655 lines
24 KiB
Rust
655 lines
24 KiB
Rust
//! ### Inferring borrow kinds for upvars
|
|
//!
|
|
//! Whenever there is a closure expression, we need to determine how each
|
|
//! upvar is used. We do this by initially assigning each upvar an
|
|
//! immutable "borrow kind" (see `ty::BorrowKind` for details) and then
|
|
//! "escalating" the kind as needed. The borrow kind proceeds according to
|
|
//! the following lattice:
|
|
//!
|
|
//! ty::ImmBorrow -> ty::UniqueImmBorrow -> ty::MutBorrow
|
|
//!
|
|
//! So, for example, if we see an assignment `x = 5` to an upvar `x`, we
|
|
//! will promote its borrow kind to mutable borrow. If we see an `&mut x`
|
|
//! we'll do the same. Naturally, this applies not just to the upvar, but
|
|
//! to everything owned by `x`, so the result is the same for something
|
|
//! like `x.f = 5` and so on (presuming `x` is not a borrowed pointer to a
|
|
//! struct). These adjustments are performed in
|
|
//! `adjust_upvar_borrow_kind()` (you can trace backwards through the code
|
|
//! from there).
|
|
//!
|
|
//! The fact that we are inferring borrow kinds as we go results in a
|
|
//! semi-hacky interaction with mem-categorization. In particular,
|
|
//! mem-categorization will query the current borrow kind as it
|
|
//! categorizes, and we'll return the *current* value, but this may get
|
|
//! adjusted later. Therefore, in this module, we generally ignore the
|
|
//! borrow kind (and derived mutabilities) that are returned from
|
|
//! mem-categorization, since they may be inaccurate. (Another option
|
|
//! would be to use a unification scheme, where instead of returning a
|
|
//! concrete borrow kind like `ty::ImmBorrow`, we return a
|
|
//! `ty::InferBorrow(upvar_id)` or something like that, but this would
|
|
//! then mean that all later passes would have to check for these figments
|
|
//! and report an error, and it just seems like more mess in the end.)
|
|
|
|
use super::FnCtxt;
|
|
|
|
use crate::middle::expr_use_visitor as euv;
|
|
use crate::middle::mem_categorization as mc;
|
|
use crate::middle::mem_categorization::Categorization;
|
|
use rustc::hir;
|
|
use rustc::hir::def_id::DefId;
|
|
use rustc::hir::def_id::LocalDefId;
|
|
use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
|
|
use rustc::infer::UpvarRegion;
|
|
use rustc::ty::{self, Ty, TyCtxt, UpvarSubsts};
|
|
use rustc_data_structures::fx::FxIndexMap;
|
|
use syntax::ast;
|
|
use syntax_pos::Span;
|
|
|
|
impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
|
|
pub fn closure_analyze(&self, body: &'gcx hir::Body) {
|
|
InferBorrowKindVisitor { fcx: self }.visit_body(body);
|
|
|
|
// it's our job to process these.
|
|
assert!(self.deferred_call_resolutions.borrow().is_empty());
|
|
}
|
|
}
|
|
|
|
struct InferBorrowKindVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
|
|
fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> Visitor<'gcx> for InferBorrowKindVisitor<'a, 'gcx, 'tcx> {
|
|
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'gcx> {
|
|
NestedVisitorMap::None
|
|
}
|
|
|
|
fn visit_expr(&mut self, expr: &'gcx hir::Expr) {
|
|
if let hir::ExprKind::Closure(cc, _, body_id, _, _) = expr.node {
|
|
let body = self.fcx.tcx.hir().body(body_id);
|
|
self.visit_body(body);
|
|
self.fcx
|
|
.analyze_closure(expr.hir_id, expr.span, body, cc);
|
|
}
|
|
|
|
intravisit::walk_expr(self, expr);
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
|
|
fn analyze_closure(
|
|
&self,
|
|
closure_hir_id: hir::HirId,
|
|
span: Span,
|
|
body: &hir::Body,
|
|
capture_clause: hir::CaptureClause,
|
|
) {
|
|
/*!
