2 use crate::ty::subst::SubstsRef;
3 use crate::ty::{CanonicalUserTypeAnnotation, Ty};
10 // There are two visitors, one for immutable and one for mutable references,
11 // but both are generated by the following macro. The code is written according
12 // to the following conventions:
14 // - introduce a `visit_foo` and a `super_foo` method for every MIR type
15 // - `visit_foo`, by default, calls `super_foo`
16 // - `super_foo`, by default, destructures the `foo` and calls `visit_foo`
18 // This allows you as a user to override `visit_foo` for types are
19 // interested in, and invoke (within that method) call
20 // `self.super_foo` to get the default behavior. Just as in an OO
21 // language, you should never call `super` methods ordinarily except
22 // in that circumstance.
24 // For the most part, we do not destructure things external to the
25 // MIR, e.g., types, spans, etc, but simply visit them and stop. This
26 // avoids duplication with other visitors like `TypeFoldable`.
30 // The code is written in a very deliberate style intended to minimize
31 // the chance of things being overlooked. You'll notice that we always
32 // use pattern matching to reference fields and we ensure that all
33 // matches are exhaustive.
35 // For example, the `super_basic_block_data` method begins like this:
38 // fn super_basic_block_data(&mut self,
40 // data: & $($mutability)? BasicBlockData<'tcx>) {
41 // let BasicBlockData {
47 // for statement in statements {
48 // self.visit_statement(block, statement);
55 // Here we used `let BasicBlockData { <fields> } = *data` deliberately,
56 // rather than writing `data.statements` in the body. This is because if one
57 // adds a new field to `BasicBlockData`, one will be forced to revise this code,
58 // and hence one will (hopefully) invoke the correct visit methods (if any).
60 // For this to work, ALL MATCHES MUST BE EXHAUSTIVE IN FIELDS AND VARIANTS.
61 // That means you never write `..` to skip over fields, nor do you write `_`
62 // to skip over variants in a `match`.
64 // The only place that `_` is acceptable is to match a field (or
65 // variant argument) that does not require visiting, as in
66 // `is_cleanup` above.
68 macro_rules! make_mir_visitor {
69 ($visitor_trait_name:ident, $($mutability:ident)?) => {
70 pub trait $visitor_trait_name<'tcx> {
71 // Override these, and call `self.super_xxx` to revert back to the
76 body: &$($mutability)? Body<'tcx>,
78 self.super_body(body);
81 fn visit_basic_block_data(&mut self,
83 data: & $($mutability)? BasicBlockData<'tcx>) {
84 self.super_basic_block_data(block, data);
87 fn visit_source_scope_data(&mut self,
88 scope_data: & $($mutability)? SourceScopeData) {
89 self.super_source_scope_data(scope_data);
92 fn visit_statement(&mut self,
93 statement: & $($mutability)? Statement<'tcx>,
95 self.super_statement(statement, location);
98 fn visit_assign(&mut self,
99 place: & $($mutability)? Place<'tcx>,
100 rvalue: & $($mutability)? Rvalue<'tcx>,
101 location: Location) {
102 self.super_assign(place, rvalue, location);
105 fn visit_terminator(&mut self,
106 terminator: & $($mutability)? Terminator<'tcx>,
107 location: Location) {
108 self.super_terminator(terminator, location);
111 fn visit_assert_message(&mut self,
112 msg: & $($mutability)? AssertMessage<'tcx>,
113 location: Location) {
114 self.super_assert_message(msg, location);
117 fn visit_rvalue(&mut self,
118 rvalue: & $($mutability)? Rvalue<'tcx>,
119 location: Location) {
