1use std::ops::ControlFlow;
2use std::sync::Arc;
3
4use rustc_ast::*;
5use rustc_ast_pretty::pprust::expr_to_string;
6use rustc_data_structures::stack::ensure_sufficient_stack;
7use rustc_hir as hir;
8use rustc_hir::attrs::AttributeKind;
9use rustc_hir::def::{DefKind, Res};
10use rustc_hir::{HirId, Target, find_attr};
11use rustc_middle::span_bug;
12use rustc_middle::ty::TyCtxt;
13use rustc_session::errors::report_lit_error;
14use rustc_span::source_map::{Spanned, respan};
15use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
16use thin_vec::{ThinVec, thin_vec};
17use visit::{Visitor, walk_expr};
18
19use super::errors::{
20 AsyncCoroutinesNotSupported, AwaitOnlyInAsyncFnAndBlocks, ClosureCannotBeStatic,
21 CoroutineTooManyParameters, FunctionalRecordUpdateDestructuringAssignment,
22 InclusiveRangeWithNoEnd, MatchArmWithNoBody, NeverPatternWithBody, NeverPatternWithGuard,
23 UnderscoreExprLhsAssign,
24};
25use super::{
26 GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
27};
28use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
29use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, fluent_generated};
30
31struct WillCreateDefIdsVisitor {}
32
33impl<'v> rustc_ast::visit::Visitor<'v> for WillCreateDefIdsVisitor {
34 type Result = ControlFlow<Span>;
35
36 fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
37 ControlFlow::Break(c.value.span)
38 }
39
40 fn visit_item(&mut self, item: &'v Item) -> Self::Result {
41 ControlFlow::Break(item.span)
42 }
43
44 fn visit_expr(&mut self, ex: &'v Expr) -> Self::Result {
45 match ex.kind {
46 ExprKind::Gen(..) | ExprKind::ConstBlock(..) | ExprKind::Closure(..) => {
47 ControlFlow::Break(ex.span)
48 }
49 _ => walk_expr(self, ex),
50 }
51 }
52}
53
54impl<'hir> LoweringContext<'_, 'hir> {
55 fn lower_exprs(&mut self, exprs: &[Box<Expr>]) -> &'hir [hir::Expr<'hir>] {
56 self.arena.alloc_from_iter(exprs.iter().map(|x| self.lower_expr_mut(x)))
57 }
58
59 pub(super) fn lower_expr(&mut self, e: &Expr) -> &'hir hir::Expr<'hir> {
60 self.arena.alloc(self.lower_expr_mut(e))
61 }
62
63 pub(super) fn lower_expr_mut(&mut self, e: &Expr) -> hir::Expr<'hir> {
64 ensure_sufficient_stack(|| {
65 match &e.kind {
66 ExprKind::Paren(ex) => {
68 let mut ex = self.lower_expr_mut(ex);
69 if e.span.contains(ex.span) {
71 ex.span = self.lower_span(e.span);
72 }
73 if !e.attrs.is_empty() {
75 let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
76 let new_attrs = self
77 .lower_attrs_vec(&e.attrs, e.span, ex.hir_id, Target::from_expr(e))
78 .into_iter()
79 .chain(old_attrs.iter().cloned());
80 let new_attrs = &*self.arena.alloc_from_iter(new_attrs);
81 if new_attrs.is_empty() {
82 return ex;
83 }
84 self.attrs.insert(ex.hir_id.local_id, new_attrs);
85 }
86 return ex;
87 }
88 ExprKind::ForLoop { pat, iter, body, label, kind } => {
94 return self.lower_expr_for(e, pat, iter, body, *label, *kind);
95 }
96 _ => (),
97 }
98
99 let expr_hir_id = self.lower_node_id(e.id);
100 let attrs = self.lower_attrs(expr_hir_id, &e.attrs, e.span, Target::from_expr(e));
101
102 let kind = match &e.kind {
103 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
104 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
105 ExprKind::Repeat(expr, count) => {
106 let expr = self.lower_expr(expr);
107 let count = self.lower_array_length_to_const_arg(count);
108 hir::ExprKind::Repeat(expr, count)
109 }
110 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
111 ExprKind::Call(f, args) => {
112 if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) {
113 self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
114 } else {
115 let f = self.lower_expr(f);
116 hir::ExprKind::Call(f, self.lower_exprs(args))
117 }
118 }
119 ExprKind::MethodCall(box MethodCall { seg, receiver, args, span }) => {
120 let hir_seg = self.arena.alloc(self.lower_path_segment(
121 e.span,
122 seg,
123 ParamMode::Optional,
124 GenericArgsMode::Err,
125 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
126 None,
128 ));
129 let receiver = self.lower_expr(receiver);
130 let args =
131 self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
132 hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(*span))
133 }
134 ExprKind::Binary(binop, lhs, rhs) => {
135 let binop = self.lower_binop(*binop);
136 let lhs = self.lower_expr(lhs);
137 let rhs = self.lower_expr(rhs);
138 hir::ExprKind::Binary(binop, lhs, rhs)
139 }
140 ExprKind::Unary(op, ohs) => {
141 let op = self.lower_unop(*op);
142 let ohs = self.lower_expr(ohs);
143 hir::ExprKind::Unary(op, ohs)
144 }
145 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
146 ExprKind::IncludedBytes(byte_sym) => {
147 let lit = respan(
148 self.lower_span(e.span),
149 LitKind::ByteStr(*byte_sym, StrStyle::Cooked),
150 );
151 hir::ExprKind::Lit(lit)
152 }
153 ExprKind::Cast(expr, ty) => {
154 let expr = self.lower_expr(expr);
155 let ty =
156 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
157 hir::ExprKind::Cast(expr, ty)
158 }
159 ExprKind::Type(expr, ty) => {
160 let expr = self.lower_expr(expr);
161 let ty =
162 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
163 hir::ExprKind::Type(expr, ty)
164 }
165 ExprKind::AddrOf(k, m, ohs) => {
166 let ohs = self.lower_expr(ohs);
167 hir::ExprKind::AddrOf(*k, *m, ohs)
168 }
169 ExprKind::Let(pat, scrutinee, span, recovered) => {
170 hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
171 span: self.lower_span(*span),
172 pat: self.lower_pat(pat),
173 ty: None,
174 init: self.lower_expr(scrutinee),
175 recovered: *recovered,
176 }))
177 }
178 ExprKind::If(cond, then, else_opt) => {
179 self.lower_expr_if(cond, then, else_opt.as_deref())
180 }
181 ExprKind::While(cond, body, opt_label) => {
182 self.with_loop_scope(expr_hir_id, |this| {
183 let span =
184 this.mark_span_with_reason(DesugaringKind::WhileLoop, e.span, None);
185 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
186 this.lower_expr_while_in_loop_scope(span, cond, body, opt_label)
187 })
188 }
189 ExprKind::Loop(body, opt_label, span) => {
190 self.with_loop_scope(expr_hir_id, |this| {
191 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
192 hir::ExprKind::Loop(
193 this.lower_block(body, false),
194 opt_label,
195 hir::LoopSource::Loop,
196 this.lower_span(*span),
197 )
198 })
199 }
200 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
201 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
202 self.lower_expr(expr),
203 self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
204 match kind {
205 MatchKind::Prefix => hir::MatchSource::Normal,
206 MatchKind::Postfix => hir::MatchSource::Postfix,
207 },
208 ),
209 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
210 ExprKind::Use(expr, use_kw_span) => self.lower_expr_use(*use_kw_span, expr),
211 ExprKind::Closure(box Closure {
212 binder,
213 capture_clause,
214 constness,
215 coroutine_kind,
216 movability,
217 fn_decl,
218 body,
219 fn_decl_span,
220 fn_arg_span,
221 }) => match coroutine_kind {
222 Some(coroutine_kind) => self.lower_expr_coroutine_closure(
223 binder,
224 *capture_clause,
225 e.id,
226 expr_hir_id,
227 *coroutine_kind,
228 fn_decl,
229 body,
230 *fn_decl_span,
231 *fn_arg_span,
232 ),
233 None => self.lower_expr_closure(
234 attrs,
235 binder,
236 *capture_clause,
237 e.id,
238 *constness,
239 *movability,
240 fn_decl,
241 body,
242 *fn_decl_span,
243 *fn_arg_span,
244 ),
245 },
246 ExprKind::Gen(capture_clause, block, genblock_kind, decl_span) => {
247 let desugaring_kind = match genblock_kind {
248 GenBlockKind::Async => hir::CoroutineDesugaring::Async,
249 GenBlockKind::Gen => hir::CoroutineDesugaring::Gen,
250 GenBlockKind::AsyncGen => hir::CoroutineDesugaring::AsyncGen,
251 };
252 self.make_desugared_coroutine_expr(
253 *capture_clause,
254 e.id,
255 None,
256 *decl_span,
257 e.span,
258 desugaring_kind,
259 hir::CoroutineSource::Block,
260 |this| this.with_new_scopes(e.span, |this| this.lower_block_expr(block)),
261 )
262 }
263 ExprKind::Block(blk, opt_label) => {
264 let block_hir_id = self.lower_node_id(blk.id);
267 let opt_label = self.lower_label(*opt_label, blk.id, block_hir_id);
268 let hir_block = self.arena.alloc(self.lower_block_noalloc(
269 block_hir_id,
