1use std::mem;
2use std::ops::ControlFlow;
3use std::sync::Arc;
4
5use rustc_ast::*;
6use rustc_ast_pretty::pprust::expr_to_string;
7use rustc_data_structures::stack::ensure_sufficient_stack;
8use rustc_hir as hir;
9use rustc_hir::attrs::AttributeKind;
10use rustc_hir::def::{DefKind, Res};
11use rustc_hir::definitions::DefPathData;
12use rustc_hir::{HirId, Target, find_attr};
13use rustc_middle::span_bug;
14use rustc_middle::ty::TyCtxt;
15use rustc_session::errors::report_lit_error;
16use rustc_span::source_map::{Spanned, respan};
17use rustc_span::{ByteSymbol, DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
18use thin_vec::{ThinVec, thin_vec};
19use visit::{Visitor, walk_expr};
20
21use super::errors::{
22 AsyncCoroutinesNotSupported, AwaitOnlyInAsyncFnAndBlocks, ClosureCannotBeStatic,
23 CoroutineTooManyParameters, FunctionalRecordUpdateDestructuringAssignment,
24 InclusiveRangeWithNoEnd, MatchArmWithNoBody, NeverPatternWithBody, NeverPatternWithGuard,
25 UnderscoreExprLhsAssign,
26};
27use super::{
28 GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
29};
30use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
31use crate::{
32 AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, TryBlockScope, fluent_generated,
33};
34
35struct WillCreateDefIdsVisitor {}
36
37impl<'v> rustc_ast::visit::Visitor<'v> for WillCreateDefIdsVisitor {
38 type Result = ControlFlow<Span>;
39
40 fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
41 ControlFlow::Break(c.value.span)
42 }
43
44 fn visit_item(&mut self, item: &'v Item) -> Self::Result {
45 ControlFlow::Break(item.span)
46 }
47
48 fn visit_expr(&mut self, ex: &'v Expr) -> Self::Result {
49 match ex.kind {
50 ExprKind::Gen(..) | ExprKind::ConstBlock(..) | ExprKind::Closure(..) => {
51 ControlFlow::Break(ex.span)
52 }
53 _ => walk_expr(self, ex),
54 }
55 }
56}
57
58impl<'hir> LoweringContext<'_, 'hir> {
59 fn lower_exprs(&mut self, exprs: &[Box<Expr>]) -> &'hir [hir::Expr<'hir>] {
60 self.arena.alloc_from_iter(exprs.iter().map(|x| self.lower_expr_mut(x)))
61 }
62
63 pub(super) fn lower_expr(&mut self, e: &Expr) -> &'hir hir::Expr<'hir> {
64 self.arena.alloc(self.lower_expr_mut(e))
65 }
66
67 pub(super) fn lower_expr_mut(&mut self, e: &Expr) -> hir::Expr<'hir> {
68 ensure_sufficient_stack(|| {
69 let mut span = self.lower_span(e.span);
70 match &e.kind {
71 ExprKind::Paren(ex) => {
73 let mut ex = self.lower_expr_mut(ex);
74 if e.span.contains(ex.span) {
76 ex.span = self.lower_span(e.span.with_ctxt(ex.span.ctxt()));
77 }
78 if !e.attrs.is_empty() {
80 let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
81 let new_attrs = self
82 .lower_attrs_vec(&e.attrs, e.span, ex.hir_id, Target::from_expr(e))
83 .into_iter()
84 .chain(old_attrs.iter().cloned());
85 let new_attrs = &*self.arena.alloc_from_iter(new_attrs);
86 if new_attrs.is_empty() {
87 return ex;
88 }
89 self.attrs.insert(ex.hir_id.local_id, new_attrs);
90 }
91 return ex;
92 }
93 ExprKind::ForLoop { pat, iter, body, label, kind } => {
99 return self.lower_expr_for(e, pat, iter, body, *label, *kind);
100 }
101 _ => (),
102 }
103
104 let expr_hir_id = self.lower_node_id(e.id);
105 let attrs = self.lower_attrs(expr_hir_id, &e.attrs, e.span, Target::from_expr(e));
106
107 let kind = match &e.kind {
108 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
109 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
110 ExprKind::Repeat(expr, count) => {
111 let expr = self.lower_expr(expr);
112 let count = self.lower_array_length_to_const_arg(count);
113 hir::ExprKind::Repeat(expr, count)
114 }
115 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
116 ExprKind::Call(f, args) => {
117 if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f, self.tcx)
118 {
119 self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
120 } else {
121 let f = self.lower_expr(f);
122 hir::ExprKind::Call(f, self.lower_exprs(args))
123 }
124 }
125 ExprKind::MethodCall(box MethodCall { seg, receiver, args, span }) => {
126 let hir_seg = self.arena.alloc(self.lower_path_segment(
127 e.span,
128 seg,
129 ParamMode::Optional,
130 GenericArgsMode::Err,
131 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
132 None,
134 ));
135 let receiver = self.lower_expr(receiver);
136 let args =
137 self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
138 hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(*span))
139 }
140 ExprKind::Binary(binop, lhs, rhs) => {
141 let binop = self.lower_binop(*binop);
142 let lhs = self.lower_expr(lhs);
143 let rhs = self.lower_expr(rhs);
144 hir::ExprKind::Binary(binop, lhs, rhs)
145 }
146 ExprKind::Unary(op, ohs) => {
147 let op = self.lower_unop(*op);
148 let ohs = self.lower_expr(ohs);
149 hir::ExprKind::Unary(op, ohs)
150 }
151 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
152 ExprKind::IncludedBytes(byte_sym) => {
153 let lit = respan(
154 self.lower_span(e.span),
155 LitKind::ByteStr(*byte_sym, StrStyle::Cooked),
156 );
157 hir::ExprKind::Lit(lit)
158 }
159 ExprKind::Cast(expr, ty) => {
160 let expr = self.lower_expr(expr);
161 let ty =
162 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
163 hir::ExprKind::Cast(expr, ty)
164 }
165 ExprKind::Type(expr, ty) => {
166 let expr = self.lower_expr(expr);
167 let ty =
168 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
169 hir::ExprKind::Type(expr, ty)
170 }
171 ExprKind::AddrOf(k, m, ohs) => {
172 let ohs = self.lower_expr(ohs);
173 hir::ExprKind::AddrOf(*k, *m, ohs)
174 }
175 ExprKind::Let(pat, scrutinee, span, recovered) => {
176 hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
177 span: self.lower_span(*span),
178 pat: self.lower_pat(pat),
179 ty: None,
180 init: self.lower_expr(scrutinee),
181 recovered: *recovered,
182 }))
183 }
184 ExprKind::If(cond, then, else_opt) => {
185 self.lower_expr_if(cond, then, else_opt.as_deref())
186 }
187 ExprKind::While(cond, body, opt_label) => {
188 self.with_loop_scope(expr_hir_id, |this| {
189 let span =
190 this.mark_span_with_reason(DesugaringKind::WhileLoop, e.span, None);
191 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
192 this.lower_expr_while_in_loop_scope(span, cond, body, opt_label)
193 })
194 }
195 ExprKind::Loop(body, opt_label, span) => {
196 self.with_loop_scope(expr_hir_id, |this| {
197 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
198 hir::ExprKind::Loop(
199 this.lower_block(body, false),
200 opt_label,
201 hir::LoopSource::Loop,
202 this.lower_span(*span),
203 )
204 })
205 }
206 ExprKind::TryBlock(body, opt_ty) => {
207 self.lower_expr_try_block(body, opt_ty.as_deref())
208 }
209 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
210 self.lower_expr(expr),
211 self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
212 match kind {
213 MatchKind::Prefix => hir::MatchSource::Normal,
214 MatchKind::Postfix => hir::MatchSource::Postfix,
215 },
216 ),
217 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
218 ExprKind::Use(expr, use_kw_span) => self.lower_expr_use(*use_kw_span, expr),
219 ExprKind::Closure(box Closure {
220 binder,
221 capture_clause,
222 constness,
223 coroutine_kind,
224 movability,
225 fn_decl,
226 body,
227 fn_decl_span,
228 fn_arg_span,
229 }) => match coroutine_kind {
230 Some(coroutine_kind) => self.lower_expr_coroutine_closure(
231 binder,
232 *capture_clause,
233 e.id,
234 expr_hir_id,
235 *coroutine_kind,
236 fn_decl,
237 body,
238 *fn_decl_span,
239 *fn_arg_span,
240 ),
241 None => self.lower_expr_closure(
242 attrs,
243 binder,
244 *capture_clause,
245 e.id,
246 *constness,
247 *movability,
248 fn_decl,
249 body,
250 *fn_decl_span,
251 *fn_arg_span,
252 ),
253 },
254 ExprKind::Gen(capture_clause, block, genblock_kind, decl_span) => {
255 let desugaring_kind = match genblock_kind {
256 GenBlockKind::Async => hir::CoroutineDesugaring::Async,
