addr_of(head_span, iter);
1857 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1859 head_span,
1860 hir::LangItem::PinNewUnchecked,
1861 arena_vec![self; iter],
1862 ));
1863 let iter = self.arena.alloc(self.expr_unsafe(iter));
1865 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1866 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1867 }
1868 };
1869 let arms = arena_vec![self; none_arm, some_arm];
1870
1871 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1873 };
1874 let match_stmt = self.stmt_expr(for_span, match_expr);
1875
1876 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1877
1878 let kind = hir::ExprKind::Loop(
1880 loop_block,
1881 label,
1882 hir::LoopSource::ForLoop,
1883 self.lower_span(for_span.with_hi(head.span.hi())),
1884 );
1885 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1886
1887 let iter_arm = self.arm(iter_pat, loop_expr);
1889
1890 let match_expr = match loop_kind {
1891 ForLoopKind::For => {
1892 let into_iter_expr = self.expr_call_lang_item_fn(
1894 head_span,
1895 hir::LangItem::IntoIterIntoIter,
1896 arena_vec![self; head],
1897 );
1898
1899 self.arena.alloc(self.expr_match(
1900 for_span,
1901 into_iter_expr,
1902 arena_vec![self; iter_arm],
1903 hir::MatchSource::ForLoopDesugar,
1904 ))
1905 }
1906 ForLoopKind::ForAwait => {
1908 let iter_ident = iter;
1909 let (async_iter_pat, async_iter_pat_id) =
1910 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1911 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1912 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1914 head_span,
1915 hir::LangItem::PinNewUnchecked,
1916 arena_vec![self; iter],
1917 ));
1918 let iter = self.arena.alloc(self.expr_unsafe(iter));
1920 let inner_match_expr = self.arena.alloc(self.expr_match(
1921 for_span,
1922 iter,
1923 arena_vec![self; iter_arm],
1924 hir::MatchSource::ForLoopDesugar,
1925 ));
1926
1927 let iter = self.expr_call_lang_item_fn(
1929 head_span,
1930 hir::LangItem::IntoAsyncIterIntoIter,
1931 arena_vec![self; head],
1932 );
1933 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1934 self.arena.alloc(self.expr_match(
1935 for_span,
1936 iter,
1937 arena_vec![self; iter_arm],
1938 hir::MatchSource::ForLoopDesugar,
1939 ))
1940 }
1941 };
1942
1943 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1950 self.lower_attrs(expr.hir_id, &e.attrs, e.span);
1951 expr
1952 }
1953
1954 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1967 let unstable_span = self.mark_span_with_reason(
1968 DesugaringKind::QuestionMark,
1969 span,
1970 Some(Arc::clone(&self.allow_try_trait)),
1971 );
1972 let try_span = self.tcx.sess.source_map().end_point(span);
1973 let try_span = self.mark_span_with_reason(
1974 DesugaringKind::QuestionMark,
1975 try_span,
1976 Some(Arc::clone(&self.allow_try_trait)),
1977 );
1978
1979 let scrutinee = {
1981 let sub_expr = self.lower_expr_mut(sub_expr);
1983
1984 self.expr_call_lang_item_fn(
1985 unstable_span,
1986 hir::LangItem::TryTraitBranch,
1987 arena_vec![self; sub_expr],
1988 )
1989 };
1990
1991 let attr = attr::mk_attr_nested_word(
1993 &self.tcx.sess.psess.attr_id_generator,
1994 AttrStyle::Outer,
1995 Safety::Default,
1996 sym::allow,
1997 sym::unreachable_code,
1998 try_span,
1999 );
2000 let attrs: AttrVec = thin_vec![attr];
2001
2002 let continue_arm = {
2004 let val_ident = Ident::with_dummy_span(sym::val);
2005 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
2006 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
2007 self.lower_attrs(val_expr.hir_id, &attrs, span);
2008 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
2009 self.arm(continue_pat, val_expr)
2010 };
2011
2012 let break_arm = {
2016 let residual_ident = Ident::with_dummy_span(sym::residual);
2017 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
2018 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
2019 let from_residual_expr = self.wrap_in_try_constructor(
2020 hir::LangItem::TryTraitFromResidual,
2021 try_span,
2022 self.arena.alloc(residual_expr),
2023 unstable_span,
2024 );