120 self.super_rvalue(rvalue, location);
123 fn visit_operand(&mut self,
124 operand: & $($mutability)? Operand<'tcx>,
125 location: Location) {
126 self.super_operand(operand, location);
129 fn visit_ascribe_user_ty(&mut self,
130 place: & $($mutability)? Place<'tcx>,
131 variance: & $($mutability)? ty::Variance,
132 user_ty: & $($mutability)? UserTypeProjection,
133 location: Location) {
134 self.super_ascribe_user_ty(place, variance, user_ty, location);
137 fn visit_coverage(&mut self,
138 coverage: & $($mutability)? Coverage,
139 location: Location) {
140 self.super_coverage(coverage, location);
143 fn visit_retag(&mut self,
144 kind: & $($mutability)? RetagKind,
145 place: & $($mutability)? Place<'tcx>,
146 location: Location) {
147 self.super_retag(kind, place, location);
150 fn visit_place(&mut self,
151 place: & $($mutability)? Place<'tcx>,
152 context: PlaceContext,
153 location: Location) {
154 self.super_place(place, context, location);
157 visit_place_fns!($($mutability)?);
159 fn visit_constant(&mut self,
160 constant: & $($mutability)? Constant<'tcx>,
161 location: Location) {
162 self.super_constant(constant, location);
165 fn visit_span(&mut self,
166 span: & $($mutability)? Span) {
167 self.super_span(span);
170 fn visit_source_info(&mut self,
171 source_info: & $($mutability)? SourceInfo) {
172 self.super_source_info(source_info);
175 fn visit_ty(&mut self,
176 ty: $(& $mutability)? Ty<'tcx>,
181 fn visit_user_type_projection(
183 ty: & $($mutability)? UserTypeProjection,
185 self.super_user_type_projection(ty);
188 fn visit_user_type_annotation(
190 index: UserTypeAnnotationIndex,
191 ty: & $($mutability)? CanonicalUserTypeAnnotation<'tcx>,
193 self.super_user_type_annotation(index, ty);
196 fn visit_region(&mut self,
197 region: & $($mutability)? ty::Region<'tcx>,
199 self.super_region(region);
202 fn visit_const(&mut self,
203 constant: & $($mutability)? &'tcx ty::Const<'tcx>,
205 self.super_const(constant);
208 fn visit_substs(&mut self,
209 substs: & $($mutability)? SubstsRef<'tcx>,
211 self.super_substs(substs);
214 fn visit_local_decl(&mut self,
216 local_decl: & $($mutability)? LocalDecl<'tcx>) {
217 self.super_local_decl(local, local_decl);
220 fn visit_var_debug_info(&mut self,
221 var_debug_info: & $($mutability)* VarDebugInfo<'tcx>) {
222 self.super_var_debug_info(var_debug_info);
225 fn visit_local(&mut self,
226 _local: & $($mutability)? Local,
227 _context: PlaceContext,
228 _location: Location) {
231 fn visit_source_scope(&mut self,
232 scope: & $($mutability)? SourceScope) {
233 self.super_source_scope(scope);
236 // The `super_xxx` methods comprise the default behavior and are
237 // not meant to be overridden.
241 body: &$($mutability)? Body<'tcx>,
243 let span = body.span;
244 if let Some(yield_ty) = &$($mutability)? body.yield_ty {
247 TyContext::YieldTy(SourceInfo::outermost(span))
251 // for best performance, we want to use an iterator rather
252 // than a for-loop, to avoid calling `body::Body::invalidate` for
254 macro_rules! basic_blocks {
255 (mut) => (body.basic_blocks_mut().iter_enumerated_mut());
256 () => (body.basic_blocks().iter_enumerated());
258 for (bb, data) in basic_blocks!($($mutability)?) {
259 self.visit_basic_block_data(bb, data);
262 for scope in &$($mutability)? body.source_scopes {
263 self.visit_source_scope_data(scope);
267 &$($mutability)? body.return_ty(),
268 TyContext::ReturnTy(SourceInfo::outermost(body.span))
271 for local in body.local_decls.indices() {