|
|
* Analysis starting point.
|
|
*/
|
|
|
|
debug!(
|
|
"analyze_closure(id={:?}, body.id={:?})",
|
|
closure_hir_id,
|
|
body.id()
|
|
);
|
|
|
|
// Extract the type of the closure.
|
|
let ty = self.node_ty(closure_hir_id);
|
|
let (closure_def_id, substs) = match ty.sty {
|
|
ty::Closure(def_id, substs) => (def_id, UpvarSubsts::Closure(substs)),
|
|
ty::Generator(def_id, substs, _) => (def_id, UpvarSubsts::Generator(substs)),
|
|
ty::Error => {
|
|
// #51714: skip analysis when we have already encountered type errors
|
|
return;
|
|
}
|
|
_ => {
|
|
span_bug!(
|
|
span,
|
|
"type of closure expr {:?} is not a closure {:?}",
|
|
closure_hir_id,
|
|
ty
|
|
);
|
|
}
|
|
};
|
|
|
|
let infer_kind = if let UpvarSubsts::Closure(closure_substs) = substs {
|
|
if self.closure_kind(closure_def_id, closure_substs).is_none() {
|
|
Some(closure_substs)
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
None
|
|
};
|
|
|
|
if let Some(upvars) = self.tcx.upvars(closure_def_id) {
|
|
let mut upvar_list: FxIndexMap<hir::HirId, ty::UpvarId> =
|
|
FxIndexMap::with_capacity_and_hasher(upvars.len(), Default::default());
|
|
for (&var_hir_id, _) in upvars.iter() {
|
|
let upvar_id = ty::UpvarId {
|
|
var_path: ty::UpvarPath {
|
|
hir_id: var_hir_id,
|
|
},
|
|
closure_expr_id: LocalDefId::from_def_id(closure_def_id),
|
|
};
|
|
debug!("seed upvar_id {:?}", upvar_id);
|
|
// Adding the upvar Id to the list of Upvars, which will be added
|
|
// to the map for the closure at the end of the for loop.
|
|
upvar_list.insert(var_hir_id, upvar_id);
|
|
|
|
let capture_kind = match capture_clause {
|
|
hir::CaptureByValue => ty::UpvarCapture::ByValue,
|
|
hir::CaptureByRef => {
|
|
let origin = UpvarRegion(upvar_id, span);
|
|
let upvar_region = self.next_region_var(origin);
|
|
let upvar_borrow = ty::UpvarBorrow {
|
|
kind: ty::ImmBorrow,
|
|
region: upvar_region,
|
|
};
|
|
ty::UpvarCapture::ByRef(upvar_borrow)
|
|
}
|
|
};
|
|
|
|
self.tables
|
|
.borrow_mut()
|
|
.upvar_capture_map
|
|
.insert(upvar_id, capture_kind);
|
|
}
|
|
// Add the vector of upvars to the map keyed with the closure id.
|
|
// This gives us an easier access to them without having to call
|
|
// tcx.upvars again..
|
|
if !upvar_list.is_empty() {
|
|
self.tables
|
|
.borrow_mut()
|
|
.upvar_list
|
|
.insert(closure_def_id, upvar_list);
|
|
}
|
|
}
|
|
|
|
let body_owner_def_id = self.tcx.hir().body_owner_def_id(body.id());
|
|
let region_scope_tree = &self.tcx.region_scope_tree(body_owner_def_id);
|
|
let mut delegate = InferBorrowKind {
|
|
fcx: self,
|
|
closure_def_id: closure_def_id,
|
|
current_closure_kind: ty::ClosureKind::LATTICE_BOTTOM,
|
|
current_origin: None,
|
|
adjust_upvar_captures: ty::UpvarCaptureMap::default(),
|
|
};
|
|
euv::ExprUseVisitor::with_infer(
|
|
&mut delegate,
|
|
&self.infcx,
|
|
self.param_env,
|
|
region_scope_tree,
|
|
&self.tables.borrow(),
|
|
)
|
|
.consume_body(body);
|
|
|
|
if let Some(closure_substs) = infer_kind {
|
|
// Unify the (as yet unbound) type variable in the closure
|
|
// substs with the kind we inferred.
