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, Namespace};
6 use crate::hir::def_id::DefId;
7 use crate::hir::{self, HirId, InlineAsm as HirInlineAsm};
8 use crate::mir::interpret::{ConstValue, InterpError, 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 rustc_macros::HashStable;
19 use crate::rustc_serialize::{self as serialize};
20 use smallvec::SmallVec;
22 use std::fmt::{self, Debug, Formatter, Write};
23 use std::ops::{Index, IndexMut};
25 use std::vec::IntoIter;
26 use std::{iter, mem, option, u32};
27 use syntax::ast::{self, Name};
28 use syntax::symbol::{InternedString, Symbol};
29 use syntax_pos::{Span, DUMMY_SP};
30 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
31 use crate::ty::subst::{Subst, SubstsRef};
32 use crate::ty::layout::VariantIdx;
34 self, AdtDef, CanonicalUserTypeAnnotations, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
35 UserTypeAnnotationIndex,
37 use crate::ty::print::{FmtPrinter, Printer};
38 use crate::ty::adjustment::{PointerCast};
40 pub use crate::mir::interpret::AssertMessage;
50 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
52 pub trait HasLocalDecls<'tcx> {
53 fn local_decls(&self) -> &LocalDecls<'tcx>;
56 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
57 fn local_decls(&self) -> &LocalDecls<'tcx> {
62 impl<'tcx> HasLocalDecls<'tcx> for Mir<'tcx> {
63 fn local_decls(&self) -> &LocalDecls<'tcx> {
68 /// The various "big phases" that MIR goes through.
70 /// Warning: ordering of variants is significant
71 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, PartialOrd, Ord)]
80 /// Gets the index of the current MirPhase within the set of all MirPhases.
81 pub fn phase_index(&self) -> usize {
86 /// Lowered representation of a single function.
87 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
88 pub struct Mir<'tcx> {
89 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
90 /// that indexes into this vector.
91 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
93 /// Records how far through the "desugaring and optimization" process this particular
94 /// MIR has traversed. This is particularly useful when inlining, since in that context
95 /// we instantiate the promoted constants and add them to our promoted vector -- but those
96 /// promoted items have already been optimized, whereas ours have not. This field allows
97 /// us to see the difference and forego optimization on the inlined promoted items.
100 /// List of source scopes; these are referenced by statements
101 /// and used for debuginfo. Indexed by a `SourceScope`.
102 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
104 /// Crate-local information for each source scope, that can't (and
105 /// needn't) be tracked across crates.
106 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
108 /// Rvalues promoted from this function, such as borrows of constants.
109 /// Each of them is the Mir of a constant with the fn's type parameters
110 /// in scope, but a separate set of locals.
111 pub promoted: IndexVec<Promoted, Mir<'tcx>>,
113 /// Yields type of the function, if it is a generator.
114 pub yield_ty: Option<Ty<'tcx>>,
116 /// Generator drop glue
117 pub generator_drop: Option<Box<Mir<'tcx>>>,
119 /// The layout of a generator. Produced by the state transformation.
120 pub generator_layout: Option<GeneratorLayout<'tcx>>,
122 /// Declarations of locals.
124 /// The first local is the return value pointer, followed by `arg_count`
125 /// locals for the function arguments, followed by any user-declared
126 /// variables and temporaries.
127 pub local_decls: LocalDecls<'tcx>,
129 /// User type annotations
130 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
132 /// Number of arguments this function takes.
134 /// Starting at local 1, `arg_count` locals will be provided by the caller
135 /// and can be assumed to be initialized.
137 /// If this MIR was built for a constant, this will be 0.
138 pub arg_count: usize,
140 /// Names and capture modes of all the closure upvars, assuming
141 /// the first argument is either the closure or a reference to it.
142 pub upvar_decls: Vec<UpvarDecl>,
144 /// Mark an argument local (which must be a tuple) as getting passed as
145 /// its individual components at the LLVM level.
147 /// This is used for the "rust-call" ABI.
148 pub spread_arg: Option<Local>,
150 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
151 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
152 /// this conversion from happening and use short circuiting, we will cause the following code
153 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
155 /// List of places where control flow was destroyed. Used for error reporting.
156 pub control_flow_destroyed: Vec<(Span, String)>,
158 /// A span representing this MIR, for error reporting
161 /// A cache for various calculations
165 impl<'tcx> Mir<'tcx> {
167 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
168 source_scopes: IndexVec<SourceScope, SourceScopeData>,
169 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
170 promoted: IndexVec<Promoted, Mir<'tcx>>,
171 yield_ty: Option<Ty<'tcx>>,
172 local_decls: LocalDecls<'tcx>,
173 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
175 upvar_decls: Vec<UpvarDecl>,
177 control_flow_destroyed: Vec<(Span, String)>,
179 // We need `arg_count` locals, and one for the return place
181 local_decls.len() >= arg_count + 1,
182 "expected at least {} locals, got {}",
188 phase: MirPhase::Build,
191 source_scope_local_data,
194 generator_drop: None,
195 generator_layout: None,
197 user_type_annotations,
202 cache: cache::Cache::new(),
203 control_flow_destroyed,
208 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
213 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
214 self.cache.invalidate();
215 &mut self.basic_blocks
219 pub fn basic_blocks_and_local_decls_mut(
222 &mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
223 &mut LocalDecls<'tcx>,
225 self.cache.invalidate();
226 (&mut self.basic_blocks, &mut self.local_decls)
230 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
231 self.cache.predecessors(self)
235 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
236 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
240 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
241 let if_zero_locations = if loc.statement_index == 0 {
242 let predecessor_blocks = self.predecessors_for(loc.block);
243 let num_predecessor_blocks = predecessor_blocks.len();
245 (0..num_predecessor_blocks)
246 .map(move |i| predecessor_blocks[i])
247 .map(move |bb| self.terminator_loc(bb)),
253 let if_not_zero_locations = if loc.statement_index == 0 {
258 statement_index: loc.statement_index - 1,
265 .chain(if_not_zero_locations)
269 pub fn dominators(&self) -> Dominators<BasicBlock> {
274 pub fn local_kind(&self, local: Local) -> LocalKind {
275 let index = local.as_usize();
278 self.local_decls[local].mutability == Mutability::Mut,
279 "return place should be mutable"
282 LocalKind::ReturnPointer
283 } else if index < self.arg_count + 1 {
285 } else if self.local_decls[local].name.is_some() {
292 /// Returns an iterator over all temporaries.
294 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
295 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
296 let local = Local::new(index);
297 if self.local_decls[local].is_user_variable.is_some() {
305 /// Returns an iterator over all user-declared locals.
307 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
308 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
309 let local = Local::new(index);
310 if self.local_decls[local].is_user_variable.is_some() {
318 /// Returns an iterator over all user-declared mutable locals.
320 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
321 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
322 let local = Local::new(index);
323 let decl = &self.local_decls[local];
324 if decl.is_user_variable.is_some() && decl.mutability == Mutability::Mut {
332 /// Returns an iterator over all user-declared mutable arguments and locals.
334 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
335 (1..self.local_decls.len()).filter_map(move |index| {
336 let local = Local::new(index);
337 let decl = &self.local_decls[local];
338 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
339 && decl.mutability == Mutability::Mut
348 /// Returns an iterator over all function arguments.
350 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
351 let arg_count = self.arg_count;
352 (1..=arg_count).map(Local::new)
355 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
356 /// locals that are neither arguments nor the return place).
358 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
359 let arg_count = self.arg_count;
360 let local_count = self.local_decls.len();
361 (arg_count + 1..local_count).map(Local::new)
364 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
365 /// invalidating statement indices in `Location`s.
366 pub fn make_statement_nop(&mut self, location: Location) {
367 let block = &mut self[location.block];
368 debug_assert!(location.statement_index < block.statements.len());
369 block.statements[location.statement_index].make_nop()
372 /// Returns the source info associated with `location`.
373 pub fn source_info(&self, location: Location) -> &SourceInfo {
374 let block = &self[location.block];
375 let stmts = &block.statements;
376 let idx = location.statement_index;
377 if idx < stmts.len() {
378 &stmts[idx].source_info
380 assert_eq!(idx, stmts.len());
381 &block.terminator().source_info
385 /// Checks if `sub` is a sub scope of `sup`
386 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
388 match self.source_scopes[sub].parent_scope {
389 None => return false,
396 /// Returns the return type, it always return first element from `local_decls` array
397 pub fn return_ty(&self) -> Ty<'tcx> {
398 self.local_decls[RETURN_PLACE].ty
401 /// Gets the location of the terminator for the given block
402 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
405 statement_index: self[bb].statements.len(),
410 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
413 /// Unsafe because of a PushUnsafeBlock
415 /// Unsafe because of an unsafe fn
417 /// Unsafe because of an `unsafe` block
418 ExplicitUnsafe(hir::HirId),
421 impl_stable_hash_for!(struct Mir<'tcx> {
425 source_scope_local_data,
431 user_type_annotations,
435 control_flow_destroyed,
440 impl<'tcx> Index<BasicBlock> for Mir<'tcx> {
441 type Output = BasicBlockData<'tcx>;
444 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
445 &self.basic_blocks()[index]
449 impl<'tcx> IndexMut<BasicBlock> for Mir<'tcx> {
451 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
452 &mut self.basic_blocks_mut()[index]
456 #[derive(Copy, Clone, Debug, HashStable)]
457 pub enum ClearCrossCrate<T> {
462 impl<T> ClearCrossCrate<T> {
463 pub fn assert_crate_local(self) -> T {
465 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
466 ClearCrossCrate::Set(v) => v,
471 impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
472 impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
474 /// Grouped information about the source code origin of a MIR entity.
475 /// Intended to be inspected by diagnostics and debuginfo.