272 self.visit_local_decl(local, & $($mutability)? body.local_decls[local]);
275 macro_rules! type_annotations {
276 (mut) => (body.user_type_annotations.iter_enumerated_mut());
277 () => (body.user_type_annotations.iter_enumerated());
280 for (index, annotation) in type_annotations!($($mutability)?) {
281 self.visit_user_type_annotation(
286 for var_debug_info in &$($mutability)? body.var_debug_info {
287 self.visit_var_debug_info(var_debug_info);
290 self.visit_span(&$($mutability)? body.span);
292 for const_ in &$($mutability)? body.required_consts {
293 let location = START_BLOCK.start_location();
294 self.visit_constant(const_, location);
298 fn super_basic_block_data(&mut self,
300 data: & $($mutability)? BasicBlockData<'tcx>) {
308 for statement in statements {
309 let location = Location { block: block, statement_index: index };
310 self.visit_statement(statement, location);
314 if let Some(terminator) = terminator {
315 let location = Location { block: block, statement_index: index };
316 self.visit_terminator(terminator, location);
320 fn super_source_scope_data(&mut self, scope_data: & $($mutability)? SourceScopeData) {
321 let SourceScopeData {
327 self.visit_span(span);
328 if let Some(parent_scope) = parent_scope {
329 self.visit_source_scope(parent_scope);
333 fn super_statement(&mut self,
334 statement: & $($mutability)? Statement<'tcx>,
335 location: Location) {
341 self.visit_source_info(source_info);
343 StatementKind::Assign(
344 box(ref $($mutability)? place, ref $($mutability)? rvalue)
346 self.visit_assign(place, rvalue, location);
348 StatementKind::FakeRead(_, place) => {
351 PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
355 StatementKind::SetDiscriminant { place, .. } => {
358 PlaceContext::MutatingUse(MutatingUseContext::Store),
362 StatementKind::StorageLive(local) => {
365 PlaceContext::NonUse(NonUseContext::StorageLive),
369 StatementKind::StorageDead(local) => {
372 PlaceContext::NonUse(NonUseContext::StorageDead),
376 StatementKind::LlvmInlineAsm(asm) => {
377 for output in & $($mutability)? asm.outputs[..] {
380 PlaceContext::MutatingUse(MutatingUseContext::AsmOutput),
384 for (span, input) in & $($mutability)? asm.inputs[..] {
385 self.visit_span(span);
386 self.visit_operand(input, location);
389 StatementKind::Retag(kind, place) => {
390 self.visit_retag(kind, place, location);
392 StatementKind::AscribeUserType(
393 box(ref $($mutability)? place, ref $($mutability)? user_ty),
396 self.visit_ascribe_user_ty(place, variance, user_ty, location);
398 StatementKind::Coverage(coverage) => {
404 StatementKind::Nop => {}
408 fn super_assign(&mut self,
409 place: &$($mutability)? Place<'tcx>,
410 rvalue: &$($mutability)? Rvalue<'tcx>,
411 location: Location) {
414 PlaceContext::MutatingUse(MutatingUseContext::Store),
417 self.visit_rvalue(rvalue, location);
420 fn super_terminator(&mut self,
421 terminator: &$($mutability)? Terminator<'tcx>,
422 location: Location) {
423 let Terminator { source_info, kind } = terminator;
425 self.visit_source_info(source_info);
427 TerminatorKind::Goto { .. } |
428 TerminatorKind::Resume |
429 TerminatorKind::Abort |
430 TerminatorKind::GeneratorDrop |
431 TerminatorKind::Unreachable |
432 TerminatorKind::FalseEdge { .. } |
433 TerminatorKind::FalseUnwind { .. } => {
436 TerminatorKind::Return => {
437 // `return` logically moves from the return place `_0`. Note that the place
438 // cannot be changed by any visitor, though.
