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::definitions::DefPathData;
11use rustc_hir::{HirId, Target, find_attr};
12use rustc_middle::span_bug;
13use rustc_middle::ty::TyCtxt;
14use rustc_session::errors::report_lit_error;
15use rustc_span::source_map::{Spanned, respan};
16use rustc_span::{DUMMY_SP, DesugaringKind, Ident, Span, Symbol, sym};
17use thin_vec::{ThinVec, thin_vec};
18use visit::{Visitor, walk_expr};
19
20use super::errors::{
21 AsyncCoroutinesNotSupported, AwaitOnlyInAsyncFnAndBlocks, ClosureCannotBeStatic,
22 CoroutineTooManyParameters, FunctionalRecordUpdateDestructuringAssignment,
23 InclusiveRangeWithNoEnd, MatchArmWithNoBody, NeverPatternWithBody, NeverPatternWithGuard,
24 UnderscoreExprLhsAssign,
25};
26use super::{
27 GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode, ResolverAstLoweringExt,
28};
29use crate::errors::{InvalidLegacyConstGenericArg, UseConstGenericArg, YieldInClosure};
30use crate::{AllowReturnTypeNotation, FnDeclKind, ImplTraitPosition, fluent_generated};
31
32struct WillCreateDefIdsVisitor {}
33
34impl<'v> rustc_ast::visit::Visitor<'v> for WillCreateDefIdsVisitor {
35 type Result = ControlFlow<Span>;
36
37 fn visit_anon_const(&mut self, c: &'v AnonConst) -> Self::Result {
38 ControlFlow::Break(c.value.span)
39 }
40
41 fn visit_item(&mut self, item: &'v Item) -> Self::Result {
42 ControlFlow::Break(item.span)
43 }
44
45 fn visit_expr(&mut self, ex: &'v Expr) -> Self::Result {
46 match ex.kind {
47 ExprKind::Gen(..) | ExprKind::ConstBlock(..) | ExprKind::Closure(..) => {
48 ControlFlow::Break(ex.span)
49 }
50 _ => walk_expr(self, ex),
51 }
52 }
53}
54
55impl<'hir> LoweringContext<'_, 'hir> {
56 fn lower_exprs(&mut self, exprs: &[Box<Expr>]) -> &'hir [hir::Expr<'hir>] {
57 self.arena.alloc_from_iter(exprs.iter().map(|x| self.lower_expr_mut(x)))
58 }
59
60 pub(super) fn lower_expr(&mut self, e: &Expr) -> &'hir hir::Expr<'hir> {
61 self.arena.alloc(self.lower_expr_mut(e))
62 }
63
64 pub(super) fn lower_expr_mut(&mut self, e: &Expr) -> hir::Expr<'hir> {
65 ensure_sufficient_stack(|| {
66 let mut span = self.lower_span(e.span);
67 match &e.kind {
68 ExprKind::Paren(ex) => {
70 let mut ex = self.lower_expr_mut(ex);
71 if e.span.contains(ex.span) {
73 ex.span = self.lower_span(e.span.with_ctxt(ex.span.ctxt()));
74 }
75 if !e.attrs.is_empty() {
77 let old_attrs = self.attrs.get(&ex.hir_id.local_id).copied().unwrap_or(&[]);
78 let new_attrs = self
79 .lower_attrs_vec(&e.attrs, e.span, ex.hir_id, Target::from_expr(e))
80 .into_iter()
81 .chain(old_attrs.iter().cloned());
82 let new_attrs = &*self.arena.alloc_from_iter(new_attrs);
83 if new_attrs.is_empty() {
84 return ex;
85 }
86 self.attrs.insert(ex.hir_id.local_id, new_attrs);
87 }
88 return ex;
89 }
90 ExprKind::ForLoop { pat, iter, body, label, kind } => {
96 return self.lower_expr_for(e, pat, iter, body, *label, *kind);
97 }
98 _ => (),
99 }
100
101 let expr_hir_id = self.lower_node_id(e.id);
102 let attrs = self.lower_attrs(expr_hir_id, &e.attrs, e.span, Target::from_expr(e));
103
104 let kind = match &e.kind {
105 ExprKind::Array(exprs) => hir::ExprKind::Array(self.lower_exprs(exprs)),
106 ExprKind::ConstBlock(c) => hir::ExprKind::ConstBlock(self.lower_const_block(c)),
107 ExprKind::Repeat(expr, count) => {
108 let expr = self.lower_expr(expr);
109 let count = self.lower_array_length_to_const_arg(count);
110 hir::ExprKind::Repeat(expr, count)
111 }
112 ExprKind::Tup(elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),
113 ExprKind::Call(f, args) => {
114 if let Some(legacy_args) = self.resolver.legacy_const_generic_args(f) {
115 self.lower_legacy_const_generics((**f).clone(), args.clone(), &legacy_args)
116 } else {
117 let f = self.lower_expr(f);
118 hir::ExprKind::Call(f, self.lower_exprs(args))
119 }
120 }
121 ExprKind::MethodCall(box MethodCall { seg, receiver, args, span }) => {
122 let hir_seg = self.arena.alloc(self.lower_path_segment(
123 e.span,
124 seg,
125 ParamMode::Optional,
126 GenericArgsMode::Err,
127 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
128 None,
130 ));
131 let receiver = self.lower_expr(receiver);
132 let args =
133 self.arena.alloc_from_iter(args.iter().map(|x| self.lower_expr_mut(x)));
134 hir::ExprKind::MethodCall(hir_seg, receiver, args, self.lower_span(*span))
135 }
136 ExprKind::Binary(binop, lhs, rhs) => {
137 let binop = self.lower_binop(*binop);
138 let lhs = self.lower_expr(lhs);
139 let rhs = self.lower_expr(rhs);
140 hir::ExprKind::Binary(binop, lhs, rhs)
141 }
142 ExprKind::Unary(op, ohs) => {
143 let op = self.lower_unop(*op);
144 let ohs = self.lower_expr(ohs);
145 hir::ExprKind::Unary(op, ohs)
146 }
147 ExprKind::Lit(token_lit) => hir::ExprKind::Lit(self.lower_lit(token_lit, e.span)),
148 ExprKind::IncludedBytes(byte_sym) => {
149 let lit = respan(
150 self.lower_span(e.span),
151 LitKind::ByteStr(*byte_sym, StrStyle::Cooked),
152 );
153 hir::ExprKind::Lit(lit)
154 }
155 ExprKind::Cast(expr, ty) => {
156 let expr = self.lower_expr(expr);
157 let ty =
158 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
159 hir::ExprKind::Cast(expr, ty)
160 }
161 ExprKind::Type(expr, ty) => {
162 let expr = self.lower_expr(expr);
163 let ty =
164 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast));
165 hir::ExprKind::Type(expr, ty)
166 }
167 ExprKind::AddrOf(k, m, ohs) => {
168 let ohs = self.lower_expr(ohs);
169 hir::ExprKind::AddrOf(*k, *m, ohs)
170 }
171 ExprKind::Let(pat, scrutinee, span, recovered) => {
172 hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
173 span: self.lower_span(*span),
174 pat: self.lower_pat(pat),
175 ty: None,
176 init: self.lower_expr(scrutinee),
177 recovered: *recovered,
178 }))
179 }
180 ExprKind::If(cond, then, else_opt) => {
181 self.lower_expr_if(cond, then, else_opt.as_deref())
182 }
183 ExprKind::While(cond, body, opt_label) => {
184 self.with_loop_scope(expr_hir_id, |this| {
185 let span =
186 this.mark_span_with_reason(DesugaringKind::WhileLoop, e.span, None);
187 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
188 this.lower_expr_while_in_loop_scope(span, cond, body, opt_label)
189 })
190 }
191 ExprKind::Loop(body, opt_label, span) => {
192 self.with_loop_scope(expr_hir_id, |this| {
193 let opt_label = this.lower_label(*opt_label, e.id, expr_hir_id);
194 hir::ExprKind::Loop(
195 this.lower_block(body, false),
196 opt_label,
197 hir::LoopSource::Loop,
198 this.lower_span(*span),
199 )
200 })
201 }
202 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
203 ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
204 self.lower_expr(expr),
205 self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
206 match kind {
207 MatchKind::Prefix => hir::MatchSource::Normal,
208 MatchKind::Postfix => hir::MatchSource::Postfix,
209 },
210 ),
211 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
212 ExprKind::Use(expr, use_kw_span) => self.lower_expr_use(*use_kw_span, expr),
213 ExprKind::Closure(box Closure {
214 binder,
215 capture_clause,
216 constness,
217 coroutine_kind,
218 movability,
219 fn_decl,
220 body,
221 fn_decl_span,
222 fn_arg_span,
223 }) => match coroutine_kind {
224 Some(coroutine_kind) => self.lower_expr_coroutine_closure(
225 binder,
226 *capture_clause,
227 e.id,
228 expr_hir_id,
229 *coroutine_kind,
230 fn_decl,
231 body,
232 *fn_decl_span,
233 *fn_arg_span,
234 ),
235 None => self.lower_expr_closure(
236 attrs,
237 binder,
238 *capture_clause,
239 e.id,
240 *constness,
241 *movability,
242 fn_decl,
243 body,
244 *fn_decl_span,
245 *fn_arg_span,
246 ),
247 },
248 ExprKind::Gen(capture_clause, block, genblock_kind, decl_span) => {
249 let desugaring_kind = match genblock_kind {
250 GenBlockKind::Async => hir::CoroutineDesugaring::Async,
251 GenBlockKind::Gen => hir::CoroutineDesugaring::Gen,
252 GenBlockKind::AsyncGen => hir::CoroutineDesugaring::AsyncGen,
253 };
254 self.make_desugared_coroutine_expr(
255 *capture_clause,
256 e.id,
257 None,
258 *decl_span,