270 blk,
271 opt_label.is_some(),
272 ));
273 hir::ExprKind::Block(hir_block, opt_label)
274 }
275 ExprKind::Assign(el, er, span) => self.lower_expr_assign(el, er, *span, e.span),
276 ExprKind::AssignOp(op, el, er) => hir::ExprKind::AssignOp(
277 self.lower_assign_op(*op),
278 self.lower_expr(el),
279 self.lower_expr(er),
280 ),
281 ExprKind::Field(el, ident) => {
282 hir::ExprKind::Field(self.lower_expr(el), self.lower_ident(*ident))
283 }
284 ExprKind::Index(el, er, brackets_span) => hir::ExprKind::Index(
285 self.lower_expr(el),
286 self.lower_expr(er),
287 self.lower_span(*brackets_span),
288 ),
289 ExprKind::Range(e1, e2, lims) => {
290 self.lower_expr_range(e.span, e1.as_deref(), e2.as_deref(), *lims)
291 }
292 ExprKind::Underscore => {
293 let guar = self.dcx().emit_err(UnderscoreExprLhsAssign { span: e.span });
294 hir::ExprKind::Err(guar)
295 }
296 ExprKind::Path(qself, path) => {
297 let qpath = self.lower_qpath(
298 e.id,
299 qself,
300 path,
301 ParamMode::Optional,
302 AllowReturnTypeNotation::No,
303 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
304 None,
305 );
306 hir::ExprKind::Path(qpath)
307 }
308 ExprKind::Break(opt_label, opt_expr) => {
309 let opt_expr = opt_expr.as_ref().map(|x| self.lower_expr(x));
310 hir::ExprKind::Break(self.lower_jump_destination(e.id, *opt_label), opt_expr)
311 }
312 ExprKind::Continue(opt_label) => {
313 hir::ExprKind::Continue(self.lower_jump_destination(e.id, *opt_label))
314 }
315 ExprKind::Ret(e) => {
316 let expr = e.as_ref().map(|x| self.lower_expr(x));
317 self.checked_return(expr)
318 }
319 ExprKind::Yeet(sub_expr) => self.lower_expr_yeet(e.span, sub_expr.as_deref()),
320 ExprKind::Become(sub_expr) => {
321 let sub_expr = self.lower_expr(sub_expr);
322 hir::ExprKind::Become(sub_expr)
323 }
324 ExprKind::InlineAsm(asm) => {
325 hir::ExprKind::InlineAsm(self.lower_inline_asm(e.span, asm))
326 }
327 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
328 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
329 self.lower_ty(
330 container,
331 ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
332 ),
333 self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
334 ),
335 ExprKind::Struct(se) => {
336 let rest = match &se.rest {
337 StructRest::Base(e) => hir::StructTailExpr::Base(self.lower_expr(e)),
338 StructRest::Rest(sp) => {
339 hir::StructTailExpr::DefaultFields(self.lower_span(*sp))
340 }
341 StructRest::None => hir::StructTailExpr::None,
342 };
343 hir::ExprKind::Struct(
344 self.arena.alloc(self.lower_qpath(
345 e.id,
346 &se.qself,
347 &se.path,
348 ParamMode::Optional,
349 AllowReturnTypeNotation::No,
350 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
351 None,
352 )),
353 self.arena
354 .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
355 rest,
356 )
357 }
358 ExprKind::Yield(kind) => self.lower_expr_yield(e.span, kind.expr().map(|x| &**x)),
359 ExprKind::Err(guar) => hir::ExprKind::Err(*guar),
360
361 ExprKind::UnsafeBinderCast(kind, expr, ty) => hir::ExprKind::UnsafeBinderCast(
362 *kind,
363 self.lower_expr(expr),
364 ty.as_ref().map(|ty| {
365 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
366 }),
367 ),
368
369 ExprKind::Dummy => {
370 span_bug!(e.span, "lowered ExprKind::Dummy")
371 }
372
373 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
374
375 ExprKind::Paren(_) | ExprKind::ForLoop { .. } => {
376 unreachable!("already handled")
377 }
378
379 ExprKind::MacCall(_) => panic!("{:?} shouldn't exist here", e.span),
380 };
381
382 hir::Expr { hir_id: expr_hir_id, kind, span: self.lower_span(e.span) }
383 })
384 }
385
386 pub(crate) fn lower_const_block(&mut self, c: &AnonConst) -> hir::ConstBlock {
387 self.with_new_scopes(c.value.span, |this| {
388 let def_id = this.local_def_id(c.id);
389 hir::ConstBlock {
390 def_id,
391 hir_id: this.lower_node_id(c.id),
392 body: this.lower_const_body(c.value.span, Some(&c.value)),
393 }
394 })
395 }
396
397 pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
398 let lit_kind = match LitKind::from_token_lit(*token_lit) {
399 Ok(lit_kind) => lit_kind,
400 Err(err) => {
401 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
402 LitKind::Err(guar)
403 }
404 };
405 respan(self.lower_span(span), lit_kind)
406 }
407
408 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
409 match u {
410 UnOp::Deref => hir::UnOp::Deref,
411 UnOp::Not => hir::UnOp::Not,
412 UnOp::Neg => hir::UnOp::Neg,
413 }
414 }
415
416 fn lower_binop(&mut self, b: BinOp) -> BinOp {
417 Spanned { node: b.node, span: self.lower_span(b.span) }
418 }
419
420 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
421 Spanned { node: a.node, span: self.lower_span(a.span) }
422 }
423
424 fn lower_legacy_const_generics(
425 &mut self,
426 mut f: Expr,
427 args: ThinVec<Box<Expr>>,
428 legacy_args_idx: &[usize],
429 ) -> hir::ExprKind<'hir> {
430 let ExprKind::Path(None, path) = &mut f.kind else {
431 unreachable!();
432 };
433
434 let mut error = None;
435 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
436 if error.is_none() {
438 let mut const_args = vec![];
439 let mut other_args = vec![];
440 for (idx, arg) in args.iter().enumerate() {
441 if legacy_args_idx.contains(&idx) {
442 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
443 } else {
444 other_args.push(expr_to_string(arg));
445 }
446 }
447 let suggestion = UseConstGenericArg {
448 end_of_fn: f.span.shrink_to_hi(),
449 const_args: const_args.join(", "),
450 other_args: other_args.join(", "),
451 call_args: args[0].span.to(args.last().unwrap().span),
452 };
453 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
454 }
455 error.unwrap()
456 };
457
458 let mut real_args = vec![];
460 let mut generic_args = ThinVec::new();
461 for (idx, arg) in args.iter().cloned().enumerate() {
462 if legacy_args_idx.contains(&idx) {
463 let node_id = self.next_node_id();
464 self.create_def(node_id, None, DefKind::AnonConst, f.span);
465 let mut visitor = WillCreateDefIdsVisitor {};
466 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
467 Box::new(Expr {
468 id: self.next_node_id(),
469 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
470 span: f.span,
471 attrs: [].into(),
472 tokens: None,
473 })
474 } else {
475 arg
476 };
477
478 let anon_const = AnonConst { id: node_id, value: const_value };
479 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
480 } else {
481 real_args.push(arg);
482 }
483 }
484
485 let last_segment = path.segments.last_mut().unwrap();
487 assert!(last_segment.args.is_none());
488 last_segment.args = Some(Box::new(GenericArgs::AngleBracketed(AngleBracketedArgs {
489 span: DUMMY_SP,
490 args: generic_args,
491 })));
492
493 let f = self.lower_expr(&f);
495 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
496 }
497
498 fn lower_expr_if(
499 &mut self,
500 cond: &Expr,
501 then: &Block,
502 else_opt: Option<&Expr>,
503 ) -> hir::ExprKind<'hir> {
504 let lowered_cond = self.lower_expr(cond);
505 let then_expr = self.lower_block_expr(then);
506 if let Some(rslt) = else_opt {
507 hir::ExprKind::If(
508 lowered_cond,
509 self.arena.alloc(then_expr),
510 Some(self.lower_expr(rslt)),
511 )
512 } else {
513 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
514 }
515 }
516
517 fn lower_expr_while_in_loop_scope(
534 &mut self,
535 span: Span,
536 cond: &Expr,
537 body: &Block,
538 opt_label: Option<Label>,
539 ) -> hir::ExprKind<'hir> {
540 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_expr(cond));
541 let then = self.lower_block_expr(body);
542 let expr_break = self.expr_break(span);
543 let stmt_break = self.stmt_expr(span, expr_break);
544 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
545 let else_expr = self.arena.alloc(self.expr_block(else_blk));
546 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
547 let if_expr = self.expr(span, if_kind);
548 let block = self.block_expr(self.arena.alloc(if_expr));
549 let span = self.lower_span(span.with_hi(cond.span.hi()));
550 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
551 }
552
553 fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
557 let body_hir_id = self.lower_node_id(body.id);
558 self.with_catch_scope(body_hir_id, |this| {
