1 //! MIR datatypes and passes. See the [rustc guide] for more info.
3 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
5 use crate::hir::def::CtorKind;
6 use crate::hir::def_id::DefId;
7 use crate::hir::{self, HirId, InlineAsm};
8 use crate::mir::interpret::{ConstValue, EvalErrorKind, Scalar};
9 use crate::mir::visit::MirVisitable;
10 use rustc_apfloat::ieee::{Double, Single};
11 use rustc_apfloat::Float;
12 use rustc_data_structures::fx::FxHashSet;
13 use rustc_data_structures::graph::dominators::{dominators, Dominators};
14 use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
15 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
16 use rustc_data_structures::sync::Lrc;
17 use rustc_data_structures::sync::MappedReadGuard;
18 use crate::rustc_serialize::{self as serialize};
19 use smallvec::SmallVec;
21 use std::fmt::{self, Debug, Formatter, Write};
22 use std::ops::{Index, IndexMut};
24 use std::vec::IntoIter;
25 use std::{iter, mem, option, u32};
26 use syntax::ast::{self, Name};
27 use syntax::symbol::InternedString;
28 use syntax_pos::{Span, DUMMY_SP};
29 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
30 use crate::ty::subst::{Subst, Substs};
31 use crate::ty::layout::VariantIdx;
33 self, AdtDef, CanonicalUserTypeAnnotations, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
34 UserTypeAnnotationIndex,
36 use crate::util::ppaux;
38 pub use crate::mir::interpret::AssertMessage;
48 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
50 pub trait HasLocalDecls<'tcx> {
51 fn local_decls(&self) -> &LocalDecls<'tcx>;
54 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
55 fn local_decls(&self) -> &LocalDecls<'tcx> {
60 impl<'tcx> HasLocalDecls<'tcx> for Mir<'tcx> {
61 fn local_decls(&self) -> &LocalDecls<'tcx> {
66 /// The various "big phases" that MIR goes through.
68 /// Warning: ordering of variants is significant
69 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, PartialOrd, Ord)]
78 /// Gets the index of the current MirPhase within the set of all MirPhases.
79 pub fn phase_index(&self) -> usize {
84 /// Lowered representation of a single function.
85 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
86 pub struct Mir<'tcx> {
87 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
88 /// that indexes into this vector.
89 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
91 /// Records how far through the "desugaring and optimization" process this particular
92 /// MIR has traversed. This is particularly useful when inlining, since in that context
93 /// we instantiate the promoted constants and add them to our promoted vector -- but those
94 /// promoted items have already been optimized, whereas ours have not. This field allows
95 /// us to see the difference and forego optimization on the inlined promoted items.
98 /// List of source scopes; these are referenced by statements
99 /// and used for debuginfo. Indexed by a `SourceScope`.
100 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
102 /// Crate-local information for each source scope, that can't (and
103 /// needn't) be tracked across crates.
104 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
106 /// Rvalues promoted from this function, such as borrows of constants.
107 /// Each of them is the Mir of a constant with the fn's type parameters
108 /// in scope, but a separate set of locals.
109 pub promoted: IndexVec<Promoted, Mir<'tcx>>,
111 /// Yields type of the function, if it is a generator.
112 pub yield_ty: Option<Ty<'tcx>>,
114 /// Generator drop glue
115 pub generator_drop: Option<Box<Mir<'tcx>>>,
117 /// The layout of a generator. Produced by the state transformation.
118 pub generator_layout: Option<GeneratorLayout<'tcx>>,
120 /// Declarations of locals.
122 /// The first local is the return value pointer, followed by `arg_count`
123 /// locals for the function arguments, followed by any user-declared
124 /// variables and temporaries.
125 pub local_decls: LocalDecls<'tcx>,
127 /// User type annotations
128 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
130 /// Number of arguments this function takes.
132 /// Starting at local 1, `arg_count` locals will be provided by the caller
133 /// and can be assumed to be initialized.
135 /// If this MIR was built for a constant, this will be 0.
136 pub arg_count: usize,
138 /// Names and capture modes of all the closure upvars, assuming
139 /// the first argument is either the closure or a reference to it.
140 pub upvar_decls: Vec<UpvarDecl>,
142 /// Mark an argument local (which must be a tuple) as getting passed as
143 /// its individual components at the LLVM level.
145 /// This is used for the "rust-call" ABI.
146 pub spread_arg: Option<Local>,
148 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
149 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
150 /// this conversion from happening and use short circuiting, we will cause the following code
151 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
153 /// List of places where control flow was destroyed. Used for error reporting.
154 pub control_flow_destroyed: Vec<(Span, String)>,
156 /// A span representing this MIR, for error reporting
159 /// A cache for various calculations
163 impl<'tcx> Mir<'tcx> {
165 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
166 source_scopes: IndexVec<SourceScope, SourceScopeData>,
167 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
168 promoted: IndexVec<Promoted, Mir<'tcx>>,
169 yield_ty: Option<Ty<'tcx>>,
170 local_decls: LocalDecls<'tcx>,
171 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
173 upvar_decls: Vec<UpvarDecl>,
175 control_flow_destroyed: Vec<(Span, String)>,
177 // We need `arg_count` locals, and one for the return place
179 local_decls.len() >= arg_count + 1,
180 "expected at least {} locals, got {}",
186 phase: MirPhase::Build,
189 source_scope_local_data,
192 generator_drop: None,
193 generator_layout: None,
195 user_type_annotations,
200 cache: cache::Cache::new(),
201 control_flow_destroyed,
206 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
211 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
212 self.cache.invalidate();
213 &mut self.basic_blocks
217 pub fn basic_blocks_and_local_decls_mut(
220 &mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
221 &mut LocalDecls<'tcx>,
223 self.cache.invalidate();
224 (&mut self.basic_blocks, &mut self.local_decls)
228 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
229 self.cache.predecessors(self)
233 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
234 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
238 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
239 let if_zero_locations = if loc.statement_index == 0 {
240 let predecessor_blocks = self.predecessors_for(loc.block);
241 let num_predecessor_blocks = predecessor_blocks.len();
243 (0..num_predecessor_blocks)
244 .map(move |i| predecessor_blocks[i])
245 .map(move |bb| self.terminator_loc(bb)),
251 let if_not_zero_locations = if loc.statement_index == 0 {
256 statement_index: loc.statement_index - 1,
263 .chain(if_not_zero_locations)
267 pub fn dominators(&self) -> Dominators<BasicBlock> {
272 pub fn local_kind(&self, local: Local) -> LocalKind {
273 let index = local.as_usize();
276 self.local_decls[local].mutability == Mutability::Mut,
277 "return place should be mutable"
280 LocalKind::ReturnPointer
281 } else if index < self.arg_count + 1 {
283 } else if self.local_decls[local].name.is_some() {
290 /// Returns an iterator over all temporaries.
292 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
293 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
294 let local = Local::new(index);
295 if self.local_decls[local].is_user_variable.is_some() {
303 /// Returns an iterator over all user-declared locals.
305 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
306 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
307 let local = Local::new(index);
308 if self.local_decls[local].is_user_variable.is_some() {
316 /// Returns an iterator over all user-declared mutable locals.
318 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
319 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
320 let local = Local::new(index);
321 let decl = &self.local_decls[local];
322 if decl.is_user_variable.is_some() && decl.mutability == Mutability::Mut {
330 /// Returns an iterator over all user-declared mutable arguments and locals.
332 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
333 (1..self.local_decls.len()).filter_map(move |index| {
334 let local = Local::new(index);
335 let decl = &self.local_decls[local];
336 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
337 && decl.mutability == Mutability::Mut
346 /// Returns an iterator over all function arguments.
348 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
349 let arg_count = self.arg_count;
350 (1..=arg_count).map(Local::new)
353 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
354 /// locals that are neither arguments nor the return place).
356 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
357 let arg_count = self.arg_count;
358 let local_count = self.local_decls.len();
359 (arg_count + 1..local_count).map(Local::new)
362 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
363 /// invalidating statement indices in `Location`s.
364 pub fn make_statement_nop(&mut self, location: Location) {
365 let block = &mut self[location.block];
366 debug_assert!(location.statement_index < block.statements.len());
367 block.statements[location.statement_index].make_nop()
370 /// Returns the source info associated with `location`.
371 pub fn source_info(&self, location: Location) -> &SourceInfo {
372 let block = &self[location.block];
373 let stmts = &block.statements;
374 let idx = location.statement_index;
375 if idx < stmts.len() {
376 &stmts[idx].source_info
378 assert_eq!(idx, stmts.len());
379 &block.terminator().source_info
383 /// Checks if `sub` is a sub scope of `sup`
384 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
386 match self.source_scopes[sub].parent_scope {
387 None => return false,
394 /// Returns the return type, it always return first element from `local_decls` array
395 pub fn return_ty(&self) -> Ty<'tcx> {
396 self.local_decls[RETURN_PLACE].ty
399 /// Gets the location of the terminator for the given block
400 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
403 statement_index: self[bb].statements.len(),
408 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
411 /// Unsafe because of a PushUnsafeBlock
413 /// Unsafe because of an unsafe fn
415 /// Unsafe because of an `unsafe` block
416 ExplicitUnsafe(ast::NodeId),
419 impl_stable_hash_for!(struct Mir<'tcx> {
423 source_scope_local_data,
429 user_type_annotations,
433 control_flow_destroyed,
438 impl<'tcx> Index<BasicBlock> for Mir<'tcx> {
439 type Output = BasicBlockData<'tcx>;
442 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
443 &self.basic_blocks()[index]
447 impl<'tcx> IndexMut<BasicBlock> for Mir<'tcx> {
449 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
450 &mut self.basic_blocks_mut()[index]
454 #[derive(Copy, Clone, Debug)]
455 pub enum ClearCrossCrate<T> {
460 impl<T> ClearCrossCrate<T> {
461 pub fn assert_crate_local(self) -> T {
463 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
464 ClearCrossCrate::Set(v) => v,
469 impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
470 impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
472 /// Grouped information about the source code origin of a MIR entity.