259 e.span,
260 desugaring_kind,
261 hir::CoroutineSource::Block,
262 |this| this.with_new_scopes(e.span, |this| this.lower_block_expr(block)),
263 )
264 }
265 ExprKind::Block(blk, opt_label) => {
266 let block_hir_id = self.lower_node_id(blk.id);
269 let opt_label = self.lower_label(*opt_label, blk.id, block_hir_id);
270 let hir_block = self.arena.alloc(self.lower_block_noalloc(
271 block_hir_id,
272 blk,
273 opt_label.is_some(),
274 ));
275 hir::ExprKind::Block(hir_block, opt_label)
276 }
277 ExprKind::Assign(el, er, span) => self.lower_expr_assign(el, er, *span, e.span),
278 ExprKind::AssignOp(op, el, er) => hir::ExprKind::AssignOp(
279 self.lower_assign_op(*op),
280 self.lower_expr(el),
281 self.lower_expr(er),
282 ),
283 ExprKind::Field(el, ident) => {
284 hir::ExprKind::Field(self.lower_expr(el), self.lower_ident(*ident))
285 }
286 ExprKind::Index(el, er, brackets_span) => hir::ExprKind::Index(
287 self.lower_expr(el),
288 self.lower_expr(er),
289 self.lower_span(*brackets_span),
290 ),
291 ExprKind::Range(e1, e2, lims) => {
292 span = self.mark_span_with_reason(DesugaringKind::RangeExpr, span, None);
293 self.lower_expr_range(span, e1.as_deref(), e2.as_deref(), *lims)
294 }
295 ExprKind::Underscore => {
296 let guar = self.dcx().emit_err(UnderscoreExprLhsAssign { span: e.span });
297 hir::ExprKind::Err(guar)
298 }
299 ExprKind::Path(qself, path) => {
300 let qpath = self.lower_qpath(
301 e.id,
302 qself,
303 path,
304 ParamMode::Optional,
305 AllowReturnTypeNotation::No,
306 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
307 None,
308 );
309 hir::ExprKind::Path(qpath)
310 }
311 ExprKind::Break(opt_label, opt_expr) => {
312 let opt_expr = opt_expr.as_ref().map(|x| self.lower_expr(x));
313 hir::ExprKind::Break(self.lower_jump_destination(e.id, *opt_label), opt_expr)
314 }
315 ExprKind::Continue(opt_label) => {
316 hir::ExprKind::Continue(self.lower_jump_destination(e.id, *opt_label))
317 }
318 ExprKind::Ret(e) => {
319 let expr = e.as_ref().map(|x| self.lower_expr(x));
320 self.checked_return(expr)
321 }
322 ExprKind::Yeet(sub_expr) => self.lower_expr_yeet(e.span, sub_expr.as_deref()),
323 ExprKind::Become(sub_expr) => {
324 let sub_expr = self.lower_expr(sub_expr);
325 hir::ExprKind::Become(sub_expr)
326 }
327 ExprKind::InlineAsm(asm) => {
328 hir::ExprKind::InlineAsm(self.lower_inline_asm(e.span, asm))
329 }
330 ExprKind::FormatArgs(fmt) => self.lower_format_args(e.span, fmt),
331 ExprKind::OffsetOf(container, fields) => hir::ExprKind::OffsetOf(
332 self.lower_ty(
333 container,
334 ImplTraitContext::Disallowed(ImplTraitPosition::OffsetOf),
335 ),
336 self.arena.alloc_from_iter(fields.iter().map(|&ident| self.lower_ident(ident))),
337 ),
338 ExprKind::Struct(se) => {
339 let rest = match &se.rest {
340 StructRest::Base(e) => hir::StructTailExpr::Base(self.lower_expr(e)),
341 StructRest::Rest(sp) => {
342 hir::StructTailExpr::DefaultFields(self.lower_span(*sp))
343 }
344 StructRest::None => hir::StructTailExpr::None,
345 };
346 hir::ExprKind::Struct(
347 self.arena.alloc(self.lower_qpath(
348 e.id,
349 &se.qself,
350 &se.path,
351 ParamMode::Optional,
352 AllowReturnTypeNotation::No,
353 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
354 None,
355 )),
356 self.arena
357 .alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
358 rest,
359 )
360 }
361 ExprKind::Yield(kind) => self.lower_expr_yield(e.span, kind.expr().map(|x| &**x)),
362 ExprKind::Err(guar) => hir::ExprKind::Err(*guar),
363
364 ExprKind::UnsafeBinderCast(kind, expr, ty) => hir::ExprKind::UnsafeBinderCast(
365 *kind,
366 self.lower_expr(expr),
367 ty.as_ref().map(|ty| {
368 self.lower_ty(ty, ImplTraitContext::Disallowed(ImplTraitPosition::Cast))
369 }),
370 ),
371
372 ExprKind::Dummy => {
373 span_bug!(e.span, "lowered ExprKind::Dummy")
374 }
375
376 ExprKind::Try(sub_expr) => self.lower_expr_try(e.span, sub_expr),
377
378 ExprKind::Paren(_) | ExprKind::ForLoop { .. } => {
379 unreachable!("already handled")
380 }
381
382 ExprKind::MacCall(_) => panic!("{:?} shouldn't exist here", e.span),
383 };
384
385 hir::Expr { hir_id: expr_hir_id, kind, span }
386 })
387 }
388
389 pub(crate) fn lower_const_block(&mut self, c: &AnonConst) -> hir::ConstBlock {
390 self.with_new_scopes(c.value.span, |this| {
391 let def_id = this.local_def_id(c.id);
392 hir::ConstBlock {
393 def_id,
394 hir_id: this.lower_node_id(c.id),
395 body: this.lower_const_body(c.value.span, Some(&c.value)),
396 }
397 })
398 }
399
400 pub(crate) fn lower_lit(&mut self, token_lit: &token::Lit, span: Span) -> hir::Lit {
401 let lit_kind = match LitKind::from_token_lit(*token_lit) {
402 Ok(lit_kind) => lit_kind,
403 Err(err) => {
404 let guar = report_lit_error(&self.tcx.sess.psess, err, *token_lit, span);
405 LitKind::Err(guar)
406 }
407 };
408 respan(self.lower_span(span), lit_kind)
409 }
410
411 fn lower_unop(&mut self, u: UnOp) -> hir::UnOp {
412 match u {
413 UnOp::Deref => hir::UnOp::Deref,
414 UnOp::Not => hir::UnOp::Not,
415 UnOp::Neg => hir::UnOp::Neg,
416 }
417 }
418
419 fn lower_binop(&mut self, b: BinOp) -> BinOp {
420 Spanned { node: b.node, span: self.lower_span(b.span) }
421 }
422
423 fn lower_assign_op(&mut self, a: AssignOp) -> AssignOp {
424 Spanned { node: a.node, span: self.lower_span(a.span) }
425 }
426
427 fn lower_legacy_const_generics(
428 &mut self,
429 mut f: Expr,
430 args: ThinVec<Box<Expr>>,
431 legacy_args_idx: &[usize],
432 ) -> hir::ExprKind<'hir> {
433 let ExprKind::Path(None, path) = &mut f.kind else {
434 unreachable!();
435 };
436
437 let mut error = None;
438 let mut invalid_expr_error = |tcx: TyCtxt<'_>, span| {
439 if error.is_none() {
441 let mut const_args = vec![];
442 let mut other_args = vec![];
443 for (idx, arg) in args.iter().enumerate() {
444 if legacy_args_idx.contains(&idx) {
445 const_args.push(format!("{{ {} }}", expr_to_string(arg)));
446 } else {
447 other_args.push(expr_to_string(arg));
448 }
449 }
450 let suggestion = UseConstGenericArg {
451 end_of_fn: f.span.shrink_to_hi(),
452 const_args: const_args.join(", "),
453 other_args: other_args.join(", "),
454 call_args: args[0].span.to(args.last().unwrap().span),
455 };
456 error = Some(tcx.dcx().emit_err(InvalidLegacyConstGenericArg { span, suggestion }));
457 }
458 error.unwrap()
459 };
460
461 let mut real_args = vec![];
463 let mut generic_args = ThinVec::new();
464 for (idx, arg) in args.iter().cloned().enumerate() {
465 if legacy_args_idx.contains(&idx) {
466 let node_id = self.next_node_id();
467 self.create_def(
468 node_id,
469 None,
470 DefKind::AnonConst,
471 DefPathData::LateAnonConst,
472 f.span,
473 );
474 let mut visitor = WillCreateDefIdsVisitor {};
475 let const_value = if let ControlFlow::Break(span) = visitor.visit_expr(&arg) {
476 Box::new(Expr {
477 id: self.next_node_id(),
478 kind: ExprKind::Err(invalid_expr_error(self.tcx, span)),
479 span: f.span,
480 attrs: [].into(),
481 tokens: None,
482 })
483 } else {
484 arg
485 };
486
487 let anon_const = AnonConst { id: node_id, value: const_value };
488 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));
489 } else {
490 real_args.push(arg);
491 }
492 }
493
494 let last_segment = path.segments.last_mut().unwrap();
496 assert!(last_segment.args.is_none());
497 last_segment.args = Some(Box::new(GenericArgs::AngleBracketed(AngleBracketedArgs {
498 span: DUMMY_SP,
499 args: generic_args,
500 })));
501
502 let f = self.lower_expr(&f);
504 hir::ExprKind::Call(f, self.lower_exprs(&real_args))
505 }
506
507 fn lower_expr_if(
508 &mut self,
509 cond: &Expr,
510 then: &Block,
511 else_opt: Option<&Expr>,
512 ) -> hir::ExprKind<'hir> {
513 let lowered_cond = self.lower_expr(cond);
514 let then_expr = self.lower_block_expr(then);
515 if let Some(rslt) = else_opt {
516 hir::ExprKind::If(
517 lowered_cond,
518 self.arena.alloc(then_expr),
519 Some(self.lower_expr(rslt)),
520 )
521 } else {
522 hir::ExprKind::If(lowered_cond, self.arena.alloc(then_expr), None)
523 }