476 /// Most passes can work with it as a whole, within a single function.
477 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, HashStable)]
478 pub struct SourceInfo {
479 /// Source span for the AST pertaining to this MIR entity.
482 /// The source scope, keeping track of which bindings can be
483 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
484 pub scope: SourceScope,
487 ///////////////////////////////////////////////////////////////////////////
488 // Mutability and borrow kinds
490 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
491 pub enum Mutability {
496 impl From<Mutability> for hir::Mutability {
497 fn from(m: Mutability) -> Self {
499 Mutability::Mut => hir::MutMutable,
500 Mutability::Not => hir::MutImmutable,
505 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd,
506 Ord, RustcEncodable, RustcDecodable, HashStable)]
507 pub enum BorrowKind {
508 /// Data must be immutable and is aliasable.
511 /// The immediately borrowed place must be immutable, but projections from
512 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
513 /// conflict with a mutable borrow of `a.b.c`.
515 /// This is used when lowering matches: when matching on a place we want to
516 /// ensure that place have the same value from the start of the match until
517 /// an arm is selected. This prevents this code from compiling:
519 /// let mut x = &Some(0);
522 /// Some(_) if { x = &None; false } => (),
526 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
527 /// should not prevent `if let None = x { ... }`, for example, because the
528 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
529 /// We can also report errors with this kind of borrow differently.
532 /// Data must be immutable but not aliasable. This kind of borrow
533 /// cannot currently be expressed by the user and is used only in
534 /// implicit closure bindings. It is needed when the closure is
535 /// borrowing or mutating a mutable referent, e.g.:
537 /// let x: &mut isize = ...;
538 /// let y = || *x += 5;
540 /// If we were to try to translate this closure into a more explicit
541 /// form, we'd encounter an error with the code as written:
543 /// struct Env { x: & &mut isize }
544 /// let x: &mut isize = ...;
545 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
546 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
548 /// This is then illegal because you cannot mutate an `&mut` found
549 /// in an aliasable location. To solve, you'd have to translate with
550 /// an `&mut` borrow:
552 /// struct Env { x: & &mut isize }
553 /// let x: &mut isize = ...;
554 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
555 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
557 /// Now the assignment to `**env.x` is legal, but creating a
558 /// mutable pointer to `x` is not because `x` is not mutable. We
559 /// could fix this by declaring `x` as `let mut x`. This is ok in
560 /// user code, if awkward, but extra weird for closures, since the
561 /// borrow is hidden.
563 /// So we introduce a "unique imm" borrow -- the referent is
564 /// immutable, but not aliasable. This solves the problem. For
565 /// simplicity, we don't give users the way to express this
566 /// borrow, it's just used when translating closures.
569 /// Data is mutable and not aliasable.
571 /// `true` if this borrow arose from method-call auto-ref
572 /// (i.e., `adjustment::Adjust::Borrow`).
573 allow_two_phase_borrow: bool,
578 pub fn allows_two_phase_borrow(&self) -> bool {
580 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
581 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
586 ///////////////////////////////////////////////////////////////////////////
587 // Variables and temps
592 DEBUG_FORMAT = "_{}",
593 const RETURN_PLACE = 0,
597 /// Classifies locals into categories. See `Mir::local_kind`.
598 #[derive(PartialEq, Eq, Debug, HashStable)]
600 /// User-declared variable binding
602 /// Compiler-introduced temporary
604 /// Function argument
606 /// Location of function's return value
610 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
611 pub struct VarBindingForm<'tcx> {
612 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
613 pub binding_mode: ty::BindingMode,
614 /// If an explicit type was provided for this variable binding,
615 /// this holds the source Span of that type.
617 /// NOTE: if you want to change this to a `HirId`, be wary that
618 /// doing so breaks incremental compilation (as of this writing),
619 /// while a `Span` does not cause our tests to fail.
620 pub opt_ty_info: Option<Span>,
621 /// Place of the RHS of the =, or the subject of the `match` where this
622 /// variable is initialized. None in the case of `let PATTERN;`.
623 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
624 /// (a) the right-hand side isn't evaluated as a place expression.
625 /// (b) it gives a way to separate this case from the remaining cases
627 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
628 /// Span of the pattern in which this variable was bound.
632 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
633 pub enum BindingForm<'tcx> {
634 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
635 Var(VarBindingForm<'tcx>),
636 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
637 ImplicitSelf(ImplicitSelfKind),
638 /// Reference used in a guard expression to ensure immutability.
642 /// Represents what type of implicit self a function has, if any.
643 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
644 pub enum ImplicitSelfKind {
645 /// Represents a `fn x(self);`.
647 /// Represents a `fn x(mut self);`.
649 /// Represents a `fn x(&self);`.
651 /// Represents a `fn x(&mut self);`.
653 /// Represents when a function does not have a self argument or
654 /// when a function has a `self: X` argument.
658 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
660 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
667 impl_stable_hash_for!(enum self::ImplicitSelfKind {
675 impl_stable_hash_for!(enum self::MirPhase {
682 mod binding_form_impl {
683 use crate::ich::StableHashingContext;
684 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
686 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
687 fn hash_stable<W: StableHasherResult>(
689 hcx: &mut StableHashingContext<'a>,
690 hasher: &mut StableHasher<W>,
692 use super::BindingForm::*;
693 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
696 Var(binding) => binding.hash_stable(hcx, hasher),
697 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
704 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
705 /// created during evaluation of expressions in a block tail
706 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
708 /// It is used to improve diagnostics when such temporaries are
709 /// involved in borrow_check errors, e.g., explanations of where the
710 /// temporaries come from, when their destructors are run, and/or how
711 /// one might revise the code to satisfy the borrow checker's rules.
712 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
713 pub struct BlockTailInfo {
714 /// If `true`, then the value resulting from evaluating this tail
715 /// expression is ignored by the block's expression context.
717 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
718 /// but not e.g., `let _x = { ...; tail };`
719 pub tail_result_is_ignored: bool,
722 impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
726 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
727 /// argument, or the return place.
728 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
729 pub struct LocalDecl<'tcx> {
730 /// `let mut x` vs `let x`.
732 /// Temporaries and the return place are always mutable.
733 pub mutability: Mutability,
735 /// Some(binding_mode) if this corresponds to a user-declared local variable.
737 /// This is solely used for local diagnostics when generating
738 /// warnings/errors when compiling the current crate, and
739 /// therefore it need not be visible across crates. pnkfelix
740 /// currently hypothesized we *need* to wrap this in a
741 /// `ClearCrossCrate` as long as it carries as `HirId`.
742 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
744 /// `true` if this is an internal local.
746 /// These locals are not based on types in the source code and are only used
747 /// for a few desugarings at the moment.
749 /// The generator transformation will sanity check the locals which are live
750 /// across a suspension point against the type components of the generator
751 /// which type checking knows are live across a suspension point. We need to
752 /// flag drop flags to avoid triggering this check as they are introduced
755 /// Unsafety checking will also ignore dereferences of these locals,
756 /// so they can be used for raw pointers only used in a desugaring.
758 /// This should be sound because the drop flags are fully algebraic, and
759 /// therefore don't affect the OIBIT or outlives properties of the
763 /// If this local is a temporary and `is_block_tail` is `Some`,
764 /// then it is a temporary created for evaluation of some
765 /// subexpression of some block's tail expression (with no
766 /// intervening statement context).
767 pub is_block_tail: Option<BlockTailInfo>,
769 /// Type of this local.
772 /// If the user manually ascribed a type to this variable,
773 /// e.g., via `let x: T`, then we carry that type here. The MIR
774 /// borrow checker needs this information since it can affect
775 /// region inference.
776 pub user_ty: UserTypeProjections,
778 /// Name of the local, used in debuginfo and pretty-printing.
780 /// Note that function arguments can also have this set to `Some(_)`
781 /// to generate better debuginfo.
782 pub name: Option<Name>,
784 /// The *syntactic* (i.e., not visibility) source scope the local is defined
785 /// in. If the local was defined in a let-statement, this
786 /// is *within* the let-statement, rather than outside
789 /// This is needed because the visibility source scope of locals within
790 /// a let-statement is weird.
792 /// The reason is that we want the local to be *within* the let-statement
793 /// for lint purposes, but we want the local to be *after* the let-statement
794 /// for names-in-scope purposes.
796 /// That's it, if we have a let-statement like the one in this
800 /// fn foo(x: &str) {
801 /// #[allow(unused_mut)]
802 /// let mut x: u32 = { // <- one unused mut
803 /// let mut y: u32 = x.parse().unwrap();
810 /// Then, from a lint point of view, the declaration of `x: u32`
811 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
812 /// lint scopes are the same as the AST/HIR nesting.
814 /// However, from a name lookup point of view, the scopes look more like
815 /// as if the let-statements were `match` expressions:
818 /// fn foo(x: &str) {
820 /// match x.parse().unwrap() {
829 /// We care about the name-lookup scopes for debuginfo - if the
830 /// debuginfo instruction pointer is at the call to `x.parse()`, we
831 /// want `x` to refer to `x: &str`, but if it is at the call to
832 /// `drop(x)`, we want it to refer to `x: u32`.
834 /// To allow both uses to work, we need to have more than a single scope
835 /// for a local. We have the `source_info.scope` represent the
836 /// "syntactic" lint scope (with a variable being under its let
837 /// block) while the `visibility_scope` represents the "local variable"
838 /// scope (where the "rest" of a block is under all prior let-statements).
840 /// The end result looks like this:
844 /// │{ argument x: &str }
846 /// │ │{ #[allow(unused_mut)] } // this is actually split into 2 scopes
847 /// │ │ // in practice because I'm lazy.
