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::{ByteSymbol, 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 if is_async_gen => Some(Arc::clone(&self.allow_async_gen)),
869 FutureKind::Future => None,
870 FutureKind::AsyncIterator => Some(Arc::clone(&self.allow_for_await)),
871 };
872 let span = self.mark_span_with_reason(DesugaringKind::Await, await_kw_span, features);
873 let gen_future_span = self.mark_span_with_reason(
874 DesugaringKind::Await,
875 full_span,
876 Some(Arc::clone(&self.allow_gen_future)),
877 );
878 let expr_hir_id = expr.hir_id;
879
880 let awaitee_ident = Ident::with_dummy_span(sym::__awaitee);
884 let (awaitee_pat, awaitee_pat_hid) =
885 self.pat_ident_binding_mode(gen_future_span, awaitee_ident, hir::BindingMode::MUT);
886
887 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
888
889 let poll_expr = {
896 let awaitee = self.expr_ident(span, awaitee_ident, awaitee_pat_hid);
897 let ref_mut_awaitee = self.expr_mut_addr_of(span, awaitee);
898
899 let Some(task_context_hid) = self.task_context else {
900 unreachable!("use of `await` outside of an async context.");
901 };
902
903 let task_context = self.expr_ident_mut(span, task_context_ident, task_context_hid);
904
905 let new_unchecked = self.expr_call_lang_item_fn_mut(
906 span,
907 hir::LangItem::PinNewUnchecked,
908 arena_vec![self; ref_mut_awaitee],
909 );
910 let get_context = self.expr_call_lang_item_fn_mut(
911 gen_future_span,
912 hir::LangItem::GetContext,
913 arena_vec![self; task_context],
914 );
915 let call = match await_kind {
916 FutureKind::Future => self.expr_call_lang_item_fn(
917 span,
918 hir::LangItem::FuturePoll,
919 arena_vec![self; new_unchecked, get_context],
920 ),
921 FutureKind::AsyncIterator => self.expr_call_lang_item_fn(
922 span,
923 hir::LangItem::AsyncIteratorPollNext,
924 arena_vec![self; new_unchecked, get_context],
925 ),
926 };
927 self.arena.alloc(self.expr_unsafe(span, call))
928 };
929
930 let loop_node_id = self.next_node_id();
932 let loop_hir_id = self.lower_node_id(loop_node_id);
933 let ready_arm = {
934 let x_ident = Ident::with_dummy_span(sym::result);
935 let (x_pat, x_pat_hid) = self.pat_ident(gen_future_span, x_ident);
936 let x_expr = self.expr_ident(gen_future_span, x_ident, x_pat_hid);
937 let ready_field = self.single_pat_field(gen_future_span, x_pat);
938 let ready_pat = self.pat_lang_item_variant(span, hir::LangItem::PollReady, ready_field);
939 let break_x = self.with_loop_scope(loop_hir_id, move |this| {
940 let expr_break =
941 hir::ExprKind::Break(this.lower_loop_destination(None), Some(x_expr));
942 this.arena.alloc(this.expr(gen_future_span, expr_break))
943 });
944 self.arm(ready_pat, break_x)
945 };
946
947 let pending_arm = {
949 let pending_pat = self.pat_lang_item_variant(span, hir::LangItem::PollPending, &[]);
950 let empty_block = self.expr_block_empty(span);
951 self.arm(pending_pat, empty_block)
952 };
953
954 let inner_match_stmt = {
955 let match_expr = self.expr_match(
956 span,
957 poll_expr,
958 arena_vec![self; ready_arm, pending_arm],
959 hir::MatchSource::AwaitDesugar,
960 );
961 self.stmt_expr(span, match_expr)
962 };
963
964 let yield_stmt = {
968 let yielded = if is_async_gen {
969 self.arena.alloc(self.expr_lang_item_path(span, hir::LangItem::AsyncGenPending))
970 } else {
971 self.expr_unit(span)
972 };
973
974 let yield_expr = self.expr(
975 span,
976 hir::ExprKind::Yield(yielded, hir::YieldSource::Await { expr: Some(expr_hir_id) }),
977 );
978 let yield_expr = self.arena.alloc(yield_expr);
979
980 let Some(task_context_hid) = self.task_context else {
981 unreachable!("use of `await` outside of an async context.");
982 };
983
984 let lhs = self.expr_ident(span, task_context_ident, task_context_hid);
985 let assign =
986 self.expr(span, hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span)));
987 self.stmt_expr(span, assign)
988 };
989
990 let loop_block = self.block_all(span, arena_vec![self; inner_match_stmt, yield_stmt], None);
991
992 let loop_expr = self.arena.alloc(hir::Expr {
994 hir_id: loop_hir_id,
995 kind: hir::ExprKind::Loop(
996 loop_block,
997 None,
998 hir::LoopSource::Loop,
999 self.lower_span(span),
1000 ),
1001 span: self.lower_span(span),
1002 });
1003
1004 let awaitee_arm = self.arm(awaitee_pat, loop_expr);
1006
1007 let into_future_expr = match await_kind {
1009 FutureKind::Future => self.expr_call_lang_item_fn(
1010 span,
1011 hir::LangItem::IntoFutureIntoFuture,
1012 arena_vec![self; *expr],
1013 ),
1014 FutureKind::AsyncIterator => expr,
1017 };
1018
1019 hir::ExprKind::Match(
1023 into_future_expr,
1024 arena_vec![self; awaitee_arm],
1025 hir::MatchSource::AwaitDesugar,
1026 )
1027 }
1028
1029 fn lower_expr_use(&mut self, use_kw_span: Span, expr: &Expr) -> hir::ExprKind<'hir> {
1030 hir::ExprKind::Use(self.lower_expr(expr), self.lower_span(use_kw_span))
1031 }
1032
1033 fn lower_expr_closure(
1034 &mut self,
1035 attrs: &[rustc_hir::Attribute],
1036 binder: &ClosureBinder,
1037 capture_clause: CaptureBy,
1038 closure_id: NodeId,
1039 constness: Const,
1040 movability: Movability,
1041 decl: &FnDecl,
1042 body: &Expr,
1043 fn_decl_span: Span,
1044 fn_arg_span: Span,
1045 ) -> hir::ExprKind<'hir> {