257 GenBlockKind::Gen => hir::CoroutineDesugaring::Gen,
258 GenBlockKind::AsyncGen => hir::CoroutineDesugaring::AsyncGen,
259 };
260 self.make_desugared_coroutine_expr(
261 *capture_clause,
262 e.id,
263 None,
264 *decl_span,
265 e.span,
266 desugaring_kind,
267 hir::CoroutineSource::Block,
268 |this| this.with_new_scopes(e.span, |this| this.lower_block_expr(block)),
269 )
270 }
271 ExprKind::Block(blk, opt_label) => {
272 let block_hir_id = self.lower_node_id(blk.id);
275 let opt_label = self.lower_label(*opt_label, blk.id, block_hir_id);
276 let hir_block = self.arena.alloc(self.lower_block_noalloc(
277 block_hir_id,
278 blk,
279 opt_label.is_some(),
280 ));
281 hir::ExprKind::Block(hir_block, opt_label)
282 }
283 ExprKind::Assign(el, er, span) => self.lower_expr_assign(el, er, *span, e.span),
284 ExprKind::AssignOp(op, el, er) => hir::ExprKind::AssignOp(
285 self.lower_assign_op(*op),
286 self.lower_expr(el),
287 self.lower_expr(er),
288 ),
289 ExprKind::Field(el, ident) => {
290 hir::ExprKind::Field(self.lower_expr(el), self.lower_ident(*ident))
291 }
292 ExprKind::Index(el, er, brackets_span) => hir::ExprKind::Index(
293 self.lower_expr(el),
294 self.lower_expr(er),
295 self.lower_span(*brackets_span),
296 ),
297 ExprKind::Range(e1, e2, lims) => {
298 span = self.mark_span_with_reason(DesugaringKind::RangeExpr, span, None);
299 self.lower_expr_range(span, e1.as_deref(), e2.as_deref(), *lims)
300 }
301 ExprKind::Underscore => {
302 let guar = self.dcx().emit_err(UnderscoreExprLhsAssign { span: e.span });
303 hir::ExprKind::Err(guar)
304 }
305 ExprKind::Path(qself, path) => {
306 let qpath = self.lower_qpath(
307 e.id,
308 qself,
309 path,
310 ParamMode::Optional,
311 AllowReturnTypeNotation::No,
312 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
313 None,
314 );
315 hir::ExprKind::Path(qpath)
316 }
317 ExprKind::Break(opt_label, opt_expr) => {
318 let opt_expr = opt_expr.as_ref().map(|x| self.lower_expr(x));
319 hir::ExprKind::Break(self.lower_jump_destination(e.id, *opt_label), opt_expr)
320 }
321 ExprKind::Continue(opt_label) => {
322 hir::ExprKind::Continue(self.lower_jump_destination(e.id, *opt_label))
323 }
324 ExprKind::Ret(e) => {
325 let expr = e.as_ref().map(|x| self.lower_expr(x));
326 self.checked_return(expr)
327 }
328 ExprKind::Yeet(sub_expr) => self.lower_expr_yeet(e.span, sub_expr.as_deref()),
329 ExprKind::Become(sub_expr) => {
330 let sub_expr = self.lower_expr(sub_expr);
331 hir::ExprKind::Become(sub_expr)
332 }
333 ExprKind::InlineAsm(asm) => {
334 hir::ExprKind::InlineAsm(self.lower_inline_asm(e.span, asm))
335 }
336 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
337 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
338 self.lower_ty(
339 container,
340 ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
341 ),
342 self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
343 ),
344 ExprKind::Struct(se) => {
345 let rest = match &se.rest {
346 StructRest::Base(e) => hir::StructTailExpr::Base(self.lower_expr(e)),
347 StructRest::Rest(sp) => {
348 hir::StructTailExpr::DefaultFields(self.lower_span(*sp))
349 }
350 StructRest::None => hir::StructTailExpr::None,
351 };
352 hir::ExprKind::Struct(
353 self.arena.alloc(self.lower_qpath(
354 e.id,
355 &se.qself,
356 &se.path,
357 ParamMode::Optional,
358 AllowReturnTypeNotation::No,
359 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
360 None,
361 )),
362 self.arena
363 .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
364 rest,
365 )
366 }
367 ExprKind::Yield(kind) => self.lower_expr_yield(e.span, kind.expr().map(|x| &**x)),
368 ExprKind::Err(guar) => hir::ExprKind::Err(*guar),
369
370 ExprKind::UnsafeBinderCast(kind, expr, ty) => hir::ExprKind::UnsafeBinderCast(
371 *kind,
372 self.lower_expr(expr),
373 ty.as_ref().map(|ty| {
374 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
375 }),
376 ),
377
378 ExprKind::Dummy => {
379 span_bug!(e.span, "lowered ExprKind::Dummy")
380 }
381
382 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
383
384 ExprKind::Paren(_) | ExprKind::ForLoop { .. } => {
385 unreachable!("already handled")
386 }
387
388 ExprKind::MacCall(_) => panic!("{:?} shouldn't exist here", e.span),
389 };
390
391 hir::Expr { hir_id: expr_hir_id, kind, span }
392 })
393 }
394
395 pub(crate) fn lower_const_block(&mut self, c: &AnonConst) -> hir::ConstBlock {
396 self.with_new_scopes(c.value.span, |this| {
397 let def_id = this.local_def_id(c.id);
398 hir::ConstBlock {
399 def_id,
400 hir_id: this.lower_node_id(c.id),
401 body: this.lower_const_body(c.value.span, Some(&c.value)),
402 }
403 })
404 }
405
406 pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
407 let lit_kind = match LitKind::from_token_lit(*token_lit) {
408 Ok(lit_kind) => lit_kind,
409 Err(err) => {
410 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
411 LitKind::Err(guar)
412 }
413 };
414 respan(self.lower_span(span), lit_kind)
415 }
416
417 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
418 match u {
419 UnOp::Deref => hir::UnOp::Deref,
420 UnOp::Not => hir::UnOp::Not,
421 UnOp::Neg => hir::UnOp::Neg,
422 }
423 }
424
425 fn lower_binop(&mut self, b: BinOp) -> BinOp {
426 Spanned { node: b.node, span: self.lower_span(b.span) }
427 }
428
429 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
430 Spanned { node: a.node, span: self.lower_span(a.span) }
431 }
432
433 fn lower_legacy_const_generics(
434 &mut self,
435 mut f: Expr,
436 args: ThinVec<Box<Expr>>,
437 legacy_args_idx: &[usize],
438 ) -> hir::ExprKind<'hir> {
439 let ExprKind::Path(None, path) = &mut f.kind else {
440 unreachable!();
441 };
442
443 let mut error = None;
444 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
445 if error.is_none() {
447 let mut const_args = vec![];
448 let mut other_args = vec![];
449 for (idx, arg) in args.iter().enumerate() {
450 if legacy_args_idx.contains(&idx) {
451 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
452 } else {
453 other_args.push(expr_to_string(arg));
454 }
455 }
456 let suggestion = UseConstGenericArg {
457 end_of_fn: f.span.shrink_to_hi(),
458 const_args: const_args.join(", "),
459 other_args: other_args.join(", "),
460 call_args: args[0].span.to(args.last().unwrap().span),
461 };
462 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
463 }
464 error.unwrap()
465 };
466
467 let mut real_args = vec![];
469 let mut generic_args = ThinVec::new();
470 for (idx, arg) in args.iter().cloned().enumerate() {
471 if legacy_args_idx.contains(&idx) {
472 let node_id = self.next_node_id();
473 self.create_def(
474 node_id,
475 None,
476 DefKind::AnonConst,
477 DefPathData::LateAnonConst,
478 f.span,
479 );
480 let mut visitor = WillCreateDefIdsVisitor {};
481 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
482 Box::new(Expr {
483 id: self.next_node_id(),
484 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
485 span: f.span,
486 attrs: [].into(),
487 tokens: None,
488 })
489 } else {
490 arg
491 };
492
493 let anon_const = AnonConst {
494 id: node_id,
495 value: const_value,
496 mgca_disambiguation: MgcaDisambiguation::AnonConst,
497 };
498 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
499 } else {
500 real_args.push(arg);
501 }
502 }
503
504 let last_segment = path.segments.last_mut().unwrap();
506 assert!(last_segment.args.is_none());
507 last_segment.args = Some(Box::new(GenericArgs::AngleBracketed(AngleBracketedArgs {
508 span: DUMMY_SP,
509 args: generic_args,
510 })));
511
512 let f = self.lower_expr(&f);
514 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
515 }
516
517 fn lower_expr_if(
518 &mut self,
519 cond: &Expr,
520 then: &Block,
521 else_opt: Option<&Expr>,
522 ) -> hir::ExprKind<'hir> {
523 let lowered_cond = self.lower_expr(cond);
524 let then_expr = self.lower_block_expr(then);