559 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
560
561 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
563 (
564 this.mark_span_with_reason(
565 DesugaringKind::TryBlock,
566 expr.span,
567 Some(Arc::clone(&this.allow_try_trait)),
568 ),
569 expr,
570 )
571 } else {
572 let try_span = this.mark_span_with_reason(
573 DesugaringKind::TryBlock,
574 this.tcx.sess.source_map().end_point(body.span),
575 Some(Arc::clone(&this.allow_try_trait)),
576 );
577
578 (try_span, this.expr_unit(try_span))
579 };
580
581 let ok_wrapped_span =
582 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
583
584 block.expr = Some(this.wrap_in_try_constructor(
586 hir::LangItem::TryTraitFromOutput,
587 try_span,
588 tail_expr,
589 ok_wrapped_span,
590 ));
591
592 hir::ExprKind::Block(this.arena.alloc(block), None)
593 })
594 }
595
596 fn wrap_in_try_constructor(
597 &mut self,
598 lang_item: hir::LangItem,
599 method_span: Span,
600 expr: &'hir hir::Expr<'hir>,
601 overall_span: Span,
602 ) -> &'hir hir::Expr<'hir> {
603 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
604 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
605 }
606
607 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
608 let pat = self.lower_pat(&arm.pat);
609 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
610 let hir_id = self.next_id();
611 let span = self.lower_span(arm.span);
612 self.lower_attrs(hir_id, &arm.attrs, arm.span, Target::Arm);
613 let is_never_pattern = pat.is_never_pattern();
614 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
617 let body = if let Some(body) = body
618 && !is_never_pattern
619 {
620 body
621 } else {
622 if !is_never_pattern {
624 if self.tcx.features().never_patterns() {
625 let suggestion = span.shrink_to_hi();
627 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
628 }
629 } else if let Some(body) = &arm.body {
630 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
631 } else if let Some(g) = &arm.guard {
632 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
633 }
634
635 let block = self.arena.alloc(hir::Block {
638 stmts: &[],
639 expr: None,
640 hir_id: self.next_id(),
641 rules: hir::BlockCheckMode::DefaultBlock,
642 span,
643 targeted_by_break: false,
644 });
645 self.arena.alloc(hir::Expr {
646 hir_id: self.next_id(),
647 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
648 span,
649 })
650 };
651 hir::Arm { hir_id, pat, guard, body, span }
652 }
653
654 fn lower_capture_clause(&mut self, capture_clause: CaptureBy) -> CaptureBy {
655 match capture_clause {
656 CaptureBy::Ref => CaptureBy::Ref,
657 CaptureBy::Use { use_kw } => CaptureBy::Use { use_kw: self.lower_span(use_kw) },
658 CaptureBy::Value { move_kw } => CaptureBy::Value { move_kw: self.lower_span(move_kw) },
659 }
660 }
661
662 pub(super) fn make_desugared_coroutine_expr(
674 &mut self,
675 capture_clause: CaptureBy,
676 closure_node_id: NodeId,
677 return_ty: Option<hir::FnRetTy<'hir>>,
678 fn_decl_span: Span,
679 span: Span,
680 desugaring_kind: hir::CoroutineDesugaring,
681 coroutine_source: hir::CoroutineSource,
682 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
683 ) -> hir::ExprKind<'hir> {
684 let closure_def_id = self.local_def_id(closure_node_id);
685 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
686
687 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
690 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
691 let unstable_span = self.mark_span_with_reason(
693 DesugaringKind::Async,
694 self.lower_span(span),
695 Some(Arc::clone(&self.allow_gen_future)),
696 );
697 let resume_ty =
698 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
699 let input_ty = hir::Ty {
700 hir_id: self.next_id(),
701 kind: hir::TyKind::Path(resume_ty),
702 span: unstable_span,
703 };
704 let inputs = arena_vec![self; input_ty];
705
706 let (pat, task_context_hid) = self.pat_ident_binding_mode(
708 span,
709 Ident::with_dummy_span(sym::_task_context),
710 hir::BindingMode::MUT,
711 );
712 let param = hir::Param {
713 hir_id: self.next_id(),
714 pat,
715 ty_span: self.lower_span(span),
716 span: self.lower_span(span),
717 };
718 let params = arena_vec![self; param];
719
720 (inputs, params, Some(task_context_hid))
721 }
722 hir::CoroutineDesugaring::Gen => (&[], &[], None),
723 };
724
725 let output =
726 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
727
728 let fn_decl = self.arena.alloc(hir::FnDecl {
729 inputs,
730 output,
731 c_variadic: false,
732 implicit_self: hir::ImplicitSelfKind::None,
733 lifetime_elision_allowed: false,
734 });
735
736 let body = self.lower_body(move |this| {
737 this.coroutine_kind = Some(coroutine_kind);
738
739 let old_ctx = this.task_context;
740 if task_context.is_some() {
741 this.task_context = task_context;
742 }
743 let res = body(this);
744 this.task_context = old_ctx;
745
746 (params, res)
747 });
748
749 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
751 def_id: closure_def_id,
752 binder: hir::ClosureBinder::Default,
753 capture_clause: self.lower_capture_clause(capture_clause),
754 bound_generic_params: &[],
755 fn_decl,
756 body,
757 fn_decl_span: self.lower_span(fn_decl_span),
758 fn_arg_span: None,
759 kind: hir::ClosureKind::Coroutine(coroutine_kind),
760 constness: hir::Constness::NotConst,
761 }))
762 }
763
764 pub(super) fn maybe_forward_track_caller(
767 &mut self,
768 span: Span,
769 outer_hir_id: HirId,
770 inner_hir_id: HirId,
771 ) {
772 if self.tcx.features().async_fn_track_caller()
773 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
774 && find_attr!(*attrs, AttributeKind::TrackCaller(_))
775 {
776 let unstable_span = self.mark_span_with_reason(
777 DesugaringKind::Async,
778 span,
779 Some(Arc::clone(&self.allow_gen_future)),
780 );
781 self.lower_attrs(
782 inner_hir_id,
783 &[Attribute {
784 kind: AttrKind::Normal(Box::new(NormalAttr::from_ident(Ident::new(
785 sym::track_caller,
786 span,
787 )))),
788 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
789 style: AttrStyle::Outer,
790 span: unstable_span,
791 }],
792 span,
793 Target::Fn,
794 );
795 }
796 }
797
798 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
814 let expr = self.arena.alloc(self.lower_expr_mut(expr));
815 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
816 }
817
818 fn make_lowered_await(
820 &mut self,
821 await_kw_span: Span,
822 expr: &'hir hir::Expr<'hir>,
823 await_kind: FutureKind,
824 ) -> hir::ExprKind<'hir> {
825 let full_span = expr.span.to(await_kw_span);
826
827 let is_async_gen = match self.coroutine_kind {
828 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
829 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
830 Some(hir::CoroutineKind::Coroutine(_))
831 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
832 | None => {
833 let stmt_id = self.next_id();
836 let expr_err = self.expr(
837 expr.span,
838 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
839 await_kw_span,
840 item_span: self.current_item,
841 })),
842 );
843 return hir::ExprKind::Block(
844 self.block_all(
845 expr.span,
846 arena_vec![self; hir::Stmt {
847 hir_id: stmt_id,
848 kind: hir::StmtKind::Semi(expr),
849 span: expr.span,
850 }],
851 Some(self.arena.alloc(expr_err)),
852 ),
853 None,
854 );
855 }
856 };
857
858 let features = match await_kind {
859 FutureKind::Future => None,
860 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
861 };
862 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
863 let gen_future_span = self.mark_span_with_reason(
864 DesugaringKind::Await,
865 full_span,
866 Some(Arc::clone(&self.allow_gen_future)),
867 );
868 let expr_hir_id = expr.hir_id;
869
870 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
874 let (awaitee_pat, awaitee_pat_hid) =
875 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
876
877 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
878
879 let poll_expr = {
886 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
887 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
888
889 let Some(task_context_hid) = self.task_context else {
890 unreachable!("use of `await` outside of an async context.");
891 };
892
893 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