473 /// Intended to be inspected by diagnostics and debuginfo.
474 /// Most passes can work with it as a whole, within a single function.
475 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
476 pub struct SourceInfo {
477 /// Source span for the AST pertaining to this MIR entity.
480 /// The source scope, keeping track of which bindings can be
481 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
482 pub scope: SourceScope,
485 ///////////////////////////////////////////////////////////////////////////
486 // Mutability and borrow kinds
488 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
489 pub enum Mutability {
494 impl From<Mutability> for hir::Mutability {
495 fn from(m: Mutability) -> Self {
497 Mutability::Mut => hir::MutMutable,
498 Mutability::Not => hir::MutImmutable,
503 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
504 pub enum BorrowKind {
505 /// Data must be immutable and is aliasable.
508 /// The immediately borrowed place must be immutable, but projections from
509 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
510 /// conflict with a mutable borrow of `a.b.c`.
512 /// This is used when lowering matches: when matching on a place we want to
513 /// ensure that place have the same value from the start of the match until
514 /// an arm is selected. This prevents this code from compiling:
516 /// let mut x = &Some(0);
519 /// Some(_) if { x = &None; false } => (),
523 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
524 /// should not prevent `if let None = x { ... }`, for example, because the
525 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
526 /// We can also report errors with this kind of borrow differently.
529 /// Data must be immutable but not aliasable. This kind of borrow
530 /// cannot currently be expressed by the user and is used only in
531 /// implicit closure bindings. It is needed when the closure is
532 /// borrowing or mutating a mutable referent, e.g.:
534 /// let x: &mut isize = ...;
535 /// let y = || *x += 5;
537 /// If we were to try to translate this closure into a more explicit
538 /// form, we'd encounter an error with the code as written:
540 /// struct Env { x: & &mut isize }
541 /// let x: &mut isize = ...;
542 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
543 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
545 /// This is then illegal because you cannot mutate an `&mut` found
546 /// in an aliasable location. To solve, you'd have to translate with
547 /// an `&mut` borrow:
549 /// struct Env { x: & &mut isize }
550 /// let x: &mut isize = ...;
551 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
552 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
554 /// Now the assignment to `**env.x` is legal, but creating a
555 /// mutable pointer to `x` is not because `x` is not mutable. We
556 /// could fix this by declaring `x` as `let mut x`. This is ok in
557 /// user code, if awkward, but extra weird for closures, since the
558 /// borrow is hidden.
560 /// So we introduce a "unique imm" borrow -- the referent is
561 /// immutable, but not aliasable. This solves the problem. For
562 /// simplicity, we don't give users the way to express this
563 /// borrow, it's just used when translating closures.
566 /// Data is mutable and not aliasable.
568 /// `true` if this borrow arose from method-call auto-ref
569 /// (i.e., `adjustment::Adjust::Borrow`).
570 allow_two_phase_borrow: bool,
575 pub fn allows_two_phase_borrow(&self) -> bool {
577 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
578 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
583 ///////////////////////////////////////////////////////////////////////////
584 // Variables and temps
588 DEBUG_FORMAT = "_{}",
589 const RETURN_PLACE = 0,
593 /// Classifies locals into categories. See `Mir::local_kind`.
594 #[derive(PartialEq, Eq, Debug)]
596 /// User-declared variable binding
598 /// Compiler-introduced temporary
600 /// Function argument
602 /// Location of function's return value
606 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
607 pub struct VarBindingForm<'tcx> {
608 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
609 pub binding_mode: ty::BindingMode,
610 /// If an explicit type was provided for this variable binding,
611 /// this holds the source Span of that type.
613 /// NOTE: if you want to change this to a `HirId`, be wary that
614 /// doing so breaks incremental compilation (as of this writing),
615 /// while a `Span` does not cause our tests to fail.
616 pub opt_ty_info: Option<Span>,
617 /// Place of the RHS of the =, or the subject of the `match` where this
618 /// variable is initialized. None in the case of `let PATTERN;`.
619 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
620 /// (a) the right-hand side isn't evaluated as a place expression.
621 /// (b) it gives a way to separate this case from the remaining cases
623 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
624 /// Span of the pattern in which this variable was bound.
628 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
629 pub enum BindingForm<'tcx> {
630 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
631 Var(VarBindingForm<'tcx>),
632 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
633 ImplicitSelf(ImplicitSelfKind),
634 /// Reference used in a guard expression to ensure immutability.
638 /// Represents what type of implicit self a function has, if any.
639 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
640 pub enum ImplicitSelfKind {
641 /// Represents a `fn x(self);`.
643 /// Represents a `fn x(mut self);`.
645 /// Represents a `fn x(&self);`.
647 /// Represents a `fn x(&mut self);`.
649 /// Represents when a function does not have a self argument or
650 /// when a function has a `self: X` argument.
654 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
656 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
663 impl_stable_hash_for!(enum self::ImplicitSelfKind {
671 impl_stable_hash_for!(enum self::MirPhase {
678 mod binding_form_impl {
679 use crate::ich::StableHashingContext;
680 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
682 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
683 fn hash_stable<W: StableHasherResult>(
685 hcx: &mut StableHashingContext<'a>,
686 hasher: &mut StableHasher<W>,
688 use super::BindingForm::*;
689 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
692 Var(binding) => binding.hash_stable(hcx, hasher),
693 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
700 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
701 /// created during evaluation of expressions in a block tail
702 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
704 /// It is used to improve diagnostics when such temporaries are
705 /// involved in borrow_check errors, e.g., explanations of where the
706 /// temporaries come from, when their destructors are run, and/or how
707 /// one might revise the code to satisfy the borrow checker's rules.
708 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
709 pub struct BlockTailInfo {
710 /// If `true`, then the value resulting from evaluating this tail
711 /// expression is ignored by the block's expression context.
713 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
714 /// but not e.g., `let _x = { ...; tail };`
715 pub tail_result_is_ignored: bool,
718 impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
722 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
723 /// argument, or the return place.
724 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
725 pub struct LocalDecl<'tcx> {
726 /// `let mut x` vs `let x`.
728 /// Temporaries and the return place are always mutable.
729 pub mutability: Mutability,
731 /// Some(binding_mode) if this corresponds to a user-declared local variable.
733 /// This is solely used for local diagnostics when generating
734 /// warnings/errors when compiling the current crate, and
735 /// therefore it need not be visible across crates. pnkfelix
736 /// currently hypothesized we *need* to wrap this in a
737 /// `ClearCrossCrate` as long as it carries as `HirId`.
738 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
740 /// `true` if this is an internal local.
742 /// These locals are not based on types in the source code and are only used
743 /// for a few desugarings at the moment.
745 /// The generator transformation will sanity check the locals which are live
746 /// across a suspension point against the type components of the generator
747 /// which type checking knows are live across a suspension point. We need to
748 /// flag drop flags to avoid triggering this check as they are introduced
751 /// Unsafety checking will also ignore dereferences of these locals,
752 /// so they can be used for raw pointers only used in a desugaring.
754 /// This should be sound because the drop flags are fully algebraic, and
755 /// therefore don't affect the OIBIT or outlives properties of the
759 /// If this local is a temporary and `is_block_tail` is `Some`,
760 /// then it is a temporary created for evaluation of some
761 /// subexpression of some block's tail expression (with no
762 /// intervening statement context).
763 pub is_block_tail: Option<BlockTailInfo>,
765 /// Type of this local.
768 /// If the user manually ascribed a type to this variable,
769 /// e.g., via `let x: T`, then we carry that type here. The MIR
770 /// borrow checker needs this information since it can affect
771 /// region inference.
772 pub user_ty: UserTypeProjections<'tcx>,
774 /// Name of the local, used in debuginfo and pretty-printing.
776 /// Note that function arguments can also have this set to `Some(_)`
777 /// to generate better debuginfo.
778 pub name: Option<Name>,
780 /// The *syntactic* (i.e., not visibility) source scope the local is defined
781 /// in. If the local was defined in a let-statement, this
782 /// is *within* the let-statement, rather than outside
785 /// This is needed because the visibility source scope of locals within
786 /// a let-statement is weird.
788 /// The reason is that we want the local to be *within* the let-statement
789 /// for lint purposes, but we want the local to be *after* the let-statement
790 /// for names-in-scope purposes.
792 /// That's it, if we have a let-statement like the one in this
796 /// fn foo(x: &str) {
797 /// #[allow(unused_mut)]
798 /// let mut x: u32 = { // <- one unused mut
799 /// let mut y: u32 = x.parse().unwrap();
806 /// Then, from a lint point of view, the declaration of `x: u32`
807 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
808 /// lint scopes are the same as the AST/HIR nesting.
810 /// However, from a name lookup point of view, the scopes look more like
811 /// as if the let-statements were `match` expressions:
814 /// fn foo(x: &str) {
816 /// match x.parse().unwrap() {
825 /// We care about the name-lookup scopes for debuginfo - if the
826 /// debuginfo instruction pointer is at the call to `x.parse()`, we
827 /// want `x` to refer to `x: &str`, but if it is at the call to
828 /// `drop(x)`, we want it to refer to `x: u32`.
830 /// To allow both uses to work, we need to have more than a single scope
831 /// for a local. We have the `source_info.scope` represent the
832 /// "syntactic" lint scope (with a variable being under its let
833 /// block) while the `visibility_scope` represents the "local variable"
834 /// scope (where the "rest" of a block is under all prior let-statements).
836 /// The end result looks like this:
840 /// │{ argument x: &str }
842 /// │ │{ #[allow(unused_mut)] } // this is actually split into 2 scopes
843 /// │ │ // in practice because I'm lazy.