525 if let Some(rslt) = else_opt {
526 hir::ExprKind::If(
527 lowered_cond,
528 self.arena.alloc(then_expr),
529 Some(self.lower_expr(rslt)),
530 )
531 } else {
532 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
533 }
534 }
535
536 fn lower_expr_while_in_loop_scope(
553 &mut self,
554 span: Span,
555 cond: &Expr,
556 body: &Block,
557 opt_label: Option<Label>,
558 ) -> hir::ExprKind<'hir> {
559 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_expr(cond));
560 let then = self.lower_block_expr(body);
561 let expr_break = self.expr_break(span);
562 let stmt_break = self.stmt_expr(span, expr_break);
563 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
564 let else_expr = self.arena.alloc(self.expr_block(else_blk));
565 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
566 let if_expr = self.expr(span, if_kind);
567 let block = self.block_expr(self.arena.alloc(if_expr));
568 let span = self.lower_span(span.with_hi(cond.span.hi()));
569 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
570 }
571
572 fn lower_expr_try_block(&mut self, body: &Block, opt_ty: Option<&Ty>) -> hir::ExprKind<'hir> {
576 let body_hir_id = self.lower_node_id(body.id);
577 let new_scope = if opt_ty.is_some() {
578 TryBlockScope::Heterogeneous(body_hir_id)
579 } else {
580 TryBlockScope::Homogeneous(body_hir_id)
581 };
582 let whole_block = self.with_try_block_scope(new_scope, |this| {
583 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
584
585 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
587 (
588 this.mark_span_with_reason(
589 DesugaringKind::TryBlock,
590 expr.span,
591 Some(Arc::clone(&this.allow_try_trait)),
592 ),
593 expr,
594 )
595 } else {
596 let try_span = this.mark_span_with_reason(
597 DesugaringKind::TryBlock,
598 this.tcx.sess.source_map().end_point(body.span),
599 Some(Arc::clone(&this.allow_try_trait)),
600 );
601
602 (try_span, this.expr_unit(try_span))
603 };
604
605 let ok_wrapped_span =
606 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
607
608 block.expr = Some(this.wrap_in_try_constructor(
610 hir::LangItem::TryTraitFromOutput,
611 try_span,
612 tail_expr,
613 ok_wrapped_span,
614 ));
615
616 this.arena.alloc(block)
617 });
618
619 if let Some(ty) = opt_ty {
620 let ty = self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Path));
621 let block_expr = self.arena.alloc(self.expr_block(whole_block));
622 hir::ExprKind::Type(block_expr, ty)
623 } else {
624 hir::ExprKind::Block(whole_block, None)
625 }
626 }
627
628 fn wrap_in_try_constructor(
629 &mut self,
630 lang_item: hir::LangItem,
631 method_span: Span,
632 expr: &'hir hir::Expr<'hir>,
633 overall_span: Span,
634 ) -> &'hir hir::Expr<'hir> {
635 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
636 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
637 }
638
639 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
640 let pat = self.lower_pat(&arm.pat);
641 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
642 let hir_id = self.next_id();
643 let span = self.lower_span(arm.span);
644 self.lower_attrs(hir_id, &arm.attrs, arm.span, Target::Arm);
645 let is_never_pattern = pat.is_never_pattern();
646 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
649 let body = if let Some(body) = body
650 && !is_never_pattern
651 {
652 body
653 } else {
654 if !is_never_pattern {
656 if self.tcx.features().never_patterns() {
657 let suggestion = span.shrink_to_hi();
659 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
660 }
661 } else if let Some(body) = &arm.body {
662 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
663 } else if let Some(g) = &arm.guard {
664 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
665 }
666
667 let block = self.arena.alloc(hir::Block {
670 stmts: &[],
671 expr: None,
672 hir_id: self.next_id(),
673 rules: hir::BlockCheckMode::DefaultBlock,
674 span,
675 targeted_by_break: false,
676 });
677 self.arena.alloc(hir::Expr {
678 hir_id: self.next_id(),
679 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
680 span,
681 })
682 };
683 hir::Arm { hir_id, pat, guard, body, span }
684 }
685
686 fn lower_capture_clause(&mut self, capture_clause: CaptureBy) -> CaptureBy {
687 match capture_clause {
688 CaptureBy::Ref => CaptureBy::Ref,
689 CaptureBy::Use { use_kw } => CaptureBy::Use { use_kw: self.lower_span(use_kw) },
690 CaptureBy::Value { move_kw } => CaptureBy::Value { move_kw: self.lower_span(move_kw) },
691 }
692 }
693
694 pub(super) fn make_desugared_coroutine_expr(
706 &mut self,
707 capture_clause: CaptureBy,
708 closure_node_id: NodeId,
709 return_ty: Option<hir::FnRetTy<'hir>>,
710 fn_decl_span: Span,
711 span: Span,
712 desugaring_kind: hir::CoroutineDesugaring,
713 coroutine_source: hir::CoroutineSource,
714 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
715 ) -> hir::ExprKind<'hir> {
716 let closure_def_id = self.local_def_id(closure_node_id);
717 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
718
719 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
722 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
723 let unstable_span = self.mark_span_with_reason(
725 DesugaringKind::Async,
726 self.lower_span(span),
727 Some(Arc::clone(&self.allow_gen_future)),
728 );
729 let resume_ty =
730 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
731 let input_ty = hir::Ty {
732 hir_id: self.next_id(),
733 kind: hir::TyKind::Path(resume_ty),
734 span: unstable_span,
735 };
736 let inputs = arena_vec![self; input_ty];
737
738 let (pat, task_context_hid) = self.pat_ident_binding_mode(
740 span,
741 Ident::with_dummy_span(sym::_task_context),
742 hir::BindingMode::MUT,
743 );
744 let param = hir::Param {
745 hir_id: self.next_id(),
746 pat,
747 ty_span: self.lower_span(span),
748 span: self.lower_span(span),
749 };
750 let params = arena_vec![self; param];
751
752 (inputs, params, Some(task_context_hid))
753 }
754 hir::CoroutineDesugaring::Gen => (&[], &[], None),
755 };
756
757 let output =
758 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
759
760 let fn_decl = self.arena.alloc(hir::FnDecl {
761 inputs,
762 output,
763 c_variadic: false,
764 implicit_self: hir::ImplicitSelfKind::None,
765 lifetime_elision_allowed: false,
766 });
767
768 let body = self.lower_body(move |this| {
769 this.coroutine_kind = Some(coroutine_kind);
770
771 let old_ctx = this.task_context;
772 if task_context.is_some() {
773 this.task_context = task_context;
774 }
775 let res = body(this);
776 this.task_context = old_ctx;
777
778 (params, res)
779 });
780
781 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
783 def_id: closure_def_id,
784 binder: hir::ClosureBinder::Default,
785 capture_clause: self.lower_capture_clause(capture_clause),
786 bound_generic_params: &[],
787 fn_decl,
788 body,
789 fn_decl_span: self.lower_span(fn_decl_span),
790 fn_arg_span: None,
791 kind: hir::ClosureKind::Coroutine(coroutine_kind),
792 constness: hir::Constness::NotConst,
793 }))
794 }
795
796 pub(super) fn maybe_forward_track_caller(
799 &mut self,
800 span: Span,
801 outer_hir_id: HirId,
802 inner_hir_id: HirId,
803 ) {
804 if self.tcx.features().async_fn_track_caller()
805 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
806 && find_attr!(*attrs, AttributeKind::TrackCaller(_))
807 {
808 let unstable_span = self.mark_span_with_reason(
809 DesugaringKind::Async,
810 span,
811 Some(Arc::clone(&self.allow_gen_future)),
812 );
813 self.lower_attrs(
814 inner_hir_id,
815 &[Attribute {
816 kind: AttrKind::Normal(Box::new(NormalAttr::from_ident(Ident::new(
817 sym::track_caller,
818 span,
819 )))),
820 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
821 style: AttrStyle::Outer,
822 span: unstable_span,
823 }],
824 span,
825 Target::Fn,
826 );
827 }
828 }
829
830 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