849 /// │ │← x.source_info.scope
850 /// │ │← `x.parse().unwrap()`
852 /// │ │ │← y.source_info.scope
854 /// │ │ │{ let y: u32 }
856 /// │ │ │← y.visibility_scope
859 /// │ │{ let x: u32 }
860 /// │ │← x.visibility_scope
861 /// │ │← `drop(x)` // this accesses `x: u32`
863 pub source_info: SourceInfo,
865 /// Source scope within which the local is visible (for debuginfo)
866 /// (see `source_info` for more details).
867 pub visibility_scope: SourceScope,
870 impl<'tcx> LocalDecl<'tcx> {
871 /// Returns `true` only if local is a binding that can itself be
872 /// made mutable via the addition of the `mut` keyword, namely
873 /// something like the occurrences of `x` in:
874 /// - `fn foo(x: Type) { ... }`,
876 /// - or `match ... { C(x) => ... }`
877 pub fn can_be_made_mutable(&self) -> bool {
878 match self.is_user_variable {
879 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
880 binding_mode: ty::BindingMode::BindByValue(_),
886 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)))
893 /// Returns `true` if local is definitely not a `ref ident` or
894 /// `ref mut ident` binding. (Such bindings cannot be made into
895 /// mutable bindings, but the inverse does not necessarily hold).
896 pub fn is_nonref_binding(&self) -> bool {
897 match self.is_user_variable {
898 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
899 binding_mode: ty::BindingMode::BindByValue(_),
905 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
911 /// Creates a new `LocalDecl` for a temporary.
913 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
914 Self::new_local(ty, Mutability::Mut, false, span)
917 /// Converts `self` into same `LocalDecl` except tagged as immutable.
919 pub fn immutable(mut self) -> Self {
920 self.mutability = Mutability::Not;
924 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
926 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
927 assert!(self.is_block_tail.is_none());
928 self.is_block_tail = Some(info);
932 /// Creates a new `LocalDecl` for a internal temporary.
934 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
935 Self::new_local(ty, Mutability::Mut, true, span)
941 mutability: Mutability,
948 user_ty: UserTypeProjections::none(),
950 source_info: SourceInfo {
952 scope: OUTERMOST_SOURCE_SCOPE,
954 visibility_scope: OUTERMOST_SOURCE_SCOPE,
956 is_user_variable: None,
961 /// Builds a `LocalDecl` for the return place.
963 /// This must be inserted into the `local_decls` list as the first local.
965 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
967 mutability: Mutability::Mut,
969 user_ty: UserTypeProjections::none(),
970 source_info: SourceInfo {
972 scope: OUTERMOST_SOURCE_SCOPE,
974 visibility_scope: OUTERMOST_SOURCE_SCOPE,
977 name: None, // FIXME maybe we do want some name here?
978 is_user_variable: None,
983 /// A closure capture, with its name and mode.
984 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
985 pub struct UpvarDecl {
986 pub debug_name: Name,
988 /// `HirId` of the captured variable
989 pub var_hir_id: ClearCrossCrate<HirId>,
991 /// If true, the capture is behind a reference.
994 pub mutability: Mutability,
997 ///////////////////////////////////////////////////////////////////////////
1001 pub struct BasicBlock {
1003 DEBUG_FORMAT = "bb{}",
1004 const START_BLOCK = 0,
1009 pub fn start_location(self) -> Location {
1017 ///////////////////////////////////////////////////////////////////////////
1018 // BasicBlockData and Terminator
1020 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1021 pub struct BasicBlockData<'tcx> {
1022 /// List of statements in this block.
1023 pub statements: Vec<Statement<'tcx>>,
1025 /// Terminator for this block.
1027 /// N.B., this should generally ONLY be `None` during construction.
1028 /// Therefore, you should generally access it via the
1029 /// `terminator()` or `terminator_mut()` methods. The only
1030 /// exception is that certain passes, such as `simplify_cfg`, swap
1031 /// out the terminator temporarily with `None` while they continue
1032 /// to recurse over the set of basic blocks.
1033 pub terminator: Option<Terminator<'tcx>>,
1035 /// If true, this block lies on an unwind path. This is used
1036 /// during codegen where distinct kinds of basic blocks may be
1037 /// generated (particularly for MSVC cleanup). Unwind blocks must
1038 /// only branch to other unwind blocks.
1039 pub is_cleanup: bool,
1042 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1043 pub struct Terminator<'tcx> {
1044 pub source_info: SourceInfo,
1045 pub kind: TerminatorKind<'tcx>,
1048 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1049 pub enum TerminatorKind<'tcx> {
1050 /// block should have one successor in the graph; we jump there
1051 Goto { target: BasicBlock },
1053 /// operand evaluates to an integer; jump depending on its value
1054 /// to one of the targets, and otherwise fallback to `otherwise`
1056 /// discriminant value being tested
1057 discr: Operand<'tcx>,
1059 /// type of value being tested
1060 switch_ty: Ty<'tcx>,
1062 /// Possible values. The locations to branch to in each case
1063 /// are found in the corresponding indices from the `targets` vector.
1064 values: Cow<'tcx, [u128]>,
1066 /// Possible branch sites. The last element of this vector is used
1067 /// for the otherwise branch, so targets.len() == values.len() + 1
1069 // This invariant is quite non-obvious and also could be improved.
1070 // One way to make this invariant is to have something like this instead:
1072 // branches: Vec<(ConstInt, BasicBlock)>,
1073 // otherwise: Option<BasicBlock> // exhaustive if None
1075 // However we’ve decided to keep this as-is until we figure a case
1076 // where some other approach seems to be strictly better than other.
1077 targets: Vec<BasicBlock>,
1080 /// Indicates that the landing pad is finished and unwinding should
1081 /// continue. Emitted by build::scope::diverge_cleanup.
1084 /// Indicates that the landing pad is finished and that the process
1085 /// should abort. Used to prevent unwinding for foreign items.
1088 /// Indicates a normal return. The return place should have
1089 /// been filled in by now. This should occur at most once.
1092 /// Indicates a terminator that can never be reached.
1097 location: Place<'tcx>,
1099 unwind: Option<BasicBlock>,
1102 /// Drop the Place and assign the new value over it. This ensures
1103 /// that the assignment to `P` occurs *even if* the destructor for
1104 /// place unwinds. Its semantics are best explained by the
1109 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1117 /// Drop(P, goto BB1, unwind BB2)
1120 /// // P is now uninitialized
1124 /// // P is now uninitialized -- its dtor panicked
1129 location: Place<'tcx>,
1130 value: Operand<'tcx>,
1132 unwind: Option<BasicBlock>,
1135 /// Block ends with a call of a converging function
1137 /// The function that’s being called
1138 func: Operand<'tcx>,
1139 /// Arguments the function is called with.
1140 /// These are owned by the callee, which is free to modify them.
1141 /// This allows the memory occupied by "by-value" arguments to be
1142 /// reused across function calls without duplicating the contents.
1143 args: Vec<Operand<'tcx>>,
1144 /// Destination for the return value. If some, the call is converging.
1145 destination: Option<(Place<'tcx>, BasicBlock)>,
1146 /// Cleanups to be done if the call unwinds.
1147 cleanup: Option<BasicBlock>,
1148 /// Whether this is from a call in HIR, rather than from an overloaded
1149 /// operator. True for overloaded function call.
1150 from_hir_call: bool,
1153 /// Jump to the target if the condition has the expected value,
1154 /// otherwise panic with a message and a cleanup target.
1156 cond: Operand<'tcx>,
1158 msg: AssertMessage<'tcx>,
1160 cleanup: Option<BasicBlock>,
1165 /// The value to return
1166 value: Operand<'tcx>,
1167 /// Where to resume to
1169 /// Cleanup to be done if the generator is dropped at this suspend point
1170 drop: Option<BasicBlock>,
1173 /// Indicates the end of the dropping of a generator
1176 /// A block where control flow only ever takes one real path, but borrowck
1177 /// needs to be more conservative.
1179 /// The target normal control flow will take
1180 real_target: BasicBlock,
1181 /// The list of blocks control flow could conceptually take, but won't
1183 imaginary_targets: Vec<BasicBlock>,
1185 /// A terminator for blocks that only take one path in reality, but where we
1186 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1187 /// This can arise in infinite loops with no function calls for example.
