diff options
| -rw-r--r-- | src/librustc_trans/mir/constant.rs | 5 | ||||
| -rw-r--r-- | src/test/run-pass/union/union-const-eval-field.rs | 26 |
2 files changed, 30 insertions, 1 deletions
diff --git a/src/librustc_trans/mir/constant.rs b/src/librustc_trans/mir/constant.rs index 71ce0aa3da9..f519e27dce9 100644 --- a/src/librustc_trans/mir/constant.rs +++ b/src/librustc_trans/mir/constant.rs @@ -140,7 +140,10 @@ impl<'a, 'tcx> Const<'tcx> { } } _ => { - const_get_elt(self.llval, layout.llvm_field_index(i)) + match layout.fields { + layout::FieldPlacement::Union(_) => self.llval, + _ => const_get_elt(self.llval, layout.llvm_field_index(i)), + } } } } diff --git a/src/test/run-pass/union/union-const-eval-field.rs b/src/test/run-pass/union/union-const-eval-field.rs new file mode 100644 index 00000000000..a58b8bc34cd --- /dev/null +++ b/src/test/run-pass/union/union-const-eval-field.rs @@ -0,0 +1,26 @@ +// 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 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(const_fn)] + +union DummyUnion { + field1: i32, + field2: i32, +} + +const fn read_field() -> i32 { + const UNION: DummyUnion = DummyUnion { field1: 5 }; + const FIELD: i32 = unsafe { UNION.field2 }; + FIELD +} + +fn main() { + assert_eq!(read_field(), 5); +} |