1046 let closure_def_id = self.local_def_id(closure_id);
1047 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1048
1049 let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
1050
1051 let mut coroutine_kind = find_attr!(attrs, AttributeKind::Coroutine(_) => hir::CoroutineKind::Coroutine(Movability::Movable));
1052
1053 let body_id = this.lower_fn_body(decl, None, |this| {
1055 this.coroutine_kind = coroutine_kind;
1056 let e = this.lower_expr_mut(body);
1057 coroutine_kind = this.coroutine_kind;
1058 e
1059 });
1060 let coroutine_option =
1061 this.closure_movability_for_fn(decl, fn_decl_span, coroutine_kind, movability);
1062 (body_id, coroutine_option)
1063 });
1064
1065 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1066 let fn_decl = self.lower_fn_decl(decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1068
1069 let c = self.arena.alloc(hir::Closure {
1070 def_id: closure_def_id,
1071 binder: binder_clause,
1072 capture_clause: self.lower_capture_clause(capture_clause),
1073 bound_generic_params,
1074 fn_decl,
1075 body: body_id,
1076 fn_decl_span: self.lower_span(fn_decl_span),
1077 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1078 kind: closure_kind,
1079 constness: self.lower_constness(constness),
1080 });
1081
1082 hir::ExprKind::Closure(c)
1083 }
1084
1085 fn closure_movability_for_fn(
1086 &mut self,
1087 decl: &FnDecl,
1088 fn_decl_span: Span,
1089 coroutine_kind: Option<hir::CoroutineKind>,
1090 movability: Movability,
1091 ) -> hir::ClosureKind {
1092 match coroutine_kind {
1093 Some(hir::CoroutineKind::Coroutine(_)) => {
1094 if decl.inputs.len() > 1 {
1095 self.dcx().emit_err(CoroutineTooManyParameters { fn_decl_span });
1096 }
1097 hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(movability))
1098 }
1099 Some(
1100 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)
1101 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)
1102 | hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _),
1103 ) => {
1104 panic!("non-`async`/`gen` closure body turned `async`/`gen` during lowering");
1105 }
1106 None => {
1107 if movability == Movability::Static {
1108 self.dcx().emit_err(ClosureCannotBeStatic { fn_decl_span });
1109 }
1110 hir::ClosureKind::Closure
1111 }
1112 }
1113 }
1114
1115 fn lower_closure_binder<'c>(
1116 &mut self,
1117 binder: &'c ClosureBinder,
1118 ) -> (hir::ClosureBinder, &'c [GenericParam]) {
1119 let (binder, params) = match binder {
1120 ClosureBinder::NotPresent => (hir::ClosureBinder::Default, &[][..]),
1121 ClosureBinder::For { span, generic_params } => {
1122 let span = self.lower_span(*span);
1123 (hir::ClosureBinder::For { span }, &**generic_params)
1124 }
1125 };
1126
1127 (binder, params)
1128 }
1129
1130 fn lower_expr_coroutine_closure(
1131 &mut self,
1132 binder: &ClosureBinder,
1133 capture_clause: CaptureBy,
1134 closure_id: NodeId,
1135 closure_hir_id: HirId,
1136 coroutine_kind: CoroutineKind,
1137 decl: &FnDecl,
1138 body: &Expr,
1139 fn_decl_span: Span,
1140 fn_arg_span: Span,
1141 ) -> hir::ExprKind<'hir> {
1142 let closure_def_id = self.local_def_id(closure_id);
1143 let (binder_clause, generic_params) = self.lower_closure_binder(binder);
1144
1145 let coroutine_desugaring = match coroutine_kind {
1146 CoroutineKind::Async { .. } => hir::CoroutineDesugaring::Async,
1147 CoroutineKind::Gen { .. } => hir::CoroutineDesugaring::Gen,
1148 CoroutineKind::AsyncGen { span, .. } => {
1149 span_bug!(span, "only async closures and `iter!` closures are supported currently")
1150 }
1151 };
1152
1153 let body = self.with_new_scopes(fn_decl_span, |this| {
1154 let inner_decl =
1155 FnDecl { inputs: decl.inputs.clone(), output: FnRetTy::Default(fn_decl_span) };
1156
1157 let body_id = this.lower_body(|this| {
1160 let (parameters, expr) = this.lower_coroutine_body_with_moved_arguments(
1161 &inner_decl,
1162 |this| this.with_new_scopes(fn_decl_span, |this| this.lower_expr_mut(body)),
1163 fn_decl_span,
1164 body.span,
1165 coroutine_kind,
1166 hir::CoroutineSource::Closure,
1167 );
1168
1169 this.maybe_forward_track_caller(body.span, closure_hir_id, expr.hir_id);
1170
1171 (parameters, expr)
1172 });
1173 body_id
1174 });
1175
1176 let bound_generic_params = self.lower_lifetime_binder(closure_id, generic_params);
1177 let fn_decl =
1181 self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
1182
1183 let c = self.arena.alloc(hir::Closure {
1184 def_id: closure_def_id,
1185 binder: binder_clause,
1186 capture_clause: self.lower_capture_clause(capture_clause),
1187 bound_generic_params,
1188 fn_decl,
1189 body,
1190 fn_decl_span: self.lower_span(fn_decl_span),
1191 fn_arg_span: Some(self.lower_span(fn_arg_span)),
1192 kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
1196 constness: hir::Constness::NotConst,
1197 });
1198 hir::ExprKind::Closure(c)
1199 }
1200
1201 fn lower_expr_assign(
1204 &mut self,
1205 lhs: &Expr,
1206 rhs: &Expr,
1207 eq_sign_span: Span,
1208 whole_span: Span,
1209 ) -> hir::ExprKind<'hir> {
1210 fn is_ordinary(lower_ctx: &mut LoweringContext<'_, '_>, lhs: &Expr) -> bool {
1212 match &lhs.kind {
1213 ExprKind::Array(..)
1214 | ExprKind::Struct(..)
1215 | ExprKind::Tup(..)
