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Improve cannot move out of error message

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This commit is contained in:
Obei Sideg 2022-07-23 00:35:35 +03:00
parent e5a7d8f945
commit 86dd457e6a
10 changed files with 154 additions and 61 deletions
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30
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
View File

@ -39,7 +39,7 @@
use super::{
explain_borrow::{BorrowExplanation, LaterUseKind},
IncludingDowncast, RegionName, RegionNameSource, UseSpans,
DescribePlaceOpt, RegionName, RegionNameSource, UseSpans,
};
#[derive(Debug)]
@ -137,7 +137,10 @@ pub(crate) fn report_use_of_moved_or_uninitialized(
span,
desired_action.as_noun(),
partially_str,
self.describe_place_with_options(moved_place, IncludingDowncast(true)),
self.describe_place_with_options(
moved_place,
DescribePlaceOpt { including_downcast: true, including_tuple_field: true },
),
);
let reinit_spans = maybe_reinitialized_locations
@ -274,8 +277,10 @@ pub(crate) fn report_use_of_moved_or_uninitialized(
}
}
let opt_name =
self.describe_place_with_options(place.as_ref(), IncludingDowncast(true));
let opt_name = self.describe_place_with_options(
place.as_ref(),
DescribePlaceOpt { including_downcast: true, including_tuple_field: true },
);
let note_msg = match opt_name {
Some(ref name) => format!("`{}`", name),
None => "value".to_owned(),
@ -341,12 +346,17 @@ fn report_use_of_uninitialized(
}
}
let (name, desc) =
match self.describe_place_with_options(moved_place, IncludingDowncast(true)) {
Some(name) => (format!("`{name}`"), format!("`{name}` ")),
None => ("the variable".to_string(), String::new()),
};
let path = match self.describe_place_with_options(used_place, IncludingDowncast(true)) {
let (name, desc) = match self.describe_place_with_options(
moved_place,
DescribePlaceOpt { including_downcast: true, including_tuple_field: true },
) {
Some(name) => (format!("`{name}`"), format!("`{name}` ")),
None => ("the variable".to_string(), String::new()),
};
let path = match self.describe_place_with_options(
used_place,
DescribePlaceOpt { including_downcast: true, including_tuple_field: true },
) {
Some(name) => format!("`{name}`"),
None => "value".to_string(),
};