|
|
let inferred_kind = delegate.current_closure_kind;
|
|
let closure_kind_ty = closure_substs.closure_kind_ty(closure_def_id, self.tcx);
|
|
self.demand_eqtype(span, inferred_kind.to_ty(self.tcx), closure_kind_ty);
|
|
|
|
// If we have an origin, store it.
|
|
if let Some(origin) = delegate.current_origin {
|
|
self.tables
|
|
.borrow_mut()
|
|
.closure_kind_origins_mut()
|
|
.insert(closure_hir_id, origin);
|
|
}
|
|
}
|
|
|
|
self.tables
|
|
.borrow_mut()
|
|
.upvar_capture_map
|
|
.extend(delegate.adjust_upvar_captures);
|
|
|
|
// Now that we've analyzed the closure, we know how each
|
|
// variable is borrowed, and we know what traits the closure
|
|
// implements (Fn vs FnMut etc). We now have some updates to do
|
|
// with that information.
|
|
//
|
|
// Note that no closure type C may have an upvar of type C
|
|
// (though it may reference itself via a trait object). This
|
|
// results from the desugaring of closures to a struct like
|
|
// `Foo<..., UV0...UVn>`. If one of those upvars referenced
|
|
// C, then the type would have infinite size (and the
|
|
// inference algorithm will reject it).
|
|
|
|
// Equate the type variables for the upvars with the actual types.
|
|
let final_upvar_tys = self.final_upvar_tys(closure_hir_id);
|
|
debug!(
|
|
"analyze_closure: id={:?} substs={:?} final_upvar_tys={:?}",
|
|
closure_hir_id, substs, final_upvar_tys
|
|
);
|
|
for (upvar_ty, final_upvar_ty) in substs
|
|
.upvar_tys(closure_def_id, self.tcx)
|
|
.zip(final_upvar_tys)
|
|
{
|
|
self.demand_suptype(span, upvar_ty, final_upvar_ty);
|
|
}
|
|
|
|
// If we are also inferred the closure kind here,
|
|
// process any deferred resolutions.
|
|
let deferred_call_resolutions = self.remove_deferred_call_resolutions(closure_def_id);
|
|
for deferred_call_resolution in deferred_call_resolutions {
|
|
deferred_call_resolution.resolve(self);
|
|
}
|
|
}
|
|
|
|
// Returns a list of `ClosureUpvar`s for each upvar.
|
|
fn final_upvar_tys(&self, closure_id: hir::HirId) -> Vec<Ty<'tcx>> {
|
|
// Presently an unboxed closure type cannot "escape" out of a
|
|
// function, so we will only encounter ones that originated in the
|
|
// local crate or were inlined into it along with some function.
|
|
// This may change if abstract return types of some sort are
|
|
// implemented.
|
|
let tcx = self.tcx;
|
|
let closure_def_id = tcx.hir().local_def_id_from_hir_id(closure_id);
|
|
|
|
tcx.upvars(closure_def_id).iter().flat_map(|upvars| {
|
|
upvars
|
|
.iter()
|
|
.map(|(&var_hir_id, _)| {
|
|
let upvar_ty = self.node_ty(var_hir_id);
|
|
let upvar_id = ty::UpvarId {
|
|
var_path: ty::UpvarPath { hir_id: var_hir_id },
|
|
closure_expr_id: LocalDefId::from_def_id(closure_def_id),
|
|
};
|
|
let capture = self.tables.borrow().upvar_capture(upvar_id);
|
|
|
|
debug!(
|
|
"var_id={:?} upvar_ty={:?} capture={:?}",
|
|
var_hir_id, upvar_ty, capture
|
|
);
|
|
|
|
match capture {
|
|
ty::UpvarCapture::ByValue => upvar_ty,
|
|
ty::UpvarCapture::ByRef(borrow) => tcx.mk_ref(
|
|
borrow.region,
|
|
ty::TypeAndMut {
|
|
ty: upvar_ty,
|
|
mutbl: borrow.kind.to_mutbl_lossy(),
|
|
},
|
|
),
|
|
}
|
|
})
|
|
})
|
|
.collect()
|
|
}
|
|
}
|
|
|
|
struct InferBorrowKind<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
|
|
fcx: &'a FnCtxt<'a, 'gcx, 'tcx>,
|
|
|
|
// The def-id of the closure whose kind and upvar accesses are being inferred.