524 }
525
526 fn lower_expr_while_in_loop_scope(
543 &mut self,
544 span: Span,
545 cond: &Expr,
546 body: &Block,
547 opt_label: Option<Label>,
548 ) -> hir::ExprKind<'hir> {
549 let lowered_cond = self.with_loop_condition_scope(|t| t.lower_expr(cond));
550 let then = self.lower_block_expr(body);
551 let expr_break = self.expr_break(span);
552 let stmt_break = self.stmt_expr(span, expr_break);
553 let else_blk = self.block_all(span, arena_vec![self; stmt_break], None);
554 let else_expr = self.arena.alloc(self.expr_block(else_blk));
555 let if_kind = hir::ExprKind::If(lowered_cond, self.arena.alloc(then), Some(else_expr));
556 let if_expr = self.expr(span, if_kind);
557 let block = self.block_expr(self.arena.alloc(if_expr));
558 let span = self.lower_span(span.with_hi(cond.span.hi()));
559 hir::ExprKind::Loop(block, opt_label, hir::LoopSource::While, span)
560 }
561
562 fn lower_expr_try_block(&mut self, body: &Block) -> hir::ExprKind<'hir> {
566 let body_hir_id = self.lower_node_id(body.id);
567 self.with_catch_scope(body_hir_id, |this| {
568 let mut block = this.lower_block_noalloc(body_hir_id, body, true);
569
570 let (try_span, tail_expr) = if let Some(expr) = block.expr.take() {
572 (
573 this.mark_span_with_reason(
574 DesugaringKind::TryBlock,
575 expr.span,
576 Some(Arc::clone(&this.allow_try_trait)),
577 ),
578 expr,
579 )
580 } else {
581 let try_span = this.mark_span_with_reason(
582 DesugaringKind::TryBlock,
583 this.tcx.sess.source_map().end_point(body.span),
584 Some(Arc::clone(&this.allow_try_trait)),
585 );
586
587 (try_span, this.expr_unit(try_span))
588 };
589
590 let ok_wrapped_span =
591 this.mark_span_with_reason(DesugaringKind::TryBlock, tail_expr.span, None);
592
593 block.expr = Some(this.wrap_in_try_constructor(
595 hir::LangItem::TryTraitFromOutput,
596 try_span,
597 tail_expr,
598 ok_wrapped_span,
599 ));
600
601 hir::ExprKind::Block(this.arena.alloc(block), None)
602 })
603 }
604
605 fn wrap_in_try_constructor(
606 &mut self,
607 lang_item: hir::LangItem,
608 method_span: Span,
609 expr: &'hir hir::Expr<'hir>,
610 overall_span: Span,
611 ) -> &'hir hir::Expr<'hir> {
612 let constructor = self.arena.alloc(self.expr_lang_item_path(method_span, lang_item));
613 self.expr_call(overall_span, constructor, std::slice::from_ref(expr))
614 }
615
616 fn lower_arm(&mut self, arm: &Arm) -> hir::Arm<'hir> {
617 let pat = self.lower_pat(&arm.pat);
618 let guard = arm.guard.as_ref().map(|cond| self.lower_expr(cond));
619 let hir_id = self.next_id();
620 let span = self.lower_span(arm.span);
621 self.lower_attrs(hir_id, &arm.attrs, arm.span, Target::Arm);
622 let is_never_pattern = pat.is_never_pattern();
623 let body = arm.body.as_ref().map(|x| self.lower_expr(x));
626 let body = if let Some(body) = body
627 && !is_never_pattern
628 {
629 body
630 } else {
631 if !is_never_pattern {
633 if self.tcx.features().never_patterns() {
634 let suggestion = span.shrink_to_hi();
636 self.dcx().emit_err(MatchArmWithNoBody { span, suggestion });
637 }
638 } else if let Some(body) = &arm.body {
639 self.dcx().emit_err(NeverPatternWithBody { span: body.span });
640 } else if let Some(g) = &arm.guard {
641 self.dcx().emit_err(NeverPatternWithGuard { span: g.span });
642 }
643
644 let block = self.arena.alloc(hir::Block {
647 stmts: &[],
648 expr: None,
649 hir_id: self.next_id(),
650 rules: hir::BlockCheckMode::DefaultBlock,
651 span,
652 targeted_by_break: false,
653 });
654 self.arena.alloc(hir::Expr {
655 hir_id: self.next_id(),
656 kind: hir::ExprKind::Loop(block, None, hir::LoopSource::Loop, span),
657 span,
658 })
659 };
660 hir::Arm { hir_id, pat, guard, body, span }
661 }
662
663 fn lower_capture_clause(&mut self, capture_clause: CaptureBy) -> CaptureBy {
664 match capture_clause {
665 CaptureBy::Ref => CaptureBy::Ref,
666 CaptureBy::Use { use_kw } => CaptureBy::Use { use_kw: self.lower_span(use_kw) },
667 CaptureBy::Value { move_kw } => CaptureBy::Value { move_kw: self.lower_span(move_kw) },
668 }
669 }
670
671 pub(super) fn make_desugared_coroutine_expr(
683 &mut self,
684 capture_clause: CaptureBy,
685 closure_node_id: NodeId,
686 return_ty: Option<hir::FnRetTy<'hir>>,
687 fn_decl_span: Span,
688 span: Span,
689 desugaring_kind: hir::CoroutineDesugaring,
690 coroutine_source: hir::CoroutineSource,
691 body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
692 ) -> hir::ExprKind<'hir> {
693 let closure_def_id = self.local_def_id(closure_node_id);
694 let coroutine_kind = hir::CoroutineKind::Desugared(desugaring_kind, coroutine_source);
695
696 let (inputs, params, task_context): (&[_], &[_], _) = match desugaring_kind {
699 hir::CoroutineDesugaring::Async | hir::CoroutineDesugaring::AsyncGen => {
700 let unstable_span = self.mark_span_with_reason(
702 DesugaringKind::Async,
703 self.lower_span(span),
704 Some(Arc::clone(&self.allow_gen_future)),
705 );
706 let resume_ty =
707 self.make_lang_item_qpath(hir::LangItem::ResumeTy, unstable_span, None);
708 let input_ty = hir::Ty {
709 hir_id: self.next_id(),
710 kind: hir::TyKind::Path(resume_ty),
711 span: unstable_span,
712 };
713 let inputs = arena_vec![self; input_ty];
714
715 let (pat, task_context_hid) = self.pat_ident_binding_mode(
717 span,
718 Ident::with_dummy_span(sym::_task_context),
719 hir::BindingMode::MUT,
720 );
721 let param = hir::Param {
722 hir_id: self.next_id(),
723 pat,
724 ty_span: self.lower_span(span),
725 span: self.lower_span(span),
726 };
727 let params = arena_vec![self; param];
728
729 (inputs, params, Some(task_context_hid))
730 }
731 hir::CoroutineDesugaring::Gen => (&[], &[], None),
732 };
733
734 let output =
735 return_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));
736
737 let fn_decl = self.arena.alloc(hir::FnDecl {
738 inputs,
739 output,
740 c_variadic: false,
741 implicit_self: hir::ImplicitSelfKind::None,
742 lifetime_elision_allowed: false,
743 });
744
745 let body = self.lower_body(move |this| {
746 this.coroutine_kind = Some(coroutine_kind);
747
748 let old_ctx = this.task_context;
749 if task_context.is_some() {
750 this.task_context = task_context;
751 }
752 let res = body(this);
753 this.task_context = old_ctx;
754
755 (params, res)
756 });
757
758 hir::ExprKind::Closure(self.arena.alloc(hir::Closure {
760 def_id: closure_def_id,
761 binder: hir::ClosureBinder::Default,
762 capture_clause: self.lower_capture_clause(capture_clause),
763 bound_generic_params: &[],
764 fn_decl,
765 body,
766 fn_decl_span: self.lower_span(fn_decl_span),
767 fn_arg_span: None,
768 kind: hir::ClosureKind::Coroutine(coroutine_kind),
769 constness: hir::Constness::NotConst,
770 }))
771 }
772
773 pub(super) fn maybe_forward_track_caller(
776 &mut self,
777 span: Span,
778 outer_hir_id: HirId,
779 inner_hir_id: HirId,
780 ) {
781 if self.tcx.features().async_fn_track_caller()
782 && let Some(attrs) = self.attrs.get(&outer_hir_id.local_id)
783 && find_attr!(*attrs, AttributeKind::TrackCaller(_))
784 {
785 let unstable_span = self.mark_span_with_reason(
786 DesugaringKind::Async,
787 span,
788 Some(Arc::clone(&self.allow_gen_future)),
789 );
790 self.lower_attrs(
791 inner_hir_id,
792 &[Attribute {
793 kind: AttrKind::Normal(Box::new(NormalAttr::from_ident(Ident::new(
794 sym::track_caller,
795 span,
796 )))),
797 id: self.tcx.sess.psess.attr_id_generator.mk_attr_id(),
798 style: AttrStyle::Outer,
799 span: unstable_span,
800 }],
801 span,
802 Target::Fn,
803 );
804 }
805 }
806
807 fn lower_expr_await(&mut self, await_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
823 let expr = self.arena.alloc(self.lower_expr_mut(expr));
824 self.make_lowered_await(await_kw_span, expr, FutureKind::Future)
825 }
826
827 fn make_lowered_await(
829 &mut self,
830 await_kw_span: Span,
831 expr: &'hir hir::Expr<'hir>,
832 await_kind: FutureKind,
833 ) -> hir::ExprKind<'hir> {
834 let full_span = expr.span.to(await_kw_span);
835
836 let is_async_gen = match self.coroutine_kind {