2025 let ret_expr = if let Some(catch_id) = self.catch_scope {
2026 let target_id = Ok(catch_id);
2027 self.arena.alloc(self.expr(
2028 try_span,
2029 hir::ExprKind::Break(
2030 hir::Destination { label: None, target_id },
2031 Some(from_residual_expr),
2032 ),
2033 ))
2034 } else {
2035 let ret_expr = self.checked_return(Some(from_residual_expr));
2036 self.arena.alloc(self.expr(try_span, ret_expr))
2037 };
2038 self.lower_attrs(ret_expr.hir_id, &attrs, span);
2039
2040 let break_pat = self.pat_cf_break(try_span, residual_local);
2041 self.arm(break_pat, ret_expr)
2042 };
2043
2044 hir::ExprKind::Match(
2045 scrutinee,
2046 arena_vec![self; break_arm, continue_arm],
2047 hir::MatchSource::TryDesugar(scrutinee.hir_id),
2048 )
2049 }
2050
2051 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2061 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2063 (sub_expr.span, self.lower_expr(sub_expr))
2064 } else {
2065 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2066 };
2067
2068 let unstable_span = self.mark_span_with_reason(
2069 DesugaringKind::YeetExpr,
2070 span,
2071 Some(Arc::clone(&self.allow_try_trait)),
2072 );
2073
2074 let from_yeet_expr = self.wrap_in_try_constructor(
2075 hir::LangItem::TryTraitFromYeet,
2076 unstable_span,
2077 yeeted_expr,
2078 yeeted_span,
2079 );
2080
2081 if let Some(catch_id) = self.catch_scope {
2082 let target_id = Ok(catch_id);
2083 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2084 } else {
2085 self.checked_return(Some(from_yeet_expr))
2086 }
2087 }
2088
2089 pub(super) fn expr_drop_temps(
2100 &mut self,
2101 span: Span,
2102 expr: &'hir hir::Expr<'hir>,
2103 ) -> &'hir hir::Expr<'hir> {
2104 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2105 }
2106
2107 pub(super) fn expr_drop_temps_mut(
2108 &mut self,
2109 span: Span,
2110 expr: &'hir hir::Expr<'hir>,
2111 ) -> hir::Expr<'hir> {
2112 self.expr(span, hir::ExprKind::DropTemps(expr))
2113 }
2114
2115 pub(super) fn expr_match(
2116 &mut self,
2117 span: Span,
2118 arg: &'hir hir::Expr<'hir>,
2119 arms: &'hir [hir::Arm<'hir>],
2120 source: hir::MatchSource,
2121 ) -> hir::Expr<'hir> {
2122 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2123 }
2124
2125 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2126 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2127 self.expr(span, expr_break)
2128 }
2129
2130 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2131 let expr_break = self.expr_break(span);
2132 self.arena.alloc(expr_break)
2133 }
2134
2135 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2136 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2137 }
2138
2139 fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2140 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2141 }
2142
2143 fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
2144 let lit = self.arena.alloc(hir::Lit {
2145 span: sp,
2146 node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
2147 });
2148 self.expr(sp, hir::ExprKind::Lit(lit))
2149 }
2150
2151 pub(super) fn expr_usize(&mut self, sp: Span, value: usize) -> hir::Expr<'hir> {
2152 self.expr_uint(sp, ast::UintTy::Usize, value as u128)
2153 }
2154
2155 pub(super) fn expr_u32(&mut self, sp: Span, value: u32) -> hir::Expr<'hir> {
2156 self.expr_uint(sp, ast::UintTy::U32, value as u128)
2157 }
2158
2159 pub(super) fn expr_u16(&mut self, sp: Span, value: u16) -> hir::Expr<'hir> {
2160 self.expr_uint(sp, ast::UintTy::U16, value as u128)
2161 }
2162
2163 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2164 let lit = self
2165 .arena
2166 .alloc(hir::Lit { span: sp, node: ast::LitKind::Str(value, ast::StrStyle::Cooked) });
2167 self.expr(sp, hir::ExprKind::Lit(lit))
2168 }
2169
2170 pub(super) fn expr_call_mut(
2171 &mut self,
2172 span: Span,
2173 e: &'hir hir::Expr<'hir>,
2174 args: &'hir [hir::Expr<'hir>],
2175 ) -> hir::Expr<'hir> {
2176 self.expr(span, hir::ExprKind::Call(e, args))
2177 }
2178
2179 pub(super) fn expr_call(
2180 &mut self,
2181 span: Span,
2182 e: &'hir hir::Expr<'hir>,
2183 args: &'hir [hir::Expr<'hir>],
2184 ) -> &'hir hir::Expr<'hir> {