1189 /// The target normal control flow will take
1190 real_target: BasicBlock,
1191 /// The imaginary cleanup block link. This particular path will never be taken
1192 /// in practice, but in order to avoid fragility we want to always
1193 /// consider it in borrowck. We don't want to accept programs which
1194 /// pass borrowck only when panic=abort or some assertions are disabled
1195 /// due to release vs. debug mode builds. This needs to be an Option because
1196 /// of the remove_noop_landing_pads and no_landing_pads passes
1197 unwind: Option<BasicBlock>,
1201 pub type Successors<'a> =
1202 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1203 pub type SuccessorsMut<'a> =
1204 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1206 impl<'tcx> Terminator<'tcx> {
1207 pub fn successors(&self) -> Successors<'_> {
1208 self.kind.successors()
1211 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1212 self.kind.successors_mut()
1215 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1219 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1220 self.kind.unwind_mut()
1224 impl<'tcx> TerminatorKind<'tcx> {
1225 pub fn if_<'a, 'gcx>(
1226 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1227 cond: Operand<'tcx>,
1230 ) -> TerminatorKind<'tcx> {
1231 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1232 TerminatorKind::SwitchInt {
1234 switch_ty: tcx.types.bool,
1235 values: From::from(BOOL_SWITCH_FALSE),
1236 targets: vec![f, t],
1240 pub fn successors(&self) -> Successors<'_> {
1241 use self::TerminatorKind::*;
1252 } => None.into_iter().chain(&[]),
1253 Goto { target: ref t }
1256 cleanup: Some(ref t),
1260 destination: Some((_, ref t)),
1287 } => Some(t).into_iter().chain(&[]),
1289 destination: Some((_, ref t)),
1290 cleanup: Some(ref u),
1300 unwind: Some(ref u),
1305 unwind: Some(ref u),
1310 cleanup: Some(ref u),
1315 unwind: Some(ref u),
1316 } => Some(t).into_iter().chain(slice::from_ref(u)),
1317 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1320 ref imaginary_targets,
1321 } => Some(real_target).into_iter().chain(&imaginary_targets[..]),
1325 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1326 use self::TerminatorKind::*;
1337 } => None.into_iter().chain(&mut []),
1338 Goto { target: ref mut t }
1341 cleanup: Some(ref mut t),
1345 destination: Some((_, ref mut t)),
1370 real_target: ref mut t,
1372 } => Some(t).into_iter().chain(&mut []),
1374 destination: Some((_, ref mut t)),
1375 cleanup: Some(ref mut u),
1380 drop: Some(ref mut u),
1385 unwind: Some(ref mut u),
1390 unwind: Some(ref mut u),
1395 cleanup: Some(ref mut u),
1399 real_target: ref mut t,
1400 unwind: Some(ref mut u),
1401 } => Some(t).into_iter().chain(slice::from_mut(u)),
1404 } => None.into_iter().chain(&mut targets[..]),
1406 ref mut real_target,
1407 ref mut imaginary_targets,
1408 } => Some(real_target)
1410 .chain(&mut imaginary_targets[..]),
1414 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1416 TerminatorKind::Goto { .. }
1417 | TerminatorKind::Resume
1418 | TerminatorKind::Abort
1419 | TerminatorKind::Return
1420 | TerminatorKind::Unreachable
1421 | TerminatorKind::GeneratorDrop
1422 | TerminatorKind::Yield { .. }
1423 | TerminatorKind::SwitchInt { .. }
1424 | TerminatorKind::FalseEdges { .. } => None,
1425 TerminatorKind::Call {
1426 cleanup: ref unwind,
1429 | TerminatorKind::Assert {
1430 cleanup: ref unwind,
1433 | TerminatorKind::DropAndReplace { ref unwind, .. }
1434 | TerminatorKind::Drop { ref unwind, .. }
1435 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1439 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1441 TerminatorKind::Goto { .. }
1442 | TerminatorKind::Resume
1443 | TerminatorKind::Abort
1444 | TerminatorKind::Return
1445 | TerminatorKind::Unreachable
1446 | TerminatorKind::GeneratorDrop
1447 | TerminatorKind::Yield { .. }
1448 | TerminatorKind::SwitchInt { .. }
1449 | TerminatorKind::FalseEdges { .. } => None,
1450 TerminatorKind::Call {
1451 cleanup: ref mut unwind,
1454 | TerminatorKind::Assert {
1455 cleanup: ref mut unwind,
1458 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1459 | TerminatorKind::Drop { ref mut unwind, .. }
1460 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1465 impl<'tcx> BasicBlockData<'tcx> {
1466 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1474 /// Accessor for terminator.
1476 /// Terminator may not be None after construction of the basic block is complete. This accessor
1477 /// provides a convenience way to reach the terminator.
1478 pub fn terminator(&self) -> &Terminator<'tcx> {
1479 self.terminator.as_ref().expect("invalid terminator state")
1482 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1483 self.terminator.as_mut().expect("invalid terminator state")
1486 pub fn retain_statements<F>(&mut self, mut f: F)
1488 F: FnMut(&mut Statement<'_>) -> bool,
1490 for s in &mut self.statements {
1497 pub fn expand_statements<F, I>(&mut self, mut f: F)
1499 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1500 I: iter::TrustedLen<Item = Statement<'tcx>>,
1502 // Gather all the iterators we'll need to splice in, and their positions.
1503 let mut splices: Vec<(usize, I)> = vec![];
1504 let mut extra_stmts = 0;
1505 for (i, s) in self.statements.iter_mut().enumerate() {
1506 if let Some(mut new_stmts) = f(s) {
1507 if let Some(first) = new_stmts.next() {
1508 // We can already store the first new statement.
1511 // Save the other statements for optimized splicing.
1512 let remaining = new_stmts.size_hint().0;
1514 splices.push((i + 1 + extra_stmts, new_stmts));
1515 extra_stmts += remaining;
1523 // Splice in the new statements, from the end of the block.
1524 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1525 // where a range of elements ("gap") is left uninitialized, with
1526 // splicing adding new elements to the end of that gap and moving
1527 // existing elements from before the gap to the end of the gap.
1528 // For now, this is safe code, emulating a gap but initializing it.
1529 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1530 self.statements.resize(
1533 source_info: SourceInfo {
1535 scope: OUTERMOST_SOURCE_SCOPE,
1537 kind: StatementKind::Nop,
1540 for (splice_start, new_stmts) in splices.into_iter().rev() {
1541 let splice_end = splice_start + new_stmts.size_hint().0;
1542 while gap.end > splice_end {
1545 self.statements.swap(gap.start, gap.end);
1547 self.statements.splice(splice_start..splice_end, new_stmts);
1548 gap.end = splice_start;
1552 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1553 if index < self.statements.len() {
1554 &self.statements[index]
1561 impl<'tcx> Debug for TerminatorKind<'tcx> {
1562 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1563 self.fmt_head(fmt)?;
1564 let successor_count = self.successors().count();
1565 let labels = self.fmt_successor_labels();
1566 assert_eq!(successor_count, labels.len());
1568 match successor_count {
1571 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1574 write!(fmt, " -> [")?;
1575 for (i, target) in self.successors().enumerate() {
1579 write!(fmt, "{}: {:?}", labels[i], target)?;
1587 impl<'tcx> TerminatorKind<'tcx> {
1588 /// Write the "head" part of the terminator; that is, its name and the data it uses to pick the
1589 /// successor basic block, if any. The only information not included is the list of possible
1590 /// successors, which may be rendered differently between the text and the graphviz format.
1591 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1592 use self::TerminatorKind::*;
1594 Goto { .. } => write!(fmt, "goto"),
1596 discr: ref place, ..
1597 } => write!(fmt, "switchInt({:?})", place),
1598 Return => write!(fmt, "return"),
1599 GeneratorDrop => write!(fmt, "generator_drop"),
1600 Resume => write!(fmt, "resume"),
1601 Abort => write!(fmt, "abort"),
1602 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1603 Unreachable => write!(fmt, "unreachable"),
1604 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1609 } => write!(fmt, "replace({:?} <- {:?})", location, value),
1616 if let Some((ref destination, _)) = *destination {
1617 write!(fmt, "{:?} = ", destination)?;
1619 write!(fmt, "{:?}(", func)?;
1620 for (index, arg) in args.iter().enumerate() {
1624 write!(fmt, "{:?}", arg)?;
1634 write!(fmt, "assert(")?;
1638 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1640 FalseEdges { .. } => write!(fmt, "falseEdges"),
1641 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1645 /// Returns the list of labels for the edges to the successor basic blocks.
1646 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1647 use self::TerminatorKind::*;
1649 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1650 Goto { .. } => vec!["".into()],
1656 let size = ty::tls::with(|tcx| {
1657 let param_env = ty::ParamEnv::empty();
1658 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1659 tcx.layout_of(param_env.and(switch_ty)).unwrap().size
1664 let mut s = String::new();
1666 val: ConstValue::Scalar(
1669 size: size.bytes() as u8,
1674 fmt_const_val(&mut s, c).unwrap();
1676 }).chain(iter::once("otherwise".into()))
1680 destination: Some(_),
1683 } => vec!["return".into(), "unwind".into()],
1685 destination: Some(_),
1688 } => vec!["return".into()],
1693 } => vec!["unwind".into()],
1699 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1700 Yield { drop: None, .. } => vec!["resume".into()],
1701 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1702 vec!["return".into()]
1709 } => vec!["return".into(), "unwind".into()],
1710 Assert { cleanup: None, .. } => vec!["".into()],
1711 Assert { .. } => vec!["success".into(), "unwind".into()],
1713 ref imaginary_targets,
1716 let mut l = vec!["real".into()];
1717 l.resize(imaginary_targets.len() + 1, "imaginary".into());
1722 } => vec!["real".into(), "cleanup".into()],
1723 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1728 ///////////////////////////////////////////////////////////////////////////
1731 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1732 pub struct Statement<'tcx> {
1733 pub source_info: SourceInfo,
1734 pub kind: StatementKind<'tcx>,
1737 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1738 #[cfg(target_arch = "x86_64")]
1739 static_assert!(MEM_SIZE_OF_STATEMENT: mem::size_of::<Statement<'_>>() == 48);
1741 impl<'tcx> Statement<'tcx> {
1742 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1743 /// invalidating statement indices in `Location`s.
1744 pub fn make_nop(&mut self) {
1745 self.kind = StatementKind::Nop
1748 /// Changes a statement to a nop and returns the original statement.
1749 pub fn replace_nop(&mut self) -> Self {
1751 source_info: self.source_info,
1752 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1757 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1758 pub enum StatementKind<'tcx> {
1759 /// Write the RHS Rvalue to the LHS Place.
1760 Assign(Place<'tcx>, Box<Rvalue<'tcx>>),
1762 /// This represents all the reading that a pattern match may do
1763 /// (e.g., inspecting constants and discriminant values), and the
1764 /// kind of pattern it comes from. This is in order to adapt potential
1765 /// error messages to these specific patterns.
1767 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1768 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1769 FakeRead(FakeReadCause, Place<'tcx>),
1771 /// Write the discriminant for a variant to the enum Place.
1774 variant_index: VariantIdx,
1777 /// Start a live range for the storage of the local.
