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Improved how upvars are detected when presenting errors using prefixes.

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This commit is contained in:
David Wood 2018-08-07 19:50:19 +02:00
parent 2c6b0e5cf7
commit 5532e9dec5
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GPG Key ID: 01760B4F9F53F154
8 changed files with 68 additions and 27 deletions
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17
src/librustc/mir/tcx.rs
View File

@ -151,25 +151,10 @@ impl<'tcx> Place<'tcx> {
}
},
_ => None,
},
}
_ => None,
}
}
/// Strip the deref projections from a `Place`. For example, given `(*(*((*_1).0: &&T)))`, this
/// will return `((*_1).0)`. Once stripped of any deref projections, places can then be
/// checked as upvar field projections using `is_upvar_field_projection`.
pub fn strip_deref_projections(&self) -> &Place<'tcx> {
let mut current = self;
while let Place::Projection(ref proj) = current {
if let ProjectionElem::Deref = proj.elem {
current = &proj.base;
} else {
break;
}
}
current
}
}
pub enum RvalueInitializationState {

29
src/librustc_mir/borrow_check/move_errors.rs
View File

@ -16,6 +16,7 @@ use rustc_data_structures::indexed_vec::Idx;
use syntax_pos::Span;
use borrow_check::MirBorrowckCtxt;
use borrow_check::prefixes::PrefixSet;
use dataflow::move_paths::{IllegalMoveOrigin, IllegalMoveOriginKind};
use dataflow::move_paths::{LookupResult, MoveError, MovePathIndex};
use util::borrowck_errors::{BorrowckErrors, Origin};
@ -254,15 +255,16 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
// borrow to provide feedback about why this
// was a move rather than a copy.
let ty = place.ty(self.mir, self.tcx).to_ty(self.tcx);
let is_upvar_field_projection =
self.prefixes(&original_path, PrefixSet::All)
.any(|p| p.is_upvar_field_projection(self.mir, &self.tcx)
.is_some());
match ty.sty {
ty::TyArray(..) | ty::TySlice(..) => self
.tcx
.cannot_move_out_of_interior_noncopy(span, ty, None, origin),
ty::TyClosure(def_id, closure_substs)
if !self.mir.upvar_decls.is_empty() &&
original_path.strip_deref_projections()
.is_upvar_field_projection(self.mir, &self.tcx)
.is_some()
if !self.mir.upvar_decls.is_empty() && is_upvar_field_projection
=> {
let closure_kind_ty =
closure_substs.closure_kind_ty(def_id, self.tcx);
@ -286,13 +288,18 @@ impl<'a, 'gcx, 'tcx> MirBorrowckCtxt<'a, 'gcx, 'tcx> {
let mut diag = self.tcx.cannot_move_out_of(
span, place_description, origin);
if let Some(field) = original_path.is_upvar_field_projection(
self.mir, &self.tcx) {
let upvar_decl = &self.mir.upvar_decls[field.index()];
let upvar_hir_id = upvar_decl.var_hir_id.assert_crate_local();
let upvar_node_id = self.tcx.hir.hir_to_node_id(upvar_hir_id);
let upvar_span = self.tcx.hir.span(upvar_node_id);
diag.span_label(upvar_span, "captured outer variable");
for prefix in self.prefixes(&original_path, PrefixSet::All) {
if let Some(field) = prefix.is_upvar_field_projection(
self.mir, &self.tcx) {
let upvar_decl = &self.mir.upvar_decls[field.index()];
let upvar_hir_id =
upvar_decl.var_hir_id.assert_crate_local();
let upvar_node_id =
self.tcx.hir.hir_to_node_id(upvar_hir_id);
let upvar_span = self.tcx.hir.span(upvar_node_id);
diag.span_label(upvar_span, "captured outer variable");
break;
}
}
diag