845 /// │ │← x.source_info.scope
846 /// │ │← `x.parse().unwrap()`
848 /// │ │ │← y.source_info.scope
850 /// │ │ │{ let y: u32 }
852 /// │ │ │← y.visibility_scope
855 /// │ │{ let x: u32 }
856 /// │ │← x.visibility_scope
857 /// │ │← `drop(x)` // this accesses `x: u32`
859 pub source_info: SourceInfo,
861 /// Source scope within which the local is visible (for debuginfo)
862 /// (see `source_info` for more details).
863 pub visibility_scope: SourceScope,
866 impl<'tcx> LocalDecl<'tcx> {
867 /// Returns `true` only if local is a binding that can itself be
868 /// made mutable via the addition of the `mut` keyword, namely
869 /// something like the occurrences of `x` in:
870 /// - `fn foo(x: Type) { ... }`,
872 /// - or `match ... { C(x) => ... }`
873 pub fn can_be_made_mutable(&self) -> bool {
874 match self.is_user_variable {
875 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
876 binding_mode: ty::BindingMode::BindByValue(_),
882 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)))
889 /// Returns `true` if local is definitely not a `ref ident` or
890 /// `ref mut ident` binding. (Such bindings cannot be made into
891 /// mutable bindings, but the inverse does not necessarily hold).
892 pub fn is_nonref_binding(&self) -> bool {
893 match self.is_user_variable {
894 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
895 binding_mode: ty::BindingMode::BindByValue(_),
901 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
907 /// Creates a new `LocalDecl` for a temporary.
909 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
910 Self::new_local(ty, Mutability::Mut, false, span)
913 /// Converts `self` into same `LocalDecl` except tagged as immutable.
915 pub fn immutable(mut self) -> Self {
916 self.mutability = Mutability::Not;
920 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
922 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
923 assert!(self.is_block_tail.is_none());
924 self.is_block_tail = Some(info);
928 /// Creates a new `LocalDecl` for a internal temporary.
930 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
931 Self::new_local(ty, Mutability::Mut, true, span)
937 mutability: Mutability,
944 user_ty: UserTypeProjections::none(),
946 source_info: SourceInfo {
948 scope: OUTERMOST_SOURCE_SCOPE,
950 visibility_scope: OUTERMOST_SOURCE_SCOPE,
952 is_user_variable: None,
957 /// Builds a `LocalDecl` for the return place.
959 /// This must be inserted into the `local_decls` list as the first local.
961 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
963 mutability: Mutability::Mut,
965 user_ty: UserTypeProjections::none(),
966 source_info: SourceInfo {
968 scope: OUTERMOST_SOURCE_SCOPE,
970 visibility_scope: OUTERMOST_SOURCE_SCOPE,
973 name: None, // FIXME maybe we do want some name here?
974 is_user_variable: None,
979 /// A closure capture, with its name and mode.
980 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
981 pub struct UpvarDecl {
982 pub debug_name: Name,
984 /// `HirId` of the captured variable
985 pub var_hir_id: ClearCrossCrate<HirId>,
987 /// If true, the capture is behind a reference.
990 pub mutability: Mutability,
993 ///////////////////////////////////////////////////////////////////////////
997 pub struct BasicBlock {
998 DEBUG_FORMAT = "bb{}",
999 const START_BLOCK = 0,
1004 pub fn start_location(self) -> Location {
1012 ///////////////////////////////////////////////////////////////////////////
1013 // BasicBlockData and Terminator
1015 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1016 pub struct BasicBlockData<'tcx> {
1017 /// List of statements in this block.
1018 pub statements: Vec<Statement<'tcx>>,
1020 /// Terminator for this block.
1022 /// N.B., this should generally ONLY be `None` during construction.
1023 /// Therefore, you should generally access it via the
1024 /// `terminator()` or `terminator_mut()` methods. The only
1025 /// exception is that certain passes, such as `simplify_cfg`, swap
1026 /// out the terminator temporarily with `None` while they continue
1027 /// to recurse over the set of basic blocks.
1028 pub terminator: Option<Terminator<'tcx>>,
1030 /// If true, this block lies on an unwind path. This is used
1031 /// during codegen where distinct kinds of basic blocks may be
1032 /// generated (particularly for MSVC cleanup). Unwind blocks must
1033 /// only branch to other unwind blocks.
1034 pub is_cleanup: bool,
1037 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1038 pub struct Terminator<'tcx> {
1039 pub source_info: SourceInfo,
1040 pub kind: TerminatorKind<'tcx>,
1043 #[derive(Clone, RustcEncodable, RustcDecodable)]
1044 pub enum TerminatorKind<'tcx> {
1045 /// block should have one successor in the graph; we jump there
1046 Goto { target: BasicBlock },
1048 /// operand evaluates to an integer; jump depending on its value
1049 /// to one of the targets, and otherwise fallback to `otherwise`
1051 /// discriminant value being tested
1052 discr: Operand<'tcx>,
1054 /// type of value being tested
1055 switch_ty: Ty<'tcx>,
1057 /// Possible values. The locations to branch to in each case
1058 /// are found in the corresponding indices from the `targets` vector.
1059 values: Cow<'tcx, [u128]>,
1061 /// Possible branch sites. The last element of this vector is used
1062 /// for the otherwise branch, so targets.len() == values.len() + 1
1064 // This invariant is quite non-obvious and also could be improved.
1065 // One way to make this invariant is to have something like this instead:
1067 // branches: Vec<(ConstInt, BasicBlock)>,
1068 // otherwise: Option<BasicBlock> // exhaustive if None
1070 // However we’ve decided to keep this as-is until we figure a case
1071 // where some other approach seems to be strictly better than other.
1072 targets: Vec<BasicBlock>,
1075 /// Indicates that the landing pad is finished and unwinding should
1076 /// continue. Emitted by build::scope::diverge_cleanup.
1079 /// Indicates that the landing pad is finished and that the process
1080 /// should abort. Used to prevent unwinding for foreign items.
1083 /// Indicates a normal return. The return place should have
1084 /// been filled in by now. This should occur at most once.
1087 /// Indicates a terminator that can never be reached.
1092 location: Place<'tcx>,
1094 unwind: Option<BasicBlock>,
1097 /// Drop the Place and assign the new value over it. This ensures
1098 /// that the assignment to `P` occurs *even if* the destructor for
1099 /// place unwinds. Its semantics are best explained by the
1104 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1112 /// Drop(P, goto BB1, unwind BB2)
1115 /// // P is now uninitialized
1119 /// // P is now uninitialized -- its dtor panicked
1124 location: Place<'tcx>,
1125 value: Operand<'tcx>,
1127 unwind: Option<BasicBlock>,
1130 /// Block ends with a call of a converging function
1132 /// The function that’s being called
1133 func: Operand<'tcx>,
1134 /// Arguments the function is called with.
1135 /// These are owned by the callee, which is free to modify them.
1136 /// This allows the memory occupied by "by-value" arguments to be
1137 /// reused across function calls without duplicating the contents.
1138 args: Vec<Operand<'tcx>>,
1139 /// Destination for the return value. If some, the call is converging.
1140 destination: Option<(Place<'tcx>, BasicBlock)>,
1141 /// Cleanups to be done if the call unwinds.
1142 cleanup: Option<BasicBlock>,
1143 /// Whether this is from a call in HIR, rather than from an overloaded
1144 /// operator. True for overloaded function call.
1145 from_hir_call: bool,
1148 /// Jump to the target if the condition has the expected value,
1149 /// otherwise panic with a message and a cleanup target.
1151 cond: Operand<'tcx>,
1153 msg: AssertMessage<'tcx>,
1155 cleanup: Option<BasicBlock>,
1160 /// The value to return
1161 value: Operand<'tcx>,
1162 /// Where to resume to
1164 /// Cleanup to be done if the generator is dropped at this suspend point
1165 drop: Option<BasicBlock>,
1168 /// Indicates the end of the dropping of a generator
1171 /// A block where control flow only ever takes one real path, but borrowck
1172 /// needs to be more conservative.
1174 /// The target normal control flow will take
1175 real_target: BasicBlock,
1176 /// The list of blocks control flow could conceptually take, but won't
1178 imaginary_targets: Vec<BasicBlock>,
1180 /// A terminator for blocks that only take one path in reality, but where we
1181 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1182 /// This can arise in infinite loops with no function calls for example.
