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Rollup merge of #80635 - sexxi-goose:use-place-instead-of-symbol, r=nikomatsakis` 

Improve diagnostics when closure doesn't meet trait bound

Improves the diagnostics when closure doesn't meet trait bound by modifying `TypeckResuts::closure_kind_origins` such that `hir::Place` is used instead of `Symbol`. Using `hir::Place` to describe which capture influenced the decision of selecting a trait a closure satisfies to (Fn/FnMut/FnOnce, Copy) allows us to show precise path in the diagnostics when `capture_disjoint_field` feature is enabled.

Closes rust-lang/project-rfc-2229/issues/21

r? ```@nikomatsakis```
This commit is contained in:
Mara Bos 2021-01-17 12:24:44 +00:00 committed by GitHub
parent 152f425dcb b498870d9c
commit 19f97802ca
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GPG Key ID: 4AEE18F83AFDEB23
16 changed files with 328 additions and 23 deletions
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9
compiler/rustc_middle/src/ty/context.rs
View File

@ -3,6 +3,7 @@
use crate::arena::Arena;
use crate::dep_graph::DepGraph;
use crate::hir::exports::ExportMap;
use crate::hir::place::Place as HirPlace;
use crate::ich::{NodeIdHashingMode, StableHashingContext};
use crate::infer::canonical::{Canonical, CanonicalVarInfo, CanonicalVarInfos};
use crate::lint::{struct_lint_level, LintDiagnosticBuilder, LintLevelSource};
@ -379,7 +380,7 @@ pub struct TypeckResults<'tcx> {
/// Records the reasons that we picked the kind of each closure;
/// not all closures are present in the map.
closure_kind_origins: ItemLocalMap<(Span, Symbol)>,
closure_kind_origins: ItemLocalMap<(Span, HirPlace<'tcx>)>,
/// For each fn, records the "liberated" types of its arguments
/// and return type. Liberated means that all bound regions
@ -642,11 +643,13 @@ impl<'tcx> TypeckResults<'tcx> {
self.upvar_capture_map[&upvar_id]
}
pub fn closure_kind_origins(&self) -> LocalTableInContext<'_, (Span, Symbol)> {
pub fn closure_kind_origins(&self) -> LocalTableInContext<'_, (Span, HirPlace<'tcx>)> {
LocalTableInContext { hir_owner: self.hir_owner, data: &self.closure_kind_origins }
}
pub fn closure_kind_origins_mut(&mut self) -> LocalTableInContextMut<'_, (Span, Symbol)> {
pub fn closure_kind_origins_mut(
&mut self,
) -> LocalTableInContextMut<'_, (Span, HirPlace<'tcx>)> {
LocalTableInContextMut { hir_owner: self.hir_owner, data: &mut self.closure_kind_origins }
}

41
compiler/rustc_middle/src/ty/mod.rs
View File

@ -17,7 +17,9 @@ pub use self::IntVarValue::*;
pub use self::Variance::*;
use crate::hir::exports::ExportMap;
use crate::hir::place::Place as HirPlace;
use crate::hir::place::{
Place as HirPlace, PlaceBase as HirPlaceBase, ProjectionKind as HirProjectionKind,
};
use crate::ich::StableHashingContext;
use crate::middle::cstore::CrateStoreDyn;
use crate::middle::resolve_lifetime::ObjectLifetimeDefault;
@ -734,6 +736,43 @@ pub struct CapturedPlace<'tcx> {
pub info: CaptureInfo<'tcx>,
}
pub fn place_to_string_for_capture(tcx: TyCtxt<'tcx>, place: &HirPlace<'tcx>) -> String {
let name = match place.base {
HirPlaceBase::Upvar(upvar_id) => tcx.hir().name(upvar_id.var_path.hir_id).to_string(),
_ => bug!("Capture_information should only contain upvars"),
};
let mut curr_string = name;
for (i, proj) in place.projections.iter().enumerate() {
match proj.kind {
HirProjectionKind::Deref => {
curr_string = format!("*{}", curr_string);
}
HirProjectionKind::Field(idx, variant) => match place.ty_before_projection(i).kind() {
ty::Adt(def, ..) => {
curr_string = format!(
"{}.{}",
curr_string,
def.variants[variant].fields[idx as usize].ident.name.as_str()
);
}
ty::Tuple(_) => {
curr_string = format!("{}.{}", curr_string, idx);
}
_ => {
bug!(
"Field projection applied to a type other than Adt or Tuple: {:?}.",
place.ty_before_projection(i).kind()
)
}
},
proj => bug!("{:?} unexpected because it isn't captured", proj),
}
}
curr_string.to_string()
}
/// Part of `MinCaptureInformationMap`; describes the capture kind (&, &mut, move)
/// for a particular capture as well as identifying the part of the source code
/// that triggered this capture to occur.