439 let $($mutability)? local = RETURN_PLACE;
441 & $($mutability)? local,
442 PlaceContext::NonMutatingUse(NonMutatingUseContext::Move),
449 "`MutVisitor` tried to mutate return place of `return` terminator"
453 TerminatorKind::SwitchInt {
459 self.visit_operand(discr, location);
460 self.visit_ty(switch_ty, TyContext::Location(location));
463 TerminatorKind::Drop {
470 PlaceContext::MutatingUse(MutatingUseContext::Drop),
475 TerminatorKind::DropAndReplace {
483 PlaceContext::MutatingUse(MutatingUseContext::Drop),
486 self.visit_operand(value, location);
489 TerminatorKind::Call {
497 self.visit_operand(func, location);
499 self.visit_operand(arg, location);
501 if let Some((destination, _)) = destination {
504 PlaceContext::MutatingUse(MutatingUseContext::Call),
510 TerminatorKind::Assert {
517 self.visit_operand(cond, location);
518 self.visit_assert_message(msg, location);
521 TerminatorKind::Yield {
527 self.visit_operand(value, location);
530 PlaceContext::MutatingUse(MutatingUseContext::Yield),
535 TerminatorKind::InlineAsm {
544 InlineAsmOperand::In { value, .. }
545 | InlineAsmOperand::Const { value } => {
546 self.visit_operand(value, location);
548 InlineAsmOperand::Out { place, .. } => {
549 if let Some(place) = place {
552 PlaceContext::MutatingUse(MutatingUseContext::Store),
557 InlineAsmOperand::InOut { in_value, out_place, .. } => {
558 self.visit_operand(in_value, location);
559 if let Some(out_place) = out_place {
562 PlaceContext::MutatingUse(MutatingUseContext::Store),
567 InlineAsmOperand::SymFn { value } => {
568 self.visit_constant(value, location);
570 InlineAsmOperand::SymStatic { def_id: _ } => {}
577 fn super_assert_message(&mut self,
578 msg: & $($mutability)? AssertMessage<'tcx>,
579 location: Location) {
580 use crate::mir::AssertKind::*;
582 BoundsCheck { len, index } => {
583 self.visit_operand(len, location);
584 self.visit_operand(index, location);
586 Overflow(_, l, r) => {
587 self.visit_operand(l, location);
588 self.visit_operand(r, location);
590 OverflowNeg(op) | DivisionByZero(op) | RemainderByZero(op) => {
591 self.visit_operand(op, location);
593 ResumedAfterReturn(_) | ResumedAfterPanic(_) => {
599 fn super_rvalue(&mut self,
600 rvalue: & $($mutability)? Rvalue<'tcx>,
601 location: Location) {
603 Rvalue::Use(operand) => {
604 self.visit_operand(operand, location);
607 Rvalue::Repeat(value, _) => {
608 self.visit_operand(value, location);
611 Rvalue::ThreadLocalRef(_) => {}
613 Rvalue::Ref(r, bk, path) => {
614 self.visit_region(r, location);
616 BorrowKind::Shared => PlaceContext::NonMutatingUse(
617 NonMutatingUseContext::SharedBorrow
619 BorrowKind::Shallow => PlaceContext::NonMutatingUse(
620 NonMutatingUseContext::ShallowBorrow
622 BorrowKind::Unique => PlaceContext::NonMutatingUse(
623 NonMutatingUseContext::UniqueBorrow
625 BorrowKind::Mut { .. } =>
626 PlaceContext::MutatingUse(MutatingUseContext::Borrow),
628 self.visit_place(path, ctx, location);
631 Rvalue::AddressOf(m, path) => {
633 Mutability::Mut => PlaceContext::MutatingUse(
634 MutatingUseContext::AddressOf
636 Mutability::Not => PlaceContext::NonMutatingUse(
637 NonMutatingUseContext::AddressOf
640 self.visit_place(path, ctx, location);
643 Rvalue::Len(path) => {
646 PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
651 Rvalue::Cast(_cast_kind, operand, ty) => {
652 self.visit_operand(operand, location);
653 self.visit_ty(ty, TyContext::Location(location));
656 Rvalue::BinaryOp(_bin_op, lhs, rhs)
657 | Rvalue::CheckedBinaryOp(_bin_op, lhs, rhs) => {
658 self.visit_operand(lhs, location);
659 self.visit_operand(rhs, location);
662 Rvalue::UnaryOp(_un_op, op) => {
663 self.visit_operand(op, location);
666 Rvalue::Discriminant(place) => {
669 PlaceContext::NonMutatingUse(NonMutatingUseContext::Inspect),