837 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => false,
838 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
839 Some(hir::CoroutineKind::Coroutine(_))
840 | Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _))
841 | None => {
842 let stmt_id = self.next_id();
845 let expr_err = self.expr(
846 expr.span,
847 hir::ExprKind::Err(self.dcx().emit_err(AwaitOnlyInAsyncFnAndBlocks {
848 await_kw_span,
849 item_span: self.current_item,
850 })),
851 );
852 return hir::ExprKind::Block(
853 self.block_all(
854 expr.span,
855 arena_vec![self; hir::Stmt {
856 hir_id: stmt_id,
857 kind: hir::StmtKind::Semi(expr),
858 span: expr.span,
859 }],
860 Some(self.arena.alloc(expr_err)),
861 ),
862 None,
863 );
864 }
865 };
866
867 let features = match await_kind {
868 FutureKind::Future => None,
869 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
870 };
871 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
872 let gen_future_span = self.mark_span_with_reason(
873 DesugaringKind::Await,
874 full_span,
875 Some(Arc::clone(&self.allow_gen_future)),
876 );
877 let expr_hir_id = expr.hir_id;
878
879 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
883 let (awaitee_pat, awaitee_pat_hid) =
884 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
885
886 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
887
888 let poll_expr = {
895 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
896 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
897
898 let Some(task_context_hid) = self.task_context else {
899 unreachable!("use of `await` outside of an async context.");
900 };
901
902 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
903
904 let new_unchecked = self.expr_call_lang_item_fn_mut(
905 span,
906 hir::LangItem::PinNewUnchecked,
907 arena_vec![self; ref_mut_awaitee],
908 );
909 let get_context = self.expr_call_lang_item_fn_mut(
910 gen_future_span,
911 hir::LangItem::GetContext,
912 arena_vec![self; task_context],
913 );
914 let call = match await_kind {
915 FutureKind::Future => self.expr_call_lang_item_fn(
916 span,
917 hir::LangItem::FuturePoll,
918 arena_vec![self; new_unchecked, get_context],
919 ),
920 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
921 span,
922 hir::LangItem::AsyncIteratorPollNext,
923 arena_vec![self; new_unchecked, get_context],
924 ),
925 };
926 self.arena.alloc(self.expr_unsafe(call))
927 };
928
929 let loop_node_id = self.next_node_id();
931 let loop_hir_id = self.lower_node_id(loop_node_id);
932 let ready_arm = {
933 let x_ident = Ident::with_dummy_span(sym::result);
934 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
935 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
936 let ready_field = self.single_pat_field(gen_future_span, x_pat);
937 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
938 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
939 let expr_break =
940 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
941 this.arena.alloc(this.expr(gen_future_span, expr_break))
942 });
943 self.arm(ready_pat, break_x)
944 };
945
946 let pending_arm = {
948 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
949 let empty_block = self.expr_block_empty(span);
950 self.arm(pending_pat, empty_block)
951 };
952
953 let inner_match_stmt = {
954 let match_expr = self.expr_match(
955 span,
956 poll_expr,
957 arena_vec![self; ready_arm, pending_arm],
958 hir::MatchSource::AwaitDesugar,
959 );
960 self.stmt_expr(span, match_expr)
961 };
962
963 let yield_stmt = {
967 let yielded = if is_async_gen {
968 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
969 } else {
970 self.expr_unit(span)
971 };
972
973 let yield_expr = self.expr(
974 span,
975 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
976 );
977 let yield_expr = self.arena.alloc(yield_expr);
978
979 let Some(task_context_hid) = self.task_context else {
980 unreachable!("use of `await` outside of an async context.");
981 };
982
983 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
984 let assign =
985 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
986 self.stmt_expr(span, assign)
987 };
988
989 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
990
991 let loop_expr = self.arena.alloc(hir::Expr {
993 hir_id: loop_hir_id,
994 kind: hir::ExprKind::Loop(
995 loop_block,
996 None,
997 hir::LoopSource::Loop,
998 self.lower_span(span),
999 ),
1000 span: self.lower_span(span),
1001 });
1002
1003 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1005
1006 let into_future_expr = match await_kind {
1008 FutureKind::Future => self.expr_call_lang_item_fn(
1009 span,
1010 hir::LangItem::IntoFutureIntoFuture,
1011 arena_vec![self; *expr],
1012 ),
1013 FutureKind::AsyncIterator => expr,
1016 };
1017
1018 hir::ExprKind::Match(
1022 into_future_expr,
1023 arena_vec![self; awaitee_arm],
1024 hir::MatchSource::AwaitDesugar,
1025 )
1026 }
1027
1028 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1029 hir::ExprKind::Use(self.lower_expr(expr), self.lower_span(use_kw_span))
1030 }
1031
1032 fn lower_expr_closure(
1033 &mut self,
1034 attrs: &[rustc_hir::Attribute],
1035 binder: &ClosureBinder,
1036 capture_clause: CaptureBy,
1037 closure_id: NodeId,
1038 constness: Const,
1039 movability: Movability,
1040 decl: &FnDecl,
1041 body: &Expr,
1042 fn_decl_span: Span,
1043 fn_arg_span: Span,
1044 ) -> hir::ExprKind<'hir> {
1045 let closure_def_id = self.local_def_id(closure_id);
1046 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1047
1048 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1049
1050 let mut coroutine_kind = find_attr!(attrs, AttributeKind::Coroutine(_) => hir::CoroutineKind::Coroutine(Movability::Movable));
1051
1052 let body_id = this.lower_fn_body(decl, None, |this| {
1054 this.coroutine_kind = coroutine_kind;
1055 let e = this.lower_expr_mut(body);
1056 coroutine_kind = this.coroutine_kind;
1057 e
1058 });
1059 let coroutine_option =
1060 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1061 (body_id, coroutine_option)
1062 });
1063
1064 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1065 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1067
1068 let c = self.arena.alloc(hir::Closure {
1069 def_id: closure_def_id,
1070 binder: binder_clause,
1071 capture_clause: self.lower_capture_clause(capture_clause),
1072 bound_generic_params,
1073 fn_decl,
1074 body: body_id,
1075 fn_decl_span: self.lower_span(fn_decl_span),
1076 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1077 kind: closure_kind,
1078 constness: self.lower_constness(constness),
1079 });
1080
1081 hir::ExprKind::Closure(c)
1082 }
1083
1084 fn closure_movability_for_fn(
1085 &mut self,
1086 decl: &FnDecl,
1087 fn_decl_span: Span,
1088 coroutine_kind: Option<hir::CoroutineKind>,
1089 movability: Movability,
1090 ) -> hir::ClosureKind {
1091 match coroutine_kind {
1092 Some(hir::CoroutineKind::Coroutine(_)) => {
1093 if decl.inputs.len() > 1 {
1094 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1095 }
1096 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1097 }
1098 Some(
1099 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1100 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1101 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1102 ) => {
1103 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1104 }
1105 None => {
1106 if movability == Movability::Static {
1107 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1108 }
1109 hir::ClosureKind::Closure
1110 }
1111 }
1112 }
1113
1114 fn lower_closure_binder<'c>(
1115 &mut self,
1116 binder: &'c ClosureBinder,
1117 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1118 let (binder, params) = match binder {
1119 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1120 ClosureBinder::For { span, generic_params } => {
1121 let span = self.lower_span(*span);
1122 (hir::ClosureBinder::For { span }, &**generic_params)
1123 }
1124 };
1125
1126 (binder, params)
1127 }
1128
