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Try to fix issue 68049

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This commit is contained in:
hamidreza kalbasi 2021-05-09 05:26:59 +04:30
parent 1773f14a24
commit efc8f65b85
5 changed files with 170 additions and 10 deletions
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113
compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
View file

@ -6,7 +6,7 @@ use rustc_middle::mir::{Mutability, Place, PlaceRef, ProjectionElem};
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::{
hir::place::PlaceBase,
mir::{self, ClearCrossCrate, Local, LocalDecl, LocalInfo, Location},
mir::{self, ClearCrossCrate, Local, LocalDecl, LocalInfo, LocalKind, Location},
};
use rustc_span::source_map::DesugaringKind;
use rustc_span::symbol::{kw, Symbol};
@ -424,15 +424,108 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
match label {
Some((true, err_help_span, suggested_code)) => {
err.span_suggestion(
err_help_span,
&format!(
"consider changing this to be a mutable {}",
pointer_desc
),
suggested_code,
Applicability::MachineApplicable,
);
/// User cannot make signature of a trait mutable
/// without changing the trait. So we find if this
/// error belongs to a trait and if so we move
/// suggestion to the trait or disable it if it is
/// out of scope of this crate
let (is_trait_sig, local_trait) = {
if self.body.local_kind(local) != LocalKind::Arg {
(false, None)
} else {
let hir_map = self.infcx.tcx.hir();
let my_hir = hir_map.local_def_id_to_hir_id(
self.body.source.def_id().as_local().unwrap(),
);
match hir_map.find(hir_map.get_parent_node(my_hir)) {
Some(Node::Item(hir::Item {
kind:
hir::ItemKind::Impl(hir::Impl {
of_trait:
Some(hir::TraitRef {
path:
hir::Path {
res:
hir::def::Res::Def(_, td),
..
},
..
}),
..
}),
..
})) => {
(true, td.as_local().and_then(|tld| {
let h = hir_map.local_def_id_to_hir_id(tld);
match hir_map.find(h) {
Some(Node::Item(hir::Item {
kind: hir::ItemKind::Trait(
_, _, _, _,
items
),
..
})) => {
let mut f_in_trait_opt = None;
for hir::TraitItemRef { id: fi, kind: k, .. } in *items {
let hi = fi.hir_id();
if !matches!(k, hir::AssocItemKind::Fn { .. }) {
continue;
}
if hir_map.name(hi) != hir_map.name(my_hir) {
continue;
}
f_in_trait_opt = Some(hi);
break;
}
f_in_trait_opt.and_then(|f_in_trait| {
match hir_map.find(f_in_trait) {
Some(Node::TraitItem(hir::TraitItem {
kind: hir::TraitItemKind::Fn(hir::FnSig {
decl: hir::FnDecl {
inputs,
..
},
..
}, _),
..
})) => {
let hir::Ty { span, .. } = inputs[local.index() - 1];
Some(span)
},
_ => None,
}
})
//Some(hir_map.span(h))
}
_ => None
}
}))
}
_ => (false, None),
}
}
};
if !is_trait_sig {
err.span_suggestion(
err_help_span,
&format!(
"consider changing this to be a mutable {}",
pointer_desc
),
suggested_code,
Applicability::MachineApplicable,
);
} else if let Some(x) = local_trait {
err.span_suggestion(
x,
&format!(
"consider changing that to be a mutable {}",
pointer_desc
),
suggested_code,
Applicability::MachineApplicable,
);
}
}
Some((false, err_label_span, message)) => {
err.span_label(err_label_span, &message);

16
src/test/ui/suggestions/issue-68049-1.rs Normal file
View file

@ -0,0 +1,16 @@
use std::alloc::{GlobalAlloc, Layout};
struct Test(u32);
unsafe impl GlobalAlloc for Test {
unsafe fn alloc(&self, _layout: Layout) -> *mut u8 {
self.0 += 1;
0 as *mut u8
}
unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {
unimplemented!();
}
}
fn main() { }

9
src/test/ui/suggestions/issue-68049-1.stderr Normal file
View file

@ -0,0 +1,9 @@
error[E0594]: cannot assign to `self.0` which is behind a `&` reference
--> $DIR/issue-68049-1.rs:7:9
|
LL | self.0 += 1;
| ^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be written
error: aborting due to previous error
For more information about this error, try `rustc --explain E0594`.

21
src/test/ui/suggestions/issue-68049-2.rs Normal file
View file

@ -0,0 +1,21 @@
trait Hello {
fn example(&self, input: &i32); // should suggest here
}
struct Test1(i32);
impl Hello for Test1 {
fn example(&self, input: &i32) { // should not suggest here
*input = self.0;
}
}
struct Test2(i32);
impl Hello for Test2 {
fn example(&self, input: &i32) { // should not suggest here
self.0 += *input;
}
}
fn main() { }

21
src/test/ui/suggestions/issue-68049-2.stderr Normal file
View file

@ -0,0 +1,21 @@
error[E0594]: cannot assign to `*input` which is behind a `&` reference
--> $DIR/issue-68049-2.rs:9:7
|
LL | fn example(&self, input: &i32); // should suggest here
| ---- help: consider changing that to be a mutable reference: `&mut i32`
...
LL | *input = self.0;
| ^^^^^^^^^^^^^^^ `input` is a `&` reference, so the data it refers to cannot be written
error[E0594]: cannot assign to `self.0` which is behind a `&` reference
--> $DIR/issue-68049-2.rs:17:5
|
LL | fn example(&self, input: &i32); // should suggest here
| ----- help: consider changing that to be a mutable reference: `&mut self`
...
LL | self.0 += *input;
| ^^^^^^^^^^^^^^^^ `self` is a `&` reference, so the data it refers to cannot be written
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0594`.