1216 | ExprKind::Underscore => false,
1217 ExprKind::Path(..) => lower_ctx.extract_unit_struct_path(lhs).is_none(),
1219 ExprKind::Call(callee, ..) => lower_ctx.extract_tuple_struct_path(callee).is_none(),
1221 ExprKind::Paren(e) => {
1222 match e.kind {
1223 ExprKind::Range(None, None, RangeLimits::HalfOpen) => false,
1225 _ => is_ordinary(lower_ctx, e),
1226 }
1227 }
1228 _ => true,
1229 }
1230 }
1231 if is_ordinary(self, lhs) {
1232 return hir::ExprKind::Assign(
1233 self.lower_expr(lhs),
1234 self.lower_expr(rhs),
1235 self.lower_span(eq_sign_span),
1236 );
1237 }
1238
1239 let mut assignments = vec![];
1240
1241 let pat = self.destructure_assign(lhs, eq_sign_span, &mut assignments);
1243 let rhs = self.lower_expr(rhs);
1244
1245 let destructure_let =
1247 self.stmt_let_pat(None, whole_span, Some(rhs), pat, hir::LocalSource::AssignDesugar);
1248
1249 let stmts = self.arena.alloc_from_iter(std::iter::once(destructure_let).chain(assignments));
1251
1252 hir::ExprKind::Block(self.block_all(whole_span, stmts, None), None)
1254 }
1255
1256 fn extract_tuple_struct_path<'a>(
1261 &mut self,
1262 expr: &'a Expr,
1263 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1264 if let ExprKind::Path(qself, path) = &expr.kind {
1265 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1267 if let Some(res) = partial_res.full_res()
1268 && !res.expected_in_tuple_struct_pat()
1269 {
1270 return None;
1271 }
1272 }
1273 return Some((qself, path));
1274 }
1275 None
1276 }
1277
1278 fn extract_unit_struct_path<'a>(
1283 &mut self,
1284 expr: &'a Expr,
1285 ) -> Option<(&'a Option<Box<QSelf>>, &'a Path)> {
1286 if let ExprKind::Path(qself, path) = &expr.kind {
1287 if let Some(partial_res) = self.resolver.get_partial_res(expr.id) {
1289 if let Some(res) = partial_res.full_res()
1290 && !res.expected_in_unit_struct_pat()
1291 {
1292 return None;
1293 }
1294 }
1295 return Some((qself, path));
1296 }
1297 None
1298 }
1299
1300 fn destructure_assign(
1303 &mut self,
1304 lhs: &Expr,
1305 eq_sign_span: Span,
1306 assignments: &mut Vec<hir::Stmt<'hir>>,
1307 ) -> &'hir hir::Pat<'hir> {
1308 self.arena.alloc(self.destructure_assign_mut(lhs, eq_sign_span, assignments))
1309 }
1310
1311 fn destructure_assign_mut(
1312 &mut self,
1313 lhs: &Expr,
1314 eq_sign_span: Span,
1315 assignments: &mut Vec<hir::Stmt<'hir>>,
1316 ) -> hir::Pat<'hir> {
1317 match &lhs.kind {
1318 ExprKind::Underscore => {
1320 return self.pat_without_dbm(lhs.span, hir::PatKind::Wild);
1321 }
1322 ExprKind::Array(elements) => {
1324 let (pats, rest) =
1325 self.destructure_sequence(elements, "slice", eq_sign_span, assignments);
1326 let slice_pat = if let Some((i, span)) = rest {
1327 let (before, after) = pats.split_at(i);
1328 hir::PatKind::Slice(
1329 before,
1330 Some(self.arena.alloc(self.pat_without_dbm(span, hir::PatKind::Wild))),
1331 after,
1332 )
1333 } else {
1334 hir::PatKind::Slice(pats, None, &[])
1335 };
1336 return self.pat_without_dbm(lhs.span, slice_pat);
1337 }
1338 ExprKind::Call(callee, args) => {
1340 if let Some((qself, path)) = self.extract_tuple_struct_path(callee) {
1341 let (pats, rest) = self.destructure_sequence(
1342 args,
1343 "tuple struct or variant",
1344 eq_sign_span,
1345 assignments,
1346 );
1347 let qpath = self.lower_qpath(
1348 callee.id,
1349 qself,
1350 path,
1351 ParamMode::Optional,
1352 AllowReturnTypeNotation::No,
1353 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1354 None,
1355 );
1356 let tuple_struct_pat = hir::PatKind::TupleStruct(
1358 qpath,
1359 pats,
1360 hir::DotDotPos::new(rest.map(|r| r.0)),
1361 );
1362 return self.pat_without_dbm(lhs.span, tuple_struct_pat);
1363 }
1364 }
1365 ExprKind::Path(..) => {
1367 if let Some((qself, path)) = self.extract_unit_struct_path(lhs) {
1368 let qpath = self.lower_qpath(
1369 lhs.id,
1370 qself,
1371 path,
1372 ParamMode::Optional,
1373 AllowReturnTypeNotation::No,
1374 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1375 None,
1376 );
1377 let unit_struct_pat = hir::PatKind::Expr(self.arena.alloc(hir::PatExpr {
1379 kind: hir::PatExprKind::Path(qpath),
1380 hir_id: self.next_id(),
1381 span: self.lower_span(lhs.span),
1382 }));
1383 return self.pat_without_dbm(lhs.span, unit_struct_pat);
1384 }
1385 }
1386 ExprKind::Struct(se) => {
1388 let field_pats = self.arena.alloc_from_iter(se.fields.iter().map(|f| {
1389 let pat = self.destructure_assign(&f.expr, eq_sign_span, assignments);
1390 hir::PatField {
1391 hir_id: self.next_id(),
1392 ident: self.lower_ident(f.ident),
1393 pat,
1394 is_shorthand: f.is_shorthand,
1395 span: self.lower_span(f.span),
1396 }
1397 }));
1398 let qpath = self.lower_qpath(
1399 lhs.id,
1400 &se.qself,
1401 &se.path,
1402 ParamMode::Optional,
1403 AllowReturnTypeNotation::No,
1404 ImplTraitContext::Disallowed(ImplTraitPosition::Path),
1405 None,
1406 );
1407 let fields_omitted = match &se.rest {
1408 StructRest::Base(e) => {
1409 self.dcx().emit_err(FunctionalRecordUpdateDestructuringAssignment {
1410 span: e.span,
1411 });
1412 Some(self.lower_span(e.span))
1413 }
1414 StructRest::Rest(span) => Some(self.lower_span(*span)),
1415 StructRest::None => None,
1416 };