1780 /// End the current live range for the storage of the local.
1783 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1784 /// of `StatementKind` low.
1785 InlineAsm(Box<InlineAsm<'tcx>>),
1787 /// Retag references in the given place, ensuring they got fresh tags. This is
1788 /// part of the Stacked Borrows model. These statements are currently only interpreted
1789 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1790 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1791 /// for more details.
1792 Retag(RetagKind, Place<'tcx>),
1794 /// Encodes a user's type ascription. These need to be preserved
1795 /// intact so that NLL can respect them. For example:
1799 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1800 /// to the user-given type `T`. The effect depends on the specified variance:
1802 /// - `Covariant` -- requires that `T_y <: T`
1803 /// - `Contravariant` -- requires that `T_y :> T`
1804 /// - `Invariant` -- requires that `T_y == T`
1805 /// - `Bivariant` -- no effect
1806 AscribeUserType(Place<'tcx>, ty::Variance, Box<UserTypeProjection>),
1808 /// No-op. Useful for deleting instructions without affecting statement indices.
1812 /// `RetagKind` describes what kind of retag is to be performed.
1813 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1814 pub enum RetagKind {
1815 /// The initial retag when entering a function
1817 /// Retag preparing for a two-phase borrow
1819 /// Retagging raw pointers
1821 /// A "normal" retag
1825 /// The `FakeReadCause` describes the type of pattern why a `FakeRead` statement exists.
1826 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
1827 pub enum FakeReadCause {
1828 /// Inject a fake read of the borrowed input at the end of each guards
1831 /// This should ensure that you cannot change the variant for an enum while
1832 /// you are in the midst of matching on it.
1835 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1836 /// generate a read of x to check that it is initialized and safe.
1839 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1840 /// in a match guard to ensure that it's value hasn't change by the time
1841 /// we create the OutsideGuard version.
1844 /// Officially, the semantics of
1846 /// `let pattern = <expr>;`
1848 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1849 /// into the pattern.
1851 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1852 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1853 /// but in some cases it can affect the borrow checker, as in #53695.
1854 /// Therefore, we insert a "fake read" here to ensure that we get
1855 /// appropriate errors.
1859 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1860 pub struct InlineAsm<'tcx> {
1861 pub asm: HirInlineAsm,
1862 pub outputs: Box<[Place<'tcx>]>,
1863 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1866 impl<'tcx> Debug for Statement<'tcx> {
1867 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1868 use self::StatementKind::*;
1870 Assign(ref place, ref rv) => write!(fmt, "{:?} = {:?}", place, rv),
1871 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1872 Retag(ref kind, ref place) =>
1873 write!(fmt, "Retag({}{:?})",
1875 RetagKind::FnEntry => "[fn entry] ",
1876 RetagKind::TwoPhase => "[2phase] ",
1877 RetagKind::Raw => "[raw] ",
1878 RetagKind::Default => "",
1882 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1883 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1887 } => write!(fmt, "discriminant({:?}) = {:?}", place, variant_index),
1888 InlineAsm(ref asm) =>
1889 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs),
1890 AscribeUserType(ref place, ref variance, ref c_ty) => {
1891 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1893 Nop => write!(fmt, "nop"),
1898 ///////////////////////////////////////////////////////////////////////////
1901 /// A path to a value; something that can be evaluated without
1902 /// changing or disturbing program state.
1903 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable)]
1904 pub enum Place<'tcx> {
1905 Base(PlaceBase<'tcx>),
1907 /// projection out of a place (access a field, deref a pointer, etc)
1908 Projection(Box<PlaceProjection<'tcx>>),
1911 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable)]
1912 pub enum PlaceBase<'tcx> {
1916 /// static or static mut variable
1917 Static(Box<Static<'tcx>>),
1920 /// We store the normalized type to avoid requiring normalization when reading MIR
1921 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1922 pub struct Static<'tcx> {
1924 pub kind: StaticKind,
1927 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable)]
1928 pub enum StaticKind {
1933 impl_stable_hash_for!(struct Static<'tcx> {
1938 /// The `Projection` data structure defines things of the form `B.x`
1939 /// or `*B` or `B[index]`. Note that it is parameterized because it is
1940 /// shared between `Constant` and `Place`. See the aliases
1941 /// `PlaceProjection` etc below.
1942 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord,
1943 Hash, RustcEncodable, RustcDecodable, HashStable)]
1944 pub struct Projection<B, V, T> {
1946 pub elem: ProjectionElem<V, T>,
1949 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord,
1950 Hash, RustcEncodable, RustcDecodable, HashStable)]
1951 pub enum ProjectionElem<V, T> {
1956 /// These indices are generated by slice patterns. Easiest to explain
1960 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1961 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1962 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1963 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1966 /// index or -index (in Python terms), depending on from_end
1968 /// thing being indexed must be at least this long
1970 /// counting backwards from end?
1974 /// These indices are generated by slice patterns.
1976 /// slice[from:-to] in Python terms.
1982 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1983 /// this for ADTs with more than one variant. It may be better to
1984 /// just introduce it always, or always for enums.
1986 /// The included Symbol is the name of the variant, used for printing MIR.
1987 Downcast(Option<Symbol>, VariantIdx),
1990 /// Alias for projections as they appear in places, where the base is a place
1991 /// and the index is a local.
1992 pub type PlaceProjection<'tcx> = Projection<Place<'tcx>, Local, Ty<'tcx>>;
1994 /// Alias for projections as they appear in places, where the base is a place
1995 /// and the index is a local.
1996 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1998 // at least on 64 bit systems, `PlaceElem` should not be larger than two pointers
1999 static_assert!(PROJECTION_ELEM_IS_2_PTRS_LARGE:
2000 mem::size_of::<PlaceElem<'_>>() <= 16
2003 /// Alias for projections as they appear in `UserTypeProjection`, where we
2004 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
2005 pub type ProjectionKind = ProjectionElem<(), ()>;
2010 DEBUG_FORMAT = "field[{}]"
2014 impl<'tcx> Place<'tcx> {
2015 pub const RETURN_PLACE: Place<'tcx> = Place::Base(PlaceBase::Local(RETURN_PLACE));
2017 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
2018 self.elem(ProjectionElem::Field(f, ty))
2021 pub fn deref(self) -> Place<'tcx> {
2022 self.elem(ProjectionElem::Deref)
2025 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
2026 self.elem(ProjectionElem::Downcast(
2027 Some(adt_def.variants[variant_index].ident.name),
2031 pub fn index(self, index: Local) -> Place<'tcx> {
2032 self.elem(ProjectionElem::Index(index))
2035 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
2036 Place::Projection(Box::new(PlaceProjection { base: self, elem }))
2039 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
2040 /// a single deref of a local.
2042 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
2043 pub fn local(&self) -> Option<Local> {
2045 Place::Base(PlaceBase::Local(local)) |
2046 Place::Projection(box Projection {
2047 base: Place::Base(PlaceBase::Local(local)),
2048 elem: ProjectionElem::Deref,
2054 /// Finds the innermost `Local` from this `Place`.
2055 pub fn base_local(&self) -> Option<Local> {
2057 Place::Base(PlaceBase::Local(local)) => Some(*local),
2058 Place::Projection(box Projection { base, elem: _ }) => base.base_local(),
2059 Place::Base(PlaceBase::Static(..)) => None,
2064 impl<'tcx> Debug for Place<'tcx> {
2065 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2069 Base(PlaceBase::Local(id)) => write!(fmt, "{:?}", id),
2070 Base(PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static(def_id) })) => {
2074 ty::tls::with(|tcx| tcx.def_path_str(def_id)),
2078 Base(PlaceBase::Static(
2079 box self::Static { ty, kind: StaticKind::Promoted(promoted) })
2088 Projection(ref data) => match data.elem {
2089 ProjectionElem::Downcast(Some(name), _index) => {
2090 write!(fmt, "({:?} as {})", data.base, name)
2092 ProjectionElem::Downcast(None, index) => {
2093 write!(fmt, "({:?} as variant#{:?})", data.base, index)
2095 ProjectionElem::Deref => write!(fmt, "(*{:?})", data.base),
2096 ProjectionElem::Field(field, ty) => {
2097 write!(fmt, "({:?}.{:?}: {:?})", data.base, field.index(), ty)
2099 ProjectionElem::Index(ref index) => write!(fmt, "{:?}[{:?}]", data.base, index),
2100 ProjectionElem::ConstantIndex {
2104 } => write!(fmt, "{:?}[{:?} of {:?}]", data.base, offset, min_length),
2105 ProjectionElem::ConstantIndex {
2109 } => write!(fmt, "{:?}[-{:?} of {:?}]", data.base, offset, min_length),
2110 ProjectionElem::Subslice { from, to } if to == 0 => {
2111 write!(fmt, "{:?}[{:?}:]", data.base, from)
2113 ProjectionElem::Subslice { from, to } if from == 0 => {
2114 write!(fmt, "{:?}[:-{:?}]", data.base, to)
2116 ProjectionElem::Subslice { from, to } => {
2117 write!(fmt, "{:?}[{:?}:-{:?}]", data.base, from, to)
2124 ///////////////////////////////////////////////////////////////////////////
2128 pub struct SourceScope {
2130 DEBUG_FORMAT = "scope[{}]",
2131 const OUTERMOST_SOURCE_SCOPE = 0,
2135 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2136 pub struct SourceScopeData {
2138 pub parent_scope: Option<SourceScope>,
2141 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2142 pub struct SourceScopeLocalData {
2143 /// A HirId with lint levels equivalent to this scope's lint levels.
2144 pub lint_root: hir::HirId,
2145 /// The unsafe block that contains this node.