1184 /// The target normal control flow will take
1185 real_target: BasicBlock,
1186 /// The imaginary cleanup block link. This particular path will never be taken
1187 /// in practice, but in order to avoid fragility we want to always
1188 /// consider it in borrowck. We don't want to accept programs which
1189 /// pass borrowck only when panic=abort or some assertions are disabled
1190 /// due to release vs. debug mode builds. This needs to be an Option because
1191 /// of the remove_noop_landing_pads and no_landing_pads passes
1192 unwind: Option<BasicBlock>,
1196 pub type Successors<'a> =
1197 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1198 pub type SuccessorsMut<'a> =
1199 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1201 impl<'tcx> Terminator<'tcx> {
1202 pub fn successors(&self) -> Successors<'_> {
1203 self.kind.successors()
1206 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1207 self.kind.successors_mut()
1210 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1214 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1215 self.kind.unwind_mut()
1219 impl<'tcx> TerminatorKind<'tcx> {
1220 pub fn if_<'a, 'gcx>(
1221 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1222 cond: Operand<'tcx>,
1225 ) -> TerminatorKind<'tcx> {
1226 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1227 TerminatorKind::SwitchInt {
1229 switch_ty: tcx.types.bool,
1230 values: From::from(BOOL_SWITCH_FALSE),
1231 targets: vec![f, t],
1235 pub fn successors(&self) -> Successors<'_> {
1236 use self::TerminatorKind::*;
1247 } => None.into_iter().chain(&[]),
1248 Goto { target: ref t }
1251 cleanup: Some(ref t),
1255 destination: Some((_, ref t)),
1282 } => Some(t).into_iter().chain(&[]),
1284 destination: Some((_, ref t)),
1285 cleanup: Some(ref u),
1295 unwind: Some(ref u),
1300 unwind: Some(ref u),
1305 cleanup: Some(ref u),
1310 unwind: Some(ref u),
1311 } => Some(t).into_iter().chain(slice::from_ref(u)),
1312 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1315 ref imaginary_targets,
1316 } => Some(real_target).into_iter().chain(&imaginary_targets[..]),
1320 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1321 use self::TerminatorKind::*;
1332 } => None.into_iter().chain(&mut []),
1333 Goto { target: ref mut t }
1336 cleanup: Some(ref mut t),
1340 destination: Some((_, ref mut t)),
1365 real_target: ref mut t,
1367 } => Some(t).into_iter().chain(&mut []),
1369 destination: Some((_, ref mut t)),
1370 cleanup: Some(ref mut u),
1375 drop: Some(ref mut u),
1380 unwind: Some(ref mut u),
1385 unwind: Some(ref mut u),
1390 cleanup: Some(ref mut u),
1394 real_target: ref mut t,
1395 unwind: Some(ref mut u),
1396 } => Some(t).into_iter().chain(slice::from_mut(u)),
1399 } => None.into_iter().chain(&mut targets[..]),
1401 ref mut real_target,
1402 ref mut imaginary_targets,
1403 } => Some(real_target)
1405 .chain(&mut imaginary_targets[..]),
1409 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1411 TerminatorKind::Goto { .. }
1412 | TerminatorKind::Resume
1413 | TerminatorKind::Abort
1414 | TerminatorKind::Return
1415 | TerminatorKind::Unreachable
1416 | TerminatorKind::GeneratorDrop
1417 | TerminatorKind::Yield { .. }
1418 | TerminatorKind::SwitchInt { .. }
1419 | TerminatorKind::FalseEdges { .. } => None,
1420 TerminatorKind::Call {
1421 cleanup: ref unwind,
1424 | TerminatorKind::Assert {
1425 cleanup: ref unwind,
1428 | TerminatorKind::DropAndReplace { ref unwind, .. }
1429 | TerminatorKind::Drop { ref unwind, .. }
1430 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1434 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1436 TerminatorKind::Goto { .. }
1437 | TerminatorKind::Resume
1438 | TerminatorKind::Abort
1439 | TerminatorKind::Return
1440 | TerminatorKind::Unreachable
1441 | TerminatorKind::GeneratorDrop
1442 | TerminatorKind::Yield { .. }
1443 | TerminatorKind::SwitchInt { .. }
1444 | TerminatorKind::FalseEdges { .. } => None,
1445 TerminatorKind::Call {
1446 cleanup: ref mut unwind,
1449 | TerminatorKind::Assert {
1450 cleanup: ref mut unwind,
1453 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1454 | TerminatorKind::Drop { ref mut unwind, .. }
1455 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1460 impl<'tcx> BasicBlockData<'tcx> {
1461 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1469 /// Accessor for terminator.
1471 /// Terminator may not be None after construction of the basic block is complete. This accessor
1472 /// provides a convenience way to reach the terminator.
1473 pub fn terminator(&self) -> &Terminator<'tcx> {
1474 self.terminator.as_ref().expect("invalid terminator state")
1477 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1478 self.terminator.as_mut().expect("invalid terminator state")
1481 pub fn retain_statements<F>(&mut self, mut f: F)
1483 F: FnMut(&mut Statement<'_>) -> bool,
1485 for s in &mut self.statements {
1492 pub fn expand_statements<F, I>(&mut self, mut f: F)
1494 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1495 I: iter::TrustedLen<Item = Statement<'tcx>>,
1497 // Gather all the iterators we'll need to splice in, and their positions.
1498 let mut splices: Vec<(usize, I)> = vec![];
1499 let mut extra_stmts = 0;
1500 for (i, s) in self.statements.iter_mut().enumerate() {
1501 if let Some(mut new_stmts) = f(s) {
1502 if let Some(first) = new_stmts.next() {
1503 // We can already store the first new statement.
1506 // Save the other statements for optimized splicing.
1507 let remaining = new_stmts.size_hint().0;
1509 splices.push((i + 1 + extra_stmts, new_stmts));
1510 extra_stmts += remaining;
1518 // Splice in the new statements, from the end of the block.
1519 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1520 // where a range of elements ("gap") is left uninitialized, with
1521 // splicing adding new elements to the end of that gap and moving
1522 // existing elements from before the gap to the end of the gap.
1523 // For now, this is safe code, emulating a gap but initializing it.
1524 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1525 self.statements.resize(
1528 source_info: SourceInfo {
1530 scope: OUTERMOST_SOURCE_SCOPE,
1532 kind: StatementKind::Nop,
1535 for (splice_start, new_stmts) in splices.into_iter().rev() {
1536 let splice_end = splice_start + new_stmts.size_hint().0;
1537 while gap.end > splice_end {
1540 self.statements.swap(gap.start, gap.end);
1542 self.statements.splice(splice_start..splice_end, new_stmts);
1543 gap.end = splice_start;
1547 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1548 if index < self.statements.len() {
1549 &self.statements[index]
1556 impl<'tcx> Debug for TerminatorKind<'tcx> {
1557 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1558 self.fmt_head(fmt)?;
1559 let successor_count = self.successors().count();
1560 let labels = self.fmt_successor_labels();
1561 assert_eq!(successor_count, labels.len());
1563 match successor_count {
1566 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1569 write!(fmt, " -> [")?;
1570 for (i, target) in self.successors().enumerate() {
1574 write!(fmt, "{}: {:?}", labels[i], target)?;
1582 impl<'tcx> TerminatorKind<'tcx> {
1583 /// Write the "head" part of the terminator; that is, its name and the data it uses to pick the
1584 /// successor basic block, if any. The only information not included is the list of possible
1585 /// successors, which may be rendered differently between the text and the graphviz format.
1586 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1587 use self::TerminatorKind::*;
1589 Goto { .. } => write!(fmt, "goto"),
1591 discr: ref place, ..
1592 } => write!(fmt, "switchInt({:?})", place),
1593 Return => write!(fmt, "return"),
1594 GeneratorDrop => write!(fmt, "generator_drop"),
1595 Resume => write!(fmt, "resume"),
1596 Abort => write!(fmt, "abort"),
1597 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1598 Unreachable => write!(fmt, "unreachable"),
1599 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1604 } => write!(fmt, "replace({:?} <- {:?})", location, value),
1611 if let Some((ref destination, _)) = *destination {
1612 write!(fmt, "{:?} = ", destination)?;
1614 write!(fmt, "{:?}(", func)?;
1615 for (index, arg) in args.iter().enumerate() {
1619 write!(fmt, "{:?}", arg)?;
1629 write!(fmt, "assert(")?;
1633 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1635 FalseEdges { .. } => write!(fmt, "falseEdges"),
1636 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1640 /// Returns the list of labels for the edges to the successor basic blocks.
1641 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1642 use self::TerminatorKind::*;
1644 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1645 Goto { .. } => vec!["".into()],
1651 let size = ty::tls::with(|tcx| {
1652 let param_env = ty::ParamEnv::empty();
1653 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1654 tcx.layout_of(param_env.and(switch_ty)).unwrap().size
1659 let mut s = String::new();
1661 val: ConstValue::Scalar(
1664 size: size.bytes() as u8,
1669 fmt_const_val(&mut s, c).unwrap();
1671 }).chain(iter::once("otherwise".into()))
1675 destination: Some(_),
1678 } => vec!["return".into(), "unwind".into()],
1680 destination: Some(_),
1683 } => vec!["return".into()],
1688 } => vec!["unwind".into()],
1694 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1695 Yield { drop: None, .. } => vec!["resume".into()],
1696 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1697 vec!["return".into()]
1704 } => vec!["return".into(), "unwind".into()],
1705 Assert { cleanup: None, .. } => vec!["".into()],
1706 Assert { .. } => vec!["success".into(), "unwind".into()],
1708 ref imaginary_targets,
1711 let mut l = vec!["real".into()];
1712 l.resize(imaginary_targets.len() + 1, "imaginary".into());
1717 } => vec!["real".into(), "cleanup".into()],
1718 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1723 ///////////////////////////////////////////////////////////////////////////
1726 #[derive(Clone, RustcEncodable, RustcDecodable)]
1727 pub struct Statement<'tcx> {
1728 pub source_info: SourceInfo,
1729 pub kind: StatementKind<'tcx>,
1732 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1733 #[cfg(target_arch = "x86_64")]
1734 static_assert!(MEM_SIZE_OF_STATEMENT: mem::size_of::<Statement<'_>>() == 56);
1736 impl<'tcx> Statement<'tcx> {
1737 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1738 /// invalidating statement indices in `Location`s.
1739 pub fn make_nop(&mut self) {
1740 self.kind = StatementKind::Nop
1743 /// Changes a statement to a nop and returns the original statement.
1744 pub fn replace_nop(&mut self) -> Self {
1746 source_info: self.source_info,
1747 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1752 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1753 pub enum StatementKind<'tcx> {
1754 /// Write the RHS Rvalue to the LHS Place.
1755 Assign(Place<'tcx>, Box<Rvalue<'tcx>>),
1757 /// This represents all the reading that a pattern match may do
1758 /// (e.g., inspecting constants and discriminant values), and the
1759 /// kind of pattern it comes from. This is in order to adapt potential
1760 /// error messages to these specific patterns.
1762 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1763 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1764 FakeRead(FakeReadCause, Place<'tcx>),
1766 /// Write the discriminant for a variant to the enum Place.