894
895 let new_unchecked = self.expr_call_lang_item_fn_mut(
896 span,
897 hir::LangItem::PinNewUnchecked,
898 arena_vec![self; ref_mut_awaitee],
899 );
900 let get_context = self.expr_call_lang_item_fn_mut(
901 gen_future_span,
902 hir::LangItem::GetContext,
903 arena_vec![self; task_context],
904 );
905 let call = match await_kind {
906 FutureKind::Future => self.expr_call_lang_item_fn(
907 span,
908 hir::LangItem::FuturePoll,
909 arena_vec![self; new_unchecked, get_context],
910 ),
911 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
912 span,
913 hir::LangItem::AsyncIteratorPollNext,
914 arena_vec![self; new_unchecked, get_context],
915 ),
916 };
917 self.arena.alloc(self.expr_unsafe(call))
918 };
919
920 let loop_node_id = self.next_node_id();
922 let loop_hir_id = self.lower_node_id(loop_node_id);
923 let ready_arm = {
924 let x_ident = Ident::with_dummy_span(sym::result);
925 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
926 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
927 let ready_field = self.single_pat_field(gen_future_span, x_pat);
928 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
929 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
930 let expr_break =
931 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
932 this.arena.alloc(this.expr(gen_future_span, expr_break))
933 });
934 self.arm(ready_pat, break_x)
935 };
936
937 let pending_arm = {
939 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
940 let empty_block = self.expr_block_empty(span);
941 self.arm(pending_pat, empty_block)
942 };
943
944 let inner_match_stmt = {
945 let match_expr = self.expr_match(
946 span,
947 poll_expr,
948 arena_vec![self; ready_arm, pending_arm],
949 hir::MatchSource::AwaitDesugar,
950 );
951 self.stmt_expr(span, match_expr)
952 };
953
954 let yield_stmt = {
958 let yielded = if is_async_gen {
959 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
960 } else {
961 self.expr_unit(span)
962 };
963
964 let yield_expr = self.expr(
965 span,
966 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
967 );
968 let yield_expr = self.arena.alloc(yield_expr);
969
970 let Some(task_context_hid) = self.task_context else {
971 unreachable!("use of `await` outside of an async context.");
972 };
973
974 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
975 let assign =
976 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
977 self.stmt_expr(span, assign)
978 };
979
980 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
981
982 let loop_expr = self.arena.alloc(hir::Expr {
984 hir_id: loop_hir_id,
985 kind: hir::ExprKind::Loop(
986 loop_block,
987 None,
988 hir::LoopSource::Loop,
989 self.lower_span(span),
990 ),
991 span: self.lower_span(span),
992 });
993
994 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
996
997 let into_future_expr = match await_kind {
999 FutureKind::Future => self.expr_call_lang_item_fn(
1000 span,
1001 hir::LangItem::IntoFutureIntoFuture,
1002 arena_vec![self; *expr],
1003 ),
1004 FutureKind::AsyncIterator => expr,
1007 };
1008
1009 hir::ExprKind::Match(
1013 into_future_expr,
1014 arena_vec![self; awaitee_arm],
1015 hir::MatchSource::AwaitDesugar,
1016 )
1017 }
1018
1019 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1020 hir::ExprKind::Use(self.lower_expr(expr), self.lower_span(use_kw_span))
1021 }
1022
1023 fn lower_expr_closure(
1024 &mut self,
1025 attrs: &[rustc_hir::Attribute],
1026 binder: &ClosureBinder,
1027 capture_clause: CaptureBy,
1028 closure_id: NodeId,
1029 constness: Const,
1030 movability: Movability,
1031 decl: &FnDecl,
1032 body: &Expr,
1033 fn_decl_span: Span,
1034 fn_arg_span: Span,
1035 ) -> hir::ExprKind<'hir> {
1036 let closure_def_id = self.local_def_id(closure_id);
1037 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1038
1039 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1040
1041 let mut coroutine_kind = find_attr!(attrs, AttributeKind::Coroutine(_) => hir::CoroutineKind::Coroutine(Movability::Movable));
1042
1043 let body_id = this.lower_fn_body(decl, None, |this| {
1045 this.coroutine_kind = coroutine_kind;
1046 let e = this.lower_expr_mut(body);
1047 coroutine_kind = this.coroutine_kind;
1048 e
1049 });
1050 let coroutine_option =
1051 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1052 (body_id, coroutine_option)
1053 });
1054
1055 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1056 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1058
1059 let c = self.arena.alloc(hir::Closure {
1060 def_id: closure_def_id,
1061 binder: binder_clause,
1062 capture_clause: self.lower_capture_clause(capture_clause),
1063 bound_generic_params,
1064 fn_decl,
1065 body: body_id,
1066 fn_decl_span: self.lower_span(fn_decl_span),
1067 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1068 kind: closure_kind,
1069 constness: self.lower_constness(constness),
1070 });
1071
1072 hir::ExprKind::Closure(c)
1073 }
1074
1075 fn closure_movability_for_fn(
1076 &mut self,
1077 decl: &FnDecl,
1078 fn_decl_span: Span,
1079 coroutine_kind: Option<hir::CoroutineKind>,
1080 movability: Movability,
1081 ) -> hir::ClosureKind {
1082 match coroutine_kind {
1083 Some(hir::CoroutineKind::Coroutine(_)) => {
1084 if decl.inputs.len() > 1 {
1085 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1086 }
1087 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1088 }
1089 Some(
1090 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1091 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1092 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1093 ) => {
1094 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1095 }
1096 None => {
1097 if movability == Movability::Static {
1098 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1099 }
1100 hir::ClosureKind::Closure
1101 }
1102 }
1103 }
1104
1105 fn lower_closure_binder<'c>(
1106 &mut self,
1107 binder: &'c ClosureBinder,
1108 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1109 let (binder, params) = match binder {
1110 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1111 ClosureBinder::For { span, generic_params } => {
1112 let span = self.lower_span(*span);
1113 (hir::ClosureBinder::For { span }, &**generic_params)
1114 }
1115 };
1116
1117 (binder, params)
1118 }
1119
1120 fn lower_expr_coroutine_closure(
1121 &mut self,
1122 binder: &ClosureBinder,
1123 capture_clause: CaptureBy,
1124 closure_id: NodeId,
1125 closure_hir_id: HirId,
1126 coroutine_kind: CoroutineKind,
1127 decl: &FnDecl,
1128 body: &Expr,
1129 fn_decl_span: Span,
1130 fn_arg_span: Span,
1131 ) -> hir::ExprKind<'hir> {
1132 let closure_def_id = self.local_def_id(closure_id);
1133 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1134
1135 let coroutine_desugaring = match coroutine_kind {
1136 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1137 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1138 CoroutineKind::AsyncGen { span, .. } => {
1139 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1140 }
1141 };
1142
1143 let body = self.with_new_scopes(fn_decl_span, |this| {
1144 let inner_decl =
1145 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1146
1147 let body_id = this.lower_body(|this| {
1150 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1151 &inner_decl,
1152 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1153 fn_decl_span,
1154 body.span,
1155 coroutine_kind,
1156 hir::CoroutineSource::Closure,
1157 );
1158
1159 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1160
1161 (parameters, expr)
1162 });
1163 body_id
1164 });
1165
1166 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1167 let fn_decl =
1171 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1172
1173 let c = self.arena.alloc(hir::Closure {
1174 def_id: closure_def_id,
1175 binder: binder_clause,
1176 capture_clause: self.lower_capture_clause(capture_clause),
1177 bound_generic_params,
1178 fn_decl,
1179 body,
1180 fn_decl_span: self.lower_span(fn_decl_span),
1181 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1182 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1186 constness: hir::Constness::NotConst,
1187 });
1188 hir::ExprKind::Closure(c)