3
src/test/ui/borrowck/borrowck-move-by-capture.nll.stderr
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@ -1,6 +1,9 @@
error[E0507]: cannot move out of captured variable in an `FnMut` closure
--> $DIR/borrowck-move-by-capture.rs:19:29
|
LL | let bar: Box<_> = box 3;
| --- captured outer variable
LL | let _g = to_fn_mut(|| {
LL | let _h = to_fn_once(move || -> isize { *bar }); //~ ERROR cannot move out of
| ^^^^^^^^^^^^^^^^^^^^^^^^^ cannot move out of captured variable in an `FnMut` closure

2
src/test/ui/issues/issue-4335.nll.stderr
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@ -1,6 +1,8 @@
error[E0507]: cannot move out of captured variable in an `FnMut` closure
--> $DIR/issue-4335.rs:16:20
|
LL | fn f<'r, T>(v: &'r T) -> Box<FnMut() -> T + 'r> {
| - captured outer variable
LL | id(Box::new(|| *v))
| ^^ cannot move out of captured variable in an `FnMut` closure

2
src/test/ui/moves/moves-based-on-type-move-out-of-closure-env-issue-1965.nll.stderr
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@ -1,6 +1,8 @@
error[E0507]: cannot move out of captured variable in an `Fn` closure
--> $DIR/moves-based-on-type-move-out-of-closure-env-issue-1965.rs:21:28
|
LL | let i = box 3;
| - captured outer variable
LL | let _f = to_fn(|| test(i)); //~ ERROR cannot move out
| ^ cannot move out of captured variable in an `Fn` closure

23
src/test/ui/nll/issue-52663-span-decl-captured-variable.rs Normal file
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@ -0,0 +1,23 @@
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![feature(nll)]
fn expect_fn<F>(f: F) where F : Fn() {
f();
}
fn main() {
{
let x = (vec![22], vec![44]);
expect_fn(|| drop(x.0));
//~^ ERROR cannot move out of captured variable in an `Fn` closure [E0507]
}
}

11
src/test/ui/nll/issue-52663-span-decl-captured-variable.stderr Normal file
View File

@ -0,0 +1,11 @@
error[E0507]: cannot move out of captured variable in an `Fn` closure
--> $DIR/issue-52663-span-decl-captured-variable.rs:20:26
|
LL | let x = (vec![22], vec![44]);
| - captured outer variable
LL | expect_fn(|| drop(x.0));
| ^^^ cannot move out of captured variable in an `Fn` closure
error: aborting due to previous error
For more information about this error, try `rustc --explain E0507`.

8
src/test/ui/unboxed-closures/unboxed-closure-illegal-move.nll.stderr
View File

@ -1,24 +1,32 @@
error[E0507]: cannot move out of captured variable in an `Fn` closure
--> $DIR/unboxed-closure-illegal-move.rs:25:31
|
LL | let x = Box::new(0);
| - captured outer variable
LL | let f = to_fn(|| drop(x)); //~ ERROR cannot move
| ^ cannot move out of captured variable in an `Fn` closure
error[E0507]: cannot move out of captured variable in an `FnMut` closure
--> $DIR/unboxed-closure-illegal-move.rs:29:35
|
LL | let x = Box::new(0);
| - captured outer variable
LL | let f = to_fn_mut(|| drop(x)); //~ ERROR cannot move
| ^ cannot move out of captured variable in an `FnMut` closure
error[E0507]: cannot move out of captured variable in an `Fn` closure
--> $DIR/unboxed-closure-illegal-move.rs:38:36
|
LL | let x = Box::new(0);
| - captured outer variable
LL | let f = to_fn(move || drop(x)); //~ ERROR cannot move
| ^ cannot move out of captured variable in an `Fn` closure
error[E0507]: cannot move out of captured variable in an `FnMut` closure
--> $DIR/unboxed-closure-illegal-move.rs:42:40
|
LL | let x = Box::new(0);
| - captured outer variable
LL | let f = to_fn_mut(move || drop(x)); //~ ERROR cannot move
| ^ cannot move out of captured variable in an `FnMut` closure