8
compiler/rustc_mir/src/borrow_check/diagnostics/mod.rs
View File

@ -103,7 +103,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
let did = did.expect_local();
let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(did);
if let Some((span, name)) =
if let Some((span, hir_place)) =
self.infcx.tcx.typeck(did).closure_kind_origins().get(hir_id)
{
diag.span_note(
@ -111,7 +111,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
&format!(
"closure cannot be invoked more than once because it moves the \
variable `{}` out of its environment",
name,
ty::place_to_string_for_capture(self.infcx.tcx, hir_place)
),
);
return;
@ -127,7 +127,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
let did = did.expect_local();
let hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(did);
if let Some((span, name)) =
if let Some((span, hir_place)) =
self.infcx.tcx.typeck(did).closure_kind_origins().get(hir_id)
{
diag.span_note(
@ -135,7 +135,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
&format!(
"closure cannot be moved more than once as it is not `Copy` due to \
moving the variable `{}` out of its environment",
name
ty::place_to_string_for_capture(self.infcx.tcx, hir_place)
),
);
}

8
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View File

@ -589,23 +589,23 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
if let Some(typeck_results) = self.in_progress_typeck_results {
let typeck_results = typeck_results.borrow();
match (found_kind, typeck_results.closure_kind_origins().get(hir_id)) {
(ty::ClosureKind::FnOnce, Some((span, name))) => {
(ty::ClosureKind::FnOnce, Some((span, place))) => {
err.span_label(
*span,
format!(
"closure is `FnOnce` because it moves the \
variable `{}` out of its environment",
name
ty::place_to_string_for_capture(tcx, place)
),
);
}
(ty::ClosureKind::FnMut, Some((span, name))) => {
(ty::ClosureKind::FnMut, Some((span, place))) => {
err.span_label(
*span,
format!(
"closure is `FnMut` because it mutates the \
variable `{}` here",
name
ty::place_to_string_for_capture(tcx, place)
),
);
}

26
compiler/rustc_typeck/src/check/upvar.rs
View File

@ -176,7 +176,17 @@ impl<'a, 'tcx> FnCtxt<'a, '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 {
if let Some(origin) = delegate.current_origin.clone() {
let origin = if self.tcx.features().capture_disjoint_fields {
origin
} else {
// FIXME(project-rfc-2229#26): Once rust-lang#80092 is merged, we should restrict the
// precision of origin as well. Otherwise, this will cause issues when project-rfc-2229#26
// is fixed as we might see Index projections in the origin, which we can't print because
// we don't store enough information.
(origin.0, Place { projections: vec![], ..origin.1 })
};
self.typeck_results
.borrow_mut()
.closure_kind_origins_mut()
@ -563,7 +573,7 @@ struct InferBorrowKind<'a, 'tcx> {
// 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, Symbol)>,
current_origin: Option<(Span, Place<'tcx>)>,
/// For each Place that is captured by the closure, we track the minimal kind of
/// access we need (ref, ref mut, move, etc) and the expression that resulted in such access.
@ -628,7 +638,7 @@ impl<'a, 'tcx> InferBorrowKind<'a, 'tcx> {
upvar_id.closure_expr_id,
ty::ClosureKind::FnOnce,
usage_span,
var_name(tcx, upvar_id.var_path.hir_id),
place_with_id.place.clone(),
);
let capture_info = ty::CaptureInfo {
@ -720,7 +730,7 @@ impl<'a, 'tcx> InferBorrowKind<'a, 'tcx> {
upvar_id.closure_expr_id,
ty::ClosureKind::FnMut,
tcx.hir().span(diag_expr_id),
var_name(tcx, upvar_id.var_path.hir_id),
place_with_id.place.clone(),
);
}
}
@ -765,11 +775,11 @@ impl<'a, 'tcx> InferBorrowKind<'a, 'tcx> {
closure_id: LocalDefId,
new_kind: ty::ClosureKind,
upvar_span: Span,
var_name: Symbol,
place: Place<'tcx>,
) {
debug!(
"adjust_closure_kind(closure_id={:?}, new_kind={:?}, upvar_span={:?}, var_name={})",
closure_id, new_kind, upvar_span, var_name
"adjust_closure_kind(closure_id={:?}, new_kind={:?}, upvar_span={:?}, place={:?})",
closure_id, new_kind, upvar_span, place
);
// Is this the closure whose kind is currently being inferred?
@ -797,7 +807,7 @@ impl<'a, 'tcx> InferBorrowKind<'a, 'tcx> {
| (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));
self.current_origin = Some((upvar_span, place));
}
}
}