1189 }
1190
1191 fn lower_expr_assign(
1194 &mut self,
1195 lhs: &Expr,
1196 rhs: &Expr,
1197 eq_sign_span: Span,
1198 whole_span: Span,
1199 ) -> hir::ExprKind<'hir> {
1200 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1202 match &lhs.kind {
1203 ExprKind::Array(..)
1204 | ExprKind::Struct(..)
1205 | ExprKind::Tup(..)
1206 | ExprKind::Underscore => false,
1207 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1209 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1211 ExprKind::Paren(e) => {
1212 match e.kind {
1213 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1215 _ => is_ordinary(lower_ctx, e),
1216 }
1217 }
1218 _ => true,
1219 }
1220 }
1221 if is_ordinary(self, lhs) {
1222 return hir::ExprKind::Assign(
1223 self.lower_expr(lhs),
1224 self.lower_expr(rhs),
1225 self.lower_span(eq_sign_span),
1226 );
1227 }
1228
1229 let mut assignments = vec![];
1230
1231 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1233 let rhs = self.lower_expr(rhs);
1234
1235 let destructure_let = self.stmt_let_pat(
1237 None,
1238 whole_span,
1239 Some(rhs),
1240 pat,
1241 hir::LocalSource::AssignDesugar(self.lower_span(eq_sign_span)),
1242 );
1243
1244 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1246
1247 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1249 }
1250
1251 fn extract_tuple_struct_path<'a>(
1256 &mut self,
1257 expr: &'a Expr,
1258 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1259 if let ExprKind::Path(qself, path) = &expr.kind {
1260 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1262 if let Some(res) = partial_res.full_res()
1263 && !res.expected_in_tuple_struct_pat()
1264 {
1265 return None;
1266 }
1267 }
1268 return Some((qself, path));
1269 }
1270 None
1271 }
1272
1273 fn extract_unit_struct_path<'a>(
1278 &mut self,
1279 expr: &'a Expr,
1280 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1281 if let ExprKind::Path(qself, path) = &expr.kind {
1282 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1284 if let Some(res) = partial_res.full_res()
1285 && !res.expected_in_unit_struct_pat()
1286 {
1287 return None;
1288 }
1289 }
1290 return Some((qself, path));
1291 }
1292 None
1293 }
1294
1295 fn destructure_assign(
1298 &mut self,
1299 lhs: &Expr,
1300 eq_sign_span: Span,
1301 assignments: &mut Vec<hir::Stmt<'hir>>,
1302 ) -> &'hir hir::Pat<'hir> {
1303 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1304 }
1305
1306 fn destructure_assign_mut(
1307 &mut self,
1308 lhs: &Expr,
1309 eq_sign_span: Span,
1310 assignments: &mut Vec<hir::Stmt<'hir>>,
1311 ) -> hir::Pat<'hir> {
1312 match &lhs.kind {
1313 ExprKind::Underscore => {
1315 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1316 }
1317 ExprKind::Array(elements) => {
1319 let (pats, rest) =
1320 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1321 let slice_pat = if let Some((i, span)) = rest {
1322 let (before, after) = pats.split_at(i);
1323 hir::PatKind::Slice(
1324 before,
1325 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1326 after,
1327 )
1328 } else {
1329 hir::PatKind::Slice(pats, None, &[])
1330 };
1331 return self.pat_without_dbm(lhs.span, slice_pat);
1332 }
1333 ExprKind::Call(callee, args) => {
1335 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1336 let (pats, rest) = self.destructure_sequence(
1337 args,
1338 "tuple struct or variant",
1339 eq_sign_span,
1340 assignments,
1341 );
1342 let qpath = self.lower_qpath(
1343 callee.id,
1344 qself,
1345 path,
1346 ParamMode::Optional,
1347 AllowReturnTypeNotation::No,
1348 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1349 None,
1350 );
1351 let tuple_struct_pat = hir::PatKind::TupleStruct(
1353 qpath,
1354 pats,
1355 hir::DotDotPos::new(rest.map(|r| r.0)),
1356 );
1357 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1358 }
1359 }
1360 ExprKind::Path(..) => {
1362 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1363 let qpath = self.lower_qpath(
1364 lhs.id,
1365 qself,
1366 path,
1367 ParamMode::Optional,
1368 AllowReturnTypeNotation::No,
1369 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1370 None,
1371 );
1372 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1374 kind: hir::PatExprKind::Path(qpath),
1375 hir_id: self.next_id(),
1376 span: self.lower_span(lhs.span),
1377 }));
1378 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1379 }
1380 }
1381 ExprKind::Struct(se) => {
1383 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1384 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1385 hir::PatField {
1386 hir_id: self.next_id(),
1387 ident: self.lower_ident(f.ident),
1388 pat,
1389 is_shorthand: f.is_shorthand,
1390 span: self.lower_span(f.span),
1391 }
1392 }));
1393 let qpath = self.lower_qpath(
1394 lhs.id,
1395 &se.qself,
1396 &se.path,
1397 ParamMode::Optional,
1398 AllowReturnTypeNotation::No,
1399 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1400 None,
1401 );
1402 let fields_omitted = match &se.rest {
1403 StructRest::Base(e) => {
1404 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1405 span: e.span,
1406 });
1407 Some(self.lower_span(e.span))
1408 }
1409 StructRest::Rest(span) => Some(self.lower_span(*span)),
1410 StructRest::None => None,
1411 };
1412 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1413 return self.pat_without_dbm(lhs.span, struct_pat);
1414 }
1415 ExprKind::Tup(elements) => {
1417 let (pats, rest) =
1418 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1419 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1420 return self.pat_without_dbm(lhs.span, tuple_pat);
1421 }
1422 ExprKind::Paren(e) => {
1423 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1425 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1426 return self.pat_without_dbm(lhs.span, tuple_pat);
1427 } else {
1428 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1429 }
1430 }
1431 _ => {}
1432 }
1433 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1435 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1436 let ident = self.expr_ident(lhs.span, ident, binding);
1437 let assign =
1438 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1439 let expr = self.expr(lhs.span, assign);
1440 assignments.push(self.stmt_expr(lhs.span, expr));
1441 pat
1442 }
1443
1444 fn destructure_sequence(
1450 &mut self,
1451 elements: &[Box<Expr>],
1452 ctx: &str,
1453 eq_sign_span: Span,
1454 assignments: &mut Vec<hir::Stmt<'hir>>,
1455 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1456 let mut rest = None;
1457 let elements =
1458 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1459 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1461 if let Some((_, prev_span)) = rest {
1462 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1463 } else {
1464 rest = Some((i, e.span));
1465 }
1466 None
1467 } else {
1468 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1469 }
1470 }));
1471 (elements, rest)
1472 }
1473
1474 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1476 let e1 = self.lower_expr_mut(e1);
1477 let e2 = self.lower_expr_mut(e2);
1478 let fn_path = hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, self.lower_span(span));
1479 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1480 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1481 }
1482
1483 fn lower_expr_range(
1484 &mut self,
1485 span: Span,
1486 e1: Option<&Expr>,
1487 e2: Option<&Expr>,
1488 lims: RangeLimits,