74
compiler/rustc_borrowck/src/diagnostics/mod.rs
View File

@ -4,7 +4,7 @@
use rustc_const_eval::util::{call_kind, CallDesugaringKind};
use rustc_errors::{Applicability, Diagnostic};
use rustc_hir as hir;
use rustc_hir::def::Namespace;
use rustc_hir::def::{CtorKind, Namespace};
use rustc_hir::GeneratorKind;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::tcx::PlaceTy;
@ -16,7 +16,7 @@
use rustc_middle::ty::{self, DefIdTree, Instance, Ty, TyCtxt};
use rustc_mir_dataflow::move_paths::{InitLocation, LookupResult};
use rustc_span::def_id::LocalDefId;
use rustc_span::{symbol::sym, Span, DUMMY_SP};
use rustc_span::{symbol::sym, Span, Symbol, DUMMY_SP};
use rustc_target::abi::VariantIdx;
use rustc_trait_selection::traits::type_known_to_meet_bound_modulo_regions;
@ -43,7 +43,15 @@
pub(crate) use region_name::{RegionName, RegionNameSource};
pub(crate) use rustc_const_eval::util::CallKind;
pub(super) struct IncludingDowncast(pub(super) bool);
pub(super) struct DescribePlaceOpt {
pub including_downcast: bool,
/// Enable/Disable tuple fields.
/// For example `x` tuple. if it's `true` `x.0`. Otherwise `x`
pub including_tuple_field: bool,
}
pub(super) struct IncludingTupleField(pub(super) bool);
impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
/// Adds a suggestion when a closure is invoked twice with a moved variable or when a closure
@ -164,7 +172,10 @@ pub(super) fn describe_any_place(&self, place_ref: PlaceRef<'tcx>) -> String {
/// End-user visible description of `place` if one can be found.
/// If the place is a temporary for instance, `None` will be returned.
pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String> {
self.describe_place_with_options(place_ref, IncludingDowncast(false))
self.describe_place_with_options(
place_ref,
DescribePlaceOpt { including_downcast: false, including_tuple_field: true },
)
}
/// End-user visible description of `place` if one can be found. If the place is a temporary
@ -174,7 +185,7 @@ pub(super) fn describe_place(&self, place_ref: PlaceRef<'tcx>) -> Option<String>
pub(super) fn describe_place_with_options(
&self,
place: PlaceRef<'tcx>,
including_downcast: IncludingDowncast,
opt: DescribePlaceOpt,
) -> Option<String> {
let local = place.local;
let mut autoderef_index = None;
@ -224,7 +235,7 @@ pub(super) fn describe_place_with_options(
}
}
}
ProjectionElem::Downcast(..) if including_downcast.0 => return None,
ProjectionElem::Downcast(..) if opt.including_downcast => return None,
ProjectionElem::Downcast(..) => (),
ProjectionElem::Field(field, _ty) => {
// FIXME(project-rfc_2229#36): print capture precisely here.
@ -238,9 +249,12 @@ pub(super) fn describe_place_with_options(
let field_name = self.describe_field(
PlaceRef { local, projection: place.projection.split_at(index).0 },
*field,
IncludingTupleField(opt.including_tuple_field),
);
buf.push('.');
buf.push_str(&field_name);
if let Some(field_name_str) = field_name {
buf.push('.');
buf.push_str(&field_name_str);
}
}
}
ProjectionElem::Index(index) => {
@ -261,6 +275,18 @@ pub(super) fn describe_place_with_options(
ok.ok().map(|_| buf)
}
fn describe_name(&self, place: PlaceRef<'tcx>) -> Option<Symbol> {
for elem in place.projection.into_iter() {
match elem {
ProjectionElem::Downcast(Some(name), _) => {
return Some(*name);
}
_ => {}
}
}
None
}
/// Appends end-user visible description of the `local` place to `buf`. If `local` doesn't have
/// a name, or its name was generated by the compiler, then `Err` is returned
fn append_local_to_string(&self, local: Local, buf: &mut String) -> Result<(), ()> {
@ -275,7 +301,12 @@ fn append_local_to_string(&self, local: Local, buf: &mut String) -> Result<(), (
}
/// End-user visible description of the `field`nth field of `base`
fn describe_field(&self, place: PlaceRef<'tcx>, field: Field) -> String {
fn describe_field(
&self,
place: PlaceRef<'tcx>,
field: Field,
including_tuple_field: IncludingTupleField,
) -> Option<String> {
let place_ty = match place {
PlaceRef { local, projection: [] } => PlaceTy::from_ty(self.body.local_decls[local].ty),
PlaceRef { local, projection: [proj_base @ .., elem] } => match elem {
@ -289,7 +320,12 @@ fn describe_field(&self, place: PlaceRef<'tcx>, field: Field) -> String {
ProjectionElem::Field(_, field_type) => PlaceTy::from_ty(*field_type),
},
};
self.describe_field_from_ty(place_ty.ty, field, place_ty.variant_index)
self.describe_field_from_ty(
place_ty.ty,
field,
place_ty.variant_index,
including_tuple_field,
)
}
/// End-user visible description of the `field_index`nth field of `ty`
@ -298,10 +334,11 @@ fn describe_field_from_ty(
ty: Ty<'_>,
field: Field,
variant_index: Option<VariantIdx>,
) -> String {
including_tuple_field: IncludingTupleField,
) -> Option<String> {
if ty.is_box() {
// If the type is a box, the field is described from the boxed type
self.describe_field_from_ty(ty.boxed_ty(), field, variant_index)
self.describe_field_from_ty(ty.boxed_ty(), field, variant_index, including_tuple_field)
} else {
match *ty.kind() {
ty::Adt(def, _) => {
@ -311,14 +348,17 @@ fn describe_field_from_ty(
} else {
def.non_enum_variant()
};
variant.fields[field.index()].name.to_string()
if !including_tuple_field.0 && variant.ctor_kind == CtorKind::Fn {
return None;
}
Some(variant.fields[field.index()].name.to_string())
}
ty::Tuple(_) => field.index().to_string(),
ty::Tuple(_) => Some(field.index().to_string()),
ty::Ref(_, ty, _) | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
self.describe_field_from_ty(ty, field, variant_index)
self.describe_field_from_ty(ty, field, variant_index, including_tuple_field)
}
ty::Array(ty, _) | ty::Slice(ty) => {
self.describe_field_from_ty(ty, field, variant_index)
self.describe_field_from_ty(ty, field, variant_index, including_tuple_field)
}
ty::Closure(def_id, _) | ty::Generator(def_id, _, _) => {
// We won't be borrowck'ing here if the closure came from another crate,
@ -335,7 +375,7 @@ fn describe_field_from_ty(
.unwrap()
.get_root_variable();
self.infcx.tcx.hir().name(var_id).to_string()
Some(self.infcx.tcx.hir().name(var_id).to_string())
}
_ => {
// Might need a revision when the fields in trait RFC is implemented