2149 ///////////////////////////////////////////////////////////////////////////
2152 /// These are values that can appear inside an rvalue. They are intentionally
2153 /// limited to prevent rvalues from being nested in one another.
2154 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2155 pub enum Operand<'tcx> {
2156 /// Copy: The value must be available for use afterwards.
2158 /// This implies that the type of the place must be `Copy`; this is true
2159 /// by construction during build, but also checked by the MIR type checker.
2162 /// Move: The value (including old borrows of it) will not be used again.
2164 /// Safe for values of all types (modulo future developments towards `?Move`).
2165 /// Correct usage patterns are enforced by the borrow checker for safe code.
2166 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2169 /// Synthesizes a constant value.
2170 Constant(Box<Constant<'tcx>>),
2173 impl<'tcx> Debug for Operand<'tcx> {
2174 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2175 use self::Operand::*;
2177 Constant(ref a) => write!(fmt, "{:?}", a),
2178 Copy(ref place) => write!(fmt, "{:?}", place),
2179 Move(ref place) => write!(fmt, "move {:?}", place),
2184 impl<'tcx> Operand<'tcx> {
2185 /// Convenience helper to make a constant that refers to the fn
2186 /// with given `DefId` and substs. Since this is used to synthesize
2187 /// MIR, assumes `user_ty` is None.
2188 pub fn function_handle<'a>(
2189 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2191 substs: SubstsRef<'tcx>,
2194 let ty = tcx.type_of(def_id).subst(tcx, substs);
2195 Operand::Constant(box Constant {
2199 literal: tcx.mk_const(
2200 ty::Const::zero_sized(ty),
2205 pub fn to_copy(&self) -> Self {
2207 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2208 Operand::Move(ref place) => Operand::Copy(place.clone()),
2213 ///////////////////////////////////////////////////////////////////////////
2216 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2217 pub enum Rvalue<'tcx> {
2218 /// x (either a move or copy, depending on type of x)
2222 Repeat(Operand<'tcx>, u64),
2225 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2227 /// length of a [X] or [X;n] value
2230 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2232 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2233 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2235 NullaryOp(NullOp, Ty<'tcx>),
2236 UnaryOp(UnOp, Operand<'tcx>),
2238 /// Read the discriminant of an ADT.
2240 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2241 /// be defined to return, say, a 0) if ADT is not an enum.
2242 Discriminant(Place<'tcx>),
2244 /// Creates an aggregate value, like a tuple or struct. This is
2245 /// only needed because we want to distinguish `dest = Foo { x:
2246 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2247 /// that `Foo` has a destructor. These rvalues can be optimized
2248 /// away after type-checking and before lowering.
2249 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2253 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2256 Pointer(PointerCast),
2259 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2260 pub enum AggregateKind<'tcx> {
2261 /// The type is of the element
2265 /// The second field is the variant index. It's equal to 0 for struct
2266 /// and union expressions. The fourth field is
2267 /// active field number and is present only for union expressions
2268 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2269 /// active field index would identity the field `c`
2274 Option<UserTypeAnnotationIndex>,
2278 Closure(DefId, ClosureSubsts<'tcx>),
2279 Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
2282 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2284 /// The `+` operator (addition)
2286 /// The `-` operator (subtraction)
2288 /// The `*` operator (multiplication)
2290 /// The `/` operator (division)
2292 /// The `%` operator (modulus)
2294 /// The `^` operator (bitwise xor)
2296 /// The `&` operator (bitwise and)
2298 /// The `|` operator (bitwise or)
2300 /// The `<<` operator (shift left)
2302 /// The `>>` operator (shift right)
2304 /// The `==` operator (equality)
2306 /// The `<` operator (less than)
2308 /// The `<=` operator (less than or equal to)
2310 /// The `!=` operator (not equal to)
2312 /// The `>=` operator (greater than or equal to)
2314 /// The `>` operator (greater than)
2316 /// The `ptr.offset` operator
2321 pub fn is_checkable(self) -> bool {
2324 Add | Sub | Mul | Shl | Shr => true,
2330 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2332 /// Returns the size of a value of that type
2334 /// Creates a new uninitialized box for a value of that type
2338 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2340 /// The `!` operator for logical inversion
2342 /// The `-` operator for negation
2346 impl<'tcx> Debug for Rvalue<'tcx> {
2347 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2348 use self::Rvalue::*;
2351 Use(ref place) => write!(fmt, "{:?}", place),
2352 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2353 Len(ref a) => write!(fmt, "Len({:?})", a),
2354 Cast(ref kind, ref place, ref ty) => {
2355 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2357 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2358 CheckedBinaryOp(ref op, ref a, ref b) => {
2359 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2361 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2362 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2363 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2364 Ref(region, borrow_kind, ref place) => {
2365 let kind_str = match borrow_kind {
2366 BorrowKind::Shared => "",
2367 BorrowKind::Shallow => "shallow ",
2368 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2371 // When printing regions, add trailing space if necessary.
2372 let print_region = ty::tls::with(|tcx| {
2373 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2375 let region = if print_region {
2376 let mut region = region.to_string();
2377 if region.len() > 0 {
2382 // Do not even print 'static
2385 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2388 Aggregate(ref kind, ref places) => {
2389 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2390 let mut tuple_fmt = fmt.debug_tuple("");
2391 for place in places {
2392 tuple_fmt.field(place);
2398 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2400 AggregateKind::Tuple => match places.len() {
2401 0 => write!(fmt, "()"),
2402 1 => write!(fmt, "({:?},)", places[0]),
2403 _ => fmt_tuple(fmt, places),
2406 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2407 let variant_def = &adt_def.variants[variant];
2410 ty::tls::with(|tcx| {
2411 let substs = tcx.lift(&substs).expect("could not lift for printing");
2412 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2413 .print_def_path(variant_def.def_id, substs)?;
2417 match variant_def.ctor_kind {
2418 CtorKind::Const => Ok(()),
2419 CtorKind::Fn => fmt_tuple(fmt, places),
2420 CtorKind::Fictive => {
2421 let mut struct_fmt = fmt.debug_struct("");
2422 for (field, place) in variant_def.fields.iter().zip(places) {
2423 struct_fmt.field(&field.ident.as_str(), place);
2430 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2431 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2432 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2433 format!("[closure@{:?}]", hir_id)
2435 format!("[closure@{:?}]", tcx.hir().span_by_hir_id(hir_id))
2437 let mut struct_fmt = fmt.debug_struct(&name);
2439 tcx.with_freevars(hir_id, |freevars| {
2440 for (freevar, place) in freevars.iter().zip(places) {
2441 let var_name = tcx.hir().name(freevar.var_id());
2442 struct_fmt.field(&var_name.as_str(), place);
2448 write!(fmt, "[closure]")
2452 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2453 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2454 let name = format!("[generator@{:?}]",
2455 tcx.hir().span_by_hir_id(hir_id));
2456 let mut struct_fmt = fmt.debug_struct(&name);
2458 tcx.with_freevars(hir_id, |freevars| {
2459 for (freevar, place) in freevars.iter().zip(places) {
2460 let var_name = tcx.hir().name(freevar.var_id());
2461 struct_fmt.field(&var_name.as_str(), place);
2463 struct_fmt.field("$state", &places[freevars.len()]);
2464 for i in (freevars.len() + 1)..places.len() {
2466 .field(&format!("${}", i - freevars.len() - 1), &places[i]);
2472 write!(fmt, "[generator]")
2481 ///////////////////////////////////////////////////////////////////////////
2484 /// Two constants are equal if they are the same constant. Note that
2485 /// this does not necessarily mean that they are "==" in Rust -- in
2486 /// particular one must be wary of `NaN`!
2488 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2489 pub struct Constant<'tcx> {
2493 /// Optional user-given type: for something like
2494 /// `collect::<Vec<_>>`, this would be present and would
2495 /// indicate that `Vec<_>` was explicitly specified.
2497 /// Needed for NLL to impose user-given type constraints.
2498 pub user_ty: Option<UserTypeAnnotationIndex>,
2500 pub literal: &'tcx ty::Const<'tcx>,
2503 /// A collection of projections into user types.
2505 /// They are projections because a binding can occur a part of a
2506 /// parent pattern that has been ascribed a type.
2508 /// Its a collection because there can be multiple type ascriptions on
2509 /// the path from the root of the pattern down to the binding itself.
2514 /// struct S<'a>((i32, &'a str), String);
2515 /// let S((_, w): (i32, &'static str), _): S = ...;
2516 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2517 /// // --------------------------------- ^ (2)
2520 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2521 /// ascribed the type `(i32, &'static str)`.
2523 /// The highlights labelled `(2)` show the whole pattern being
2524 /// ascribed the type `S`.
2526 /// In this example, when we descend to `w`, we will have built up the
2527 /// following two projected types:
2529 /// * base: `S`, projection: `(base.0).1`
2530 /// * base: `(i32, &'static str)`, projection: `base.1`
2532 /// The first will lead to the constraint `w: &'1 str` (for some
2533 /// inferred region `'1`). The second will lead to the constraint `w:
2535 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2536 pub struct UserTypeProjections {
2537 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2540 BraceStructTypeFoldableImpl! {
2541 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjections {
2546 impl<'tcx> UserTypeProjections {
2547 pub fn none() -> Self {
2548 UserTypeProjections { contents: vec![] }
2551 pub fn from_projections(projs: impl Iterator<Item=(UserTypeProjection, Span)>) -> Self {
2552 UserTypeProjections { contents: projs.collect() }
2555 pub fn projections_and_spans(&self) -> impl Iterator<Item=&(UserTypeProjection, Span)> {
2556 self.contents.iter()
2559 pub fn projections(&self) -> impl Iterator<Item=&UserTypeProjection> {
2560 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2563 pub fn push_projection(
2565 user_ty: &UserTypeProjection,
2568 self.contents.push((user_ty.clone(), span));
2574 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection
2576 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2580 pub fn index(self) -> Self {
2581 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2584 pub fn subslice(self, from: u32, to: u32) -> Self {
2585 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2588 pub fn deref(self) -> Self {
2589 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2592 pub fn leaf(self, field: Field) -> Self {
2593 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2598 adt_def: &'tcx AdtDef,
2599 variant_index: VariantIdx,
2602 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2606 /// Encodes the effect of a user-supplied type annotation on the
2607 /// subcomponents of a pattern. The effect is determined by applying the
2608 /// given list of proejctions to some underlying base type. Often,
2609 /// the projection element list `projs` is empty, in which case this
2610 /// directly encodes a type in `base`. But in the case of complex patterns with
2611 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2612 /// in which case the `projs` vector is used.