|
|
closure_def_id: DefId,
|
|
|
|
// The kind that we have inferred that the current closure
|
|
// requires. Note that we *always* infer a minimal kind, even if
|
|
// we don't always *use* that in the final result (i.e., sometimes
|
|
// we've taken the closure kind from the expectations instead, and
|
|
// for generators we don't even implement the closure traits
|
|
// really).
|
|
current_closure_kind: ty::ClosureKind,
|
|
|
|
// If we modified `current_closure_kind`, this field contains a `Some()` with the
|
|
// variable access that caused us to do so.
|
|
current_origin: Option<(Span, ast::Name)>,
|
|
|
|
// For each upvar that we access, we track the minimal kind of
|
|
// access we need (ref, ref mut, move, etc).
|
|
adjust_upvar_captures: ty::UpvarCaptureMap<'tcx>,
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> InferBorrowKind<'a, 'gcx, 'tcx> {
|
|
fn adjust_upvar_borrow_kind_for_consume(
|
|
&mut self,
|
|
cmt: &mc::cmt_<'tcx>,
|
|
mode: euv::ConsumeMode,
|
|
) {
|
|
debug!(
|
|
"adjust_upvar_borrow_kind_for_consume(cmt={:?}, mode={:?})",
|
|
cmt, mode
|
|
);
|
|
|
|
// we only care about moves
|
|
match mode {
|
|
euv::Copy => {
|
|
return;
|
|
}
|
|
euv::Move(_) => {}
|
|
}
|
|
|
|
let tcx = self.fcx.tcx;
|
|
|
|
// watch out for a move of the deref of a borrowed pointer;
|
|
// for that to be legal, the upvar would have to be borrowed
|
|
// by value instead
|
|
let guarantor = cmt.guarantor();
|
|
debug!(
|
|
"adjust_upvar_borrow_kind_for_consume: guarantor={:?}",
|
|
guarantor
|
|
);
|
|
debug!(
|
|
"adjust_upvar_borrow_kind_for_consume: guarantor.cat={:?}",
|
|
guarantor.cat
|
|
);
|
|
if let Categorization::Deref(_, mc::BorrowedPtr(..)) = guarantor.cat {
|
|
debug!(
|
|
"adjust_upvar_borrow_kind_for_consume: found deref with note {:?}",
|
|
cmt.note
|
|
);
|
|
match guarantor.note {
|
|
mc::NoteUpvarRef(upvar_id) => {
|
|
debug!(
|
|
"adjust_upvar_borrow_kind_for_consume: \
|
|
setting upvar_id={:?} to by value",
|
|
upvar_id
|
|
);
|
|
|
|
// to move out of an upvar, this must be a FnOnce closure
|
|
self.adjust_closure_kind(
|
|
upvar_id.closure_expr_id,
|
|
ty::ClosureKind::FnOnce,
|
|
guarantor.span,
|
|
var_name(tcx, upvar_id.var_path.hir_id),
|
|
);
|
|
|
|
self.adjust_upvar_captures
|
|
.insert(upvar_id, ty::UpvarCapture::ByValue);
|
|
}
|
|
mc::NoteClosureEnv(upvar_id) => {
|
|
// we get just a closureenv ref if this is a
|
|
// `move` closure, or if the upvar has already
|
|
// been inferred to by-value. In any case, we
|
|
// must still adjust the kind of the closure
|
|
// to be a FnOnce closure to permit moves out
|
|
// of the environment.