2185 self.arena.alloc(self.expr_call_mut(span, e, args))
2186 }
2187
2188 pub(super) fn expr_call_lang_item_fn_mut(
2189 &mut self,
2190 span: Span,
2191 lang_item: hir::LangItem,
2192 args: &'hir [hir::Expr<'hir>],
2193 ) -> hir::Expr<'hir> {
2194 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2195 self.expr_call_mut(span, path, args)
2196 }
2197
2198 pub(super) fn expr_call_lang_item_fn(
2199 &mut self,
2200 span: Span,
2201 lang_item: hir::LangItem,
2202 args: &'hir [hir::Expr<'hir>],
2203 ) -> &'hir hir::Expr<'hir> {
2204 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2205 }
2206
2207 fn expr_lang_item_path(&mut self, span: Span, lang_item: hir::LangItem) -> hir::Expr<'hir> {
2208 self.expr(span, hir::ExprKind::Path(hir::QPath::LangItem(lang_item, self.lower_span(span))))
2209 }
2210
2211 pub(super) fn expr_lang_item_type_relative(
2213 &mut self,
2214 span: Span,
2215 lang_item: hir::LangItem,
2216 name: Symbol,
2217 ) -> hir::Expr<'hir> {
2218 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2219 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2220 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2221 self.arena.alloc(hir::PathSegment::new(
2222 Ident::new(name, self.lower_span(span)),
2223 self.next_id(),
2224 Res::Err,
2225 )),
2226 ));
2227 self.expr(span, path)
2228 }
2229
2230 pub(super) fn expr_ident(
2231 &mut self,
2232 sp: Span,
2233 ident: Ident,
2234 binding: HirId,
2235 ) -> &'hir hir::Expr<'hir> {
2236 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2237 }
2238
2239 pub(super) fn expr_ident_mut(
2240 &mut self,
2241 span: Span,
2242 ident: Ident,
2243 binding: HirId,
2244 ) -> hir::Expr<'hir> {
2245 let hir_id = self.next_id();
2246 let res = Res::Local(binding);
2247 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2248 None,
2249 self.arena.alloc(hir::Path {
2250 span: self.lower_span(span),
2251 res,
2252 segments: arena_vec![self; hir::PathSegment::new(ident, hir_id, res)],
2253 }),
2254 ));
2255
2256 self.expr(span, expr_path)
2257 }
2258
2259 fn expr_unsafe(&mut self, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2260 let hir_id = self.next_id();
2261 let span = expr.span;
2262 self.expr(
2263 span,
2264 hir::ExprKind::Block(
2265 self.arena.alloc(hir::Block {
2266 stmts: &[],
2267 expr: Some(expr),
2268 hir_id,
2269 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2270 span: self.lower_span(span),
2271 targeted_by_break: false,
2272 }),
2273 None,
2274 ),
2275 )
2276 }
2277
2278 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2279 let blk = self.block_all(span, &[], None);
2280 let expr = self.expr_block(blk);
2281 self.arena.alloc(expr)
2282 }
2283
2284 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2285 self.expr(b.span, hir::ExprKind::Block(b, None))
2286 }
2287
2288 pub(super) fn expr_array_ref(
2289 &mut self,
2290 span: Span,
2291 elements: &'hir [hir::Expr<'hir>],
2292 ) -> hir::Expr<'hir> {
2293 let array = self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements)));
2294 self.expr_ref(span, array)
2295 }
2296
2297 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2298 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2299 }
2300
2301 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2302 let hir_id = self.next_id();
2303 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2304 }
2305
2306 pub(super) fn expr_field(
2307 &mut self,
2308 ident: Ident,
2309 expr: &'hir hir::Expr<'hir>,
2310 span: Span,
2311 ) -> hir::ExprField<'hir> {
2312 hir::ExprField {
2313 hir_id: self.next_id(),
2314 ident,
2315 span: self.lower_span(span),
2316 expr,
2317 is_shorthand: false,
2318 }
2319 }
2320
2321 pub(super) fn arm(
2322 &mut self,
2323 pat: &'hir hir::Pat<'hir>,
2324 expr: &'hir hir::Expr<'hir>,
2325 ) -> hir::Arm<'hir> {
2326 hir::Arm {
2327 hir_id: self.next_id(),
2328 pat,
2329 guard: None,
2330 span: self.lower_span(expr.span),
2331 body: expr,
2332 }
2333 }
2334}
2335
2336#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2339enum FutureKind {
2340 Future,
2342 AsyncIterator,
2345}