diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs index 1cc69351b4750..f797bf1c3f6f9 100644 --- a/src/librustc_mir/borrow_check/mod.rs +++ b/src/librustc_mir/borrow_check/mod.rs @@ -1810,9 +1810,9 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> { } } Reservation(WriteKind::Move) + | Write(WriteKind::Move) | Reservation(WriteKind::StorageDeadOrDrop) | Reservation(WriteKind::MutableBorrow(BorrowKind::Shared)) - | Write(WriteKind::Move) | Write(WriteKind::StorageDeadOrDrop) | Write(WriteKind::MutableBorrow(BorrowKind::Shared)) => { if let Err(_place_err) = self.is_mutable(place, is_local_mutation_allowed) { @@ -1851,8 +1851,11 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> { // mutated, then it is justified to be annotated with the `mut` // keyword, since the mutation may be a possible reassignment. let mpi = self.move_data.rev_lookup.find_local(*local); - if flow_state.inits.contains(&mpi) { - self.used_mut.insert(*local); + let ii = &self.move_data.init_path_map[mpi]; + for index in ii { + if flow_state.ever_inits.contains(index) { + self.used_mut.insert(*local); + } } } } diff --git a/src/test/run-pass/nll/issue-50461-used-mut-from-moves.rs b/src/test/run-pass/nll/issue-50461-used-mut-from-moves.rs new file mode 100644 index 0000000000000..d5cf122bf3b33 --- /dev/null +++ b/src/test/run-pass/nll/issue-50461-used-mut-from-moves.rs @@ -0,0 +1,25 @@ +// Copyright 2016 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(nll)] +#![deny(unused_mut)] + +struct Foo { + pub value: i32 +} + +fn use_foo_mut(mut foo: Foo) { + foo = foo; + println!("{}", foo.value); +} + +fn main() { + use_foo_mut(Foo { value: 413 }); +}