28
compiler/rustc_borrowck/src/diagnostics/move_errors.rs
View File

@ -6,7 +6,7 @@
};
use rustc_span::Span;
use crate::diagnostics::UseSpans;
use crate::diagnostics::{DescribePlaceOpt, UseSpans};
use crate::prefixes::PrefixSet;
use crate::MirBorrowckCtxt;
@ -368,13 +368,31 @@ fn report_cannot_move_from_borrowed_content(
}
_ => {
let source = self.borrowed_content_source(deref_base);
match (self.describe_place(move_place.as_ref()), source.describe_for_named_place())
{
(Some(place_desc), Some(source_desc)) => self.cannot_move_out_of(
let move_place_ref = move_place.as_ref();
match (
self.describe_place_with_options(
move_place_ref,
DescribePlaceOpt {
including_downcast: false,
including_tuple_field: false,
},
),
self.describe_name(move_place_ref),
source.describe_for_named_place(),
) {
(Some(place_desc), Some(name), Some(source_desc)) => self.cannot_move_out_of(
span,
&format!("`{place_desc}` as enum variant `{name}` which is behind a {source_desc}"),
),
(Some(place_desc), Some(name), None) => self.cannot_move_out_of(
span,
&format!("`{place_desc}` as enum variant `{name}`"),
),
(Some(place_desc), _, Some(source_desc)) => self.cannot_move_out_of(
span,
&format!("`{place_desc}` which is behind a {source_desc}"),
),
(_, _) => self.cannot_move_out_of(
(_, _, _) => self.cannot_move_out_of(
span,
&source.describe_for_unnamed_place(self.infcx.tcx),
),

2
src/test/ui/borrowck/access-mode-in-closures.stderr
View File

@ -1,4 +1,4 @@
error[E0507]: cannot move out of `s.0` which is behind a shared reference
error[E0507]: cannot move out of `s` which is behind a shared reference
--> $DIR/access-mode-in-closures.rs:8:15
|
LL | match *s { S(v) => v }

2
src/test/ui/borrowck/borrowck-move-error-with-note.stderr
View File

@ -1,4 +1,4 @@
error[E0507]: cannot move out of `f.0` which is behind a shared reference
error[E0507]: cannot move out of `f` as enum variant `Foo1` which is behind a shared reference
--> $DIR/borrowck-move-error-with-note.rs:11:11
|
LL | match *f {