846 let expr = self.arena.alloc(self.lower_expr_mut(expr));
847 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
848 }
849
850 fn make_lowered_await(
852 &mut self,
853 await_kw_span: Span,
854 expr: &'hir hir::Expr<'hir>,
855 await_kind: FutureKind,
856 ) -> hir::ExprKind<'hir> {
857 let full_span = expr.span.to(await_kw_span);
858
859 let is_async_gen = match self.coroutine_kind {
860 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
861 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
862 Some(hir::CoroutineKind::Coroutine(_))
863 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
864 | None => {
865 let stmt_id = self.next_id();
868 let expr_err = self.expr(
869 expr.span,
870 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
871 await_kw_span,
872 item_span: self.current_item,
873 })),
874 );
875 return hir::ExprKind::Block(
876 self.block_all(
877 expr.span,
878 arena_vec![self; hir::Stmt {
879 hir_id: stmt_id,
880 kind: hir::StmtKind::Semi(expr),
881 span: expr.span,
882 }],
883 Some(self.arena.alloc(expr_err)),
884 ),
885 None,
886 );
887 }
888 };
889
890 let features = match await_kind {
891 FutureKind::Future if is_async_gen => Some(Arc::clone(&self.allow_async_gen)),
892 FutureKind::Future => None,
893 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
894 };
895 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
896 let gen_future_span = self.mark_span_with_reason(
897 DesugaringKind::Await,
898 full_span,
899 Some(Arc::clone(&self.allow_gen_future)),
900 );
901 let expr_hir_id = expr.hir_id;
902
903 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
907 let (awaitee_pat, awaitee_pat_hid) =
908 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
909
910 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
911
912 let poll_expr = {
919 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
920 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
921
922 let Some(task_context_hid) = self.task_context else {
923 unreachable!("use of `await` outside of an async context.");
924 };
925
926 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
927
928 let new_unchecked = self.expr_call_lang_item_fn_mut(
929 span,
930 hir::LangItem::PinNewUnchecked,
931 arena_vec![self; ref_mut_awaitee],
932 );
933 let get_context = self.expr_call_lang_item_fn_mut(
934 gen_future_span,
935 hir::LangItem::GetContext,
936 arena_vec![self; task_context],
937 );
938 let call = match await_kind {
939 FutureKind::Future => self.expr_call_lang_item_fn(
940 span,
941 hir::LangItem::FuturePoll,
942 arena_vec![self; new_unchecked, get_context],
943 ),
944 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
945 span,
946 hir::LangItem::AsyncIteratorPollNext,
947 arena_vec![self; new_unchecked, get_context],
948 ),
949 };
950 self.arena.alloc(self.expr_unsafe(span, call))
951 };
952
953 let loop_node_id = self.next_node_id();
955 let loop_hir_id = self.lower_node_id(loop_node_id);
956 let ready_arm = {
957 let x_ident = Ident::with_dummy_span(sym::result);
958 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
959 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
960 let ready_field = self.single_pat_field(gen_future_span, x_pat);
961 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
962 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
963 let expr_break =
964 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
965 this.arena.alloc(this.expr(gen_future_span, expr_break))
966 });
967 self.arm(ready_pat, break_x)
968 };
969
970 let pending_arm = {
972 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
973 let empty_block = self.expr_block_empty(span);
974 self.arm(pending_pat, empty_block)
975 };
976
977 let inner_match_stmt = {
978 let match_expr = self.expr_match(
979 span,
980 poll_expr,
981 arena_vec![self; ready_arm, pending_arm],
982 hir::MatchSource::AwaitDesugar,
983 );
984 self.stmt_expr(span, match_expr)
985 };
986
987 let yield_stmt = {
991 let yielded = if is_async_gen {
992 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
993 } else {
994 self.expr_unit(span)
995 };
996
997 let yield_expr = self.expr(
998 span,
999 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
1000 );
1001 let yield_expr = self.arena.alloc(yield_expr);
1002
1003 let Some(task_context_hid) = self.task_context else {
1004 unreachable!("use of `await` outside of an async context.");
1005 };
1006
1007 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1008 let assign =
1009 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
1010 self.stmt_expr(span, assign)
1011 };
1012
1013 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
1014
1015 let loop_expr = self.arena.alloc(hir::Expr {
1017 hir_id: loop_hir_id,
1018 kind: hir::ExprKind::Loop(
1019 loop_block,
1020 None,
1021 hir::LoopSource::Loop,
1022 self.lower_span(span),
1023 ),
1024 span: self.lower_span(span),
1025 });
1026
1027 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1029
1030 let into_future_expr = match await_kind {
1032 FutureKind::Future => self.expr_call_lang_item_fn(
1033 span,
1034 hir::LangItem::IntoFutureIntoFuture,
1035 arena_vec![self; *expr],
1036 ),
1037 FutureKind::AsyncIterator => expr,
1040 };
1041
1042 hir::ExprKind::Match(
1046 into_future_expr,
1047 arena_vec![self; awaitee_arm],
1048 hir::MatchSource::AwaitDesugar,
1049 )
1050 }
1051
1052 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1053 hir::ExprKind::Use(self.lower_expr(expr), self.lower_span(use_kw_span))
1054 }
1055
1056 fn lower_expr_closure(
1057 &mut self,
1058 attrs: &[rustc_hir::Attribute],
1059 binder: &ClosureBinder,
1060 capture_clause: CaptureBy,
1061 closure_id: NodeId,
1062 constness: Const,
1063 movability: Movability,
1064 decl: &FnDecl,
1065 body: &Expr,
1066 fn_decl_span: Span,
1067 fn_arg_span: Span,
1068 ) -> hir::ExprKind<'hir> {
1069 let closure_def_id = self.local_def_id(closure_id);
1070 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1071
1072 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1073
1074 let mut coroutine_kind = find_attr!(attrs, AttributeKind::Coroutine(_) => hir::CoroutineKind::Coroutine(Movability::Movable));
1075
1076 let body_id = this.lower_fn_body(decl, None, |this| {
1078 this.coroutine_kind = coroutine_kind;
1079 let e = this.lower_expr_mut(body);
1080 coroutine_kind = this.coroutine_kind;
1081 e
1082 });
1083 let coroutine_option =
1084 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1085 (body_id, coroutine_option)
1086 });
1087
1088 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1089 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1091
1092 let c = self.arena.alloc(hir::Closure {
1093 def_id: closure_def_id,
1094 binder: binder_clause,
1095 capture_clause: self.lower_capture_clause(capture_clause),
1096 bound_generic_params,
1097 fn_decl,
1098 body: body_id,
1099 fn_decl_span: self.lower_span(fn_decl_span),
1100 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1101 kind: closure_kind,
1102 constness: self.lower_constness(constness),
1103 });
1104
1105 hir::ExprKind::Closure(c)
1106 }
1107
1108 fn closure_movability_for_fn(
1109 &mut self,
1110 decl: &FnDecl,
1111 fn_decl_span: Span,
1112 coroutine_kind: Option<hir::CoroutineKind>,
1113 movability: Movability,
1114 ) -> hir::ClosureKind {
1115 match coroutine_kind {
1116 Some(hir::CoroutineKind::Coroutine(_)) => {
1117 if decl.inputs.len() > 1 {
1118 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1119 }
1120 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1121 }
1122 Some(
1123 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1124 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1125 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1126 ) => {
1127 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1128 }