1417 let struct_pat = hir::PatKind::Struct(qpath, field_pats, fields_omitted);
1418 return self.pat_without_dbm(lhs.span, struct_pat);
1419 }
1420 ExprKind::Tup(elements) => {
1422 let (pats, rest) =
1423 self.destructure_sequence(elements, "tuple", eq_sign_span, assignments);
1424 let tuple_pat = hir::PatKind::Tuple(pats, hir::DotDotPos::new(rest.map(|r| r.0)));
1425 return self.pat_without_dbm(lhs.span, tuple_pat);
1426 }
1427 ExprKind::Paren(e) => {
1428 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1430 let tuple_pat = hir::PatKind::Tuple(&[], hir::DotDotPos::new(Some(0)));
1431 return self.pat_without_dbm(lhs.span, tuple_pat);
1432 } else {
1433 return self.destructure_assign_mut(e, eq_sign_span, assignments);
1434 }
1435 }
1436 _ => {}
1437 }
1438 let ident = Ident::new(sym::lhs, self.lower_span(lhs.span));
1440 let (pat, binding) = self.pat_ident_mut(lhs.span, ident);
1441 let ident = self.expr_ident(lhs.span, ident, binding);
1442 let assign =
1443 hir::ExprKind::Assign(self.lower_expr(lhs), ident, self.lower_span(eq_sign_span));
1444 let expr = self.expr(lhs.span, assign);
1445 assignments.push(self.stmt_expr(lhs.span, expr));
1446 pat
1447 }
1448
1449 fn destructure_sequence(
1455 &mut self,
1456 elements: &[Box<Expr>],
1457 ctx: &str,
1458 eq_sign_span: Span,
1459 assignments: &mut Vec<hir::Stmt<'hir>>,
1460 ) -> (&'hir [hir::Pat<'hir>], Option<(usize, Span)>) {
1461 let mut rest = None;
1462 let elements =
1463 self.arena.alloc_from_iter(elements.iter().enumerate().filter_map(|(i, e)| {
1464 if let ExprKind::Range(None, None, RangeLimits::HalfOpen) = e.kind {
1466 if let Some((_, prev_span)) = rest {
1467 self.ban_extra_rest_pat(e.span, prev_span, ctx);
1468 } else {
1469 rest = Some((i, e.span));
1470 }
1471 None
1472 } else {
1473 Some(self.destructure_assign_mut(e, eq_sign_span, assignments))
1474 }
1475 }));
1476 (elements, rest)
1477 }
1478
1479 fn lower_expr_range_closed(&mut self, span: Span, e1: &Expr, e2: &Expr) -> hir::ExprKind<'hir> {
1481 let e1 = self.lower_expr_mut(e1);
1482 let e2 = self.lower_expr_mut(e2);
1483 let fn_path = self.make_lang_item_qpath(hir::LangItem::RangeInclusiveNew, span, None);
1484 let fn_expr = self.arena.alloc(self.expr(span, hir::ExprKind::Path(fn_path)));
1485 hir::ExprKind::Call(fn_expr, arena_vec![self; e1, e2])
1486 }
1487
1488 fn lower_expr_range(
1489 &mut self,
1490 span: Span,
1491 e1: Option<&Expr>,
1492 e2: Option<&Expr>,
1493 lims: RangeLimits,
1494 ) -> hir::ExprKind<'hir> {
1495 use rustc_ast::RangeLimits::*;
1496
1497 let lang_item = match (e1, e2, lims) {
1498 (None, None, HalfOpen) => hir::LangItem::RangeFull,
1499 (Some(..), None, HalfOpen) => {
1500 if self.tcx.features().new_range() {
1501 hir::LangItem::RangeFromCopy
1502 } else {
1503 hir::LangItem::RangeFrom
1504 }
1505 }
1506 (None, Some(..), HalfOpen) => hir::LangItem::RangeTo,
1507 (Some(..), Some(..), HalfOpen) => {
1508 if self.tcx.features().new_range() {
1509 hir::LangItem::RangeCopy
1510 } else {
1511 hir::LangItem::Range
1512 }
1513 }
1514 (None, Some(..), Closed) => {
1515 if self.tcx.features().new_range() {
1516 hir::LangItem::RangeToInclusiveCopy
1517 } else {
1518 hir::LangItem::RangeToInclusive
1519 }
1520 }
1521 (Some(e1), Some(e2), Closed) => {
1522 if self.tcx.features().new_range() {
1523 hir::LangItem::RangeInclusiveCopy
1524 } else {
1525 return self.lower_expr_range_closed(span, e1, e2);
1526 }
1527 }
1528 (start, None, Closed) => {
1529 self.dcx().emit_err(InclusiveRangeWithNoEnd { span });
1530 match start {
1531 Some(..) => {
1532 if self.tcx.features().new_range() {
1533 hir::LangItem::RangeFromCopy
1534 } else {
1535 hir::LangItem::RangeFrom
1536 }
1537 }
1538 None => hir::LangItem::RangeFull,
1539 }
1540 }
1541 };
1542
1543 let fields = self.arena.alloc_from_iter(
1544 e1.iter()
1545 .map(|e| (sym::start, e))
1546 .chain(e2.iter().map(|e| {
1547 (
1548 if matches!(
1549 lang_item,
1550 hir::LangItem::RangeInclusiveCopy | hir::LangItem::RangeToInclusiveCopy
1551 ) {
1552 sym::last
1553 } else {
1554 sym::end
1555 },
1556 e,
1557 )
1558 }))
1559 .map(|(s, e)| {
1560 let span = self.lower_span(e.span);
1561 let span = self.mark_span_with_reason(DesugaringKind::RangeExpr, span, None);
1562 let expr = self.lower_expr(e);
1563 let ident = Ident::new(s, span);
1564 self.expr_field(ident, expr, span)
1565 }),
1566 );
1567
1568 hir::ExprKind::Struct(
1569 self.arena.alloc(self.make_lang_item_qpath(lang_item, span, None)),
1570 fields,
1571 hir::StructTailExpr::None,
1572 )
1573 }
1574
1575 fn lower_label(
1578 &mut self,
1579 opt_label: Option<Label>,
1580 dest_id: NodeId,
1581 dest_hir_id: hir::HirId,
1582 ) -> Option<Label> {
1583 let label = opt_label?;
1584 self.ident_and_label_to_local_id.insert(dest_id, dest_hir_id.local_id);
1585 Some(Label { ident: self.lower_ident(label.ident) })
1586 }
1587
1588 fn lower_loop_destination(&mut self, destination: Option<(NodeId, Label)>) -> hir::Destination {
1589 let target_id = match destination {
1590 Some((id, _)) => {
1591 if let Some(loop_id) = self.resolver.get_label_res(id) {
1592 let local_id = self.ident_and_label_to_local_id[&loop_id];
1593 let loop_hir_id = HirId { owner: self.current_hir_id_owner, local_id };