8
compiler/rustc_typeck/src/check/writeback.rs
View File

@ -384,9 +384,11 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
let common_hir_owner = fcx_typeck_results.hir_owner;
for (&id, &origin) in fcx_typeck_results.closure_kind_origins().iter() {
let hir_id = hir::HirId { owner: common_hir_owner, local_id: id };
self.typeck_results.closure_kind_origins_mut().insert(hir_id, origin);
for (id, origin) in fcx_typeck_results.closure_kind_origins().iter() {
let hir_id = hir::HirId { owner: common_hir_owner, local_id: *id };
let place_span = origin.0;
let place = self.resolve(origin.1.clone(), &place_span);
self.typeck_results.closure_kind_origins_mut().insert(hir_id, (place_span, place));
}
}

31
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-multi-variant-diagnostics.rs Normal file
View File

@ -0,0 +1,31 @@
#![feature(capture_disjoint_fields)]
//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
//~| `#[warn(incomplete_features)]` on by default
//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
// Check that precise paths are being reported back in the error message.
enum MultiVariant {
Point(i32, i32),
Meta(i32)
}
fn main() {
let mut point = MultiVariant::Point(10, -10,);
let mut meta = MultiVariant::Meta(1);
let c = || {
if let MultiVariant::Point(ref mut x, _) = point {
*x += 1;
}
if let MultiVariant::Meta(ref mut v) = meta {
*v += 1;
}
};
let a = c;
let b = c; //~ ERROR use of moved value: `c` [E0382]
}

26
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-multi-variant-diagnostics.stderr Normal file
View File

@ -0,0 +1,26 @@
warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/closure-origin-multi-variant-diagnostics.rs:1:12
|
LL | #![feature(capture_disjoint_fields)]
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(incomplete_features)]` on by default
= note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
error[E0382]: use of moved value: `c`
--> $DIR/closure-origin-multi-variant-diagnostics.rs:30:13
|
LL | let a = c;
| - value moved here
LL | let b = c;
| ^ value used here after move
|
note: closure cannot be moved more than once as it is not `Copy` due to moving the variable `point.0` out of its environment
--> $DIR/closure-origin-multi-variant-diagnostics.rs:20:52
|
LL | if let MultiVariant::Point(ref mut x, _) = point {
| ^^^^^
error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0382`.

26
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-single-variant-diagnostics.rs Normal file
View File

@ -0,0 +1,26 @@
#![feature(capture_disjoint_fields)]
//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
//~| `#[warn(incomplete_features)]` on by default
//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
// Check that precise paths are being reported back in the error message.
enum SingleVariant {
Point(i32, i32),
}
fn main() {
let mut point = SingleVariant::Point(10, -10);
let c = || {
// FIXME(project-rfc-2229#24): Change this to be a destructure pattern
// once this is fixed, to remove the warning.
if let SingleVariant::Point(ref mut x, _) = point {
//~^ WARNING: irrefutable if-let pattern
*x += 1;
}
};
let b = c;
let a = c; //~ ERROR use of moved value: `c` [E0382]
}

37
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-single-variant-diagnostics.stderr Normal file
View File

@ -0,0 +1,37 @@
warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/closure-origin-single-variant-diagnostics.rs:1:12
|
LL | #![feature(capture_disjoint_fields)]
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(incomplete_features)]` on by default
= note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
warning: irrefutable if-let pattern
--> $DIR/closure-origin-single-variant-diagnostics.rs:18:9
|
LL | / if let SingleVariant::Point(ref mut x, _) = point {
LL | |
LL | | *x += 1;
LL | | }
| |_________^
|
= note: `#[warn(irrefutable_let_patterns)]` on by default
error[E0382]: use of moved value: `c`
--> $DIR/closure-origin-single-variant-diagnostics.rs:25:13
|
LL | let b = c;
| - value moved here
LL | let a = c;
| ^ value used here after move
|
note: closure cannot be moved more than once as it is not `Copy` due to moving the variable `point.0` out of its environment
--> $DIR/closure-origin-single-variant-diagnostics.rs:18:53
|
LL | if let SingleVariant::Point(ref mut x, _) = point {
| ^^^^^
error: aborting due to previous error; 2 warnings emitted
For more information about this error, try `rustc --explain E0382`.