1769 variant_index: VariantIdx,
1772 /// Start a live range for the storage of the local.
1775 /// End the current live range for the storage of the local.
1778 /// Executes a piece of inline Assembly.
1780 asm: Box<InlineAsm>,
1781 outputs: Box<[Place<'tcx>]>,
1782 inputs: Box<[(Span, Operand<'tcx>)]>,
1785 /// Retag references in the given place, ensuring they got fresh tags. This is
1786 /// part of the Stacked Borrows model. These statements are currently only interpreted
1787 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1788 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1789 /// for more details.
1790 Retag(RetagKind, Place<'tcx>),
1792 /// Encodes a user's type ascription. These need to be preserved
1793 /// intact so that NLL can respect them. For example:
1797 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1798 /// to the user-given type `T`. The effect depends on the specified variance:
1800 /// - `Covariant` -- requires that `T_y <: T`
1801 /// - `Contravariant` -- requires that `T_y :> T`
1802 /// - `Invariant` -- requires that `T_y == T`
1803 /// - `Bivariant` -- no effect
1804 AscribeUserType(Place<'tcx>, ty::Variance, Box<UserTypeProjection<'tcx>>),
1806 /// No-op. Useful for deleting instructions without affecting statement indices.
1810 /// `RetagKind` describes what kind of retag is to be performed.
1811 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq)]
1812 pub enum RetagKind {
1813 /// The initial retag when entering a function
1815 /// Retag preparing for a two-phase borrow
1817 /// Retagging raw pointers
1819 /// A "normal" retag
1823 /// The `FakeReadCause` describes the type of pattern why a `FakeRead` statement exists.
1824 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
1825 pub enum FakeReadCause {
1826 /// Inject a fake read of the borrowed input at the start of each arm's
1827 /// pattern testing code.
1829 /// This should ensure that you cannot change the variant for an enum
1830 /// while you are in the midst of matching on it.
1833 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1834 /// generate a read of x to check that it is initialized and safe.
1837 /// Officially, the semantics of
1839 /// `let pattern = <expr>;`
1841 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1842 /// into the pattern.
1844 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1845 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1846 /// but in some cases it can affect the borrow checker, as in #53695.
1847 /// Therefore, we insert a "fake read" here to ensure that we get
1848 /// appropriate errors.
1852 impl<'tcx> Debug for Statement<'tcx> {
1853 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1854 use self::StatementKind::*;
1856 Assign(ref place, ref rv) => write!(fmt, "{:?} = {:?}", place, rv),
1857 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1858 Retag(ref kind, ref place) =>
1859 write!(fmt, "Retag({}{:?})",
1861 RetagKind::FnEntry => "[fn entry] ",
1862 RetagKind::TwoPhase => "[2phase] ",
1863 RetagKind::Raw => "[raw] ",
1864 RetagKind::Default => "",
1868 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1869 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1873 } => write!(fmt, "discriminant({:?}) = {:?}", place, variant_index),
1878 } => write!(fmt, "asm!({:?} : {:?} : {:?})", asm, outputs, inputs),
1879 AscribeUserType(ref place, ref variance, ref c_ty) => {
1880 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1882 Nop => write!(fmt, "nop"),
1887 ///////////////////////////////////////////////////////////////////////////
1890 /// A path to a value; something that can be evaluated without
1891 /// changing or disturbing program state.
1892 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1893 pub enum Place<'tcx> {
1897 /// static or static mut variable
1898 Static(Box<Static<'tcx>>),
1900 /// Constant code promoted to an injected static
1901 Promoted(Box<(Promoted, Ty<'tcx>)>),
1903 /// projection out of a place (access a field, deref a pointer, etc)
1904 Projection(Box<PlaceProjection<'tcx>>),
1907 /// The `DefId` of a static, along with its normalized type (which is
1908 /// stored to avoid requiring normalization when reading MIR).
1909 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1910 pub struct Static<'tcx> {
1915 impl_stable_hash_for!(struct Static<'tcx> {
1920 /// The `Projection` data structure defines things of the form `B.x`
1921 /// or `*B` or `B[index]`. Note that it is parameterized because it is
1922 /// shared between `Constant` and `Place`. See the aliases
1923 /// `PlaceProjection` etc below.
1924 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1925 pub struct Projection<'tcx, B, V, T> {
1927 pub elem: ProjectionElem<'tcx, V, T>,
1930 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1931 pub enum ProjectionElem<'tcx, V, T> {
1936 /// These indices are generated by slice patterns. Easiest to explain
1940 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1941 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1942 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1943 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1946 /// index or -index (in Python terms), depending on from_end
1948 /// thing being indexed must be at least this long
1950 /// counting backwards from end?
1954 /// These indices are generated by slice patterns.
1956 /// slice[from:-to] in Python terms.
1962 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1963 /// this for ADTs with more than one variant. It may be better to
1964 /// just introduce it always, or always for enums.
1965 Downcast(&'tcx AdtDef, VariantIdx),
1968 /// Alias for projections as they appear in places, where the base is a place
1969 /// and the index is a local.
1970 pub type PlaceProjection<'tcx> = Projection<'tcx, Place<'tcx>, Local, Ty<'tcx>>;
1972 /// Alias for projections as they appear in places, where the base is a place
1973 /// and the index is a local.
1974 pub type PlaceElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
1976 // at least on 64 bit systems, `PlaceElem` should not be larger than two pointers
1977 static_assert!(PROJECTION_ELEM_IS_2_PTRS_LARGE:
1978 mem::size_of::<PlaceElem<'_>>() <= 16
1981 /// Alias for projections as they appear in `UserTypeProjection`, where we
1982 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1983 pub type ProjectionKind<'tcx> = ProjectionElem<'tcx, (), ()>;
1987 DEBUG_FORMAT = "field[{}]"
1991 impl<'tcx> Place<'tcx> {
1992 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
1993 self.elem(ProjectionElem::Field(f, ty))
1996 pub fn deref(self) -> Place<'tcx> {
1997 self.elem(ProjectionElem::Deref)
2000 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
2001 self.elem(ProjectionElem::Downcast(adt_def, variant_index))
2004 pub fn index(self, index: Local) -> Place<'tcx> {
2005 self.elem(ProjectionElem::Index(index))
2008 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
2009 Place::Projection(Box::new(PlaceProjection { base: self, elem }))
2012 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
2013 /// a single deref of a local.
2015 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
2016 pub fn local(&self) -> Option<Local> {
2018 Place::Local(local) |
2019 Place::Projection(box Projection {
2020 base: Place::Local(local),
2021 elem: ProjectionElem::Deref,
2027 /// Finds the innermost `Local` from this `Place`.
2028 pub fn base_local(&self) -> Option<Local> {
2030 Place::Local(local) => Some(*local),
2031 Place::Projection(box Projection { base, elem: _ }) => base.base_local(),
2032 Place::Promoted(..) | Place::Static(..) => None,
2037 impl<'tcx> Debug for Place<'tcx> {
2038 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2042 Local(id) => write!(fmt, "{:?}", id),
2043 Static(box self::Static { def_id, ty }) => write!(
2046 ty::tls::with(|tcx| tcx.item_path_str(def_id)),
2049 Promoted(ref promoted) => write!(fmt, "({:?}: {:?})", promoted.0, promoted.1),
2050 Projection(ref data) => match data.elem {
2051 ProjectionElem::Downcast(ref adt_def, index) => {
2052 write!(fmt, "({:?} as {})", data.base, adt_def.variants[index].ident)
2054 ProjectionElem::Deref => write!(fmt, "(*{:?})", data.base),
2055 ProjectionElem::Field(field, ty) => {
2056 write!(fmt, "({:?}.{:?}: {:?})", data.base, field.index(), ty)
2058 ProjectionElem::Index(ref index) => write!(fmt, "{:?}[{:?}]", data.base, index),
2059 ProjectionElem::ConstantIndex {
2063 } => write!(fmt, "{:?}[{:?} of {:?}]", data.base, offset, min_length),
2064 ProjectionElem::ConstantIndex {
2068 } => write!(fmt, "{:?}[-{:?} of {:?}]", data.base, offset, min_length),
2069 ProjectionElem::Subslice { from, to } if to == 0 => {
2070 write!(fmt, "{:?}[{:?}:]", data.base, from)
2072 ProjectionElem::Subslice { from, to } if from == 0 => {
2073 write!(fmt, "{:?}[:-{:?}]", data.base, to)
2075 ProjectionElem::Subslice { from, to } => {
2076 write!(fmt, "{:?}[{:?}:-{:?}]", data.base, from, to)
2083 ///////////////////////////////////////////////////////////////////////////
2087 pub struct SourceScope {
2088 DEBUG_FORMAT = "scope[{}]",
2089 const OUTERMOST_SOURCE_SCOPE = 0,
2093 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2094 pub struct SourceScopeData {
2096 pub parent_scope: Option<SourceScope>,
2099 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2100 pub struct SourceScopeLocalData {
2101 /// A NodeId with lint levels equivalent to this scope's lint levels.
2102 pub lint_root: ast::NodeId,
2103 /// The unsafe block that contains this node.
2107 ///////////////////////////////////////////////////////////////////////////
2110 /// These are values that can appear inside an rvalue. They are intentionally
2111 /// limited to prevent rvalues from being nested in one another.
2112 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
2113 pub enum Operand<'tcx> {
2114 /// Copy: The value must be available for use afterwards.
2116 /// This implies that the type of the place must be `Copy`; this is true
2117 /// by construction during build, but also checked by the MIR type checker.
2120 /// Move: The value (including old borrows of it) will not be used again.
2122 /// Safe for values of all types (modulo future developments towards `?Move`).
2123 /// Correct usage patterns are enforced by the borrow checker for safe code.
2124 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2127 /// Synthesizes a constant value.
