diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs index b3d7337cffe11..84e3ecd509687 100644 --- a/src/librustc_mir/borrow_check/mod.rs +++ b/src/librustc_mir/borrow_check/mod.rs @@ -1864,8 +1864,12 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> { }), } } - // promoteds may never be mutated - Place::Promoted(_) => bug!("encountered mutable promoted"), + // The rules for promotion are made by `qualify_consts`, there wouldn't even be a + // `Place::Promoted` if the promotion weren't 100% legal. So we just forward this + Place::Promoted(_) => Ok(RootPlace { + place, + is_local_mutation_allowed, + }), Place::Static(ref static_) => { if self.tcx.is_static(static_.def_id) != Some(hir::Mutability::MutMutable) { Err(place) diff --git a/src/test/ui/const-eval/promote_mutable_zst_mir_borrowck.rs b/src/test/ui/const-eval/promote_mutable_zst_mir_borrowck.rs new file mode 100644 index 0000000000000..922d7d3ab9606 --- /dev/null +++ b/src/test/ui/const-eval/promote_mutable_zst_mir_borrowck.rs @@ -0,0 +1,17 @@ +// Copyright 2018 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. + +// compile-pass + +#![feature(nll)] + +pub fn main() { + let y: &'static mut [u8; 0] = &mut []; +}