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Rollup merge of #64642 - cuviper:move-for-loop-snippet, r=varkor
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Fix the span used to suggest avoiding for-loop moves

It was using the snippet from the "use" span, which often renders the
same, but with closures that snippet is on the start of the closure
where the value is captured. We should be using the snippet from the
span where it was moved into the `for` loop, which is `move_span`.

Fixes #64559.
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Centril committed Sep 21, 2019
2 parents 1486b7f + c3f72d1 commit 97ca073
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Showing 3 changed files with 26 additions and 1 deletion.
3 changes: 2 additions & 1 deletion src/librustc_mir/borrow_check/conflict_errors.rs
Original file line number Diff line number Diff line change
Expand Up @@ -180,7 +180,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
);
}
if Some(DesugaringKind::ForLoop) == move_span.desugaring_kind() {
if let Ok(snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(span) {
let sess = self.infcx.tcx.sess;
if let Ok(snippet) = sess.source_map().span_to_snippet(move_span) {
err.span_suggestion(
move_span,
"consider borrowing to avoid moving into the for loop",
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6 changes: 6 additions & 0 deletions src/test/ui/issues/issue-64559.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
fn main() {
let orig = vec![true];
for _val in orig {}
let _closure = || orig;
//~^ ERROR use of moved value: `orig`
}
18 changes: 18 additions & 0 deletions src/test/ui/issues/issue-64559.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
error[E0382]: use of moved value: `orig`
--> $DIR/issue-64559.rs:4:20
|
LL | let orig = vec![true];
| ---- move occurs because `orig` has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
LL | for _val in orig {}
| ----
| |
| value moved here
| help: consider borrowing to avoid moving into the for loop: `&orig`
LL | let _closure = || orig;
| ^^ ---- use occurs due to use in closure
| |
| value used here after move

error: aborting due to previous error

For more information about this error, try `rustc --explain E0382`.

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