2128 Constant(Box<Constant<'tcx>>),
2131 impl<'tcx> Debug for Operand<'tcx> {
2132 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2133 use self::Operand::*;
2135 Constant(ref a) => write!(fmt, "{:?}", a),
2136 Copy(ref place) => write!(fmt, "{:?}", place),
2137 Move(ref place) => write!(fmt, "move {:?}", place),
2142 impl<'tcx> Operand<'tcx> {
2143 /// Convenience helper to make a constant that refers to the fn
2144 /// with given `DefId` and substs. Since this is used to synthesize
2145 /// MIR, assumes `user_ty` is None.
2146 pub fn function_handle<'a>(
2147 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2149 substs: &'tcx Substs<'tcx>,
2152 let ty = tcx.type_of(def_id).subst(tcx, substs);
2153 Operand::Constant(box Constant {
2157 literal: tcx.mk_lazy_const(
2158 ty::LazyConst::Evaluated(ty::Const::zero_sized(ty)),
2163 pub fn to_copy(&self) -> Self {
2165 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2166 Operand::Move(ref place) => Operand::Copy(place.clone()),
2171 ///////////////////////////////////////////////////////////////////////////
2174 #[derive(Clone, RustcEncodable, RustcDecodable)]
2175 pub enum Rvalue<'tcx> {
2176 /// x (either a move or copy, depending on type of x)
2180 Repeat(Operand<'tcx>, u64),
2183 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2185 /// length of a [X] or [X;n] value
2188 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2190 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2191 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2193 NullaryOp(NullOp, Ty<'tcx>),
2194 UnaryOp(UnOp, Operand<'tcx>),
2196 /// Read the discriminant of an ADT.
2198 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2199 /// be defined to return, say, a 0) if ADT is not an enum.
2200 Discriminant(Place<'tcx>),
2202 /// Creates an aggregate value, like a tuple or struct. This is
2203 /// only needed because we want to distinguish `dest = Foo { x:
2204 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2205 /// that `Foo` has a destructor. These rvalues can be optimized
2206 /// away after type-checking and before lowering.
2207 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2210 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2214 /// Converts unique, zero-sized type for a fn to fn()
2217 /// Converts non capturing closure to fn()
2220 /// Converts safe fn() to unsafe fn()
2223 /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
2224 /// codegen must figure out the details once full monomorphization
2225 /// is known. For example, this could be used to cast from a
2226 /// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<dyn Trait>`
2227 /// (presuming `T: Trait`).
2231 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2232 pub enum AggregateKind<'tcx> {
2233 /// The type is of the element
2237 /// The second field is the variant index. It's equal to 0 for struct
2238 /// and union expressions. The fourth field is
2239 /// active field number and is present only for union expressions
2240 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2241 /// active field index would identity the field `c`
2246 Option<UserTypeAnnotationIndex>,
2250 Closure(DefId, ClosureSubsts<'tcx>),
2251 Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
2254 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2256 /// The `+` operator (addition)
2258 /// The `-` operator (subtraction)
2260 /// The `*` operator (multiplication)
2262 /// The `/` operator (division)
2264 /// The `%` operator (modulus)
2266 /// The `^` operator (bitwise xor)
2268 /// The `&` operator (bitwise and)
2270 /// The `|` operator (bitwise or)
2272 /// The `<<` operator (shift left)
2274 /// The `>>` operator (shift right)
2276 /// The `==` operator (equality)
2278 /// The `<` operator (less than)
2280 /// The `<=` operator (less than or equal to)
2282 /// The `!=` operator (not equal to)
2284 /// The `>=` operator (greater than or equal to)
2286 /// The `>` operator (greater than)
2288 /// The `ptr.offset` operator
2293 pub fn is_checkable(self) -> bool {
2296 Add | Sub | Mul | Shl | Shr => true,
2302 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2304 /// Returns the size of a value of that type
2306 /// Creates a new uninitialized box for a value of that type
2310 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2312 /// The `!` operator for logical inversion
2314 /// The `-` operator for negation
2318 impl<'tcx> Debug for Rvalue<'tcx> {
2319 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2320 use self::Rvalue::*;
2323 Use(ref place) => write!(fmt, "{:?}", place),
2324 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2325 Len(ref a) => write!(fmt, "Len({:?})", a),
2326 Cast(ref kind, ref place, ref ty) => {
2327 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2329 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2330 CheckedBinaryOp(ref op, ref a, ref b) => {
2331 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2333 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2334 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2335 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2336 Ref(region, borrow_kind, ref place) => {
2337 let kind_str = match borrow_kind {
2338 BorrowKind::Shared => "",
2339 BorrowKind::Shallow => "shallow ",
2340 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2343 // When printing regions, add trailing space if necessary.
2344 let region = if ppaux::verbose() || ppaux::identify_regions() {
2345 let mut region = region.to_string();
2346 if region.len() > 0 {
2351 // Do not even print 'static
2354 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2357 Aggregate(ref kind, ref places) => {
2358 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2359 let mut tuple_fmt = fmt.debug_tuple("");
2360 for place in places {
2361 tuple_fmt.field(place);
2367 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2369 AggregateKind::Tuple => match places.len() {
2370 0 => write!(fmt, "()"),
2371 1 => write!(fmt, "({:?},)", places[0]),
2372 _ => fmt_tuple(fmt, places),
2375 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2376 let variant_def = &adt_def.variants[variant];
2378 ppaux::parameterized(fmt, substs, variant_def.did, &[])?;
2380 match variant_def.ctor_kind {
2381 CtorKind::Const => Ok(()),
2382 CtorKind::Fn => fmt_tuple(fmt, places),
2383 CtorKind::Fictive => {
2384 let mut struct_fmt = fmt.debug_struct("");
2385 for (field, place) in variant_def.fields.iter().zip(places) {
2386 struct_fmt.field(&field.ident.as_str(), place);
2393 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2394 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
2395 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2396 format!("[closure@{:?}]", node_id)
2398 format!("[closure@{:?}]", tcx.hir().span(node_id))
2400 let mut struct_fmt = fmt.debug_struct(&name);
2402 tcx.with_freevars(node_id, |freevars| {
2403 for (freevar, place) in freevars.iter().zip(places) {
2404 let var_name = tcx.hir().name(freevar.var_id());
2405 struct_fmt.field(&var_name.as_str(), place);
2411 write!(fmt, "[closure]")
2415 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2416 if let Some(node_id) = tcx.hir().as_local_node_id(def_id) {
2417 let name = format!("[generator@{:?}]", tcx.hir().span(node_id));
2418 let mut struct_fmt = fmt.debug_struct(&name);
2420 tcx.with_freevars(node_id, |freevars| {
2421 for (freevar, place) in freevars.iter().zip(places) {
2422 let var_name = tcx.hir().name(freevar.var_id());
2423 struct_fmt.field(&var_name.as_str(), place);
2425 struct_fmt.field("$state", &places[freevars.len()]);
2426 for i in (freevars.len() + 1)..places.len() {
2428 .field(&format!("${}", i - freevars.len() - 1), &places[i]);
2434 write!(fmt, "[generator]")
2443 ///////////////////////////////////////////////////////////////////////////
2446 /// Two constants are equal if they are the same constant. Note that
2447 /// this does not necessarily mean that they are "==" in Rust -- in
2448 /// particular one must be wary of `NaN`!
2450 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2451 pub struct Constant<'tcx> {
2455 /// Optional user-given type: for something like
2456 /// `collect::<Vec<_>>`, this would be present and would
2457 /// indicate that `Vec<_>` was explicitly specified.
2459 /// Needed for NLL to impose user-given type constraints.
2460 pub user_ty: Option<UserTypeAnnotationIndex>,
2462 pub literal: &'tcx ty::LazyConst<'tcx>,
2465 /// A collection of projections into user types.
2467 /// They are projections because a binding can occur a part of a
2468 /// parent pattern that has been ascribed a type.
2470 /// Its a collection because there can be multiple type ascriptions on
2471 /// the path from the root of the pattern down to the binding itself.
2476 /// struct S<'a>((i32, &'a str), String);
2477 /// let S((_, w): (i32, &'static str), _): S = ...;
2478 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2479 /// // --------------------------------- ^ (2)
2482 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2483 /// ascribed the type `(i32, &'static str)`.
2485 /// The highlights labelled `(2)` show the whole pattern being
2486 /// ascribed the type `S`.
2488 /// In this example, when we descend to `w`, we will have built up the
2489 /// following two projected types:
2491 /// * base: `S`, projection: `(base.0).1`
2492 /// * base: `(i32, &'static str)`, projection: `base.1`
2494 /// The first will lead to the constraint `w: &'1 str` (for some
2495 /// inferred region `'1`). The second will lead to the constraint `w:
2497 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2498 pub struct UserTypeProjections<'tcx> {
2499 pub(crate) contents: Vec<(UserTypeProjection<'tcx>, Span)>,
2502 BraceStructTypeFoldableImpl! {
2503 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjections<'tcx> {
2508 impl<'tcx> UserTypeProjections<'tcx> {
2509 pub fn none() -> Self {
2510 UserTypeProjections { contents: vec![] }
2513 pub fn from_projections(projs: impl Iterator<Item=(UserTypeProjection<'tcx>, Span)>) -> Self {
2514 UserTypeProjections { contents: projs.collect() }
2517 pub fn projections_and_spans(&self) -> impl Iterator<Item=&(UserTypeProjection<'tcx>, Span)> {
2518 self.contents.iter()
2521 pub fn projections(&self) -> impl Iterator<Item=&UserTypeProjection<'tcx>> {
2522 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2525 pub fn push_projection(
2527 user_ty: &UserTypeProjection<'tcx>,
2530 self.contents.push((user_ty.clone(), span));
2536 mut f: impl FnMut(UserTypeProjection<'tcx>) -> UserTypeProjection<'tcx>
2538 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2542 pub fn index(self) -> Self {
2543 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2546 pub fn subslice(self, from: u32, to: u32) -> Self {
2547 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2550 pub fn deref(self) -> Self {
2551 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2554 pub fn leaf(self, field: Field) -> Self {
2555 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2560 adt_def: &'tcx AdtDef,
2561 variant_index: VariantIdx,
2564 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2568 /// Encodes the effect of a user-supplied type annotation on the
2569 /// subcomponents of a pattern. The effect is determined by applying the
2570 /// given list of proejctions to some underlying base type. Often,
2571 /// the projection element list `projs` is empty, in which case this
2572 /// directly encodes a type in `base`. But in the case of complex patterns with
2573 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2574 /// in which case the `projs` vector is used.