1489 ) -> hir::ExprKind<'hir> {
1490 use rustc_ast::RangeLimits::*;
1491
1492 let lang_item = match (e1, e2, lims) {
1493 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1494 (Some(..), None, HalfOpen) => {
1495 if self.tcx.features().new_range() {
1496 hir::LangItem::RangeFromCopy
1497 } else {
1498 hir::LangItem::RangeFrom
1499 }
1500 }
1501 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1502 (Some(..), Some(..), HalfOpen) => {
1503 if self.tcx.features().new_range() {
1504 hir::LangItem::RangeCopy
1505 } else {
1506 hir::LangItem::Range
1507 }
1508 }
1509 (None, Some(..), Closed) => {
1510 if self.tcx.features().new_range() {
1511 hir::LangItem::RangeToInclusiveCopy
1512 } else {
1513 hir::LangItem::RangeToInclusive
1514 }
1515 }
1516 (Some(e1), Some(e2), Closed) => {
1517 if self.tcx.features().new_range() {
1518 hir::LangItem::RangeInclusiveCopy
1519 } else {
1520 return self.lower_expr_range_closed(span, e1, e2);
1521 }
1522 }
1523 (start, None, Closed) => {
1524 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1525 match start {
1526 Some(..) => {
1527 if self.tcx.features().new_range() {
1528 hir::LangItem::RangeFromCopy
1529 } else {
1530 hir::LangItem::RangeFrom
1531 }
1532 }
1533 None => hir::LangItem::RangeFull,
1534 }
1535 }
1536 };
1537
1538 let fields = self.arena.alloc_from_iter(
1539 e1.iter()
1540 .map(|e| (sym::start, e))
1541 .chain(e2.iter().map(|e| {
1542 (
1543 if matches!(
1544 lang_item,
1545 hir::LangItem::RangeInclusiveCopy | hir::LangItem::RangeToInclusiveCopy
1546 ) {
1547 sym::last
1548 } else {
1549 sym::end
1550 },
1551 e,
1552 )
1553 }))
1554 .map(|(s, e)| {
1555 let expr = self.lower_expr(e);
1556 let ident = Ident::new(s, self.lower_span(e.span));
1557 self.expr_field(ident, expr, e.span)
1558 }),
1559 );
1560
1561 hir::ExprKind::Struct(
1562 self.arena.alloc(hir::QPath::LangItem(lang_item, self.lower_span(span))),
1563 fields,
1564 hir::StructTailExpr::None,
1565 )
1566 }
1567
1568 fn lower_label(
1571 &mut self,
1572 opt_label: Option<Label>,
1573 dest_id: NodeId,
1574 dest_hir_id: hir::HirId,
1575 ) -> Option<Label> {
1576 let label = opt_label?;
1577 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1578 Some(Label { ident: self.lower_ident(label.ident) })
1579 }
1580
1581 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1582 let target_id = match destination {
1583 Some((id, _)) => {
1584 if let Some(loop_id) = self.resolver.get_label_res(id) {
1585 let local_id = self.ident_and_label_to_local_id[&loop_id];
1586 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1587 Ok(loop_hir_id)
1588 } else {
1589 Err(hir::LoopIdError::UnresolvedLabel)
1590 }
1591 }
1592 None => {
1593 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1594 }
1595 };
1596 let label = destination
1597 .map(|(_, label)| label)
1598 .map(|label| Label { ident: self.lower_ident(label.ident) });
1599 hir::Destination { label, target_id }
1600 }
1601
1602 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1603 if self.is_in_loop_condition && opt_label.is_none() {
1604 hir::Destination {
1605 label: None,
1606 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1607 }
1608 } else {
1609 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1610 }
1611 }
1612
1613 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1614 let old_scope = self.catch_scope.replace(catch_id);
1615 let result = f(self);
1616 self.catch_scope = old_scope;
1617 result
1618 }
1619
1620 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1621 let was_in_loop_condition = self.is_in_loop_condition;
1623 self.is_in_loop_condition = false;
1624
1625 let old_scope = self.loop_scope.replace(loop_id);
1626 let result = f(self);
1627 self.loop_scope = old_scope;
1628
1629 self.is_in_loop_condition = was_in_loop_condition;
1630
1631 result
1632 }
1633
1634 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1635 let was_in_loop_condition = self.is_in_loop_condition;
1636 self.is_in_loop_condition = true;
1637
1638 let result = f(self);
1639
1640 self.is_in_loop_condition = was_in_loop_condition;
1641
1642 result
1643 }
1644
1645 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1646 let hir_id = self.lower_node_id(f.id);
1647 self.lower_attrs(hir_id, &f.attrs, f.span, Target::ExprField);
1648 hir::ExprField {
1649 hir_id,
1650 ident: self.lower_ident(f.ident),
1651 expr: self.lower_expr(&f.expr),
1652 span: self.lower_span(f.span),
1653 is_shorthand: f.is_shorthand,
1654 }
1655 }
1656
1657 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1658 let yielded =
1659 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1660
1661 if !self.tcx.features().yield_expr()
1662 && !self.tcx.features().coroutines()
1663 && !self.tcx.features().gen_blocks()
1664 {
1665 rustc_session::parse::feature_err(
1666 &self.tcx.sess,
1667 sym::yield_expr,
1668 span,
1669 fluent_generated::ast_lowering_yield,
1670 )
1671 .emit();
1672 }
1673
1674 let is_async_gen = match self.coroutine_kind {
1675 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1676 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1677 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1678 let stmt_id = self.next_id();
1681 let expr_err = self.expr(
1682 yielded.span,
1683 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1684 );
1685 return hir::ExprKind::Block(
1686 self.block_all(
1687 yielded.span,
1688 arena_vec![self; hir::Stmt {
1689 hir_id: stmt_id,
1690 kind: hir::StmtKind::Semi(yielded),
1691 span: yielded.span,
1692 }],
1693 Some(self.arena.alloc(expr_err)),
1694 ),
1695 None,
1696 );
1697 }
1698 Some(hir::CoroutineKind::Coroutine(_)) => false,
1699 None => {
1700 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1701 self.dcx().emit_err(YieldInClosure { span, suggestion });
1702 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1703
1704 false
1705 }
1706 };
1707
1708 if is_async_gen {
1709 let wrapped_yielded = self.expr_call_lang_item_fn(
1713 span,
1714 hir::LangItem::AsyncGenReady,
1715 std::slice::from_ref(yielded),
1716 );
1717 let yield_expr = self.arena.alloc(
1718 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1719 );
1720
1721 let Some(task_context_hid) = self.task_context else {
1722 unreachable!("use of `await` outside of an async context.");
1723 };
1724 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1725 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1726
1727 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1728 } else {
1729 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1730 }
1731 }
1732
1733 fn lower_expr_for(
1750 &mut self,
1751 e: &Expr,
1752 pat: &Pat,
1753 head: &Expr,
1754 body: &Block,
1755 opt_label: Option<Label>,
1756 loop_kind: ForLoopKind,
1757 ) -> hir::Expr<'hir> {
1758 let head = self.lower_expr_mut(head);
1759 let pat = self.lower_pat(pat);
1760 let for_span =
1761 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1762 let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
1763 let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
1764
1765 let loop_hir_id = self.lower_node_id(e.id);
1766 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1767
1768 let none_arm = {
1770 let break_expr =
1771 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1772 let pat = self.pat_none(for_span);
1773 self.arm(pat, break_expr)
1774 };
1775
1776 let some_arm = {
1778 let some_pat = self.pat_some(pat_span, pat);
1779 let body_block =