1594 Ok(loop_hir_id)
1595 } else {
1596 Err(hir::LoopIdError::UnresolvedLabel)
1597 }
1598 }
1599 None => {
1600 self.loop_scope.map(|id| Ok(id)).unwrap_or(Err(hir::LoopIdError::OutsideLoopScope))
1601 }
1602 };
1603 let label = destination
1604 .map(|(_, label)| label)
1605 .map(|label| Label { ident: self.lower_ident(label.ident) });
1606 hir::Destination { label, target_id }
1607 }
1608
1609 fn lower_jump_destination(&mut self, id: NodeId, opt_label: Option<Label>) -> hir::Destination {
1610 if self.is_in_loop_condition && opt_label.is_none() {
1611 hir::Destination {
1612 label: None,
1613 target_id: Err(hir::LoopIdError::UnlabeledCfInWhileCondition),
1614 }
1615 } else {
1616 self.lower_loop_destination(opt_label.map(|label| (id, label)))
1617 }
1618 }
1619
1620 fn with_catch_scope<T>(&mut self, catch_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1621 let old_scope = self.catch_scope.replace(catch_id);
1622 let result = f(self);
1623 self.catch_scope = old_scope;
1624 result
1625 }
1626
1627 fn with_loop_scope<T>(&mut self, loop_id: hir::HirId, f: impl FnOnce(&mut Self) -> T) -> T {
1628 let was_in_loop_condition = self.is_in_loop_condition;
1630 self.is_in_loop_condition = false;
1631
1632 let old_scope = self.loop_scope.replace(loop_id);
1633 let result = f(self);
1634 self.loop_scope = old_scope;
1635
1636 self.is_in_loop_condition = was_in_loop_condition;
1637
1638 result
1639 }
1640
1641 fn with_loop_condition_scope<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> T {
1642 let was_in_loop_condition = self.is_in_loop_condition;
1643 self.is_in_loop_condition = true;
1644
1645 let result = f(self);
1646
1647 self.is_in_loop_condition = was_in_loop_condition;
1648
1649 result
1650 }
1651
1652 fn lower_expr_field(&mut self, f: &ExprField) -> hir::ExprField<'hir> {
1653 let hir_id = self.lower_node_id(f.id);
1654 self.lower_attrs(hir_id, &f.attrs, f.span, Target::ExprField);
1655 hir::ExprField {
1656 hir_id,
1657 ident: self.lower_ident(f.ident),
1658 expr: self.lower_expr(&f.expr),
1659 span: self.lower_span(f.span),
1660 is_shorthand: f.is_shorthand,
1661 }
1662 }
1663
1664 fn lower_expr_yield(&mut self, span: Span, opt_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
1665 let yielded =
1666 opt_expr.as_ref().map(|x| self.lower_expr(x)).unwrap_or_else(|| self.expr_unit(span));
1667
1668 if !self.tcx.features().yield_expr()
1669 && !self.tcx.features().coroutines()
1670 && !self.tcx.features().gen_blocks()
1671 {
1672 rustc_session::parse::feature_err(
1673 &self.tcx.sess,
1674 sym::yield_expr,
1675 span,
1676 fluent_generated::ast_lowering_yield,
1677 )
1678 .emit();
1679 }
1680
1681 let is_async_gen = match self.coroutine_kind {
1682 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Gen, _)) => false,
1683 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _)) => true,
1684 Some(hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::Async, _)) => {
1685 let stmt_id = self.next_id();
1688 let expr_err = self.expr(
1689 yielded.span,
1690 hir::ExprKind::Err(self.dcx().emit_err(AsyncCoroutinesNotSupported { span })),
1691 );
1692 return hir::ExprKind::Block(
1693 self.block_all(
1694 yielded.span,
1695 arena_vec![self; hir::Stmt {
1696 hir_id: stmt_id,
1697 kind: hir::StmtKind::Semi(yielded),
1698 span: yielded.span,
1699 }],
1700 Some(self.arena.alloc(expr_err)),
1701 ),
1702 None,
1703 );
1704 }
1705 Some(hir::CoroutineKind::Coroutine(_)) => false,
1706 None => {
1707 let suggestion = self.current_item.map(|s| s.shrink_to_lo());
1708 self.dcx().emit_err(YieldInClosure { span, suggestion });
1709 self.coroutine_kind = Some(hir::CoroutineKind::Coroutine(Movability::Movable));
1710
1711 false
1712 }
1713 };
1714
1715 if is_async_gen {
1716 let desugar_span = self.mark_span_with_reason(
1720 DesugaringKind::Async,
1721 span,
1722 Some(Arc::clone(&self.allow_async_gen)),
1723 );
1724 let wrapped_yielded = self.expr_call_lang_item_fn(
1725 desugar_span,
1726 hir::LangItem::AsyncGenReady,
1727 std::slice::from_ref(yielded),
1728 );
1729 let yield_expr = self.arena.alloc(
1730 self.expr(span, hir::ExprKind::Yield(wrapped_yielded, hir::YieldSource::Yield)),
1731 );
1732
1733 let Some(task_context_hid) = self.task_context else {
1734 unreachable!("use of `await` outside of an async context.");
1735 };
1736 let task_context_ident = Ident::with_dummy_span(sym::_task_context);
1737 let lhs = self.expr_ident(desugar_span, task_context_ident, task_context_hid);
1738
1739 hir::ExprKind::Assign(lhs, yield_expr, self.lower_span(span))
1740 } else {
1741 hir::ExprKind::Yield(yielded, hir::YieldSource::Yield)
1742 }
1743 }
1744
1745 fn lower_expr_for(
1762 &mut self,
1763 e: &Expr,
1764 pat: &Pat,
1765 head: &Expr,
1766 body: &Block,
1767 opt_label: Option<Label>,
1768 loop_kind: ForLoopKind,
1769 ) -> hir::Expr<'hir> {
1770 let head = self.lower_expr_mut(head);
1771 let pat = self.lower_pat(pat);
1772 let for_span =
1773 self.mark_span_with_reason(DesugaringKind::ForLoop, self.lower_span(e.span), None);
1774 let for_ctxt = for_span.ctxt();
1775
1776 let head_span =
1779 head.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(head.span).with_ctxt(for_ctxt);