2616 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2618 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2619 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2620 /// determined by finding the type of the `.0` field from `T`.
2621 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2622 pub struct UserTypeProjection {
2623 pub base: UserTypeAnnotationIndex,
2624 pub projs: Vec<ProjectionElem<(), ()>>,
2627 impl Copy for ProjectionKind { }
2629 impl UserTypeProjection {
2630 pub(crate) fn index(mut self) -> Self {
2631 self.projs.push(ProjectionElem::Index(()));
2635 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2636 self.projs.push(ProjectionElem::Subslice { from, to });
2640 pub(crate) fn deref(mut self) -> Self {
2641 self.projs.push(ProjectionElem::Deref);
2645 pub(crate) fn leaf(mut self, field: Field) -> Self {
2646 self.projs.push(ProjectionElem::Field(field, ()));
2650 pub(crate) fn variant(
2652 adt_def: &'tcx AdtDef,
2653 variant_index: VariantIdx,
2656 self.projs.push(ProjectionElem::Downcast(
2657 Some(adt_def.variants[variant_index].ident.name),
2659 self.projs.push(ProjectionElem::Field(field, ()));
2664 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2666 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2667 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2668 use crate::mir::ProjectionElem::*;
2670 let base = self.base.fold_with(folder);
2671 let projs: Vec<_> = self.projs
2676 Field(f, ()) => Field(f.clone(), ()),
2677 Index(()) => Index(()),
2678 elem => elem.clone(),
2682 UserTypeProjection { base, projs }
2685 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2686 self.base.visit_with(visitor)
2687 // Note: there's nothing in `self.proj` to visit.
2692 pub struct Promoted {
2694 DEBUG_FORMAT = "promoted[{}]"
2698 impl<'tcx> Debug for Constant<'tcx> {
2699 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2700 write!(fmt, "const ")?;
2701 fmt_const_val(fmt, *self.literal)
2704 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
2705 pub fn fmt_const_val(f: &mut impl Write, const_val: ty::Const<'_>) -> fmt::Result {
2706 use crate::ty::TyKind::*;
2707 let value = const_val.val;
2708 let ty = const_val.ty;
2709 // print some primitives
2710 if let ConstValue::Scalar(Scalar::Bits { bits, .. }) = value {
2712 Bool if bits == 0 => return write!(f, "false"),
2713 Bool if bits == 1 => return write!(f, "true"),
2714 Float(ast::FloatTy::F32) => return write!(f, "{}f32", Single::from_bits(bits)),
2715 Float(ast::FloatTy::F64) => return write!(f, "{}f64", Double::from_bits(bits)),
2716 Uint(ui) => return write!(f, "{:?}{}", bits, ui),
2718 let bit_width = ty::tls::with(|tcx| {
2719 let ty = tcx.lift_to_global(&ty).unwrap();
2720 tcx.layout_of(ty::ParamEnv::empty().and(ty))
2725 let shift = 128 - bit_width;
2726 return write!(f, "{:?}{}", ((bits as i128) << shift) >> shift, i);
2728 Char => return write!(f, "{:?}", ::std::char::from_u32(bits as u32).unwrap()),
2732 // print function definitions
2733 if let FnDef(did, _) = ty.sty {
2734 return write!(f, "{}", def_path_str(did));
2736 // print string literals
2737 if let ConstValue::Slice(ptr, len) = value {
2738 if let Scalar::Ptr(ptr) = ptr {
2739 if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty {
2740 return ty::tls::with(|tcx| {
2741 let alloc = tcx.alloc_map.lock().get(ptr.alloc_id);
2742 if let Some(interpret::AllocKind::Memory(alloc)) = alloc {
2743 assert_eq!(len as usize as u64, len);
2745 &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
2746 let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
2747 write!(f, "{:?}", s)
2749 write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len)
2755 // just raw dump everything else
2756 write!(f, "{:?} : {}", value, ty)
2759 fn def_path_str(def_id: DefId) -> String {
2760 ty::tls::with(|tcx| tcx.def_path_str(def_id))
2763 impl<'tcx> graph::DirectedGraph for Mir<'tcx> {
2764 type Node = BasicBlock;
2767 impl<'tcx> graph::WithNumNodes for Mir<'tcx> {
2768 fn num_nodes(&self) -> usize {
2769 self.basic_blocks.len()
2773 impl<'tcx> graph::WithStartNode for Mir<'tcx> {
2774 fn start_node(&self) -> Self::Node {
2779 impl<'tcx> graph::WithPredecessors for Mir<'tcx> {
2780 fn predecessors<'graph>(
2783 ) -> <Self as GraphPredecessors<'graph>>::Iter {
2784 self.predecessors_for(node).clone().into_iter()
2788 impl<'tcx> graph::WithSuccessors for Mir<'tcx> {
2789 fn successors<'graph>(
2792 ) -> <Self as GraphSuccessors<'graph>>::Iter {
2793 self.basic_blocks[node].terminator().successors().cloned()
2797 impl<'a, 'b> graph::GraphPredecessors<'b> for Mir<'a> {
2798 type Item = BasicBlock;
2799 type Iter = IntoIter<BasicBlock>;
2802 impl<'a, 'b> graph::GraphSuccessors<'b> for Mir<'a> {
2803 type Item = BasicBlock;
2804 type Iter = iter::Cloned<Successors<'b>>;
2807 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2808 pub struct Location {
2809 /// the location is within this block
2810 pub block: BasicBlock,
2812 /// the location is the start of the statement; or, if `statement_index`
2813 /// == num-statements, then the start of the terminator.
2814 pub statement_index: usize,
2817 impl fmt::Debug for Location {
2818 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2819 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2824 pub const START: Location = Location {
2829 /// Returns the location immediately after this one within the enclosing block.
2831 /// Note that if this location represents a terminator, then the
2832 /// resulting location would be out of bounds and invalid.
2833 pub fn successor_within_block(&self) -> Location {
2836 statement_index: self.statement_index + 1,
2840 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2841 pub fn is_predecessor_of<'tcx>(&self, other: Location, mir: &Mir<'tcx>) -> bool {
2842 // If we are in the same block as the other location and are an earlier statement
2843 // then we are a predecessor of `other`.
2844 if self.block == other.block && self.statement_index < other.statement_index {
2848 // If we're in another block, then we want to check that block is a predecessor of `other`.
2849 let mut queue: Vec<BasicBlock> = mir.predecessors_for(other.block).clone();
2850 let mut visited = FxHashSet::default();
2852 while let Some(block) = queue.pop() {
2853 // If we haven't visited this block before, then make sure we visit it's predecessors.
2854 if visited.insert(block) {
2855 queue.append(&mut mir.predecessors_for(block).clone());
2860 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2861 // we found that block by looking at the predecessors of `other`).
2862 if self.block == block {
2870 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2871 if self.block == other.block {
2872 self.statement_index <= other.statement_index
2874 dominators.is_dominated_by(other.block, self.block)
2879 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2880 pub enum UnsafetyViolationKind {
2882 /// Permitted in const fn and regular fns.
2884 ExternStatic(hir::HirId),
2885 BorrowPacked(hir::HirId),
2888 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2889 pub struct UnsafetyViolation {
2890 pub source_info: SourceInfo,
2891 pub description: InternedString,
2892 pub details: InternedString,
2893 pub kind: UnsafetyViolationKind,
2896 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2897 pub struct UnsafetyCheckResult {
2898 /// Violations that are propagated *upwards* from this function
2899 pub violations: Lrc<[UnsafetyViolation]>,
2900 /// unsafe blocks in this function, along with whether they are used. This is
2901 /// used for the "unused_unsafe" lint.
2902 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2905 /// The layout of generator state
2906 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2907 pub struct GeneratorLayout<'tcx> {
2908 pub fields: Vec<LocalDecl<'tcx>>,
2911 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2912 pub struct BorrowCheckResult<'gcx> {
2913 pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
2914 pub used_mut_upvars: SmallVec<[Field; 8]>,
2917 /// After we borrow check a closure, we are left with various
2918 /// requirements that we have inferred between the free regions that
2919 /// appear in the closure's signature or on its field types. These
2920 /// requirements are then verified and proved by the closure's
2921 /// creating function. This struct encodes those requirements.
2923 /// The requirements are listed as being between various
2924 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2925 /// vids refer to the free regions that appear in the closure (or
2926 /// generator's) type, in order of appearance. (This numbering is
2927 /// actually defined by the `UniversalRegions` struct in the NLL
2928 /// region checker. See for example
2929 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2930 /// regions in the closure's type "as if" they were erased, so their
2931 /// precise identity is not important, only their position.