9
src/test/ui/moves/issue-99470-move-out-of-some.rs Normal file
View File

@ -0,0 +1,9 @@
fn main() {
let x: &Option<Box<i32>> = &Some(Box::new(0));
match x {
//~^ ERROR cannot move out of `x` as enum variant `Some` which is behind a shared reference
&Some(_y) => (),
&None => (),
}
}

16
src/test/ui/moves/issue-99470-move-out-of-some.stderr Normal file
View File

@ -0,0 +1,16 @@
error[E0507]: cannot move out of `x` as enum variant `Some` which is behind a shared reference
--> $DIR/issue-99470-move-out-of-some.rs:4:11
|
LL | match x {
| ^
LL |
LL | &Some(_y) => (),
| ---------
| | |
| | data moved here
| | move occurs because `_y` has type `Box<i32>`, which does not implement the `Copy` trait
| help: consider removing the `&`: `Some(_y)`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0507`.

2
src/test/ui/moves/moves-based-on-type-block-bad.stderr
View File

@ -1,4 +1,4 @@
error[E0507]: cannot move out of `hellothere.x.0` which is behind a shared reference
error[E0507]: cannot move out of `hellothere.x` as enum variant `Bar` which is behind a shared reference
--> $DIR/moves-based-on-type-block-bad.rs:22:19
|
LL | match hellothere.x {

4
src/test/ui/nll/move-errors.stderr
View File

@ -45,7 +45,7 @@ LL | let a = [A("".to_string())][0];
| move occurs because value has type `A`, which does not implement the `Copy` trait
| help: consider borrowing here: `&[A("".to_string())][0]`
error[E0507]: cannot move out of `a.0` which is behind a shared reference
error[E0507]: cannot move out of `a` which is behind a shared reference
--> $DIR/move-errors.rs:38:16
|
LL | let A(s) = *a;
@ -134,7 +134,7 @@ LL | F(s, mut t) => (),
|
= note: move occurs because these variables have types that don't implement the `Copy` trait
error[E0507]: cannot move out of `x.0` which is behind a shared reference
error[E0507]: cannot move out of `x` as enum variant `Err` which is behind a shared reference
--> $DIR/move-errors.rs:110:11
|
LL | match *x {

