Rollup merge of #82442 - Aaron1011:fix/closure-mut-crash, r=matthewjasper

Skip emitting closure diagnostic when closure_kind_origins has no entry

Fixes #82438

This map is not guarnateed to have an entry for a closure.
This commit is contained in:
Dylan DPC 2021-02-27 02:34:30 +01:00 committed by GitHub
commit 5c7b383e59
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3 changed files with 66 additions and 25 deletions

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@ -513,32 +513,33 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
let id = id.expect_local(); let id = id.expect_local();
let tables = tcx.typeck(id); let tables = tcx.typeck(id);
let hir_id = tcx.hir().local_def_id_to_hir_id(id); let hir_id = tcx.hir().local_def_id_to_hir_id(id);
let (span, place) = &tables.closure_kind_origins()[hir_id]; if let Some((span, place)) = tables.closure_kind_origins().get(hir_id) {
let reason = if let PlaceBase::Upvar(upvar_id) = place.base { let reason = if let PlaceBase::Upvar(upvar_id) = place.base {
let upvar = ty::place_to_string_for_capture(tcx, place); let upvar = ty::place_to_string_for_capture(tcx, place);
match tables.upvar_capture(upvar_id) { match tables.upvar_capture(upvar_id) {
ty::UpvarCapture::ByRef(ty::UpvarBorrow { ty::UpvarCapture::ByRef(ty::UpvarBorrow {
kind: ty::BorrowKind::MutBorrow | ty::BorrowKind::UniqueImmBorrow, kind: ty::BorrowKind::MutBorrow | ty::BorrowKind::UniqueImmBorrow,
.. ..
}) => { }) => {
format!("mutable borrow of `{}`", upvar) format!("mutable borrow of `{}`", upvar)
}
ty::UpvarCapture::ByValue(_) => {
format!("possible mutation of `{}`", upvar)
}
val => bug!("upvar `{}` borrowed, but not mutably: {:?}", upvar, val),
} }
ty::UpvarCapture::ByValue(_) => { } else {
format!("possible mutation of `{}`", upvar) bug!("not an upvar")
} };
val => bug!("upvar `{}` borrowed, but not mutably: {:?}", upvar, val), err.span_label(
} *span,
} else { format!(
bug!("not an upvar") "calling `{}` requires mutable binding due to {}",
}; self.describe_place(the_place_err).unwrap(),
err.span_label( reason
*span, ),
format!( );
"calling `{}` requires mutable binding due to {}", }
self.describe_place(the_place_err).unwrap(),
reason
),
);
} }
// Attempt to search similar mutable associated items for suggestion. // Attempt to search similar mutable associated items for suggestion.

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@ -0,0 +1,28 @@
use std::error::Error;
struct A {
}
impl A {
pub fn new() -> A {
A {
}
}
pub fn f<'a>(
&'a self,
team_name: &'a str,
c: &'a mut dyn FnMut(String, String, u64, u64)
) -> Result<(), Box<dyn Error>> {
Ok(())
}
}
fn main() {
let A = A::new();
let participant_name = "A";
let c = |a, b, c, d| {};
A.f(participant_name, &mut c); //~ ERROR cannot borrow
}

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@ -0,0 +1,12 @@
error[E0596]: cannot borrow `c` as mutable, as it is not declared as mutable
--> $DIR/issue-82438-mut-without-upvar.rs:27:27
|
LL | let c = |a, b, c, d| {};
| - help: consider changing this to be mutable: `mut c`
LL |
LL | A.f(participant_name, &mut c);
| ^^^^^^ cannot borrow as mutable
error: aborting due to previous error
For more information about this error, try `rustc --explain E0596`.