2933 /// Example: If type check produces a closure with the closure substs:
2936 /// ClosureSubsts = [
2937 /// i8, // the "closure kind"
2938 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2939 /// &'a String, // some upvar
2943 /// here, there is one unique free region (`'a`) but it appears
2944 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2947 /// ClosureSubsts = [
2948 /// i8, // the "closure kind"
2949 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2950 /// &'2 String, // some upvar
2954 /// Now the code might impose a requirement like `'1: '2`. When an
2955 /// instance of the closure is created, the corresponding free regions
2956 /// can be extracted from its type and constrained to have the given
2957 /// outlives relationship.
2959 /// In some cases, we have to record outlives requirements between
2960 /// types and regions as well. In that case, if those types include
2961 /// any regions, those regions are recorded as `ReClosureBound`
2962 /// instances assigned one of these same indices. Those regions will
2963 /// be substituted away by the creator. We use `ReClosureBound` in
2964 /// that case because the regions must be allocated in the global
2965 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
2966 /// internally within the rest of the NLL code).
2967 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2968 pub struct ClosureRegionRequirements<'gcx> {
2969 /// The number of external regions defined on the closure. In our
2970 /// example above, it would be 3 -- one for `'static`, then `'1`
2971 /// and `'2`. This is just used for a sanity check later on, to
2972 /// make sure that the number of regions we see at the callsite
2974 pub num_external_vids: usize,
2976 /// Requirements between the various free regions defined in
2978 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
2981 /// Indicates an outlives constraint between a type or between two
2982 /// free-regions declared on the closure.
2983 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2984 pub struct ClosureOutlivesRequirement<'tcx> {
2985 // This region or type ...
2986 pub subject: ClosureOutlivesSubject<'tcx>,
2988 // ... must outlive this one.
2989 pub outlived_free_region: ty::RegionVid,
2991 // If not, report an error here ...
2992 pub blame_span: Span,
2994 // ... due to this reason.
2995 pub category: ConstraintCategory,
2998 /// Outlives constraints can be categorized to determine whether and why they
2999 /// are interesting (for error reporting). Order of variants indicates sort
3000 /// order of the category, thereby influencing diagnostic output.
3002 /// See also [rustc_mir::borrow_check::nll::constraints]
3003 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord,
3004 Hash, RustcEncodable, RustcDecodable, HashStable)]
3005 pub enum ConstraintCategory {
3013 /// A constraint that came from checking the body of a closure.
3015 /// We try to get the category that the closure used when reporting this.
3023 /// A "boring" constraint (caused by the given location) is one that
3024 /// the user probably doesn't want to see described in diagnostics,
3025 /// because it is kind of an artifact of the type system setup.
3026 /// Example: `x = Foo { field: y }` technically creates
3027 /// intermediate regions representing the "type of `Foo { field: y
3028 /// }`", and data flows from `y` into those variables, but they
3029 /// are not very interesting. The assignment into `x` on the other
3032 // Boring and applicable everywhere.
3035 /// A constraint that doesn't correspond to anything the user sees.
3039 /// The subject of a ClosureOutlivesRequirement -- that is, the thing
3040 /// that must outlive some region.
3041 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
3042 pub enum ClosureOutlivesSubject<'tcx> {
3043 /// Subject is a type, typically a type parameter, but could also
3044 /// be a projection. Indicates a requirement like `T: 'a` being
3045 /// passed to the caller, where the type here is `T`.
3047 /// The type here is guaranteed not to contain any free regions at
3051 /// Subject is a free region from the closure. Indicates a requirement
3052 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
3053 Region(ty::RegionVid),
3057 * TypeFoldable implementations for MIR types
3060 CloneTypeFoldableAndLiftImpls! {
3070 SourceScopeLocalData,
3071 UserTypeAnnotationIndex,
3074 BraceStructTypeFoldableImpl! {
3075 impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
3079 source_scope_local_data,
3085 user_type_annotations,
3089 control_flow_destroyed,
3095 BraceStructTypeFoldableImpl! {
3096 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
3101 BraceStructTypeFoldableImpl! {
3102 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
3115 BraceStructTypeFoldableImpl! {
3116 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
3123 BraceStructTypeFoldableImpl! {
3124 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
3129 EnumTypeFoldableImpl! {
3130 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
3131 (StatementKind::Assign)(a, b),
3132 (StatementKind::FakeRead)(cause, place),
3133 (StatementKind::SetDiscriminant) { place, variant_index },
3134 (StatementKind::StorageLive)(a),
3135 (StatementKind::StorageDead)(a),
3136 (StatementKind::InlineAsm)(a),
3137 (StatementKind::Retag)(kind, place),
3138 (StatementKind::AscribeUserType)(a, v, b),
3139 (StatementKind::Nop),
3143 BraceStructTypeFoldableImpl! {
3144 impl<'tcx> TypeFoldable<'tcx> for InlineAsm<'tcx> {
3151 EnumTypeFoldableImpl! {
3152 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
3153 (ClearCrossCrate::Clear),
3154 (ClearCrossCrate::Set)(a),
3155 } where T: TypeFoldable<'tcx>
3158 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
3159 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3160 use crate::mir::TerminatorKind::*;
3162 let kind = match self.kind {
3163 Goto { target } => Goto { target },
3170 discr: discr.fold_with(folder),
3171 switch_ty: switch_ty.fold_with(folder),
3172 values: values.clone(),
3173 targets: targets.clone(),
3180 location: location.fold_with(folder),
3189 } => DropAndReplace {
3190 location: location.fold_with(folder),
3191 value: value.fold_with(folder),
3200 value: value.fold_with(folder),
3211 let dest = destination
3213 .map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
3216 func: func.fold_with(folder),
3217 args: args.fold_with(folder),
3230 let msg = if let InterpError::BoundsCheck { ref len, ref index } = *msg {
3231 InterpError::BoundsCheck {
3232 len: len.fold_with(folder),
3233 index: index.fold_with(folder),
3239 cond: cond.fold_with(folder),
3246 GeneratorDrop => GeneratorDrop,
3250 Unreachable => Unreachable,
3253 ref imaginary_targets,
3256 imaginary_targets: imaginary_targets.clone(),
3267 source_info: self.source_info,
3272 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3273 use crate::mir::TerminatorKind::*;
3280 } => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
3281 Drop { ref location, .. } => location.visit_with(visitor),
3286 } => location.visit_with(visitor) || value.visit_with(visitor),
3287 Yield { ref value, .. } => value.visit_with(visitor),
3294 let dest = if let Some((ref loc, _)) = *destination {
3295 loc.visit_with(visitor)
3299 dest || func.visit_with(visitor) || args.visit_with(visitor)
3302 ref cond, ref msg, ..
3304 if cond.visit_with(visitor) {
3305 if let InterpError::BoundsCheck { ref len, ref index } = *msg {
3306 len.visit_with(visitor) || index.visit_with(visitor)
3321 | FalseUnwind { .. } => false,
3326 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3327 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3329 &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
3334 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3335 if let &Place::Projection(ref p) = self {
3336 p.visit_with(visitor)
3343 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3344 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3345 use crate::mir::Rvalue::*;
3347 Use(ref op) => Use(op.fold_with(folder)),
3348 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3349 Ref(region, bk, ref place) => {
3350 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3352 Len(ref place) => Len(place.fold_with(folder)),
3353 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3354 BinaryOp(op, ref rhs, ref lhs) => {
3355 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3357 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3358 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3360 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3361 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3362 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3363 Aggregate(ref kind, ref fields) => {
3364 let kind = box match **kind {
3365 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3366 AggregateKind::Tuple => AggregateKind::Tuple,
3367 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3370 substs.fold_with(folder),
3371 user_ty.fold_with(folder),
3374 AggregateKind::Closure(id, substs) => {
3375 AggregateKind::Closure(id, substs.fold_with(folder))
3377 AggregateKind::Generator(id, substs, movablity) => {
3378 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3381 Aggregate(kind, fields.fold_with(folder))
3386 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3387 use crate::mir::Rvalue::*;
3389 Use(ref op) => op.visit_with(visitor),
3390 Repeat(ref op, _) => op.visit_with(visitor),
3391 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3392 Len(ref place) => place.visit_with(visitor),
3393 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3394 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3395 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3397 UnaryOp(_, ref val) => val.visit_with(visitor),
3398 Discriminant(ref place) => place.visit_with(visitor),
3399 NullaryOp(_, ty) => ty.visit_with(visitor),
3400 Aggregate(ref kind, ref fields) => {
3402 AggregateKind::Array(ty) => ty.visit_with(visitor),
3403 AggregateKind::Tuple => false,
3404 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3405 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3407 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3408 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3409 }) || fields.visit_with(visitor)
3415 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3416 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3418 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3419 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3420 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3424 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3426 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3427 Operand::Constant(ref c) => c.visit_with(visitor),
3432 impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<B, V, T>
3434 B: TypeFoldable<'tcx>,
3435 V: TypeFoldable<'tcx>,
3436 T: TypeFoldable<'tcx>,
3438 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3439 use crate::mir::ProjectionElem::*;
3441 let base = self.base.fold_with(folder);
3442 let elem = match self.elem {
3444 Field(f, ref ty) => Field(f, ty.fold_with(folder)),
3445 Index(ref v) => Index(v.fold_with(folder)),
3446 ref elem => elem.clone(),
3449 Projection { base, elem }
3452 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3453 use crate::mir::ProjectionElem::*;
3455 self.base.visit_with(visitor) || match self.elem {
3456 Field(_, ref ty) => ty.visit_with(visitor),
3457 Index(ref v) => v.visit_with(visitor),
3463 impl<'tcx> TypeFoldable<'tcx> for Field {
3464 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
3467 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3472 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3473 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3475 span: self.span.clone(),
3476 ty: self.ty.fold_with(folder),
3477 user_ty: self.user_ty.fold_with(folder),
3478 literal: self.literal.fold_with(folder),
3481 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3482 self.ty.visit_with(visitor) || self.literal.visit_with(visitor)