1780 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1781 let body_expr = self.arena.alloc(self.expr_block(body_block));
1782 self.arm(some_pat, body_expr)
1783 };
1784
1785 let iter = Ident::with_dummy_span(sym::iter);
1787 let (iter_pat, iter_pat_nid) =
1788 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1789
1790 let match_expr = {
1791 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1792 let next_expr = match loop_kind {
1793 ForLoopKind::For => {
1794 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1796 self.expr_call_lang_item_fn(
1797 head_span,
1798 hir::LangItem::IteratorNext,
1799 arena_vec![self; ref_mut_iter],
1800 )
1801 }
1802 ForLoopKind::ForAwait => {
1803 let iter = self.expr_mut_addr_of(head_span, iter);
1810 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1812 head_span,
1813 hir::LangItem::PinNewUnchecked,
1814 arena_vec![self; iter],
1815 ));
1816 let iter = self.arena.alloc(self.expr_unsafe(iter));
1818 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1819 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1820 }
1821 };
1822 let arms = arena_vec![self; none_arm, some_arm];
1823
1824 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1826 };
1827 let match_stmt = self.stmt_expr(for_span, match_expr);
1828
1829 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1830
1831 let kind = hir::ExprKind::Loop(
1833 loop_block,
1834 label,
1835 hir::LoopSource::ForLoop,
1836 self.lower_span(for_span.with_hi(head.span.hi())),
1837 );
1838 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1839
1840 let iter_arm = self.arm(iter_pat, loop_expr);
1842
1843 let match_expr = match loop_kind {
1844 ForLoopKind::For => {
1845 let into_iter_expr = self.expr_call_lang_item_fn(
1847 head_span,
1848 hir::LangItem::IntoIterIntoIter,
1849 arena_vec![self; head],
1850 );
1851
1852 self.arena.alloc(self.expr_match(
1853 for_span,
1854 into_iter_expr,
1855 arena_vec![self; iter_arm],
1856 hir::MatchSource::ForLoopDesugar,
1857 ))
1858 }
1859 ForLoopKind::ForAwait => {
1861 let iter_ident = iter;
1862 let (async_iter_pat, async_iter_pat_id) =
1863 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1864 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1865 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1867 head_span,
1868 hir::LangItem::PinNewUnchecked,
1869 arena_vec![self; iter],
1870 ));
1871 let iter = self.arena.alloc(self.expr_unsafe(iter));
1873 let inner_match_expr = self.arena.alloc(self.expr_match(
1874 for_span,
1875 iter,
1876 arena_vec![self; iter_arm],
1877 hir::MatchSource::ForLoopDesugar,
1878 ));
1879
1880 let iter = self.expr_call_lang_item_fn(
1882 head_span,
1883 hir::LangItem::IntoAsyncIterIntoIter,
1884 arena_vec![self; head],
1885 );
1886 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1887 self.arena.alloc(self.expr_match(
1888 for_span,
1889 iter,
1890 arena_vec![self; iter_arm],
1891 hir::MatchSource::ForLoopDesugar,
1892 ))
1893 }
1894 };
1895
1896 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1903 self.lower_attrs(expr.hir_id, &e.attrs, e.span, Target::from_expr(e));
1904 expr
1905 }
1906
1907 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1920 let unstable_span = self.mark_span_with_reason(
1921 DesugaringKind::QuestionMark,
1922 span,
1923 Some(Arc::clone(&self.allow_try_trait)),
1924 );
1925 let try_span = self.tcx.sess.source_map().end_point(span);
1926 let try_span = self.mark_span_with_reason(
1927 DesugaringKind::QuestionMark,
1928 try_span,
1929 Some(Arc::clone(&self.allow_try_trait)),
1930 );
1931
1932 let scrutinee = {
1934 let sub_expr = self.lower_expr_mut(sub_expr);
1936
1937 self.expr_call_lang_item_fn(
1938 unstable_span,
1939 hir::LangItem::TryTraitBranch,
1940 arena_vec![self; sub_expr],
1941 )
1942 };
1943
1944 let attrs: AttrVec = thin_vec![self.unreachable_code_attr(try_span)];
1945
1946 let continue_arm = {
1948 let val_ident = Ident::with_dummy_span(sym::val);
1949 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
1950 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
1951 self.lower_attrs(val_expr.hir_id, &attrs, span, Target::Expression);
1952 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
1953 self.arm(continue_pat, val_expr)
1954 };
1955
1956 let break_arm = {
1960 let residual_ident = Ident::with_dummy_span(sym::residual);
1961 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
1962 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
1963 let from_residual_expr = self.wrap_in_try_constructor(
1964 hir::LangItem::TryTraitFromResidual,
1965 try_span,
1966 self.arena.alloc(residual_expr),
1967 unstable_span,
1968 );
1969 let ret_expr = if let Some(catch_id) = self.catch_scope {
1970 let target_id = Ok(catch_id);
1971 self.arena.alloc(self.expr(
1972 try_span,
1973 hir::ExprKind::Break(
1974 hir::Destination { label: None, target_id },
1975 Some(from_residual_expr),
1976 ),
1977 ))
1978 } else {
1979 let ret_expr = self.checked_return(Some(from_residual_expr));
1980 self.arena.alloc(self.expr(try_span, ret_expr))
1981 };
1982 self.lower_attrs(ret_expr.hir_id, &attrs, span, Target::Expression);
1983
1984 let break_pat = self.pat_cf_break(try_span, residual_local);
1985 self.arm(break_pat, ret_expr)
1986 };
1987
1988 hir::ExprKind::Match(
1989 scrutinee,
1990 arena_vec![self; break_arm, continue_arm],
1991 hir::MatchSource::TryDesugar(scrutinee.hir_id),
1992 )
1993 }
1994
1995 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2005 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2007 (sub_expr.span, self.lower_expr(sub_expr))
2008 } else {
2009 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2010 };
2011
2012 let unstable_span = self.mark_span_with_reason(
2013 DesugaringKind::YeetExpr,
2014 span,
2015 Some(Arc::clone(&self.allow_try_trait)),
2016 );
2017
2018 let from_yeet_expr = self.wrap_in_try_constructor(
2019 hir::LangItem::TryTraitFromYeet,
2020 unstable_span,
2021 yeeted_expr,
2022 yeeted_span,
2023 );
2024
2025 if let Some(catch_id) = self.catch_scope {
2026 let target_id = Ok(catch_id);
2027 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2028 } else {
2029 self.checked_return(Some(from_yeet_expr))
2030 }
2031 }
2032
2033 pub(super) fn expr_drop_temps(
2045 &mut self,
2046 span: Span,
2047 expr: &'hir hir::Expr<'hir>,
2048 ) -> &'hir hir::Expr<'hir> {
2049 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2050 }
2051
2052 pub(super) fn expr_drop_temps_mut(
2053 &mut self,
2054 span: Span,
2055 expr: &'hir hir::Expr<'hir>,
2056 ) -> hir::Expr<'hir> {
2057 self.expr(span, hir::ExprKind::DropTemps(expr))
2058 }
2059
2060 pub(super) fn expr_match(
2061 &mut self,
2062 span: Span,
2063 arg: &'hir hir::Expr<'hir>,
2064 arms: &'hir [hir::Arm<'hir>],
2065 source: hir::MatchSource,
2066 ) -> hir::Expr<'hir> {
2067 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2068 }
2069
2070 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2071 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2072 self.expr(span, expr_break)
2073 }
2074
2075 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2076 let expr_break = self.expr_break(span);
2077 self.arena.alloc(expr_break)
2078 }
2079
2080 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2081 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2082 }
2083
2084 pub(super) fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2085 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2086 }