|
|
self.adjust_closure_kind(
|
|
upvar_id.closure_expr_id,
|
|
ty::ClosureKind::FnOnce,
|
|
guarantor.span,
|
|
var_name(tcx, upvar_id.var_path.hir_id),
|
|
);
|
|
}
|
|
mc::NoteIndex | mc::NoteNone => {}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Indicates that `cmt` is being directly mutated (e.g., assigned
|
|
/// to). If cmt contains any by-ref upvars, this implies that
|
|
/// those upvars must be borrowed using an `&mut` borrow.
|
|
fn adjust_upvar_borrow_kind_for_mut(&mut self, cmt: &mc::cmt_<'tcx>) {
|
|
debug!("adjust_upvar_borrow_kind_for_mut(cmt={:?})", cmt);
|
|
|
|
match cmt.cat.clone() {
|
|
Categorization::Deref(base, mc::Unique)
|
|
| Categorization::Interior(base, _)
|
|
| Categorization::Downcast(base, _) => {
|
|
// Interior or owned data is mutable if base is
|
|
// mutable, so iterate to the base.
|
|
self.adjust_upvar_borrow_kind_for_mut(&base);
|
|
}
|
|
|
|
Categorization::Deref(base, mc::BorrowedPtr(..)) => {
|
|
if !self.try_adjust_upvar_deref(cmt, ty::MutBorrow) {
|
|
// assignment to deref of an `&mut`
|
|
// borrowed pointer implies that the
|
|
// pointer itself must be unique, but not
|
|
// necessarily *mutable*
|
|
self.adjust_upvar_borrow_kind_for_unique(&base);
|
|
}
|
|
}
|
|
|
|
Categorization::Deref(_, mc::UnsafePtr(..))
|
|
| Categorization::StaticItem
|
|
| Categorization::ThreadLocal(..)
|
|
| Categorization::Rvalue(..)
|
|
| Categorization::Local(_)
|
|
| Categorization::Upvar(..) => {
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
fn adjust_upvar_borrow_kind_for_unique(&mut self, cmt: &mc::cmt_<'tcx>) {
|
|
debug!("adjust_upvar_borrow_kind_for_unique(cmt={:?})", cmt);
|
|
|
|
match cmt.cat.clone() {
|
|
Categorization::Deref(base, mc::Unique)
|
|
| Categorization::Interior(base, _)
|
|
| Categorization::Downcast(base, _) => {
|
|
// Interior or owned data is unique if base is
|
|
// unique.
|
|
self.adjust_upvar_borrow_kind_for_unique(&base);
|
|
}
|
|
|
|
Categorization::Deref(base, mc::BorrowedPtr(..)) => {
|
|
if !self.try_adjust_upvar_deref(cmt, ty::UniqueImmBorrow) {
|
|
// for a borrowed pointer to be unique, its
|
|
// base must be unique
|
|
self.adjust_upvar_borrow_kind_for_unique(&base);
|
|
}
|
|
}
|
|
|
|
Categorization::Deref(_, mc::UnsafePtr(..))
|
|
| Categorization::StaticItem
|
|
| Categorization::ThreadLocal(..)
|
|
| Categorization::Rvalue(..)