1129 fn lower_expr_coroutine_closure(
1130 &mut self,
1131 binder: &ClosureBinder,
1132 capture_clause: CaptureBy,
1133 closure_id: NodeId,
1134 closure_hir_id: HirId,
1135 coroutine_kind: CoroutineKind,
1136 decl: &FnDecl,
1137 body: &Expr,
1138 fn_decl_span: Span,
1139 fn_arg_span: Span,
1140 ) -> hir::ExprKind<'hir> {
1141 let closure_def_id = self.local_def_id(closure_id);
1142 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1143
1144 let coroutine_desugaring = match coroutine_kind {
1145 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1146 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1147 CoroutineKind::AsyncGen { span, .. } => {
1148 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1149 }
1150 };
1151
1152 let body = self.with_new_scopes(fn_decl_span, |this| {
1153 let inner_decl =
1154 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1155
1156 let body_id = this.lower_body(|this| {
1159 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1160 &inner_decl,
1161 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1162 fn_decl_span,
1163 body.span,
1164 coroutine_kind,
1165 hir::CoroutineSource::Closure,
1166 );
1167
1168 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1169
1170 (parameters, expr)
1171 });
1172 body_id
1173 });
1174
1175 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1176 let fn_decl =
1180 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1181
1182 let c = self.arena.alloc(hir::Closure {
1183 def_id: closure_def_id,
1184 binder: binder_clause,
1185 capture_clause: self.lower_capture_clause(capture_clause),
1186 bound_generic_params,
1187 fn_decl,
1188 body,
1189 fn_decl_span: self.lower_span(fn_decl_span),
1190 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1191 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1195 constness: hir::Constness::NotConst,
1196 });
1197 hir::ExprKind::Closure(c)
1198 }
1199
1200 fn lower_expr_assign(
1203 &mut self,
1204 lhs: &Expr,
1205 rhs: &Expr,
1206 eq_sign_span: Span,
1207 whole_span: Span,
1208 ) -> hir::ExprKind<'hir> {
1209 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1211 match &lhs.kind {
1212 ExprKind::Array(..)
1213 | ExprKind::Struct(..)
1214 | ExprKind::Tup(..)
1215 | ExprKind::Underscore => false,
1216 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1218 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1220 ExprKind::Paren(e) => {
1221 match e.kind {
1222 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1224 _ => is_ordinary(lower_ctx, e),
1225 }
1226 }
1227 _ => true,
1228 }
1229 }
1230 if is_ordinary(self, lhs) {
1231 return hir::ExprKind::Assign(
1232 self.lower_expr(lhs),
1233 self.lower_expr(rhs),
1234 self.lower_span(eq_sign_span),
1235 );
1236 }
1237
1238 let mut assignments = vec![];
1239
1240 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1242 let rhs = self.lower_expr(rhs);
1243
1244 let destructure_let = self.stmt_let_pat(
1246 None,
1247 whole_span,
1248 Some(rhs),
1249 pat,
1250 hir::LocalSource::AssignDesugar(self.lower_span(eq_sign_span)),
1251 );
1252
1253 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1255
1256 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1258 }
1259
1260 fn extract_tuple_struct_path<'a>(
1265 &mut self,
1266 expr: &'a Expr,
1267 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1268 if let ExprKind::Path(qself, path) = &expr.kind {
1269 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1271 if let Some(res) = partial_res.full_res()
1272 && !res.expected_in_tuple_struct_pat()
1273 {
1274 return None;
1275 }
1276 }
1277 return Some((qself, path));
1278 }
1279 None
1280 }
1281
1282 fn extract_unit_struct_path<'a>(
1287 &mut self,
1288 expr: &'a Expr,
1289 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1290 if let ExprKind::Path(qself, path) = &expr.kind {
1291 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1293 if let Some(res) = partial_res.full_res()
1294 && !res.expected_in_unit_struct_pat()
1295 {
1296 return None;
1297 }
1298 }
1299 return Some((qself, path));
1300 }
1301 None
1302 }
1303
1304 fn destructure_assign(
1307 &mut self,
1308 lhs: &Expr,
1309 eq_sign_span: Span,
1310 assignments: &mut Vec<hir::Stmt<'hir>>,
1311 ) -> &'hir hir::Pat<'hir> {
1312 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1313 }
1314
1315 fn destructure_assign_mut(
1316 &mut self,
1317 lhs: &Expr,
1318 eq_sign_span: Span,
1319 assignments: &mut Vec<hir::Stmt<'hir>>,
1320 ) -> hir::Pat<'hir> {
1321 match &lhs.kind {
1322 ExprKind::Underscore => {
1324 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1325 }
1326 ExprKind::Array(elements) => {
1328 let (pats, rest) =
1329 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1330 let slice_pat = if let Some((i, span)) = rest {
1331 let (before, after) = pats.split_at(i);
1332 hir::PatKind::Slice(
1333 before,
1334 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1335 after,
1336 )
1337 } else {
1338 hir::PatKind::Slice(pats, None, &[])
1339 };
1340 return self.pat_without_dbm(lhs.span, slice_pat);
1341 }
1342 ExprKind::Call(callee, args) => {
1344 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1345 let (pats, rest) = self.destructure_sequence(
1346 args,
1347 "tuple struct or variant",
1348 eq_sign_span,
1349 assignments,
1350 );
1351 let qpath = self.lower_qpath(
1352 callee.id,
1353 qself,
1354 path,
1355 ParamMode::Optional,
1356 AllowReturnTypeNotation::No,
1357 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1358 None,
1359 );
1360 let tuple_struct_pat = hir::PatKind::TupleStruct(
1362 qpath,
1363 pats,
1364 hir::DotDotPos::new(rest.map(|r| r.0)),
1365 );
1366 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1367 }
1368 }
1369 ExprKind::Path(..) => {
1371 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1372 let qpath = self.lower_qpath(
1373 lhs.id,
1374 qself,
1375 path,
1376 ParamMode::Optional,
1377 AllowReturnTypeNotation::No,
1378 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1379 None,
1380 );
1381 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1383 kind: hir::PatExprKind::Path(qpath),
1384 hir_id: self.next_id(),
1385 span: self.lower_span(lhs.span),
1386 }));
1387 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1388 }
1389 }
1390 ExprKind::Struct(se) => {
1392 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1393 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1394 hir::PatField {
1395 hir_id: self.next_id(),
1396 ident: self.lower_ident(f.ident),
1397 pat,
1398 is_shorthand: f.is_shorthand,
1399 span: self.lower_span(f.span),
1400 }
1401 }));
1402 let qpath = self.lower_qpath(
1403 lhs.id,
1404 &se.qself,
1405 &se.path,
1406 ParamMode::Optional,
1407 AllowReturnTypeNotation::No,
1408 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1409 None,
1410 );
1411 let fields_omitted = match &se.rest {
1412 StructRest::Base(e) => {
1413 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1414 span: e.span,
1415 });
1416 Some(self.lower_span(e.span))
1417 }
1418 StructRest::Rest(span) => Some(self.lower_span(*span)),
1419 StructRest::None => None,
1420 };
1421 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1422 return self.pat_without_dbm(lhs.span, struct_pat);
1423 }
1424 ExprKind::Tup(elements) => {
1426 let (pats, rest) =
1427 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1428 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1429 return self.pat_without_dbm(lhs.span, tuple_pat);
1430 }
1431 ExprKind::Paren(e) => {
1432 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1434 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1435 return self.pat_without_dbm(lhs.span, tuple_pat);
1436 } else {
1437 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1438 }
1439 }
1440 _ => {}
1441 }
1442 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1444 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1445 let ident = self.expr_ident(lhs.span, ident, binding);