2087
2088 fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
2089 let lit = hir::Lit {
2090 span: self.lower_span(sp),
2091 node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
2092 };
2093 self.expr(sp, hir::ExprKind::Lit(lit))
2094 }
2095
2096 pub(super) fn expr_usize(&mut self, sp: Span, value: usize) -> hir::Expr<'hir> {
2097 self.expr_uint(sp, ast::UintTy::Usize, value as u128)
2098 }
2099
2100 pub(super) fn expr_u32(&mut self, sp: Span, value: u32) -> hir::Expr<'hir> {
2101 self.expr_uint(sp, ast::UintTy::U32, value as u128)
2102 }
2103
2104 pub(super) fn expr_u16(&mut self, sp: Span, value: u16) -> hir::Expr<'hir> {
2105 self.expr_uint(sp, ast::UintTy::U16, value as u128)
2106 }
2107
2108 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2109 let lit = hir::Lit {
2110 span: self.lower_span(sp),
2111 node: ast::LitKind::Str(value, ast::StrStyle::Cooked),
2112 };
2113 self.expr(sp, hir::ExprKind::Lit(lit))
2114 }
2115
2116 pub(super) fn expr_call_mut(
2117 &mut self,
2118 span: Span,
2119 e: &'hir hir::Expr<'hir>,
2120 args: &'hir [hir::Expr<'hir>],
2121 ) -> hir::Expr<'hir> {
2122 self.expr(span, hir::ExprKind::Call(e, args))
2123 }
2124
2125 pub(super) fn expr_struct(
2126 &mut self,
2127 span: Span,
2128 path: &'hir hir::QPath<'hir>,
2129 fields: &'hir [hir::ExprField<'hir>],
2130 ) -> hir::Expr<'hir> {
2131 self.expr(span, hir::ExprKind::Struct(path, fields, rustc_hir::StructTailExpr::None))
2132 }
2133
2134 pub(super) fn expr_enum_variant(
2135 &mut self,
2136 span: Span,
2137 path: &'hir hir::QPath<'hir>,
2138 fields: &'hir [hir::Expr<'hir>],
2139 ) -> hir::Expr<'hir> {
2140 let fields = self.arena.alloc_from_iter(fields.into_iter().enumerate().map(|(i, f)| {
2141 hir::ExprField {
2142 hir_id: self.next_id(),
2143 ident: Ident::from_str(&i.to_string()),
2144 expr: f,
2145 span: f.span,
2146 is_shorthand: false,
2147 }
2148 }));
2149 self.expr_struct(span, path, fields)
2150 }
2151
2152 pub(super) fn expr_enum_variant_lang_item(
2153 &mut self,
2154 span: Span,
2155 lang_item: hir::LangItem,
2156 fields: &'hir [hir::Expr<'hir>],
2157 ) -> hir::Expr<'hir> {
2158 let path = self.arena.alloc(self.lang_item_path(span, lang_item));
2159 self.expr_enum_variant(span, path, fields)
2160 }
2161
2162 pub(super) fn expr_call(
2163 &mut self,
2164 span: Span,
2165 e: &'hir hir::Expr<'hir>,
2166 args: &'hir [hir::Expr<'hir>],
2167 ) -> &'hir hir::Expr<'hir> {
2168 self.arena.alloc(self.expr_call_mut(span, e, args))
2169 }
2170
2171 pub(super) fn expr_call_lang_item_fn_mut(
2172 &mut self,
2173 span: Span,
2174 lang_item: hir::LangItem,
2175 args: &'hir [hir::Expr<'hir>],
2176 ) -> hir::Expr<'hir> {
2177 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2178 self.expr_call_mut(span, path, args)
2179 }
2180
2181 pub(super) fn expr_call_lang_item_fn(
2182 &mut self,
2183 span: Span,
2184 lang_item: hir::LangItem,
2185 args: &'hir [hir::Expr<'hir>],
2186 ) -> &'hir hir::Expr<'hir> {
2187 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2188 }
2189
2190 pub(super) fn expr_lang_item_path(
2191 &mut self,
2192 span: Span,
2193 lang_item: hir::LangItem,
2194 ) -> hir::Expr<'hir> {
2195 let path = self.lang_item_path(span, lang_item);
2196 self.expr(span, hir::ExprKind::Path(path))
2197 }
2198
2199 pub(super) fn lang_item_path(
2200 &mut self,
2201 span: Span,
2202 lang_item: hir::LangItem,
2203 ) -> hir::QPath<'hir> {
2204 hir::QPath::LangItem(lang_item, self.lower_span(span))
2205 }
2206
2207 pub(super) fn expr_lang_item_type_relative(
2209 &mut self,
2210 span: Span,
2211 lang_item: hir::LangItem,
2212 name: Symbol,
2213 ) -> hir::Expr<'hir> {
2214 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2215 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2216 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2217 self.arena.alloc(hir::PathSegment::new(
2218 Ident::new(name, self.lower_span(span)),
2219 self.next_id(),
2220 Res::Err,
2221 )),
2222 ));
2223 self.expr(span, path)
2224 }
2225
2226 pub(super) fn expr_ident(
2227 &mut self,
2228 sp: Span,
2229 ident: Ident,
2230 binding: HirId,
2231 ) -> &'hir hir::Expr<'hir> {
2232 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2233 }
2234
2235 pub(super) fn expr_ident_mut(
2236 &mut self,
2237 span: Span,
2238 ident: Ident,
2239 binding: HirId,
2240 ) -> hir::Expr<'hir> {
2241 let hir_id = self.next_id();
2242 let res = Res::Local(binding);
2243 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2244 None,
2245 self.arena.alloc(hir::Path {
2246 span: self.lower_span(span),
2247 res,
2248 segments: arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
2249 }),
2250 ));
2251
2252 self.expr(span, expr_path)
2253 }
2254
2255 fn expr_unsafe(&mut self, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2256 let hir_id = self.next_id();
2257 let span = expr.span;
2258 self.expr(
2259 span,
2260 hir::ExprKind::Block(
2261 self.arena.alloc(hir::Block {
2262 stmts: &[],
2263 expr: Some(expr),
2264 hir_id,
2265 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2266 span: self.lower_span(span),
2267 targeted_by_break: false,
2268 }),
2269 None,
2270 ),
2271 )
2272 }
2273
2274 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2275 let blk = self.block_all(span, &[], None);
2276 let expr = self.expr_block(blk);
2277 self.arena.alloc(expr)
2278 }
2279
2280 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2281 self.expr(b.span, hir::ExprKind::Block(b, None))
2282 }
2283
2284 pub(super) fn block_expr_block(
2288 &mut self,
2289 expr: &'hir hir::Expr<'hir>,
2290 ) -> &'hir hir::Expr<'hir> {
2291 let b = self.block_expr(expr);
2292 self.arena.alloc(self.expr_block(b))
2293 }
2294
2295 pub(super) fn expr_array_ref(
2296 &mut self,
2297 span: Span,
2298 elements: &'hir [hir::Expr<'hir>],
2299 ) -> hir::Expr<'hir> {
2300 let array = self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements)));
2301 self.expr_ref(span, array)
2302 }
2303
2304 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2305 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2306 }
2307
2308 pub(super) fn expr_bool_literal(&mut self, span: Span, val: bool) -> hir::Expr<'hir> {
2309 self.expr(span, hir::ExprKind::Lit(Spanned { node: LitKind::Bool(val), span }))
2310 }
2311
2312 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2313 let hir_id = self.next_id();
2314 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2315 }
2316
2317 pub(super) fn expr_field(
2318 &mut self,
2319 ident: Ident,
2320 expr: &'hir hir::Expr<'hir>,
2321 span: Span,
2322 ) -> hir::ExprField<'hir> {
2323 hir::ExprField {
2324 hir_id: self.next_id(),
2325 ident,
2326 span: self.lower_span(span),
2327 expr,
2328 is_shorthand: false,
2329 }
2330 }
2331
2332 pub(super) fn arm(
2333 &mut self,
2334 pat: &'hir hir::Pat<'hir>,
2335 expr: &'hir hir::Expr<'hir>,
2336 ) -> hir::Arm<'hir> {
2337 hir::Arm {
2338 hir_id: self.next_id(),
2339 pat,
2340 guard: None,
2341 span: self.lower_span(expr.span),
2342 body: expr,
2343 }
2344 }
2345
2346 pub(super) fn unreachable_code_attr(&mut self, span: Span) -> Attribute {
2348 let attr = attr::mk_attr_nested_word(
2349 &self.tcx.sess.psess.attr_id_generator,
2350 AttrStyle::Outer,
2351 Safety::Default,
2352 sym::allow,
2353 sym::unreachable_code,
2354 span,
2355 );
2356 attr
2357 }
2358}
2359
2360#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2363enum FutureKind {
2364 Future,
2366 AsyncIterator,
2369}