48
src/test/ui/suggestions/dont-suggest-ref/simple.stderr
View File

@ -1,4 +1,4 @@
error[E0507]: cannot move out of `s.0` which is behind a shared reference
error[E0507]: cannot move out of `s` which is behind a shared reference
--> $DIR/simple.rs:38:17
|
LL | let X(_t) = *s;
@ -7,7 +7,7 @@ LL | let X(_t) = *s;
| data moved here
| move occurs because `_t` has type `Y`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:42:30
|
LL | if let Either::One(_t) = *r { }
@ -16,7 +16,7 @@ LL | if let Either::One(_t) = *r { }
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:46:33
|
LL | while let Either::One(_t) = *r { }
@ -25,7 +25,7 @@ LL | while let Either::One(_t) = *r { }
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `Two` which is behind a shared reference
--> $DIR/simple.rs:50:11
|
LL | match *r {
@ -37,7 +37,7 @@ LL | Either::One(_t)
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:57:11
|
LL | match *r {
@ -49,7 +49,7 @@ LL | Either::One(_t) => (),
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `sm.0` which is behind a mutable reference
error[E0507]: cannot move out of `sm` which is behind a mutable reference
--> $DIR/simple.rs:66:17
|
LL | let X(_t) = *sm;
@ -58,7 +58,7 @@ LL | let X(_t) = *sm;
| data moved here
| move occurs because `_t` has type `Y`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:70:30
|
LL | if let Either::One(_t) = *rm { }
@ -67,7 +67,7 @@ LL | if let Either::One(_t) = *rm { }
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:74:33
|
LL | while let Either::One(_t) = *rm { }
@ -76,7 +76,7 @@ LL | while let Either::One(_t) = *rm { }
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `Two` which is behind a mutable reference
--> $DIR/simple.rs:78:11
|
LL | match *rm {
@ -88,7 +88,7 @@ LL | Either::One(_t)
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:85:11
|
LL | match *rm {
@ -100,7 +100,7 @@ LL | Either::One(_t) => (),
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:93:11
|
LL | match *rm {
@ -226,7 +226,7 @@ LL | Either::One(_t) => (),
| data moved here
| move occurs because `_t` has type `X`, which does not implement the `Copy` trait
error[E0507]: cannot move out of `s.0` which is behind a shared reference
error[E0507]: cannot move out of `s` which is behind a shared reference
--> $DIR/simple.rs:168:18
|
LL | let &X(_t) = s;
@ -236,7 +236,7 @@ LL | let &X(_t) = s;
| | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait
| help: consider removing the `&`: `X(_t)`
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:172:31
|
LL | if let &Either::One(_t) = r { }
@ -246,7 +246,7 @@ LL | if let &Either::One(_t) = r { }
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&`: `Either::One(_t)`
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:176:34
|
LL | while let &Either::One(_t) = r { }
@ -256,7 +256,7 @@ LL | while let &Either::One(_t) = r { }
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&`: `Either::One(_t)`
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `Two` which is behind a shared reference
--> $DIR/simple.rs:180:11
|
LL | match r {
@ -276,7 +276,7 @@ LL +
LL ~ | &Either::Two(_t) => (),
|
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:188:11
|
LL | match r {
@ -289,7 +289,7 @@ LL | &Either::One(_t) => (),
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&`: `Either::One(_t)`
error[E0507]: cannot move out of `r.0` which is behind a shared reference
error[E0507]: cannot move out of `r` as enum variant `One` which is behind a shared reference
--> $DIR/simple.rs:195:11
|
LL | match r {
@ -302,7 +302,7 @@ LL | &Either::One(_t) => (),
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&`: `Either::One(_t)`
error[E0507]: cannot move out of `sm.0` which is behind a mutable reference
error[E0507]: cannot move out of `sm` which is behind a mutable reference
--> $DIR/simple.rs:207:22
|
LL | let &mut X(_t) = sm;
@ -312,7 +312,7 @@ LL | let &mut X(_t) = sm;
| | move occurs because `_t` has type `Y`, which does not implement the `Copy` trait
| help: consider removing the `&mut`: `X(_t)`
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:211:35
|
LL | if let &mut Either::One(_t) = rm { }
@ -322,7 +322,7 @@ LL | if let &mut Either::One(_t) = rm { }
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&mut`: `Either::One(_t)`
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:215:38
|
LL | while let &mut Either::One(_t) = rm { }
@ -332,7 +332,7 @@ LL | while let &mut Either::One(_t) = rm { }
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&mut`: `Either::One(_t)`
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `Two` which is behind a mutable reference
--> $DIR/simple.rs:219:11
|
LL | match rm {
@ -354,7 +354,7 @@ help: consider removing the `&mut`
LL | Either::Two(_t) => (),
| ~~~~~~~~~~~~~~~
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:228:11
|
LL | match rm {
@ -367,7 +367,7 @@ LL | &mut Either::One(_t) => (),
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&mut`: `Either::One(_t)`
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:235:11
|
LL | match rm {
@ -380,7 +380,7 @@ LL | &mut Either::One(_t) => (),
| | move occurs because `_t` has type `X`, which does not implement the `Copy` trait
| help: consider removing the `&mut`: `Either::One(_t)`
error[E0507]: cannot move out of `rm.0` which is behind a mutable reference
error[E0507]: cannot move out of `rm` as enum variant `One` which is behind a mutable reference
--> $DIR/simple.rs:242:11
|
LL | match rm {