1446 let assign =
1447 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1448 let expr = self.expr(lhs.span, assign);
1449 assignments.push(self.stmt_expr(lhs.span, expr));
1450 pat
1451 }
1452
1453 fn destructure_sequence(
1459 &mut self,
1460 elements: &[Box<Expr>],
1461 ctx: &str,
1462 eq_sign_span: Span,
1463 assignments: &mut Vec<hir::Stmt<'hir>>,
1464 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1465 let mut rest = None;
1466 let elements =
1467 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1468 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1470 if let Some((_, prev_span)) = rest {
1471 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1472 } else {
1473 rest = Some((i, e.span));
1474 }
1475 None
1476 } else {
1477 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1478 }
1479 }));
1480 (elements, rest)
1481 }
1482
1483 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1485 let e1 = self.lower_expr_mut(e1);
1486 let e2 = self.lower_expr_mut(e2);
1487 let fn_path = hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, span);
1488 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1489 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1490 }
1491
1492 fn lower_expr_range(
1493 &mut self,
1494 span: Span,
1495 e1: Option<&Expr>,
1496 e2: Option<&Expr>,
1497 lims: RangeLimits,
1498 ) -> hir::ExprKind<'hir> {
1499 use rustc_ast::RangeLimits::*;
1500
1501 let lang_item = match (e1, e2, lims) {
1502 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1503 (Some(..), None, HalfOpen) => {
1504 if self.tcx.features().new_range() {
1505 hir::LangItem::RangeFromCopy
1506 } else {
1507 hir::LangItem::RangeFrom
1508 }
1509 }
1510 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1511 (Some(..), Some(..), HalfOpen) => {
1512 if self.tcx.features().new_range() {
1513 hir::LangItem::RangeCopy
1514 } else {
1515 hir::LangItem::Range
1516 }
1517 }
1518 (None, Some(..), Closed) => {
1519 if self.tcx.features().new_range() {
1520 hir::LangItem::RangeToInclusiveCopy
1521 } else {
1522 hir::LangItem::RangeToInclusive
1523 }
1524 }
1525 (Some(e1), Some(e2), Closed) => {
1526 if self.tcx.features().new_range() {
1527 hir::LangItem::RangeInclusiveCopy
1528 } else {
1529 return self.lower_expr_range_closed(span, e1, e2);
1530 }
1531 }
1532 (start, None, Closed) => {
1533 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1534 match start {
1535 Some(..) => {
1536 if self.tcx.features().new_range() {
1537 hir::LangItem::RangeFromCopy
1538 } else {
1539 hir::LangItem::RangeFrom
1540 }
1541 }
1542 None => hir::LangItem::RangeFull,
1543 }
1544 }
1545 };
1546
1547 let fields = self.arena.alloc_from_iter(
1548 e1.iter()
1549 .map(|e| (sym::start, e))
1550 .chain(e2.iter().map(|e| {
1551 (
1552 if matches!(
1553 lang_item,
1554 hir::LangItem::RangeInclusiveCopy | hir::LangItem::RangeToInclusiveCopy
1555 ) {
1556 sym::last
1557 } else {
1558 sym::end
1559 },
1560 e,
1561 )
1562 }))
1563 .map(|(s, e)| {
1564 let span = self.lower_span(e.span);
1565 let span = self.mark_span_with_reason(DesugaringKind::RangeExpr, span, None);
1566 let expr = self.lower_expr(e);
1567 let ident = Ident::new(s, span);
1568 self.expr_field(ident, expr, span)
1569 }),
1570 );
1571
1572 hir::ExprKind::Struct(
1573 self.arena.alloc(hir::QPath::LangItem(lang_item, span)),
1574 fields,
1575 hir::StructTailExpr::None,
1576 )
1577 }
1578
1579 fn lower_label(
1582 &mut self,
1583 opt_label: Option<Label>,
1584 dest_id: NodeId,
1585 dest_hir_id: hir::HirId,
1586 ) -> Option<Label> {
1587 let label = opt_label?;
1588 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1589 Some(Label { ident: self.lower_ident(label.ident) })
1590 }
1591
1592 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1593 let target_id = match destination {
1594 Some((id, _)) => {
1595 if let Some(loop_id) = self.resolver.get_label_res(id) {
1596 let local_id = self.ident_and_label_to_local_id[&loop_id];
1597 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1598 Ok(loop_hir_id)
1599 } else {
1600 Err(hir::LoopIdError::UnresolvedLabel)
1601 }
1602 }
1603 None => {
1604 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1605 }
1606 };
1607 let label = destination
1608 .map(|(_, label)| label)
1609 .map(|label| Label { ident: self.lower_ident(label.ident) });
1610 hir::Destination { label, target_id }
1611 }
1612
1613 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1614 if self.is_in_loop_condition && opt_label.is_none() {
1615 hir::Destination {
1616 label: None,
1617 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1618 }
1619 } else {
1620 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1621 }
1622 }
1623
1624 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1625 let old_scope = self.catch_scope.replace(catch_id);
1626 let result = f(self);
1627 self.catch_scope = old_scope;
1628 result
1629 }
1630
1631 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1632 let was_in_loop_condition = self.is_in_loop_condition;
1634 self.is_in_loop_condition = false;
1635
1636 let old_scope = self.loop_scope.replace(loop_id);
1637 let result = f(self);
1638 self.loop_scope = old_scope;
1639
1640 self.is_in_loop_condition = was_in_loop_condition;
1641
1642 result
1643 }
1644
1645 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1646 let was_in_loop_condition = self.is_in_loop_condition;
1647 self.is_in_loop_condition = true;
1648
1649 let result = f(self);
1650
1651 self.is_in_loop_condition = was_in_loop_condition;
1652
1653 result
1654 }
1655
1656 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1657 let hir_id = self.lower_node_id(f.id);
1658 self.lower_attrs(hir_id, &f.attrs, f.span, Target::ExprField);
1659 hir::ExprField {
1660 hir_id,
1661 ident: self.lower_ident(f.ident),
1662 expr: self.lower_expr(&f.expr),
1663 span: self.lower_span(f.span),
1664 is_shorthand: f.is_shorthand,
1665 }
1666 }
1667
1668 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1669 let yielded =
1670 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1671
1672 if !self.tcx.features().yield_expr()
1673 && !self.tcx.features().coroutines()
1674 && !self.tcx.features().gen_blocks()
1675 {
1676 rustc_session::parse::feature_err(
1677 &self.tcx.sess,
1678 sym::yield_expr,
1679 span,
1680 fluent_generated::ast_lowering_yield,
1681 )
1682 .emit();
1683 }
1684
1685 let is_async_gen = match self.coroutine_kind {
1686 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1687 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1688 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1689 let stmt_id = self.next_id();
1692 let expr_err = self.expr(
1693 yielded.span,
1694 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1695 );
1696 return hir::ExprKind::Block(
1697 self.block_all(
1698 yielded.span,
1699 arena_vec![self; hir::Stmt {
1700 hir_id: stmt_id,
1701 kind: hir::StmtKind::Semi(yielded),
1702 span: yielded.span,
1703 }],
1704 Some(self.arena.alloc(expr_err)),
1705 ),
1706 None,
1707 );
1708 }
1709 Some(hir::CoroutineKind::Coroutine(_)) => false,
1710 None => {
1711 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1712 self.dcx().emit_err(YieldInClosure { span, suggestion });
1713 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1714
1715 false
1716 }
1717 };
1718
1719 if is_async_gen {
1720 let wrapped_yielded = self.expr_call_lang_item_fn(
1724 span,
1725 hir::LangItem::AsyncGenReady,
1726 std::slice::from_ref(yielded),
1727 );
1728 let yield_expr = self.arena.alloc(
1729 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1730 );
1731
1732 let Some(task_context_hid) = self.task_context else {
1733 unreachable!("use of `await` outside of an async context.");
1734 };
1735 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1736 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
1737
1738 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1739 } else {
1740 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1741 }