1780 let pat_span =
1781 pat.span.find_ancestor_in_same_ctxt(e.span).unwrap_or(pat.span).with_ctxt(for_ctxt);
1782
1783 let loop_hir_id = self.lower_node_id(e.id);
1784 let label = self.lower_label(opt_label, e.id, loop_hir_id);
1785
1786 let none_arm = {
1788 let break_expr =
1789 self.with_loop_scope(loop_hir_id, |this| this.expr_break_alloc(for_span));
1790 let pat = self.pat_none(for_span);
1791 self.arm(pat, break_expr)
1792 };
1793
1794 let some_arm = {
1796 let some_pat = self.pat_some(pat_span, pat);
1797 let body_block =
1798 self.with_loop_scope(loop_hir_id, |this| this.lower_block(body, false));
1799 let body_expr = self.arena.alloc(self.expr_block(body_block));
1800 self.arm(some_pat, body_expr)
1801 };
1802
1803 let iter = Ident::with_dummy_span(sym::iter);
1805 let (iter_pat, iter_pat_nid) =
1806 self.pat_ident_binding_mode(head_span, iter, hir::BindingMode::MUT);
1807
1808 let match_expr = {
1809 let iter = self.expr_ident(head_span, iter, iter_pat_nid);
1810 let next_expr = match loop_kind {
1811 ForLoopKind::For => {
1812 let ref_mut_iter = self.expr_mut_addr_of(head_span, iter);
1814 self.expr_call_lang_item_fn(
1815 head_span,
1816 hir::LangItem::IteratorNext,
1817 arena_vec![self; ref_mut_iter],
1818 )
1819 }
1820 ForLoopKind::ForAwait => {
1821 let iter = self.expr_mut_addr_of(head_span, iter);
1828 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1830 head_span,
1831 hir::LangItem::PinNewUnchecked,
1832 arena_vec![self; iter],
1833 ));
1834 let iter = self.arena.alloc(self.expr_unsafe(head_span, iter));
1836 let kind = self.make_lowered_await(head_span, iter, FutureKind::AsyncIterator);
1837 self.arena.alloc(hir::Expr { hir_id: self.next_id(), kind, span: head_span })
1838 }
1839 };
1840 let arms = arena_vec![self; none_arm, some_arm];
1841
1842 self.expr_match(head_span, next_expr, arms, hir::MatchSource::ForLoopDesugar)
1844 };
1845 let match_stmt = self.stmt_expr(for_span, match_expr);
1846
1847 let loop_block = self.block_all(for_span, arena_vec![self; match_stmt], None);
1848
1849 let kind = hir::ExprKind::Loop(
1851 loop_block,
1852 label,
1853 hir::LoopSource::ForLoop,
1854 self.lower_span(for_span.with_hi(head.span.hi())),
1855 );
1856 let loop_expr = self.arena.alloc(hir::Expr { hir_id: loop_hir_id, kind, span: for_span });
1857
1858 let iter_arm = self.arm(iter_pat, loop_expr);
1860
1861 let match_expr = match loop_kind {
1862 ForLoopKind::For => {
1863 let into_iter_expr = self.expr_call_lang_item_fn(
1865 head_span,
1866 hir::LangItem::IntoIterIntoIter,
1867 arena_vec![self; head],
1868 );
1869
1870 self.arena.alloc(self.expr_match(
1871 for_span,
1872 into_iter_expr,
1873 arena_vec![self; iter_arm],
1874 hir::MatchSource::ForLoopDesugar,
1875 ))
1876 }
1877 ForLoopKind::ForAwait => {
1879 let iter_ident = iter;
1880 let (async_iter_pat, async_iter_pat_id) =
1881 self.pat_ident_binding_mode(head_span, iter_ident, hir::BindingMode::REF_MUT);
1882 let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
1883 let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(
1885 head_span,
1886 hir::LangItem::PinNewUnchecked,
1887 arena_vec![self; iter],
1888 ));
1889 let iter = self.arena.alloc(self.expr_unsafe(head_span, iter));
1891 let inner_match_expr = self.arena.alloc(self.expr_match(
1892 for_span,
1893 iter,
1894 arena_vec![self; iter_arm],
1895 hir::MatchSource::ForLoopDesugar,
1896 ));
1897
1898 let iter = self.expr_call_lang_item_fn(
1900 head_span,
1901 hir::LangItem::IntoAsyncIterIntoIter,
1902 arena_vec![self; head],
1903 );
1904 let iter_arm = self.arm(async_iter_pat, inner_match_expr);
1905 self.arena.alloc(self.expr_match(
1906 for_span,
1907 iter,
1908 arena_vec![self; iter_arm],
1909 hir::MatchSource::ForLoopDesugar,
1910 ))
1911 }
1912 };
1913
1914 let expr = self.expr_drop_temps_mut(for_span, match_expr);
1921 self.lower_attrs(expr.hir_id, &e.attrs, e.span, Target::from_expr(e));
1922 expr
1923 }
1924
1925 fn lower_expr_try(&mut self, span: Span, sub_expr: &Expr) -> hir::ExprKind<'hir> {
1938 let unstable_span = self.mark_span_with_reason(
1939 DesugaringKind::QuestionMark,
1940 span,
1941 Some(Arc::clone(&self.allow_try_trait)),
1942 );
1943 let try_span = self.tcx.sess.source_map().end_point(span);
1944 let try_span = self.mark_span_with_reason(
1945 DesugaringKind::QuestionMark,
1946 try_span,
1947 Some(Arc::clone(&self.allow_try_trait)),
1948 );
1949
1950 let scrutinee = {
1952 let sub_expr = self.lower_expr_mut(sub_expr);
1954
1955 self.expr_call_lang_item_fn(
1956 unstable_span,
1957 hir::LangItem::TryTraitBranch,
1958 arena_vec![self; sub_expr],
1959 )
1960 };
1961
1962 let attrs: AttrVec = thin_vec![self.unreachable_code_attr(try_span)];
1963
1964 let continue_arm = {
1966 let val_ident = Ident::with_dummy_span(sym::val);
1967 let (val_pat, val_pat_nid) = self.pat_ident(span, val_ident);
1968 let val_expr = self.expr_ident(span, val_ident, val_pat_nid);
1969 self.lower_attrs(val_expr.hir_id, &attrs, span, Target::Expression);
1970 let continue_pat = self.pat_cf_continue(unstable_span, val_pat);
1971 self.arm(continue_pat, val_expr)
1972 };
1973
1974 let break_arm = {
1978 let residual_ident = Ident::with_dummy_span(sym::residual);