25
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-struct-diagnostics.rs Normal file
View File

@ -0,0 +1,25 @@
#![feature(capture_disjoint_fields)]
//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
//~| `#[warn(incomplete_features)]` on by default
//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
// Check that precise paths are being reported back in the error message.
struct Y {
y: X
}
struct X {
a: u32,
b: u32,
}
fn main() {
let mut x = Y { y: X { a: 5, b: 0 } };
let hello = || {
x.y.a += 1;
};
let b = hello;
let c = hello; //~ ERROR use of moved value: `hello` [E0382]
}

26
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-struct-diagnostics.stderr Normal file
View File

@ -0,0 +1,26 @@
warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/closure-origin-struct-diagnostics.rs:1:12
|
LL | #![feature(capture_disjoint_fields)]
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(incomplete_features)]` on by default
= note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
error[E0382]: use of moved value: `hello`
--> $DIR/closure-origin-struct-diagnostics.rs:24:13
|
LL | let b = hello;
| ----- value moved here
LL | let c = hello;
| ^^^^^ value used here after move
|
note: closure cannot be moved more than once as it is not `Copy` due to moving the variable `x.y.a` out of its environment
--> $DIR/closure-origin-struct-diagnostics.rs:20:9
|
LL | x.y.a += 1;
| ^^^^^
error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0382`.

16
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-tuple-diagnostics-1.rs Normal file
View File

@ -0,0 +1,16 @@
#![feature(capture_disjoint_fields)]
//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
//~| `#[warn(incomplete_features)]` on by default
//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
// Check that precise paths are being reported back in the error message.
fn main() {
let mut x = (5, 0);
let hello = || {
x.0 += 1;
};
let b = hello;
let c = hello; //~ ERROR use of moved value: `hello` [E0382]
}

26
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-tuple-diagnostics-1.stderr Normal file
View File

@ -0,0 +1,26 @@
warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/closure-origin-tuple-diagnostics-1.rs:1:12
|
LL | #![feature(capture_disjoint_fields)]
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(incomplete_features)]` on by default
= note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
error[E0382]: use of moved value: `hello`
--> $DIR/closure-origin-tuple-diagnostics-1.rs:15:13
|
LL | let b = hello;
| ----- value moved here
LL | let c = hello;
| ^^^^^ value used here after move
|
note: closure cannot be moved more than once as it is not `Copy` due to moving the variable `x.0` out of its environment
--> $DIR/closure-origin-tuple-diagnostics-1.rs:11:9
|
LL | x.0 += 1;
| ^^^
error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0382`.

15
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-tuple-diagnostics.rs Normal file
View File

@ -0,0 +1,15 @@
#![feature(capture_disjoint_fields)]
//~^ WARNING: the feature `capture_disjoint_fields` is incomplete
//~| `#[warn(incomplete_features)]` on by default
//~| see issue #53488 <https://github.com/rust-lang/rust/issues/53488>
struct S(String, String);
fn expect_fn<F: Fn()>(_f: F) {}
fn main() {
let s = S(format!("s"), format!("s"));
let c = || { //~ ERROR expected a closure that implements the `Fn`
let s = s.1;
};
expect_fn(c);
}

23
src/test/ui/closures/2229_closure_analysis/diagnostics/closure-origin-tuple-diagnostics.stderr Normal file
View File

@ -0,0 +1,23 @@
warning: the feature `capture_disjoint_fields` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/closure-origin-tuple-diagnostics.rs:1:12
|
LL | #![feature(capture_disjoint_fields)]
| ^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(incomplete_features)]` on by default
= note: see issue #53488 <https://github.com/rust-lang/rust/issues/53488> for more information
error[E0525]: expected a closure that implements the `Fn` trait, but this closure only implements `FnOnce`
--> $DIR/closure-origin-tuple-diagnostics.rs:11:13
|
LL | let c = || {
| ^^ this closure implements `FnOnce`, not `Fn`
LL | let s = s.1;
| --- closure is `FnOnce` because it moves the variable `s.1` out of its environment
LL | };
LL | expect_fn(c);
| --------- the requirement to implement `Fn` derives from here
error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0525`.