674 Rvalue::NullaryOp(_op, ty) => {
675 self.visit_ty(ty, TyContext::Location(location));
678 Rvalue::Aggregate(kind, operands) => {
679 let kind = &$($mutability)? **kind;
681 AggregateKind::Array(ty) => {
682 self.visit_ty(ty, TyContext::Location(location));
684 AggregateKind::Tuple => {
693 self.visit_substs(substs, location);
695 AggregateKind::Closure(
699 self.visit_substs(closure_substs, location);
701 AggregateKind::Generator(
706 self.visit_substs(generator_substs, location);
710 for operand in operands {
711 self.visit_operand(operand, location);
717 fn super_operand(&mut self,
718 operand: & $($mutability)? Operand<'tcx>,
719 location: Location) {
721 Operand::Copy(place) => {
724 PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy),
728 Operand::Move(place) => {
731 PlaceContext::NonMutatingUse(NonMutatingUseContext::Move),
735 Operand::Constant(constant) => {
736 self.visit_constant(constant, location);
741 fn super_ascribe_user_ty(&mut self,
742 place: & $($mutability)? Place<'tcx>,
743 _variance: & $($mutability)? ty::Variance,
744 user_ty: & $($mutability)? UserTypeProjection,
745 location: Location) {
748 PlaceContext::NonUse(NonUseContext::AscribeUserTy),
751 self.visit_user_type_projection(user_ty);
754 fn super_coverage(&mut self,
755 _coverage: & $($mutability)? Coverage,
756 _location: Location) {
759 fn super_retag(&mut self,
760 _kind: & $($mutability)? RetagKind,
761 place: & $($mutability)? Place<'tcx>,
762 location: Location) {
765 PlaceContext::MutatingUse(MutatingUseContext::Retag),
770 fn super_local_decl(&mut self,
772 local_decl: & $($mutability)? LocalDecl<'tcx>) {
783 self.visit_ty(ty, TyContext::LocalDecl {
785 source_info: *source_info,
787 if let Some(user_ty) = user_ty {
788 for (user_ty, _) in & $($mutability)? user_ty.contents {
789 self.visit_user_type_projection(user_ty);
792 self.visit_source_info(source_info);
795 fn super_var_debug_info(&mut self,
796 var_debug_info: & $($mutability)? VarDebugInfo<'tcx>) {
803 self.visit_source_info(source_info);
804 let location = START_BLOCK.start_location();
807 PlaceContext::NonUse(NonUseContext::VarDebugInfo),
812 fn super_source_scope(&mut self,
813 _scope: & $($mutability)? SourceScope) {
816 fn super_constant(&mut self,
817 constant: & $($mutability)? Constant<'tcx>,
818 location: Location) {
825 self.visit_span(span);
826 drop(user_ty); // no visit method for this
827 self.visit_const(literal, location);
830 fn super_span(&mut self, _span: & $($mutability)? Span) {
833 fn super_source_info(&mut self, source_info: & $($mutability)? SourceInfo) {
839 self.visit_span(span);
840 self.visit_source_scope(scope);
843 fn super_user_type_projection(
845 _ty: & $($mutability)? UserTypeProjection,
849 fn super_user_type_annotation(
851 _index: UserTypeAnnotationIndex,
852 ty: & $($mutability)? CanonicalUserTypeAnnotation<'tcx>,
854 self.visit_span(& $($mutability)? ty.span);
855 self.visit_ty(& $($mutability)? ty.inferred_ty, TyContext::UserTy(ty.span));
858 fn super_ty(&mut self, _ty: $(& $mutability)? Ty<'tcx>) {
861 fn super_region(&mut self, _region: & $($mutability)? ty::Region<'tcx>) {
864 fn super_const(&mut self, _const: & $($mutability)? &'tcx ty::Const<'tcx>) {
867 fn super_substs(&mut self, _substs: & $($mutability)? SubstsRef<'tcx>) {
870 // Convenience methods
874 body: &$($mutability)? Body<'tcx>,
877 macro_rules! basic_blocks {
878 (mut) => (body.basic_blocks_mut());
879 () => (body.basic_blocks());
881 let basic_block = & $($mutability)? basic_blocks!($($mutability)?)[location.block];
882 if basic_block.statements.len() == location.statement_index {
883 if let Some(ref $($mutability)? terminator) = basic_block.terminator {
884 self.visit_terminator(terminator, location)
887 let statement = & $($mutability)?