2578 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2580 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2581 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2582 /// determined by finding the type of the `.0` field from `T`.
2583 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2584 pub struct UserTypeProjection<'tcx> {
2585 pub base: UserTypeAnnotationIndex,
2586 pub projs: Vec<ProjectionElem<'tcx, (), ()>>,
2589 impl<'tcx> Copy for ProjectionKind<'tcx> { }
2591 impl<'tcx> UserTypeProjection<'tcx> {
2592 pub(crate) fn index(mut self) -> Self {
2593 self.projs.push(ProjectionElem::Index(()));
2597 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2598 self.projs.push(ProjectionElem::Subslice { from, to });
2602 pub(crate) fn deref(mut self) -> Self {
2603 self.projs.push(ProjectionElem::Deref);
2607 pub(crate) fn leaf(mut self, field: Field) -> Self {
2608 self.projs.push(ProjectionElem::Field(field, ()));
2612 pub(crate) fn variant(
2614 adt_def: &'tcx AdtDef,
2615 variant_index: VariantIdx,
2618 self.projs.push(ProjectionElem::Downcast(adt_def, variant_index));
2619 self.projs.push(ProjectionElem::Field(field, ()));
2624 CloneTypeFoldableAndLiftImpls! { ProjectionKind<'tcx>, }
2626 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection<'tcx> {
2627 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2628 use crate::mir::ProjectionElem::*;
2630 let base = self.base.fold_with(folder);
2631 let projs: Vec<_> = self.projs
2636 Field(f, ()) => Field(f.clone(), ()),
2637 Index(()) => Index(()),
2638 elem => elem.clone(),
2642 UserTypeProjection { base, projs }
2645 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2646 self.base.visit_with(visitor)
2647 // Note: there's nothing in `self.proj` to visit.
2652 pub struct Promoted {
2653 DEBUG_FORMAT = "promoted[{}]"
2657 impl<'tcx> Debug for Constant<'tcx> {
2658 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2659 write!(fmt, "const ")?;
2660 fmt_lazy_const_val(fmt, self.literal)
2664 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
2665 pub fn fmt_lazy_const_val(f: &mut impl Write, const_val: &ty::LazyConst<'_>) -> fmt::Result {
2667 ty::LazyConst::Unevaluated(..) => write!(f, "{:?}", const_val),
2668 ty::LazyConst::Evaluated(c) => fmt_const_val(f, c),
2672 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
2673 pub fn fmt_const_val(f: &mut impl Write, const_val: ty::Const<'_>) -> fmt::Result {
2674 use crate::ty::TyKind::*;
2675 let value = const_val.val;
2676 let ty = const_val.ty;
2677 // print some primitives
2678 if let ConstValue::Scalar(Scalar::Bits { bits, .. }) = value {
2680 Bool if bits == 0 => return write!(f, "false"),
2681 Bool if bits == 1 => return write!(f, "true"),
2682 Float(ast::FloatTy::F32) => return write!(f, "{}f32", Single::from_bits(bits)),
2683 Float(ast::FloatTy::F64) => return write!(f, "{}f64", Double::from_bits(bits)),
2684 Uint(ui) => return write!(f, "{:?}{}", bits, ui),
2686 let bit_width = ty::tls::with(|tcx| {
2687 let ty = tcx.lift_to_global(&ty).unwrap();
2688 tcx.layout_of(ty::ParamEnv::empty().and(ty))
2693 let shift = 128 - bit_width;
2694 return write!(f, "{:?}{}", ((bits as i128) << shift) >> shift, i);
2696 Char => return write!(f, "{:?}", ::std::char::from_u32(bits as u32).unwrap()),
2700 // print function definitions
2701 if let FnDef(did, _) = ty.sty {
2702 return write!(f, "{}", item_path_str(did));
2704 // print string literals
2705 if let ConstValue::Slice(ptr, len) = value {
2706 if let Scalar::Ptr(ptr) = ptr {
2707 if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty {
2708 return ty::tls::with(|tcx| {
2709 let alloc = tcx.alloc_map.lock().get(ptr.alloc_id);
2710 if let Some(interpret::AllocKind::Memory(alloc)) = alloc {
2711 assert_eq!(len as usize as u64, len);
2713 &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
2714 let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
2715 write!(f, "{:?}", s)
2717 write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len)
2723 // just raw dump everything else
2724 write!(f, "{:?}:{}", value, ty)
2727 fn item_path_str(def_id: DefId) -> String {
2728 ty::tls::with(|tcx| tcx.item_path_str(def_id))
2731 impl<'tcx> graph::DirectedGraph for Mir<'tcx> {
2732 type Node = BasicBlock;
2735 impl<'tcx> graph::WithNumNodes for Mir<'tcx> {
2736 fn num_nodes(&self) -> usize {
2737 self.basic_blocks.len()
2741 impl<'tcx> graph::WithStartNode for Mir<'tcx> {
2742 fn start_node(&self) -> Self::Node {
2747 impl<'tcx> graph::WithPredecessors for Mir<'tcx> {
2748 fn predecessors<'graph>(
2751 ) -> <Self as GraphPredecessors<'graph>>::Iter {
2752 self.predecessors_for(node).clone().into_iter()
2756 impl<'tcx> graph::WithSuccessors for Mir<'tcx> {
2757 fn successors<'graph>(
2760 ) -> <Self as GraphSuccessors<'graph>>::Iter {
2761 self.basic_blocks[node].terminator().successors().cloned()
2765 impl<'a, 'b> graph::GraphPredecessors<'b> for Mir<'a> {
2766 type Item = BasicBlock;
2767 type Iter = IntoIter<BasicBlock>;
2770 impl<'a, 'b> graph::GraphSuccessors<'b> for Mir<'a> {
2771 type Item = BasicBlock;
2772 type Iter = iter::Cloned<Successors<'b>>;
2775 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
2776 pub struct Location {
2777 /// the location is within this block
2778 pub block: BasicBlock,
2780 /// the location is the start of the statement; or, if `statement_index`
2781 /// == num-statements, then the start of the terminator.
2782 pub statement_index: usize,
2785 impl fmt::Debug for Location {
2786 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2787 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2792 pub const START: Location = Location {
2797 /// Returns the location immediately after this one within the enclosing block.
2799 /// Note that if this location represents a terminator, then the
2800 /// resulting location would be out of bounds and invalid.
2801 pub fn successor_within_block(&self) -> Location {
2804 statement_index: self.statement_index + 1,
2808 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2809 pub fn is_predecessor_of<'tcx>(&self, other: Location, mir: &Mir<'tcx>) -> bool {
2810 // If we are in the same block as the other location and are an earlier statement
2811 // then we are a predecessor of `other`.
2812 if self.block == other.block && self.statement_index < other.statement_index {
2816 // If we're in another block, then we want to check that block is a predecessor of `other`.
2817 let mut queue: Vec<BasicBlock> = mir.predecessors_for(other.block).clone();
2818 let mut visited = FxHashSet::default();
2820 while let Some(block) = queue.pop() {
2821 // If we haven't visited this block before, then make sure we visit it's predecessors.
2822 if visited.insert(block) {
2823 queue.append(&mut mir.predecessors_for(block).clone());
2828 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2829 // we found that block by looking at the predecessors of `other`).
2830 if self.block == block {
2838 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2839 if self.block == other.block {
2840 self.statement_index <= other.statement_index
2842 dominators.is_dominated_by(other.block, self.block)
2847 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2848 pub enum UnsafetyViolationKind {
2850 /// Permitted in const fn and regular fns.
2852 ExternStatic(ast::NodeId),
2853 BorrowPacked(ast::NodeId),
2856 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2857 pub struct UnsafetyViolation {
2858 pub source_info: SourceInfo,
2859 pub description: InternedString,
2860 pub details: InternedString,
2861 pub kind: UnsafetyViolationKind,
2864 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2865 pub struct UnsafetyCheckResult {
2866 /// Violations that are propagated *upwards* from this function
2867 pub violations: Lrc<[UnsafetyViolation]>,
2868 /// unsafe blocks in this function, along with whether they are used. This is
2869 /// used for the "unused_unsafe" lint.
2870 pub unsafe_blocks: Lrc<[(ast::NodeId, bool)]>,
2873 /// The layout of generator state
2874 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2875 pub struct GeneratorLayout<'tcx> {
2876 pub fields: Vec<LocalDecl<'tcx>>,
2879 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2880 pub struct BorrowCheckResult<'gcx> {
2881 pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
2882 pub used_mut_upvars: SmallVec<[Field; 8]>,
2885 /// After we borrow check a closure, we are left with various
2886 /// requirements that we have inferred between the free regions that
2887 /// appear in the closure's signature or on its field types. These
2888 /// requirements are then verified and proved by the closure's
2889 /// creating function. This struct encodes those requirements.
2891 /// The requirements are listed as being between various
2892 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2893 /// vids refer to the free regions that appear in the closure (or
2894 /// generator's) type, in order of appearance. (This numbering is
2895 /// actually defined by the `UniversalRegions` struct in the NLL
2896 /// region checker. See for example
2897 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2898 /// regions in the closure's type "as if" they were erased, so their
2899 /// precise identity is not important, only their position.