|
|
| Categorization::Local(_)
|
|
| Categorization::Upvar(..) => {}
|
|
}
|
|
}
|
|
|
|
fn try_adjust_upvar_deref(
|
|
&mut self,
|
|
cmt: &mc::cmt_<'tcx>,
|
|
borrow_kind: ty::BorrowKind,
|
|
) -> bool {
|
|
assert!(match borrow_kind {
|
|
ty::MutBorrow => true,
|
|
ty::UniqueImmBorrow => true,
|
|
|
|
// imm borrows never require adjusting any kinds, so we don't wind up here
|
|
ty::ImmBorrow => false,
|
|
});
|
|
|
|
let tcx = self.fcx.tcx;
|
|
|
|
match cmt.note {
|
|
mc::NoteUpvarRef(upvar_id) => {
|
|
// if this is an implicit deref of an
|
|
// upvar, then we need to modify the
|
|
// borrow_kind of the upvar to make sure it
|
|
// is inferred to mutable if necessary
|
|
self.adjust_upvar_borrow_kind(upvar_id, borrow_kind);
|
|
|
|
// also need to be in an FnMut closure since this is not an ImmBorrow
|
|
self.adjust_closure_kind(
|
|
upvar_id.closure_expr_id,
|
|
ty::ClosureKind::FnMut,
|
|
cmt.span,
|
|
var_name(tcx, upvar_id.var_path.hir_id),
|
|
);
|
|
|
|
true
|
|
}
|
|
mc::NoteClosureEnv(upvar_id) => {
|
|
// this kind of deref occurs in a `move` closure, or
|
|
// for a by-value upvar; in either case, to mutate an
|
|
// upvar, we need to be an FnMut closure
|
|
self.adjust_closure_kind(
|
|
upvar_id.closure_expr_id,
|
|
ty::ClosureKind::FnMut,
|
|
cmt.span,
|
|
var_name(tcx, upvar_id.var_path.hir_id),
|
|
);
|
|
|
|
true
|
|
}
|
|
mc::NoteIndex | mc::NoteNone => false,
|
|
}
|
|
}
|
|
|
|
/// We infer the borrow_kind with which to borrow upvars in a stack closure.
|
|
/// The borrow_kind basically follows a lattice of `imm < unique-imm < mut`,
|
|
/// moving from left to right as needed (but never right to left).
|
|
/// Here the argument `mutbl` is the borrow_kind that is required by
|
|
/// some particular use.
|
|
fn adjust_upvar_borrow_kind(&mut self, upvar_id: ty::UpvarId, kind: ty::BorrowKind) {
|
|
let upvar_capture = self
|
|
.adjust_upvar_captures
|
|
.get(&upvar_id)
|
|
.cloned()
|
|
.unwrap_or_else(|| self.fcx.tables.borrow().upvar_capture(upvar_id));
|
|
debug!(
|
|
"adjust_upvar_borrow_kind(upvar_id={:?}, upvar_capture={:?}, kind={:?})",
|
|
upvar_id, upvar_capture, kind
|
|
);
|
|
|
|
match upvar_capture {
|
|
ty::UpvarCapture::ByValue => {
|
|
// Upvar is already by-value, the strongest criteria.
|
|
}
|
|
ty::UpvarCapture::ByRef(mut upvar_borrow) => {
|
|
match (upvar_borrow.kind, kind) {
|
|
// Take RHS:
|
|
(ty::ImmBorrow, ty::UniqueImmBorrow)
|
|
| (ty::ImmBorrow, ty::MutBorrow)
|
|
| (ty::UniqueImmBorrow, ty::MutBorrow) => {
|
|
upvar_borrow.kind = kind;
|
|
self.adjust_upvar_captures
|
|
.insert(upvar_id, ty::UpvarCapture::ByRef(upvar_borrow));
|
|
}
|
|
// Take LHS:
|
|
(ty::ImmBorrow, ty::ImmBorrow)
|
|
| (ty::UniqueImmBorrow, ty::ImmBorrow)
|
|
| (ty::UniqueImmBorrow, ty::UniqueImmBorrow)
|
|
| (ty::MutBorrow, _) => {}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn adjust_closure_kind(
|
|
&mut self,
|
|
closure_id: LocalDefId,
|
|
new_kind: ty::ClosureKind,
|
|
upvar_span: Span,
|
|
var_name: ast::Name,
|
|
) {
|
|
debug!(
|
|
"adjust_closure_kind(closure_id={:?}, new_kind={:?}, upvar_span={:?}, var_name={})",
|
|
closure_id, new_kind, upvar_span, var_name
|
|
);
|
|
|
|
// Is this the closure whose kind is currently being inferred?
|
|
if closure_id.to_def_id() != self.closure_def_id {
|
|
debug!("adjust_closure_kind: not current closure");
|
|
return;
|
|
}
|
|
|
|
// closures start out as `Fn`.