888 basic_block.statements[location.statement_index];
889 self.visit_statement(statement, location)
896 macro_rules! visit_place_fns {
898 fn tcx<'a>(&'a self) -> TyCtxt<'tcx>;
902 place: &mut Place<'tcx>,
903 context: PlaceContext,
906 self.visit_local(&mut place.local, context, location);
908 if let Some(new_projection) = self.process_projection(&place.projection, location) {
909 place.projection = self.tcx().intern_place_elems(&new_projection);
913 fn process_projection(
915 projection: &'a [PlaceElem<'tcx>],
917 ) -> Option<Vec<PlaceElem<'tcx>>> {
918 let mut projection = Cow::Borrowed(projection);
920 for i in 0..projection.len() {
921 if let Some(&elem) = projection.get(i) {
922 if let Some(elem) = self.process_projection_elem(elem, location) {
923 // This converts the borrowed projection into `Cow::Owned(_)` and returns a
924 // clone of the projection so we can mutate and reintern later.
925 let vec = projection.to_mut();
932 Cow::Borrowed(_) => None,
933 Cow::Owned(vec) => Some(vec),
937 fn process_projection_elem(
939 elem: PlaceElem<'tcx>,
941 ) -> Option<PlaceElem<'tcx>> {
943 PlaceElem::Index(local) => {
944 let mut new_local = local;
947 PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy),
951 if new_local == local { None } else { Some(PlaceElem::Index(new_local)) }
954 | PlaceElem::Field(..)
955 | PlaceElem::ConstantIndex { .. }
956 | PlaceElem::Subslice { .. }
957 | PlaceElem::Downcast(..) => None,
966 projection: &[PlaceElem<'tcx>],
967 context: PlaceContext,
970 self.super_projection(local, projection, context, location);
973 fn visit_projection_elem(
976 proj_base: &[PlaceElem<'tcx>],
977 elem: PlaceElem<'tcx>,
978 context: PlaceContext,
981 self.super_projection_elem(local, proj_base, elem, context, location);
984 fn super_place(&mut self, place: &Place<'tcx>, context: PlaceContext, location: Location) {
985 let mut context = context;
987 if !place.projection.is_empty() {
988 context = if context.is_mutating_use() {
989 PlaceContext::MutatingUse(MutatingUseContext::Projection)
991 PlaceContext::NonMutatingUse(NonMutatingUseContext::Projection)
995 self.visit_local(&place.local, context, location);
997 self.visit_projection(place.local, &place.projection, context, location);
1000 fn super_projection(
1003 projection: &[PlaceElem<'tcx>],
1004 context: PlaceContext,
1007 let mut cursor = projection;
1008 while let &[ref proj_base @ .., elem] = cursor {
1010 self.visit_projection_elem(local, cursor, elem, context, location);
1014 fn super_projection_elem(
1017 _proj_base: &[PlaceElem<'tcx>],
1018 elem: PlaceElem<'tcx>,
1019 _context: PlaceContext,
1023 ProjectionElem::Field(_field, ty) => {
1024 self.visit_ty(ty, TyContext::Location(location));
1026 ProjectionElem::Index(local) => {
1029 PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy),
1033 ProjectionElem::Deref
1034 | ProjectionElem::Subslice { from: _, to: _, from_end: _ }
1035 | ProjectionElem::ConstantIndex { offset: _, min_length: _, from_end: _ }
1036 | ProjectionElem::Downcast(_, _) => {}
1042 make_mir_visitor!(Visitor,);
1043 make_mir_visitor!(MutVisitor, mut);
1045 pub trait MirVisitable<'tcx> {
1046 fn apply(&self, location: Location, visitor: &mut dyn Visitor<'tcx>);
1049 impl<'tcx> MirVisitable<'tcx> for Statement<'tcx> {
1050 fn apply(&self, location: Location, visitor: &mut dyn Visitor<'tcx>) {
1051 visitor.visit_statement(self, location)
1055 impl<'tcx> MirVisitable<'tcx> for Terminator<'tcx> {
1056 fn apply(&self, location: Location, visitor: &mut dyn Visitor<'tcx>) {
1057 visitor.visit_terminator(self, location)
1061 impl<'tcx> MirVisitable<'tcx> for Option<Terminator<'tcx>> {
1062 fn apply(&self, location: Location, visitor: &mut dyn Visitor<'tcx>) {
1063 visitor.visit_terminator(self.as_ref().unwrap(), location)
1067 /// Extra information passed to `visit_ty` and friends to give context
1068 /// about where the type etc appears.