1129 None => {
1130 if movability == Movability::Static {
1131 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1132 }
1133 hir::ClosureKind::Closure
1134 }
1135 }
1136 }
1137
1138 fn lower_closure_binder<'c>(
1139 &mut self,
1140 binder: &'c ClosureBinder,
1141 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1142 let (binder, params) = match binder {
1143 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1144 ClosureBinder::For { span, generic_params } => {
1145 let span = self.lower_span(*span);
1146 (hir::ClosureBinder::For { span }, &**generic_params)
1147 }
1148 };
1149
1150 (binder, params)
1151 }
1152
1153 fn lower_expr_coroutine_closure(
1154 &mut self,
1155 binder: &ClosureBinder,
1156 capture_clause: CaptureBy,
1157 closure_id: NodeId,
1158 closure_hir_id: HirId,
1159 coroutine_kind: CoroutineKind,
1160 decl: &FnDecl,
1161 body: &Expr,
1162 fn_decl_span: Span,
1163 fn_arg_span: Span,
1164 ) -> hir::ExprKind<'hir> {
1165 let closure_def_id = self.local_def_id(closure_id);
1166 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1167
1168 let coroutine_desugaring = match coroutine_kind {
1169 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1170 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1171 CoroutineKind::AsyncGen { span, .. } => {
1172 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1173 }
1174 };
1175
1176 let body = self.with_new_scopes(fn_decl_span, |this| {
1177 let inner_decl =
1178 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1179
1180 let body_id = this.lower_body(|this| {
1183 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1184 &inner_decl,
1185 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1186 fn_decl_span,
1187 body.span,
1188 coroutine_kind,
1189 hir::CoroutineSource::Closure,
1190 );
1191
1192 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1193
1194 (parameters, expr)
1195 });
1196 body_id
1197 });
1198
1199 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1200 let fn_decl =
1204 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1205
1206 let c = self.arena.alloc(hir::Closure {
1207 def_id: closure_def_id,
1208 binder: binder_clause,
1209 capture_clause: self.lower_capture_clause(capture_clause),
1210 bound_generic_params,
1211 fn_decl,
1212 body,
1213 fn_decl_span: self.lower_span(fn_decl_span),
1214 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1215 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1219 constness: hir::Constness::NotConst,
1220 });
1221 hir::ExprKind::Closure(c)
1222 }
1223
1224 fn lower_expr_assign(
1227 &mut self,
1228 lhs: &Expr,
1229 rhs: &Expr,
1230 eq_sign_span: Span,
1231 whole_span: Span,
1232 ) -> hir::ExprKind<'hir> {
1233 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1235 match &lhs.kind {
1236 ExprKind::Array(..)
1237 | ExprKind::Struct(..)
1238 | ExprKind::Tup(..)
1239 | ExprKind::Underscore => false,
1240 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1242 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1244 ExprKind::Paren(e) => {
1245 match e.kind {
1246 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1248 _ => is_ordinary(lower_ctx, e),
1249 }
1250 }
1251 _ => true,
1252 }
1253 }
1254 if is_ordinary(self, lhs) {
1255 return hir::ExprKind::Assign(
1256 self.lower_expr(lhs),
1257 self.lower_expr(rhs),
1258 self.lower_span(eq_sign_span),
1259 );
1260 }
1261
1262 let mut assignments = vec![];
1263
1264 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1266 let rhs = self.lower_expr(rhs);
1267
1268 let destructure_let =
1270 self.stmt_let_pat(None, whole_span, Some(rhs), pat, hir::LocalSource::AssignDesugar);
1271
1272 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1274
1275 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1277 }
1278
1279 fn extract_tuple_struct_path<'a>(
1284 &mut self,
1285 expr: &'a Expr,
1286 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1287 if let ExprKind::Path(qself, path) = &expr.kind {
1288 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1290 if let Some(res) = partial_res.full_res()
1291 && !res.expected_in_tuple_struct_pat()
1292 {
1293 return None;
1294 }
1295 }
1296 return Some((qself, path));
1297 }
1298 None
1299 }
1300
1301 fn extract_unit_struct_path<'a>(
1306 &mut self,
1307 expr: &'a Expr,
1308 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1309 if let ExprKind::Path(qself, path) = &expr.kind {
1310 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1312 if let Some(res) = partial_res.full_res()
1313 && !res.expected_in_unit_struct_pat()
1314 {
1315 return None;
1316 }
1317 }
1318 return Some((qself, path));
1319 }
1320 None
1321 }
1322
1323 fn destructure_assign(
1326 &mut self,
1327 lhs: &Expr,
1328 eq_sign_span: Span,
1329 assignments: &mut Vec<hir::Stmt<'hir>>,
1330 ) -> &'hir hir::Pat<'hir> {
1331 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1332 }
1333
1334 fn destructure_assign_mut(
1335 &mut self,
1336 lhs: &Expr,
1337 eq_sign_span: Span,
1338 assignments: &mut Vec<hir::Stmt<'hir>>,
1339 ) -> hir::Pat<'hir> {
1340 match &lhs.kind {
1341 ExprKind::Underscore => {
1343 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1344 }
1345 ExprKind::Array(elements) => {
1347 let (pats, rest) =
1348 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1349 let slice_pat = if let Some((i, span)) = rest {
1350 let (before, after) = pats.split_at(i);
1351 hir::PatKind::Slice(
1352 before,
1353 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1354 after,
1355 )
1356 } else {
1357 hir::PatKind::Slice(pats, None, &[])
1358 };
1359 return self.pat_without_dbm(lhs.span, slice_pat);
1360 }
1361 ExprKind::Call(callee, args) => {
1363 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1364 let (pats, rest) = self.destructure_sequence(
1365 args,
1366 "tuple struct or variant",
1367 eq_sign_span,
1368 assignments,
1369 );
1370 let qpath = self.lower_qpath(
1371 callee.id,
1372 qself,
1373 path,
1374 ParamMode::Optional,
1375 AllowReturnTypeNotation::No,
1376 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1377 None,
1378 );
1379 let tuple_struct_pat = hir::PatKind::TupleStruct(
1381 qpath,
1382 pats,
1383 hir::DotDotPos::new(rest.map(|r| r.0)),
1384 );
1385 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1386 }
1387 }
1388 ExprKind::Path(..) => {
1390 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1391 let qpath = self.lower_qpath(
1392 lhs.id,
1393 qself,
1394 path,
1395 ParamMode::Optional,
1396 AllowReturnTypeNotation::No,
1397 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1398 None,
1399 );
1400 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1402 kind: hir::PatExprKind::Path(qpath),
1403 hir_id: self.next_id(),
1404 span: self.lower_span(lhs.span),
1405 }));
1406 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1407 }
1408 }
1409 ExprKind::Struct(se) => {
1411 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1412 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1413 hir::PatField {
1414 hir_id: self.next_id(),
1415 ident: self.lower_ident(f.ident),
1416 pat,
1417 is_shorthand: f.is_shorthand,
1418 span: self.lower_span(f.span),
1419 }
1420 }));
1421 let qpath = self.lower_qpath(
1422 lhs.id,
1423 &se.qself,
1424 &se.path,
1425 ParamMode::Optional,
1426 AllowReturnTypeNotation::No,
1427 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1428 None,
1429 );
1430 let fields_omitted = match &se.rest {
1431 StructRest::Base(e) => {
1432 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1433 span: e.span,
1434 });
1435 Some(self.lower_span(e.span))
1436 }
1437 StructRest::Rest(span) => Some(self.lower_span(*span)),
1438 StructRest::None => None,
1439 };
1440 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1441 return self.pat_without_dbm(lhs.span, struct_pat);
1442 }