|
|
let existing_kind = self.current_closure_kind;
|
|
|
|
debug!(
|
|
"adjust_closure_kind: closure_id={:?}, existing_kind={:?}, new_kind={:?}",
|
|
closure_id, existing_kind, new_kind
|
|
);
|
|
|
|
match (existing_kind, new_kind) {
|
|
(ty::ClosureKind::Fn, ty::ClosureKind::Fn)
|
|
| (ty::ClosureKind::FnMut, ty::ClosureKind::Fn)
|
|
| (ty::ClosureKind::FnMut, ty::ClosureKind::FnMut)
|
|
| (ty::ClosureKind::FnOnce, _) => {
|
|
// no change needed
|
|
}
|
|
|
|
(ty::ClosureKind::Fn, ty::ClosureKind::FnMut)
|
|
| (ty::ClosureKind::Fn, ty::ClosureKind::FnOnce)
|
|
| (ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => {
|
|
// new kind is stronger than the old kind
|
|
self.current_closure_kind = new_kind;
|
|
self.current_origin = Some((upvar_span, var_name));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> euv::Delegate<'tcx> for InferBorrowKind<'a, 'gcx, 'tcx> {
|
|
fn consume(
|
|
&mut self,
|
|
_consume_id: hir::HirId,
|
|
_consume_span: Span,
|
|
cmt: &mc::cmt_<'tcx>,
|
|
mode: euv::ConsumeMode,
|
|
) {
|
|
debug!("consume(cmt={:?},mode={:?})", cmt, mode);
|
|
self.adjust_upvar_borrow_kind_for_consume(cmt, mode);
|
|
}
|
|
|
|
fn matched_pat(
|
|
&mut self,
|
|
_matched_pat: &hir::Pat,
|
|
_cmt: &mc::cmt_<'tcx>,
|
|
_mode: euv::MatchMode,
|
|
) {
|
|
}
|
|
|
|
fn consume_pat(
|
|
&mut self,
|
|
_consume_pat: &hir::Pat,
|
|
cmt: &mc::cmt_<'tcx>,
|
|
mode: euv::ConsumeMode,
|
|
) {
|
|
debug!("consume_pat(cmt={:?},mode={:?})", cmt, mode);
|
|
self.adjust_upvar_borrow_kind_for_consume(cmt, mode);
|
|
}
|
|
|
|
fn borrow(
|
|
&mut self,
|
|
borrow_id: hir::HirId,
|
|
_borrow_span: Span,
|
|
cmt: &mc::cmt_<'tcx>,
|
|
_loan_region: ty::Region<'tcx>,
|
|
bk: ty::BorrowKind,
|
|
_loan_cause: euv::LoanCause,
|
|
) {
|
|
debug!(
|
|
"borrow(borrow_id={}, cmt={:?}, bk={:?})",
|
|
borrow_id, cmt, bk
|
|
);
|
|
|
|
match bk {
|
|
ty::ImmBorrow => {}
|
|
ty::UniqueImmBorrow => {
|
|
self.adjust_upvar_borrow_kind_for_unique(cmt);
|
|
}
|
|
ty::MutBorrow => {
|
|
self.adjust_upvar_borrow_kind_for_mut(cmt);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn decl_without_init(&mut self, _id: hir::HirId, _span: Span) {}
|
|
|
|
fn mutate(
|
|
&mut self,
|
|
_assignment_id: hir::HirId,
|
|
_assignment_span: Span,
|
|
assignee_cmt: &mc::cmt_<'tcx>,
|
|
_mode: euv::MutateMode,
|
|
) {
|
|
debug!("mutate(assignee_cmt={:?})", assignee_cmt);
|
|
|
|
self.adjust_upvar_borrow_kind_for_mut(assignee_cmt);
|
|
}
|
|
}
|
|
|
|
fn var_name(tcx: TyCtxt<'_, '_, '_>, var_hir_id: hir::HirId) -> ast::Name {
|
|
tcx.hir().name_by_hir_id(var_hir_id)
|
|
}
|