1070 pub enum TyContext {
1072 /// The index of the local variable we are visiting.
1075 /// The source location where this local variable was declared.
1076 source_info: SourceInfo,
1079 /// The inferred type of a user type annotation.
1082 /// The return type of the function.
1083 ReturnTy(SourceInfo),
1085 YieldTy(SourceInfo),
1087 /// A type found at some location.
1091 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1092 pub enum NonMutatingUseContext {
1093 /// Being inspected in some way, like loading a len.
1095 /// Consumed as part of an operand.
1097 /// Consumed as part of an operand.
1105 /// AddressOf for *const pointer.
1107 /// Used as base for another place, e.g., `x` in `x.y`. Will not mutate the place.
1108 /// For example, the projection `x.y` is not marked as a mutation in these cases:
1116 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1117 pub enum MutatingUseContext {
1118 /// Appears as LHS of an assignment.
1120 /// Can often be treated as a `Store`, but needs to be separate because
1121 /// ASM is allowed to read outputs as well, so a `Store`-`AsmOutput` sequence
1122 /// cannot be simplified the way a `Store`-`Store` can be.
1124 /// Destination of a call.
1126 /// Destination of a yield.
1132 /// AddressOf for *mut pointer.
1134 /// Used as base for another place, e.g., `x` in `x.y`. Could potentially mutate the place.
1135 /// For example, the projection `x.y` is marked as a mutation in these cases:
1141 /// Retagging, a "Stacked Borrows" shadow state operation
1145 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1146 pub enum NonUseContext {
1147 /// Starting a storage live range.
1149 /// Ending a storage live range.
1151 /// User type annotation assertions for NLL.
1153 /// The data of an user variable, for debug info.
1157 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
1158 pub enum PlaceContext {
1159 NonMutatingUse(NonMutatingUseContext),
1160 MutatingUse(MutatingUseContext),
1161 NonUse(NonUseContext),
1165 /// Returns `true` if this place context represents a drop.
1166 pub fn is_drop(&self) -> bool {
1167 matches!(self, PlaceContext::MutatingUse(MutatingUseContext::Drop))
1170 /// Returns `true` if this place context represents a borrow.
1171 pub fn is_borrow(&self) -> bool {
1174 PlaceContext::NonMutatingUse(
1175 NonMutatingUseContext::SharedBorrow
1176 | NonMutatingUseContext::ShallowBorrow
1177 | NonMutatingUseContext::UniqueBorrow
1178 ) | PlaceContext::MutatingUse(MutatingUseContext::Borrow)
1182 /// Returns `true` if this place context represents a storage live or storage dead marker.
1183 pub fn is_storage_marker(&self) -> bool {
1186 PlaceContext::NonUse(NonUseContext::StorageLive | NonUseContext::StorageDead)
1190 /// Returns `true` if this place context represents a storage live marker.
1191 pub fn is_storage_live_marker(&self) -> bool {
1192 matches!(self, PlaceContext::NonUse(NonUseContext::StorageLive))
1195 /// Returns `true` if this place context represents a storage dead marker.
1196 pub fn is_storage_dead_marker(&self) -> bool {
1197 matches!(self, PlaceContext::NonUse(NonUseContext::StorageDead))
1200 /// Returns `true` if this place context represents a use that potentially changes the value.
1201 pub fn is_mutating_use(&self) -> bool {
1202 matches!(self, PlaceContext::MutatingUse(..))
1205 /// Returns `true` if this place context represents a use that does not change the value.
1206 pub fn is_nonmutating_use(&self) -> bool {
1207 matches!(self, PlaceContext::NonMutatingUse(..))
1210 /// Returns `true` if this place context represents a use.
1211 pub fn is_use(&self) -> bool {
1212 !matches!(self, PlaceContext::NonUse(..))
1215 /// Returns `true` if this place context represents an assignment statement.
1216 pub fn is_place_assignment(&self) -> bool {
1219 PlaceContext::MutatingUse(
1220 MutatingUseContext::Store
1221 | MutatingUseContext::Call
1222 | MutatingUseContext::AsmOutput,