1979 let (residual_local, residual_local_nid) = self.pat_ident(try_span, residual_ident);
1980 let residual_expr = self.expr_ident_mut(try_span, residual_ident, residual_local_nid);
1981 let from_residual_expr = self.wrap_in_try_constructor(
1982 if self.catch_scope.is_some() {
1983 hir::LangItem::ResidualIntoTryType
1984 } else {
1985 hir::LangItem::TryTraitFromResidual
1986 },
1987 try_span,
1988 self.arena.alloc(residual_expr),
1989 unstable_span,
1990 );
1991 let ret_expr = if let Some(catch_id) = self.catch_scope {
1992 let target_id = Ok(catch_id);
1993 self.arena.alloc(self.expr(
1994 try_span,
1995 hir::ExprKind::Break(
1996 hir::Destination { label: None, target_id },
1997 Some(from_residual_expr),
1998 ),
1999 ))
2000 } else {
2001 let ret_expr = self.checked_return(Some(from_residual_expr));
2002 self.arena.alloc(self.expr(try_span, ret_expr))
2003 };
2004 self.lower_attrs(ret_expr.hir_id, &attrs, span, Target::Expression);
2005
2006 let break_pat = self.pat_cf_break(try_span, residual_local);
2007 self.arm(break_pat, ret_expr)
2008 };
2009
2010 hir::ExprKind::Match(
2011 scrutinee,
2012 arena_vec![self; break_arm, continue_arm],
2013 hir::MatchSource::TryDesugar(scrutinee.hir_id),
2014 )
2015 }
2016
2017 fn lower_expr_yeet(&mut self, span: Span, sub_expr: Option<&Expr>) -> hir::ExprKind<'hir> {
2027 let (yeeted_span, yeeted_expr) = if let Some(sub_expr) = sub_expr {
2029 (sub_expr.span, self.lower_expr(sub_expr))
2030 } else {
2031 (self.mark_span_with_reason(DesugaringKind::YeetExpr, span, None), self.expr_unit(span))
2032 };
2033
2034 let unstable_span = self.mark_span_with_reason(
2035 DesugaringKind::YeetExpr,
2036 span,
2037 Some(Arc::clone(&self.allow_try_trait)),
2038 );
2039
2040 let from_yeet_expr = self.wrap_in_try_constructor(
2041 hir::LangItem::TryTraitFromYeet,
2042 unstable_span,
2043 yeeted_expr,
2044 yeeted_span,
2045 );
2046
2047 if let Some(catch_id) = self.catch_scope {
2048 let target_id = Ok(catch_id);
2049 hir::ExprKind::Break(hir::Destination { label: None, target_id }, Some(from_yeet_expr))
2050 } else {
2051 self.checked_return(Some(from_yeet_expr))
2052 }
2053 }
2054
2055 pub(super) fn expr_drop_temps(
2067 &mut self,
2068 span: Span,
2069 expr: &'hir hir::Expr<'hir>,
2070 ) -> &'hir hir::Expr<'hir> {
2071 self.arena.alloc(self.expr_drop_temps_mut(span, expr))
2072 }
2073
2074 pub(super) fn expr_drop_temps_mut(
2075 &mut self,
2076 span: Span,
2077 expr: &'hir hir::Expr<'hir>,
2078 ) -> hir::Expr<'hir> {
2079 self.expr(span, hir::ExprKind::DropTemps(expr))
2080 }
2081
2082 pub(super) fn expr_match(
2083 &mut self,
2084 span: Span,
2085 arg: &'hir hir::Expr<'hir>,
2086 arms: &'hir [hir::Arm<'hir>],
2087 source: hir::MatchSource,
2088 ) -> hir::Expr<'hir> {
2089 self.expr(span, hir::ExprKind::Match(arg, arms, source))
2090 }
2091
2092 fn expr_break(&mut self, span: Span) -> hir::Expr<'hir> {
2093 let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
2094 self.expr(span, expr_break)
2095 }
2096
2097 fn expr_break_alloc(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2098 let expr_break = self.expr_break(span);
2099 self.arena.alloc(expr_break)
2100 }
2101
2102 fn expr_mut_addr_of(&mut self, span: Span, e: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2103 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e))
2104 }
2105
2106 pub(super) fn expr_unit(&mut self, sp: Span) -> &'hir hir::Expr<'hir> {
2107 self.arena.alloc(self.expr(sp, hir::ExprKind::Tup(&[])))
2108 }
2109
2110 pub(super) fn expr_str(&mut self, sp: Span, value: Symbol) -> hir::Expr<'hir> {
2111 let lit = hir::Lit {
2112 span: self.lower_span(sp),
2113 node: ast::LitKind::Str(value, ast::StrStyle::Cooked),
2114 };
2115 self.expr(sp, hir::ExprKind::Lit(lit))
2116 }
2117
2118 pub(super) fn expr_byte_str(&mut self, sp: Span, value: ByteSymbol) -> hir::Expr<'hir> {
2119 let lit = hir::Lit {
2120 span: self.lower_span(sp),
2121 node: ast::LitKind::ByteStr(value, ast::StrStyle::Cooked),
2122 };
2123 self.expr(sp, hir::ExprKind::Lit(lit))
2124 }
2125
2126 pub(super) fn expr_call_mut(
2127 &mut self,
2128 span: Span,
2129 e: &'hir hir::Expr<'hir>,
2130 args: &'hir [hir::Expr<'hir>],
2131 ) -> hir::Expr<'hir> {
2132 self.expr(span, hir::ExprKind::Call(e, args))
2133 }
2134
2135 pub(super) fn expr_struct(
2136 &mut self,
2137 span: Span,
2138 path: &'hir hir::QPath<'hir>,
2139 fields: &'hir [hir::ExprField<'hir>],
2140 ) -> hir::Expr<'hir> {
2141 self.expr(span, hir::ExprKind::Struct(path, fields, rustc_hir::StructTailExpr::None))
2142 }
2143
2144 pub(super) fn expr_enum_variant(
2145 &mut self,
2146 span: Span,
2147 path: &'hir hir::QPath<'hir>,
2148 fields: &'hir [hir::Expr<'hir>],
2149 ) -> hir::Expr<'hir> {
2150 let fields = self.arena.alloc_from_iter(fields.into_iter().enumerate().map(|(i, f)| {
2151 hir::ExprField {
2152 hir_id: self.next_id(),
2153 ident: Ident::from_str(&i.to_string()),
2154 expr: f,
2155 span: f.span,
2156 is_shorthand: false,
2157 }
2158 }));
2159 self.expr_struct(span, path, fields)
2160 }
2161
2162 pub(super) fn expr_enum_variant_lang_item(
2163 &mut self,
2164 span: Span,
2165 lang_item: hir::LangItem,
2166 fields: &'hir [hir::Expr<'hir>],