1742 }
1743
1744 fn lower_expr_for(
1761 &mut self,
1762 e: &Expr,
1763 pat: &Pat,
1764 head: &Expr,
1765 body: &Block,
1766 opt_label: Option<Label>,
1767 loop_kind: ForLoopKind,
1768 ) -> hir::Expr<'hir> {
1769 let head = self.lower_expr_mut(head);
1770 let pat = self.lower_pat(pat);
1771 let for_span =
1772 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1773 let head_span = self.mark_span_with_reason(DesugaringKind::ForLoop, head.span, None);
1774 let pat_span = self.mark_span_with_reason(DesugaringKind::ForLoop, pat.span, None);
1775
1776 let loop_hir_id = self.lower_node_id(e.id);
1777 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1778
1779 let none_arm = {
1781 let break_expr =
1782 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1783 let pat = self.pat_none(for_span);
1784 self.arm(pat, break_expr)
1785 };
1786
1787 let some_arm = {
1789 let some_pat = self.pat_some(pat_span, pat);
1790 let body_block =
1791 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1792 let body_expr = self.arena.alloc(self.expr_block(body_block));
1793 self.arm(some_pat, body_expr)
1794 };
1795
1796 let iter = Ident::with_dummy_span(sym::iter);
1798 let (iter_pat, iter_pat_nid) =
1799 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1800
1801 let match_expr = {
1802 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1803 let next_expr = match loop_kind {
1804 ForLoopKind::For => {
1805 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1807 self.expr_call_lang_item_fn(
1808 head_span,
1809 hir::LangItem::IteratorNext,
1810 arena_vec![self; ref_mut_iter],
1811 )
1812 }
1813 ForLoopKind::ForAwait => {
1814 let iter = self.expr_mut_addr_of(head_span, iter);
1821 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1823 head_span,
1824 hir::LangItem::PinNewUnchecked,
1825 arena_vec![self; iter],
1826 ));
1827 let iter = self.arena.alloc(self.expr_unsafe(iter));
1829 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1830 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1831 }
1832 };
1833 let arms = arena_vec![self; none_arm, some_arm];
1834
1835 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1837 };
1838 let match_stmt = self.stmt_expr(for_span, match_expr);
1839
1840 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1841
1842 let kind = hir::ExprKind::Loop(
1844 loop_block,
1845 label,
1846 hir::LoopSource::ForLoop,
1847 self.lower_span(for_span.with_hi(head.span.hi())),
1848 );
1849 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1850
1851 let iter_arm = self.arm(iter_pat, loop_expr);
1853
1854 let match_expr = match loop_kind {
1855 ForLoopKind::For => {
1856 let into_iter_expr = self.expr_call_lang_item_fn(
1858 head_span,
1859 hir::LangItem::IntoIterIntoIter,
1860 arena_vec![self; head],
1861 );
1862
1863 self.arena.alloc(self.expr_match(
1864 for_span,
1865 into_iter_expr,
1866 arena_vec![self; iter_arm],
1867 hir::MatchSource::ForLoopDesugar,
1868 ))
1869 }
1870 ForLoopKind::ForAwait => {
1872 let iter_ident = iter;
1873 let (async_iter_pat, async_iter_pat_id) =
1874 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1875 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1876 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1878 head_span,
1879 hir::LangItem::PinNewUnchecked,
1880 arena_vec![self; iter],
1881 ));
1882 let iter = self.arena.alloc(self.expr_unsafe(iter));
1884 let inner_match_expr = self.arena.alloc(self.expr_match(
1885 for_span,
1886 iter,
1887 arena_vec![self; iter_arm],
1888 hir::MatchSource::ForLoopDesugar,
1889 ));
1890
1891 let iter = self.expr_call_lang_item_fn(
1893 head_span,
1894 hir::LangItem::IntoAsyncIterIntoIter,
1895 arena_vec![self; head],
1896 );
1897 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1898 self.arena.alloc(self.expr_match(
1899 for_span,
1900 iter,
1901 arena_vec![self; iter_arm],
1902 hir::MatchSource::ForLoopDesugar,
1903 ))
1904 }
1905 };
1906
1907 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1914 self.lower_attrs(expr.hir_id, &e.attrs, e.span, Target::from_expr(e));
1915 expr
1916 }
1917
1918 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1931 let unstable_span = self.mark_span_with_reason(
1932 DesugaringKind::QuestionMark,
1933 span,
1934 Some(Arc::clone(&self.allow_try_trait)),
1935 );
1936 let try_span = self.tcx.sess.source_map().end_point(span);
1937 let try_span = self.mark_span_with_reason(
1938 DesugaringKind::QuestionMark,
1939 try_span,
1940 Some(Arc::clone(&self.allow_try_trait)),
1941 );
1942
1943 let scrutinee = {
1945 let sub_expr = self.lower_expr_mut(sub_expr);
1947
1948 self.expr_call_lang_item_fn(
1949 unstable_span,
1950 hir::LangItem::TryTraitBranch,
1951 arena_vec![self; sub_expr],
1952 )
1953 };
1954
1955 let attrs: AttrVec = thin_vec![self.unreachable_code_attr(try_span)];
1956
1957 let continue_arm = {
1959 let val_ident = Ident::with_dummy_span(sym::val);
1960 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
1961 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
1962 self.lower_attrs(val_expr.hir_id, &attrs, span, Target::Expression);
1963 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
1964 self.arm(continue_pat, val_expr)
1965 };
1966
1967 let break_arm = {
1971 let residual_ident = Ident::with_dummy_span(sym::residual);
1972 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
1973 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
1974 let from_residual_expr = self.wrap_in_try_constructor(
1975 hir::LangItem::TryTraitFromResidual,
1976 try_span,
1977 self.arena.alloc(residual_expr),
1978 unstable_span,
1979 );
1980 let ret_expr = if let Some(catch_id) = self.catch_scope {
1981 let target_id = Ok(catch_id);
1982 self.arena.alloc(self.expr(
1983 try_span,
1984 hir::ExprKind::Break(
1985 hir::Destination { label: None, target_id },
1986 Some(from_residual_expr),
1987 ),
1988 ))
1989 } else {
1990 let ret_expr = self.checked_return(Some(from_residual_expr));
1991 self.arena.alloc(self.expr(try_span, ret_expr))
1992 };
1993 self.lower_attrs(ret_expr.hir_id, &attrs, span, Target::Expression);
1994
1995 let break_pat = self.pat_cf_break(try_span, residual_local);
1996 self.arm(break_pat, ret_expr)
1997 };
1998
1999 hir::ExprKind::Match(
2000 scrutinee,
2001 arena_vec![self; break_arm, continue_arm],
2002 hir::MatchSource::TryDesugar(scrutinee.hir_id),
2003 )
2004 }
2005
2006 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2016 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2018 (sub_expr.span, self.lower_expr(sub_expr))
2019 } else {
2020 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2021 };
2022
2023 let unstable_span = self.mark_span_with_reason(
2024 DesugaringKind::YeetExpr,
2025 span,
2026 Some(Arc::clone(&self.allow_try_trait)),
2027 );
2028
2029 let from_yeet_expr = self.wrap_in_try_constructor(
2030 hir::LangItem::TryTraitFromYeet,
2031 unstable_span,
2032 yeeted_expr,
2033 yeeted_span,
2034 );
2035
2036 if let Some(catch_id) = self.catch_scope {
2037 let target_id = Ok(catch_id);
2038 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2039 } else {
2040 self.checked_return(Some(from_yeet_expr))
2041 }
2042 }
2043
2044 pub(super) fn expr_drop_temps(
2056 &mut self,
2057 span: Span,
2058 expr: &'hir hir::Expr<'hir>,
2059 ) -> &'hir hir::Expr<'hir> {
2060 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2061 }
2062
2063 pub(super) fn expr_drop_temps_mut(
2064 &mut self,
2065 span: Span,
2066 expr: &'hir hir::Expr<'hir>,
2067 ) -> hir::Expr<'hir> {
2068 self.expr(span, hir::ExprKind::DropTemps(expr))
2069 }
2070
2071 pub(super) fn expr_match(
2072 &mut self,
2073 span: Span,
2074 arg: &'hir hir::Expr<'hir>,
2075 arms: &'hir [hir::Arm<'hir>],
2076 source: hir::MatchSource,
2077 ) -> hir::Expr<'hir> {
2078 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2079 }
2080
2081 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2082 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2083 self.expr(span, expr_break)