1443 ExprKind::Tup(elements) => {
1445 let (pats, rest) =
1446 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1447 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1448 return self.pat_without_dbm(lhs.span, tuple_pat);
1449 }
1450 ExprKind::Paren(e) => {
1451 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1453 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1454 return self.pat_without_dbm(lhs.span, tuple_pat);
1455 } else {
1456 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1457 }
1458 }
1459 _ => {}
1460 }
1461 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1463 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1464 let ident = self.expr_ident(lhs.span, ident, binding);
1465 let assign =
1466 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1467 let expr = self.expr(lhs.span, assign);
1468 assignments.push(self.stmt_expr(lhs.span, expr));
1469 pat
1470 }
1471
1472 fn destructure_sequence(
1478 &mut self,
1479 elements: &[Box<Expr>],
1480 ctx: &str,
1481 eq_sign_span: Span,
1482 assignments: &mut Vec<hir::Stmt<'hir>>,
1483 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1484 let mut rest = None;
1485 let elements =
1486 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1487 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1489 if let Some((_, prev_span)) = rest {
1490 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1491 } else {
1492 rest = Some((i, e.span));
1493 }
1494 None
1495 } else {
1496 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1497 }
1498 }));
1499 (elements, rest)
1500 }
1501
1502 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1504 let e1 = self.lower_expr_mut(e1);
1505 let e2 = self.lower_expr_mut(e2);
1506 let fn_path = self.make_lang_item_qpath(hir::LangItem::RangeInclusiveNew, span, None);
1507 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1508 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1509 }
1510
1511 fn lower_expr_range(
1512 &mut self,
1513 span: Span,
1514 e1: Option<&Expr>,
1515 e2: Option<&Expr>,
1516 lims: RangeLimits,
1517 ) -> hir::ExprKind<'hir> {
1518 use rustc_ast::RangeLimits::*;
1519
1520 let lang_item = match (e1, e2, lims) {
1521 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1522 (Some(..), None, HalfOpen) => {
1523 if self.tcx.features().new_range() {
1524 hir::LangItem::RangeFromCopy
1525 } else {
1526 hir::LangItem::RangeFrom
1527 }
1528 }
1529 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1530 (Some(..), Some(..), HalfOpen) => {
1531 if self.tcx.features().new_range() {
1532 hir::LangItem::RangeCopy
1533 } else {
1534 hir::LangItem::Range
1535 }
1536 }
1537 (None, Some(..), Closed) => {
1538 if self.tcx.features().new_range() {
1539 hir::LangItem::RangeToInclusiveCopy
1540 } else {
1541 hir::LangItem::RangeToInclusive
1542 }
1543 }
1544 (Some(e1), Some(e2), Closed) => {
1545 if self.tcx.features().new_range() {
1546 hir::LangItem::RangeInclusiveCopy
1547 } else {
1548 return self.lower_expr_range_closed(span, e1, e2);
1549 }
1550 }
1551 (start, None, Closed) => {
1552 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1553 match start {
1554 Some(..) => {
1555 if self.tcx.features().new_range() {
1556 hir::LangItem::RangeFromCopy
1557 } else {
1558 hir::LangItem::RangeFrom
1559 }
1560 }
1561 None => hir::LangItem::RangeFull,
1562 }
1563 }
1564 };
1565
1566 let fields = self.arena.alloc_from_iter(
1567 e1.iter()
1568 .map(|e| (sym::start, e))
1569 .chain(e2.iter().map(|e| {
1570 (
1571 if matches!(
1572 lang_item,
1573 hir::LangItem::RangeInclusiveCopy | hir::LangItem::RangeToInclusiveCopy
1574 ) {
1575 sym::last
1576 } else {
1577 sym::end
1578 },
1579 e,
1580 )
1581 }))
1582 .map(|(s, e)| {
1583 let span = self.lower_span(e.span);
1584 let span = self.mark_span_with_reason(DesugaringKind::RangeExpr, span, None);
1585 let expr = self.lower_expr(e);
1586 let ident = Ident::new(s, span);
1587 self.expr_field(ident, expr, span)
1588 }),
1589 );
1590
1591 hir::ExprKind::Struct(
1592 self.arena.alloc(self.make_lang_item_qpath(lang_item, span, None)),
1593 fields,
1594 hir::StructTailExpr::None,
1595 )
1596 }
1597
1598 fn lower_label(
1601 &mut self,
1602 opt_label: Option<Label>,
1603 dest_id: NodeId,
1604 dest_hir_id: hir::HirId,
1605 ) -> Option<Label> {
1606 let label = opt_label?;
1607 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1608 Some(Label { ident: self.lower_ident(label.ident) })
1609 }
1610
1611 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1612 let target_id = match destination {
1613 Some((id, _)) => {
1614 if let Some(loop_id) = self.resolver.get_label_res(id) {
1615 let local_id = self.ident_and_label_to_local_id[&loop_id];
1616 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1617 Ok(loop_hir_id)
1618 } else {
1619 Err(hir::LoopIdError::UnresolvedLabel)
1620 }
1621 }
1622 None => {
1623 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1624 }
1625 };
1626 let label = destination
1627 .map(|(_, label)| label)
1628 .map(|label| Label { ident: self.lower_ident(label.ident) });
1629 hir::Destination { label, target_id }
1630 }
1631
1632 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1633 if self.is_in_loop_condition && opt_label.is_none() {
1634 hir::Destination {
1635 label: None,
1636 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1637 }
1638 } else {
1639 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1640 }
1641 }
1642
1643 fn with_try_block_scope<T>(
1644 &mut self,
1645 scope: TryBlockScope,
1646 f: impl FnOnce(&mut Self) -> T,
1647 ) -> T {
1648 let old_scope = mem::replace(&mut self.try_block_scope, scope);
1649 let result = f(self);
1650 self.try_block_scope = old_scope;
1651 result
1652 }
1653
1654 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1655 let was_in_loop_condition = self.is_in_loop_condition;
1657 self.is_in_loop_condition = false;
1658
1659 let old_scope = self.loop_scope.replace(loop_id);
1660 let result = f(self);
1661 self.loop_scope = old_scope;
1662
1663 self.is_in_loop_condition = was_in_loop_condition;
1664
1665 result
1666 }
1667
1668 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1669 let was_in_loop_condition = self.is_in_loop_condition;
1670 self.is_in_loop_condition = true;
1671
1672 let result = f(self);
1673
1674 self.is_in_loop_condition = was_in_loop_condition;
1675
1676 result
1677 }
1678
1679 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1680 let hir_id = self.lower_node_id(f.id);
1681 self.lower_attrs(hir_id, &f.attrs, f.span, Target::ExprField);
1682 hir::ExprField {
1683 hir_id,
1684 ident: self.lower_ident(f.ident),
1685 expr: self.lower_expr(&f.expr),
1686 span: self.lower_span(f.span),
1687 is_shorthand: f.is_shorthand,
1688 }
1689 }
1690
1691 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1692 let yielded =
1693 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1694
1695 if !self.tcx.features().yield_expr()
1696 && !self.tcx.features().coroutines()
1697 && !self.tcx.features().gen_blocks()
1698 {
1699 rustc_session::parse::feature_err(
1700 &self.tcx.sess,
1701 sym::yield_expr,
1702 span,
1703 fluent_generated::ast_lowering_yield,
1704 )
1705 .emit();
1706 }
1707
1708 let is_async_gen = match self.coroutine_kind {
1709 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1710 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1711 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1712 let stmt_id = self.next_id();
1715 let expr_err = self.expr(
1716 yielded.span,
1717 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1718 );
1719 return hir::ExprKind::Block(
1720 self.block_all(
1721 yielded.span,
1722 arena_vec![self; hir::Stmt {
1723 hir_id: stmt_id,
1724 kind: hir::StmtKind::Semi(yielded),
1725 span: yielded.span,
1726 }],
1727 Some(self.arena.alloc(expr_err)),
1728 ),