2167 ) -> hir::Expr<'hir> {
2168 let path = self.arena.alloc(self.make_lang_item_qpath(lang_item, span, None));
2169 self.expr_enum_variant(span, path, fields)
2170 }
2171
2172 pub(super) fn expr_call(
2173 &mut self,
2174 span: Span,
2175 e: &'hir hir::Expr<'hir>,
2176 args: &'hir [hir::Expr<'hir>],
2177 ) -> &'hir hir::Expr<'hir> {
2178 self.arena.alloc(self.expr_call_mut(span, e, args))
2179 }
2180
2181 pub(super) fn expr_call_lang_item_fn_mut(
2182 &mut self,
2183 span: Span,
2184 lang_item: hir::LangItem,
2185 args: &'hir [hir::Expr<'hir>],
2186 ) -> hir::Expr<'hir> {
2187 let path = self.arena.alloc(self.expr_lang_item_path(span, lang_item));
2188 self.expr_call_mut(span, path, args)
2189 }
2190
2191 pub(super) fn expr_call_lang_item_fn(
2192 &mut self,
2193 span: Span,
2194 lang_item: hir::LangItem,
2195 args: &'hir [hir::Expr<'hir>],
2196 ) -> &'hir hir::Expr<'hir> {
2197 self.arena.alloc(self.expr_call_lang_item_fn_mut(span, lang_item, args))
2198 }
2199
2200 pub(super) fn expr_lang_item_path(
2201 &mut self,
2202 span: Span,
2203 lang_item: hir::LangItem,
2204 ) -> hir::Expr<'hir> {
2205 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2206 self.expr(span, hir::ExprKind::Path(qpath))
2207 }
2208
2209 pub(super) fn expr_lang_item_type_relative(
2211 &mut self,
2212 span: Span,
2213 lang_item: hir::LangItem,
2214 name: Symbol,
2215 ) -> hir::Expr<'hir> {
2216 let qpath = self.make_lang_item_qpath(lang_item, self.lower_span(span), None);
2217 let path = hir::ExprKind::Path(hir::QPath::TypeRelative(
2218 self.arena.alloc(self.ty(span, hir::TyKind::Path(qpath))),
2219 self.arena.alloc(hir::PathSegment::new(
2220 Ident::new(name, self.lower_span(span)),
2221 self.next_id(),
2222 Res::Err,
2223 )),
2224 ));
2225 self.expr(span, path)
2226 }
2227
2228 pub(super) fn expr_ident(
2229 &mut self,
2230 sp: Span,
2231 ident: Ident,
2232 binding: HirId,
2233 ) -> &'hir hir::Expr<'hir> {
2234 self.arena.alloc(self.expr_ident_mut(sp, ident, binding))
2235 }
2236
2237 pub(super) fn expr_ident_mut(
2238 &mut self,
2239 span: Span,
2240 ident: Ident,
2241 binding: HirId,
2242 ) -> hir::Expr<'hir> {
2243 let hir_id = self.next_id();
2244 let res = Res::Local(binding);
2245 let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
2246 None,
2247 self.arena.alloc(hir::Path {
2248 span: self.lower_span(span),
2249 res,
2250 segments: arena_vec![self; hir::PathSegment::new(self.lower_ident(ident), hir_id, res)],
2251 }),
2252 ));
2253
2254 self.expr(span, expr_path)
2255 }
2256
2257 pub(super) fn expr_unsafe(
2258 &mut self,
2259 span: Span,
2260 expr: &'hir hir::Expr<'hir>,
2261 ) -> hir::Expr<'hir> {
2262 let hir_id = self.next_id();
2263 self.expr(
2264 span,
2265 hir::ExprKind::Block(
2266 self.arena.alloc(hir::Block {
2267 stmts: &[],
2268 expr: Some(expr),
2269 hir_id,
2270 rules: hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::CompilerGenerated),
2271 span: self.lower_span(span),
2272 targeted_by_break: false,
2273 }),
2274 None,
2275 ),
2276 )
2277 }
2278
2279 fn expr_block_empty(&mut self, span: Span) -> &'hir hir::Expr<'hir> {
2280 let blk = self.block_all(span, &[], None);
2281 let expr = self.expr_block(blk);
2282 self.arena.alloc(expr)
2283 }
2284
2285 pub(super) fn expr_block(&mut self, b: &'hir hir::Block<'hir>) -> hir::Expr<'hir> {
2286 self.expr(b.span, hir::ExprKind::Block(b, None))
2287 }
2288
2289 pub(super) fn block_expr_block(
2293 &mut self,
2294 expr: &'hir hir::Expr<'hir>,
2295 ) -> &'hir hir::Expr<'hir> {
2296 let b = self.block_expr(expr);
2297 self.arena.alloc(self.expr_block(b))
2298 }
2299
2300 pub(super) fn expr_ref(&mut self, span: Span, expr: &'hir hir::Expr<'hir>) -> hir::Expr<'hir> {
2301 self.expr(span, hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, expr))
2302 }
2303
2304 pub(super) fn expr_bool_literal(&mut self, span: Span, val: bool) -> hir::Expr<'hir> {
2305 self.expr(span, hir::ExprKind::Lit(Spanned { node: LitKind::Bool(val), span }))
2306 }
2307
2308 pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind<'hir>) -> hir::Expr<'hir> {
2309 let hir_id = self.next_id();
2310 hir::Expr { hir_id, kind, span: self.lower_span(span) }
2311 }
2312
2313 pub(super) fn expr_field(
2314 &mut self,
2315 ident: Ident,
2316 expr: &'hir hir::Expr<'hir>,
2317 span: Span,
2318 ) -> hir::ExprField<'hir> {
2319 hir::ExprField {
2320 hir_id: self.next_id(),
2321 ident,
2322 span: self.lower_span(span),
2323 expr,
2324 is_shorthand: false,
2325 }
2326 }
2327
2328 pub(super) fn arm(
2329 &mut self,
2330 pat: &'hir hir::Pat<'hir>,
2331 expr: &'hir hir::Expr<'hir>,
2332 ) -> hir::Arm<'hir> {
2333 hir::Arm {
2334 hir_id: self.next_id(),
2335 pat,
2336 guard: None,
2337 span: self.lower_span(expr.span),
2338 body: expr,
2339 }
2340 }
2341
2342 pub(super) fn unreachable_code_attr(&mut self, span: Span) -> Attribute {
2344 let attr = attr::mk_attr_nested_word(
2345 &self.tcx.sess.psess.attr_id_generator,
2346 AttrStyle::Outer,
2347 Safety::Default,
2348 sym::allow,
2349 sym::unreachable_code,
2350 span,
2351 );
2352 attr
2353 }
2354}
2355
2356#[derive(Copy, Clone, Debug, PartialEq, Eq)]
2359enum FutureKind {
2360 Future,
2362 AsyncIterator,
2365}