2901 /// Example: If type check produces a closure with the closure substs:
2904 /// ClosureSubsts = [
2905 /// i8, // the "closure kind"
2906 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2907 /// &'a String, // some upvar
2911 /// here, there is one unique free region (`'a`) but it appears
2912 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2915 /// ClosureSubsts = [
2916 /// i8, // the "closure kind"
2917 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2918 /// &'2 String, // some upvar
2922 /// Now the code might impose a requirement like `'1: '2`. When an
2923 /// instance of the closure is created, the corresponding free regions
2924 /// can be extracted from its type and constrained to have the given
2925 /// outlives relationship.
2927 /// In some cases, we have to record outlives requirements between
2928 /// types and regions as well. In that case, if those types include
2929 /// any regions, those regions are recorded as `ReClosureBound`
2930 /// instances assigned one of these same indices. Those regions will
2931 /// be substituted away by the creator. We use `ReClosureBound` in
2932 /// that case because the regions must be allocated in the global
2933 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
2934 /// internally within the rest of the NLL code).
2935 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2936 pub struct ClosureRegionRequirements<'gcx> {
2937 /// The number of external regions defined on the closure. In our
2938 /// example above, it would be 3 -- one for `'static`, then `'1`
2939 /// and `'2`. This is just used for a sanity check later on, to
2940 /// make sure that the number of regions we see at the callsite
2942 pub num_external_vids: usize,
2944 /// Requirements between the various free regions defined in
2946 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
2949 /// Indicates an outlives constraint between a type or between two
2950 /// free-regions declared on the closure.
2951 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2952 pub struct ClosureOutlivesRequirement<'tcx> {
2953 // This region or type ...
2954 pub subject: ClosureOutlivesSubject<'tcx>,
2956 // ... must outlive this one.
2957 pub outlived_free_region: ty::RegionVid,
2959 // If not, report an error here ...
2960 pub blame_span: Span,
2962 // ... due to this reason.
2963 pub category: ConstraintCategory,
2966 /// Outlives constraints can be categorized to determine whether and why they
2967 /// are interesting (for error reporting). Order of variants indicates sort
2968 /// order of the category, thereby influencing diagnostic output.
2970 /// See also [rustc_mir::borrow_check::nll::constraints]
2971 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
2972 pub enum ConstraintCategory {
2980 /// A constraint that came from checking the body of a closure.
2982 /// We try to get the category that the closure used when reporting this.
2990 /// A "boring" constraint (caused by the given location) is one that
2991 /// the user probably doesn't want to see described in diagnostics,
2992 /// because it is kind of an artifact of the type system setup.
2993 /// Example: `x = Foo { field: y }` technically creates
2994 /// intermediate regions representing the "type of `Foo { field: y
2995 /// }`", and data flows from `y` into those variables, but they
2996 /// are not very interesting. The assignment into `x` on the other
2999 // Boring and applicable everywhere.
3002 /// A constraint that doesn't correspond to anything the user sees.
3006 /// The subject of a ClosureOutlivesRequirement -- that is, the thing
3007 /// that must outlive some region.
3008 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
3009 pub enum ClosureOutlivesSubject<'tcx> {
3010 /// Subject is a type, typically a type parameter, but could also
3011 /// be a projection. Indicates a requirement like `T: 'a` being
3012 /// passed to the caller, where the type here is `T`.
3014 /// The type here is guaranteed not to contain any free regions at
3018 /// Subject is a free region from the closure. Indicates a requirement
3019 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
3020 Region(ty::RegionVid),
3024 * TypeFoldable implementations for MIR types
3027 CloneTypeFoldableAndLiftImpls! {
3037 SourceScopeLocalData,
3038 UserTypeAnnotationIndex,
3041 BraceStructTypeFoldableImpl! {
3042 impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
3046 source_scope_local_data,
3052 user_type_annotations,
3056 control_flow_destroyed,
3062 BraceStructTypeFoldableImpl! {
3063 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
3068 BraceStructTypeFoldableImpl! {
3069 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
3082 BraceStructTypeFoldableImpl! {
3083 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
3090 BraceStructTypeFoldableImpl! {
3091 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
3096 EnumTypeFoldableImpl! {
3097 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
3098 (StatementKind::Assign)(a, b),
3099 (StatementKind::FakeRead)(cause, place),
3100 (StatementKind::SetDiscriminant) { place, variant_index },
3101 (StatementKind::StorageLive)(a),
3102 (StatementKind::StorageDead)(a),
3103 (StatementKind::InlineAsm) { asm, outputs, inputs },
3104 (StatementKind::Retag)(kind, place),
3105 (StatementKind::AscribeUserType)(a, v, b),
3106 (StatementKind::Nop),
3110 EnumTypeFoldableImpl! {
3111 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
3112 (ClearCrossCrate::Clear),
3113 (ClearCrossCrate::Set)(a),
3114 } where T: TypeFoldable<'tcx>
3117 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
3118 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3119 use crate::mir::TerminatorKind::*;
3121 let kind = match self.kind {
3122 Goto { target } => Goto { target },
3129 discr: discr.fold_with(folder),
3130 switch_ty: switch_ty.fold_with(folder),
3131 values: values.clone(),
3132 targets: targets.clone(),
3139 location: location.fold_with(folder),
3148 } => DropAndReplace {
3149 location: location.fold_with(folder),
3150 value: value.fold_with(folder),
3159 value: value.fold_with(folder),
3170 let dest = destination
3172 .map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
3175 func: func.fold_with(folder),
3176 args: args.fold_with(folder),
3189 let msg = if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
3190 EvalErrorKind::BoundsCheck {
3191 len: len.fold_with(folder),
3192 index: index.fold_with(folder),
3198 cond: cond.fold_with(folder),
3205 GeneratorDrop => GeneratorDrop,
3209 Unreachable => Unreachable,
3212 ref imaginary_targets,
3215 imaginary_targets: imaginary_targets.clone(),
3226 source_info: self.source_info,
3231 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3232 use crate::mir::TerminatorKind::*;
3239 } => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
3240 Drop { ref location, .. } => location.visit_with(visitor),
3245 } => location.visit_with(visitor) || value.visit_with(visitor),
3246 Yield { ref value, .. } => value.visit_with(visitor),
3253 let dest = if let Some((ref loc, _)) = *destination {
3254 loc.visit_with(visitor)
3258 dest || func.visit_with(visitor) || args.visit_with(visitor)
3261 ref cond, ref msg, ..
3263 if cond.visit_with(visitor) {
3264 if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
3265 len.visit_with(visitor) || index.visit_with(visitor)
3280 | FalseUnwind { .. } => false,
3285 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3286 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3288 &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
3293 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3294 if let &Place::Projection(ref p) = self {
3295 p.visit_with(visitor)
3302 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3303 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3304 use crate::mir::Rvalue::*;
3306 Use(ref op) => Use(op.fold_with(folder)),
3307 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3308 Ref(region, bk, ref place) => {
3309 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3311 Len(ref place) => Len(place.fold_with(folder)),
3312 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3313 BinaryOp(op, ref rhs, ref lhs) => {
3314 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3316 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3317 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3319 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3320 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3321 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3322 Aggregate(ref kind, ref fields) => {
3323 let kind = box match **kind {
3324 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3325 AggregateKind::Tuple => AggregateKind::Tuple,
3326 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3329 substs.fold_with(folder),
3330 user_ty.fold_with(folder),
3333 AggregateKind::Closure(id, substs) => {
3334 AggregateKind::Closure(id, substs.fold_with(folder))
3336 AggregateKind::Generator(id, substs, movablity) => {
3337 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3340 Aggregate(kind, fields.fold_with(folder))
3345 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3346 use crate::mir::Rvalue::*;
3348 Use(ref op) => op.visit_with(visitor),
3349 Repeat(ref op, _) => op.visit_with(visitor),
3350 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3351 Len(ref place) => place.visit_with(visitor),
3352 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3353 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3354 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3356 UnaryOp(_, ref val) => val.visit_with(visitor),
3357 Discriminant(ref place) => place.visit_with(visitor),
3358 NullaryOp(_, ty) => ty.visit_with(visitor),
3359 Aggregate(ref kind, ref fields) => {
3361 AggregateKind::Array(ty) => ty.visit_with(visitor),
3362 AggregateKind::Tuple => false,
3363 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3364 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3366 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3367 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3368 }) || fields.visit_with(visitor)
3374 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3375 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3377 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3378 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3379 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3383 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3385 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3386 Operand::Constant(ref c) => c.visit_with(visitor),
3391 impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<'tcx, B, V, T>
3393 B: TypeFoldable<'tcx>,
3394 V: TypeFoldable<'tcx>,
3395 T: TypeFoldable<'tcx>,
3397 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3398 use crate::mir::ProjectionElem::*;
3400 let base = self.base.fold_with(folder);
3401 let elem = match self.elem {
3403 Field(f, ref ty) => Field(f, ty.fold_with(folder)),
3404 Index(ref v) => Index(v.fold_with(folder)),
3405 ref elem => elem.clone(),
3408 Projection { base, elem }
3411 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3412 use crate::mir::ProjectionElem::*;
3414 self.base.visit_with(visitor) || match self.elem {
3415 Field(_, ref ty) => ty.visit_with(visitor),
3416 Index(ref v) => v.visit_with(visitor),
3422 impl<'tcx> TypeFoldable<'tcx> for Field {
3423 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
3426 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3431 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3432 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3434 span: self.span.clone(),
3435 ty: self.ty.fold_with(folder),
3436 user_ty: self.user_ty.fold_with(folder),
3437 literal: self.literal.fold_with(folder),
3440 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3441 self.ty.visit_with(visitor) || self.literal.visit_with(visitor)