1729 None,
1730 );
1731 }
1732 Some(hir::CoroutineKind::Coroutine(_)) => false,
1733 None => {
1734 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1735 self.dcx().emit_err(YieldInClosure { span, suggestion });
1736 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1737
1738 false
1739 }
1740 };
1741
1742 if is_async_gen {
1743 let desugar_span = self.mark_span_with_reason(
1747 DesugaringKind::Async,
1748 span,
1749 Some(Arc::clone(&self.allow_async_gen)),
1750 );
1751 let wrapped_yielded = self.expr_call_lang_item_fn(
1752 desugar_span,
1753 hir::LangItem::AsyncGenReady,
1754 std::slice::from_ref(yielded),
1755 );
1756 let yield_expr = self.arena.alloc(
1757 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1758 );
1759
1760 let Some(task_context_hid) = self.task_context else {
1761 unreachable!("use of `await` outside of an async context.");
1762 };
1763 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1764 let lhs = self.expr_ident(desugar_span, task_context_ident, task_context_hid);
1765
1766 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1767 } else {
1768 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1769 }
1770 }
1771
1772 fn lower_expr_for(
1789 &mut self,
1790 e: &Expr,
1791 pat: &Pat,
1792 head: &Expr,
1793 body: &Block,
1794 opt_label: Option<Label>,
1795 loop_kind: ForLoopKind,
1796 ) -> hir::Expr<'hir> {
1797 let head = self.lower_expr_mut(head);
1798 let pat = self.lower_pat(pat);
1799 let for_span =
1800 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1801 let for_ctxt = for_span.ctxt();
1802
1803 let head_span =
1806 head.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(head.span).with_ctxt(for_ctxt);
1807 let pat_span =
1808 pat.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(pat.span).with_ctxt(for_ctxt);
1809
1810 let loop_hir_id = self.lower_node_id(e.id);
1811 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1812
1813 let none_arm = {
1815 let break_expr =
1816 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1817 let pat = self.pat_none(for_span);
1818 self.arm(pat, break_expr)
1819 };
1820
1821 let some_arm = {
1823 let some_pat = self.pat_some(pat_span, pat);
1824 let body_block =
1825 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1826 let body_expr = self.arena.alloc(self.expr_block(body_block));
1827 self.arm(some_pat, body_expr)
1828 };
1829
1830 let iter = Ident::with_dummy_span(sym::iter);
1832 let (iter_pat, iter_pat_nid) =
1833 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1834
1835 let match_expr = {
1836 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1837 let next_expr = match loop_kind {
1838 ForLoopKind::For => {
1839 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1841 self.expr_call_lang_item_fn(
1842 head_span,
1843 hir::LangItem::IteratorNext,
1844 arena_vec![self; ref_mut_iter],
1845 )
1846 }
1847 ForLoopKind::ForAwait => {
1848 let iter = self.expr_mut_addr_of(head_span, iter);
1855 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1857 head_span,
1858 hir::LangItem::PinNewUnchecked,
1859 arena_vec![self; iter],
1860 ));
1861 let iter = self.arena.alloc(self.expr_unsafe(head_span, iter));
1863 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1864 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1865 }
1866 };
1867 let arms = arena_vec![self; none_arm, some_arm];
1868
1869 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1871 };
1872 let match_stmt = self.stmt_expr(for_span, match_expr);
1873
1874 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1875
1876 let kind = hir::ExprKind::Loop(
1878 loop_block,
1879 label,
1880 hir::LoopSource::ForLoop,
1881 self.lower_span(for_span.with_hi(head.span.hi())),
1882 );
1883 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1884
1885 let iter_arm = self.arm(iter_pat, loop_expr);
1887
1888 let match_expr = match loop_kind {
1889 ForLoopKind::For => {
1890 let into_iter_expr = self.expr_call_lang_item_fn(
1892 head_span,
1893 hir::LangItem::IntoIterIntoIter,
1894 arena_vec![self; head],
1895 );
1896
1897 self.arena.alloc(self.expr_match(
1898 for_span,
1899 into_iter_expr,
1900 arena_vec![self; iter_arm],
1901 hir::MatchSource::ForLoopDesugar,
1902 ))
1903 }
1904 ForLoopKind::ForAwait => {
1906 let iter_ident = iter;
1907 let (async_iter_pat, async_iter_pat_id) =
1908 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1909 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1910 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1912 head_span,
1913 hir::LangItem::PinNewUnchecked,
1914 arena_vec![self; iter],
1915 ));
1916 let iter = self.arena.alloc(self.expr_unsafe(head_span, iter));
1918 let inner_match_expr = self.arena.alloc(self.expr_match(
1919 for_span,
1920 iter,
1921 arena_vec![self; iter_arm],
1922 hir::MatchSource::ForLoopDesugar,
1923 ));
1924
1925 let iter = self.expr_call_lang_item_fn(
1927 head_span,
1928 hir::LangItem::IntoAsyncIterIntoIter,
1929 arena_vec![self; head],
1930 );
1931 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1932 self.arena.alloc(self.expr_match(
1933 for_span,
1934 iter,
1935 arena_vec![self; iter_arm],
1936 hir::MatchSource::ForLoopDesugar,
1937 ))
1938 }
1939 };
1940
1941 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1948 self.lower_attrs(expr.hir_id, &e.attrs, e.span, Target::from_expr(e));
1949 expr
1950 }
1951
1952 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1965 let unstable_span = self.mark_span_with_reason(
1966 DesugaringKind::QuestionMark,
1967 span,
1968 Some(Arc::clone(&self.allow_try_trait)),
1969 );
1970 let try_span = self.tcx.sess.source_map().end_point(span);
1971 let try_span = self.mark_span_with_reason(
1972 DesugaringKind::QuestionMark,
1973 try_span,
1974 Some(Arc::clone(&self.allow_try_trait)),
1975 );
1976
1977 let scrutinee = {
1979 let sub_expr = self.lower_expr_mut(sub_expr);
1981
1982 self.expr_call_lang_item_fn(
1983 unstable_span,
1984 hir::LangItem::TryTraitBranch,
1985 arena_vec![self; sub_expr],
1986 )
1987 };
1988
1989 let attrs: AttrVec = thin_vec![self.unreachable_code_attr(try_span)];
1990
1991 let continue_arm = {
1993 let val_ident = Ident::with_dummy_span(sym::val);
1994 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
1995 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
1996 self.lower_attrs(val_expr.hir_id, &attrs, span, Target::Expression);
1997 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
1998 self.arm(continue_pat, val_expr)
1999 };
2000
2001 let break_arm = {
2005 let residual_ident = Ident::with_dummy_span(sym::residual);
2006 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
2007 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
2008
2009 let (constructor_item, target_id) = match self.try_block_scope {
2010 TryBlockScope::Function => {
2011 (hir::LangItem::TryTraitFromResidual, Err(hir::LoopIdError::OutsideLoopScope))
2012 }
2013 TryBlockScope::Homogeneous(block_id) => {
2014 (hir::LangItem::ResidualIntoTryType, Ok(block_id))
2015 }
2016 TryBlockScope::Heterogeneous(block_id) => {
2017 (hir::LangItem::TryTraitFromResidual, Ok(block_id))
2018 }
2019 };
2020 let from_residual_expr = self.wrap_in_try_constructor(
2021 constructor_item,
2022 try_span,
2023 self.arena.alloc(residual_expr),
2024 unstable_span,
2025 );
2026 let ret_expr = if target_id.is_ok() {
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, Target::Expression);
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 match self.try_block_scope {
2082 TryBlockScope::Homogeneous(block_id) | TryBlockScope::Heterogeneous(block_id) => {
2083 hir::ExprKind::Break(
2084 hir::Destination { label: None, target_id: Ok(block_id) },
2085 Some(from_yeet_expr),
2086 )
2087 }
2088 TryBlockScope::Function => self.checked_return(Some(from_yeet_expr)),
2089 }
2090 }
2091