2084 }
2085
2086 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2087 let expr_break = self.expr_break(span);
2088 self.arena.alloc(expr_break)
2089 }
2090
2091 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2092 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2093 }
2094
2095 pub(super) fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2096 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2097 }
2098
2099 fn expr_uint(&mut self, sp: Span, ty: ast::UintTy, value: u128) -> hir::Expr<'hir> {
2100 let lit = hir::Lit {
2101 span: self.lower_span(sp),
2102 node: ast::LitKind::Int(value.into(), ast::LitIntType::Unsigned(ty)),
2103 };
2104 self.expr(sp, hir::ExprKind::Lit(lit))
2105 }
2106
2107 pub(super) fn expr_usize(&mut self, sp: Span, value: usize) -> hir::Expr<'hir> {
2108 self.expr_uint(sp, ast::UintTy::Usize, value as u128)
2109 }
2110
2111 pub(super) fn expr_u32(&mut self, sp: Span, value: u32) -> hir::Expr<'hir> {
2112 self.expr_uint(sp, ast::UintTy::U32, value as u128)
2113 }
2114
2115 pub(super) fn expr_u16(&mut self, sp: Span, value: u16) -> hir::Expr<'hir> {
2116 self.expr_uint(sp, ast::UintTy::U16, value as u128)
2117 }
2118
2119 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2120 let lit = hir::Lit {
2121 span: self.lower_span(sp),
2122 node: ast::LitKind::Str(value, ast::StrStyle::Cooked),
2123 };
2124 self.expr(sp, hir::ExprKind::Lit(lit))
2125 }
2126
2127 pub(super) fn expr_call_mut(
2128 &mut self,
2129 span: Span,
2130 e: &'hir hir::Expr<'hir>,
2131 args: &'hir [hir::Expr<'hir>],
2132 ) -> hir::Expr<'hir> {
2133 self.expr(span, hir::ExprKind::Call(e, args))
2134 }
2135
2136 pub(super) fn expr_struct(
2137 &mut self,
2138 span: Span,
2139 path: &'hir hir::QPath<'hir>,
2140 fields: &'hir [hir::ExprField<'hir>],
2141 ) -> hir::Expr<'hir> {
2142 self.expr(span, hir::ExprKind::Struct(path, fields, rustc_hir::StructTailExpr::None))
2143 }
2144
2145 pub(super) fn expr_enum_variant(
2146 &mut self,
2147 span: Span,
2148 path: &'hir hir::QPath<'hir>,
2149 fields: &'hir [hir::Expr<'hir>],
2150 ) -> hir::Expr<'hir> {
2151 let fields = self.arena.alloc_from_iter(fields.into_iter().enumerate().map(|(i, f)| {
2152 hir::ExprField {
2153 hir_id: self.next_id(),
2154 ident: Ident::from_str(&i.to_string()),
2155 expr: f,
2156 span: f.span,
2157 is_shorthand: false,
2158 }
2159 }));
2160 self.expr_struct(span, path, fields)
2161 }
2162
2163 pub(super) fn expr_enum_variant_lang_item(
2164 &mut self,
2165 span: Span,
2166 lang_item: hir::LangItem,
2167 fields: &'hir [hir::Expr<'hir>],
2168 ) -> hir::Expr<'hir> {
2169 let path = self.arena.alloc(self.lang_item_path(span, lang_item));
2170 self.expr_enum_variant(span, path, fields)
2171 }
2172
2173 pub(super) fn expr_call(
2174 &mut self,
2175 span: Span,
2176 e: &'hir hir::Expr<'hir>,
2177 args: &'hir [hir::Expr<'hir>],
2178 ) -> &'hir hir::Expr<'hir> {
2179 self.arena.alloc(self.expr_call_mut(span, e, args))
2180 }
2181
2182 pub(super) fn expr_call_lang_item_fn_mut(
2183 &mut self,
2184 span: Span,
2185 lang_item: hir::LangItem,
2186 args: &'hir [hir::Expr<'hir>],
2187 ) -> hir::Expr<'hir> {
2188 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2189 self.expr_call_mut(span, path, args)
2190 }
2191
2192 pub(super) fn expr_call_lang_item_fn(
2193 &mut self,
2194 span: Span,
2195 lang_item: hir::LangItem,
2196 args: &'hir [hir::Expr<'hir>],
2197 ) -> &'hir hir::Expr<'hir> {
2198 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2199 }
2200
2201 pub(super) fn expr_lang_item_path(
2202 &mut self,
2203 span: Span,
2204 lang_item: hir::LangItem,
2205 ) -> hir::Expr<'hir> {
2206 let path = self.lang_item_path(span, lang_item);
2207 self.expr(span, hir::ExprKind::Path(path))
2208 }
2209
2210 pub(super) fn lang_item_path(
2211 &mut self,
2212 span: Span,
2213 lang_item: hir::LangItem,
2214 ) -> hir::QPath<'hir> {
2215 hir::QPath::LangItem(lang_item, self.lower_span(span))
2216 }
2217
2218 pub(super) fn expr_lang_item_type_relative(
2220 &mut self,
2221 span: Span,
2222 lang_item: hir::LangItem,
2223 name: Symbol,
2224 ) -> hir::Expr<'hir> {
2225 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2226 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2227 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2228 self.arena.alloc(hir::PathSegment::new(
2229 Ident::new(name, self.lower_span(span)),
2230 self.next_id(),
2231 Res::Err,
2232 )),
2233 ));
2234 self.expr(span, path)
2235 }
2236
2237 pub(super) fn expr_ident(
2238 &mut self,
2239 sp: Span,
2240 ident: Ident,
2241 binding: HirId,
2242 ) -> &'hir hir::Expr<'hir> {
2243 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2244 }
2245
2246 pub(super) fn expr_ident_mut(
2247 &mut self,
2248 span: Span,
2249 ident: Ident,
2250 binding: HirId,
2251 ) -> hir::Expr<'hir> {
2252 let hir_id = self.next_id();
2253 let res = Res::Local(binding);
2254 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2255 None,
2256 self.arena.alloc(hir::Path {
2257 span: self.lower_span(span),
2258 res,
2259 segments: arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
2260 }),
2261 ));
2262
2263 self.expr(span, expr_path)
2264 }
2265
2266 fn expr_unsafe(&mut self, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2267 let hir_id = self.next_id();
2268 let span = expr.span;
2269 self.expr(
2270 span,
2271 hir::ExprKind::Block(
2272 self.arena.alloc(hir::Block {
2273 stmts: &[],
2274 expr: Some(expr),
2275 hir_id,
2276 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2277 span: self.lower_span(span),
2278 targeted_by_break: false,
2279 }),
2280 None,
2281 ),
2282 )
2283 }
2284
2285 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2286 let blk = self.block_all(span, &[], None);
2287 let expr = self.expr_block(blk);
2288 self.arena.alloc(expr)
2289 }
2290
2291 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2292 self.expr(b.span, hir::ExprKind::Block(b, None))
2293 }
2294
2295 pub(super) fn block_expr_block(
2299 &mut self,
2300 expr: &'hir hir::Expr<'hir>,
2301 ) -> &'hir hir::Expr<'hir> {
2302 let b = self.block_expr(expr);
2303 self.arena.alloc(self.expr_block(b))
2304 }
2305
2306 pub(super) fn expr_array_ref(
2307 &mut self,
2308 span: Span,
2309 elements: &'hir [hir::Expr<'hir>],
2310 ) -> hir::Expr<'hir> {
2311 let array = self.arena.alloc(self.expr(span, hir::ExprKind::Array(elements)));
2312 self.expr_ref(span, array)
2313 }
2314
2315 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2316 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2317 }
2318
2319 pub(super) fn expr_bool_literal(&mut self, span: Span, val: bool) -> hir::Expr<'hir> {
2320 self.expr(span, hir::ExprKind::Lit(Spanned { node: LitKind::Bool(val), span }))
2321 }
2322
2323 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2324 let hir_id = self.next_id();
2325 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2326 }
2327
2328 pub(super) fn expr_field(
2329 &mut self,
2330 ident: Ident,
2331 expr: &'hir hir::Expr<'hir>,
2332 span: Span,
2333 ) -> hir::ExprField<'hir> {
2334 hir::ExprField {
2335 hir_id: self.next_id(),
2336 ident,
2337 span: self.lower_span(span),
2338 expr,
2339 is_shorthand: false,
2340 }
2341 }
2342
2343 pub(super) fn arm(
2344 &mut self,
2345 pat: &'hir hir::Pat<'hir>,
2346 expr: &'hir hir::Expr<'hir>,
2347 ) -> hir::Arm<'hir> {
2348 hir::Arm {
2349 hir_id: self.next_id(),
2350 pat,
2351 guard: None,
2352 span: self.lower_span(expr.span),
2353 body: expr,
2354 }
2355 }
2356
2357 pub(super) fn unreachable_code_attr(&mut self, span: Span) -> Attribute {
2359 let attr = attr::mk_attr_nested_word(
2360 &self.tcx.sess.psess.attr_id_generator,
2361 AttrStyle::Outer,
2362 Safety::Default,
2363 sym::allow,
2364 sym::unreachable_code,
2365 span,
2366 );
2367 attr
2368 }
2369}
2370
2371#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2374enum FutureKind {
2375 Future,
2377 AsyncIterator,
2380}