From c3f72d1c098a61f26271021460b5ae420ff28ae8 Mon Sep 17 00:00:00 2001 From: Josh Stone Date: Fri, 20 Sep 2019 16:06:32 -0700 Subject: [PATCH] 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`. --- .../borrow_check/conflict_errors.rs | 3 ++- src/test/ui/issues/issue-64559.rs | 6 ++++++ src/test/ui/issues/issue-64559.stderr | 18 ++++++++++++++++++ 3 files changed, 26 insertions(+), 1 deletion(-) create mode 100644 src/test/ui/issues/issue-64559.rs create mode 100644 src/test/ui/issues/issue-64559.stderr diff --git a/src/librustc_mir/borrow_check/conflict_errors.rs b/src/librustc_mir/borrow_check/conflict_errors.rs index 81359c6a46e99..599a0ad0d0c52 100644 --- a/src/librustc_mir/borrow_check/conflict_errors.rs +++ b/src/librustc_mir/borrow_check/conflict_errors.rs @@ -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", diff --git a/src/test/ui/issues/issue-64559.rs b/src/test/ui/issues/issue-64559.rs new file mode 100644 index 0000000000000..71e054b5d9876 --- /dev/null +++ b/src/test/ui/issues/issue-64559.rs @@ -0,0 +1,6 @@ +fn main() { + let orig = vec![true]; + for _val in orig {} + let _closure = || orig; + //~^ ERROR use of moved value: `orig` +} diff --git a/src/test/ui/issues/issue-64559.stderr b/src/test/ui/issues/issue-64559.stderr new file mode 100644 index 0000000000000..3c685dc8d089a --- /dev/null +++ b/src/test/ui/issues/issue-64559.stderr @@ -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`, 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`.