2092 pub(super) fn expr_drop_temps(
2104 &mut self,
2105 span: Span,
2106 expr: &'hir hir::Expr<'hir>,
2107 ) -> &'hir hir::Expr<'hir> {
2108 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2109 }
2110
2111 pub(super) fn expr_drop_temps_mut(
2112 &mut self,
2113 span: Span,
2114 expr: &'hir hir::Expr<'hir>,
2115 ) -> hir::Expr<'hir> {
2116 self.expr(span, hir::ExprKind::DropTemps(expr))
2117 }
2118
2119 pub(super) fn expr_match(
2120 &mut self,
2121 span: Span,
2122 arg: &'hir hir::Expr<'hir>,
2123 arms: &'hir [hir::Arm<'hir>],
2124 source: hir::MatchSource,
2125 ) -> hir::Expr<'hir> {
2126 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2127 }
2128
2129 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2130 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2131 self.expr(span, expr_break)
2132 }
2133
2134 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2135 let expr_break = self.expr_break(span);
2136 self.arena.alloc(expr_break)
2137 }
2138
2139 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2140 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2141 }
2142
2143 pub(super) fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2144 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2145 }
2146
2147 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2148 let lit = hir::Lit {
2149 span: self.lower_span(sp),
2150 node: ast::LitKind::Str(value, ast::StrStyle::Cooked),
2151 };
2152 self.expr(sp, hir::ExprKind::Lit(lit))
2153 }
2154
2155 pub(super) fn expr_byte_str(&mut self, sp: Span, value: ByteSymbol) -> hir::Expr<'hir> {
2156 let lit = hir::Lit {
2157 span: self.lower_span(sp),
2158 node: ast::LitKind::ByteStr(value, ast::StrStyle::Cooked),
2159 };
2160 self.expr(sp, hir::ExprKind::Lit(lit))
2161 }
2162
2163 pub(super) fn expr_call_mut(
2164 &mut self,
2165 span: Span,
2166 e: &'hir hir::Expr<'hir>,
2167 args: &'hir [hir::Expr<'hir>],
2168 ) -> hir::Expr<'hir> {
2169 self.expr(span, hir::ExprKind::Call(e, args))
2170 }
2171
2172 pub(super) fn expr_struct(
2173 &mut self,
2174 span: Span,
2175 path: &'hir hir::QPath<'hir>,
2176 fields: &'hir [hir::ExprField<'hir>],
2177 ) -> hir::Expr<'hir> {
2178 self.expr(span, hir::ExprKind::Struct(path, fields, rustc_hir::StructTailExpr::None))
2179 }
2180
2181 pub(super) fn expr_enum_variant(
2182 &mut self,
2183 span: Span,
2184 path: &'hir hir::QPath<'hir>,
2185 fields: &'hir [hir::Expr<'hir>],
2186 ) -> hir::Expr<'hir> {
2187 let fields = self.arena.alloc_from_iter(fields.into_iter().enumerate().map(|(i, f)| {
2188 hir::ExprField {
2189 hir_id: self.next_id(),
2190 ident: Ident::from_str(&i.to_string()),
2191 expr: f,
2192 span: f.span,
2193 is_shorthand: false,
2194 }
2195 }));
2196 self.expr_struct(span, path, fields)
2197 }
2198
2199 pub(super) fn expr_enum_variant_lang_item(
2200 &mut self,
2201 span: Span,
2202 lang_item: hir::LangItem,
2203 fields: &'hir [hir::Expr<'hir>],
2204 ) -> hir::Expr<'hir> {
2205 let path = self.arena.alloc(self.make_lang_item_qpath(lang_item, span, None));
2206 self.expr_enum_variant(span, path, fields)
2207 }
2208
2209 pub(super) fn expr_call(
2210 &mut self,
2211 span: Span,
2212 e: &'hir hir::Expr<'hir>,
2213 args: &'hir [hir::Expr<'hir>],
2214 ) -> &'hir hir::Expr<'hir> {
2215 self.arena.alloc(self.expr_call_mut(span, e, args))
2216 }
2217
2218 pub(super) fn expr_call_lang_item_fn_mut(
2219 &mut self,
2220 span: Span,
2221 lang_item: hir::LangItem,
2222 args: &'hir [hir::Expr<'hir>],
2223 ) -> hir::Expr<'hir> {
2224 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2225 self.expr_call_mut(span, path, args)
2226 }
2227
2228 pub(super) fn expr_call_lang_item_fn(
2229 &mut self,
2230 span: Span,
2231 lang_item: hir::LangItem,
2232 args: &'hir [hir::Expr<'hir>],
2233 ) -> &'hir hir::Expr<'hir> {
2234 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2235 }
2236
2237 pub(super) fn expr_lang_item_path(
2238 &mut self,
2239 span: Span,
2240 lang_item: hir::LangItem,
2241 ) -> hir::Expr<'hir> {
2242 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2243 self.expr(span, hir::ExprKind::Path(qpath))
2244 }
2245
2246 pub(super) fn expr_lang_item_type_relative(
2248 &mut self,
2249 span: Span,
2250 lang_item: hir::LangItem,
2251 name: Symbol,
2252 ) -> hir::Expr<'hir> {
2253 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2254 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2255 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2256 self.arena.alloc(hir::PathSegment::new(
2257 Ident::new(name, self.lower_span(span)),
2258 self.next_id(),
2259 Res::Err,
2260 )),
2261 ));
2262 self.expr(span, path)
2263 }
2264
2265 pub(super) fn expr_ident(
2266 &mut self,
2267 sp: Span,
2268 ident: Ident,
2269 binding: HirId,
2270 ) -> &'hir hir::Expr<'hir> {
2271 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2272 }
2273
2274 pub(super) fn expr_ident_mut(
2275 &mut self,
2276 span: Span,
2277 ident: Ident,
2278 binding: HirId,
2279 ) -> hir::Expr<'hir> {
2280 let hir_id = self.next_id();
2281 let res = Res::Local(binding);
2282 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2283 None,
2284 self.arena.alloc(hir::Path {
2285 span: self.lower_span(span),
2286 res,
2287 segments: arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
2288 }),
2289 ));
2290
2291 self.expr(span, expr_path)
2292 }
2293
2294 pub(super) fn expr_unsafe(
2295 &mut self,
2296 span: Span,
2297 expr: &'hir hir::Expr<'hir>,
2298 ) -> hir::Expr<'hir> {
2299 let hir_id = self.next_id();
2300 self.expr(
2301 span,
2302 hir::ExprKind::Block(
2303 self.arena.alloc(hir::Block {
2304 stmts: &[],
2305 expr: Some(expr),
2306 hir_id,
2307 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2308 span: self.lower_span(span),
2309 targeted_by_break: false,
2310 }),
2311 None,
2312 ),
2313 )
2314 }
2315
2316 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2317 let blk = self.block_all(span, &[], None);
2318 let expr = self.expr_block(blk);
2319 self.arena.alloc(expr)
2320 }
2321
2322 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2323 self.expr(b.span, hir::ExprKind::Block(b, None))
2324 }
2325
2326 pub(super) fn block_expr_block(
2330 &mut self,
2331 expr: &'hir hir::Expr<'hir>,
2332 ) -> &'hir hir::Expr<'hir> {
2333 let b = self.block_expr(expr);
2334 self.arena.alloc(self.expr_block(b))
2335 }
2336
2337 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2338 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2339 }
2340
2341 pub(super) fn expr_bool_literal(&mut self, span: Span, val: bool) -> hir::Expr<'hir> {
2342 self.expr(span, hir::ExprKind::Lit(Spanned { node: LitKind::Bool(val), span }))
2343 }
2344
2345 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2346 let hir_id = self.next_id();
2347 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2348 }
2349
2350 pub(super) fn expr_field(
2351 &mut self,
2352 ident: Ident,
2353 expr: &'hir hir::Expr<'hir>,
2354 span: Span,
2355 ) -> hir::ExprField<'hir> {
2356 hir::ExprField {
2357 hir_id: self.next_id(),
2358 ident,
2359 span: self.lower_span(span),
2360 expr,
2361 is_shorthand: false,
2362 }
2363 }
2364
2365 pub(super) fn arm(
2366 &mut self,
2367 pat: &'hir hir::Pat<'hir>,
2368 expr: &'hir hir::Expr<'hir>,
2369 ) -> hir::Arm<'hir> {
2370 hir::Arm {
2371 hir_id: self.next_id(),
2372 pat,
2373 guard: None,
2374 span: self.lower_span(expr.span),
2375 body: expr,
2376 }
2377 }
2378
2379 pub(super) fn unreachable_code_attr(&mut self, span: Span) -> Attribute {
2381 let attr = attr::mk_attr_nested_word(
2382 &self.tcx.sess.psess.attr_id_generator,
2383 AttrStyle::Outer,
2384 Safety::Default,
2385 sym::allow,
2386 sym::unreachable_code,
2387 span,
2388 );
2389 attr
2390 }
2391}
2392
2393#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2396enum FutureKind {
2397 Future,
2399 AsyncIterator,
2402}