diff options
| -rw-r--r-- | src/librustc_trans/trans/consts.rs | 8 | ||||
| -rw-r--r-- | src/test/run-pass/const-trait-to-trait.rs | 31 |
2 files changed, 36 insertions, 3 deletions
diff --git a/src/librustc_trans/trans/consts.rs b/src/librustc_trans/trans/consts.rs index c11bb922f1c..8ebda9a6678 100644 --- a/src/librustc_trans/trans/consts.rs +++ b/src/librustc_trans/trans/consts.rs @@ -342,9 +342,11 @@ pub fn const_expr<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, let info = expr::unsized_info(cx, pointee_ty, unsized_ty, old_info, param_substs); - let prev_const = cx.const_unsized().borrow_mut() - .insert(base, llconst); - assert!(prev_const.is_none() || prev_const == Some(llconst)); + if old_info.is_none() { + let prev_const = cx.const_unsized().borrow_mut() + .insert(base, llconst); + assert!(prev_const.is_none() || prev_const == Some(llconst)); + } assert_eq!(abi::FAT_PTR_ADDR, 0); assert_eq!(abi::FAT_PTR_EXTRA, 1); llconst = C_struct(cx, &[base, info], false); diff --git a/src/test/run-pass/const-trait-to-trait.rs b/src/test/run-pass/const-trait-to-trait.rs new file mode 100644 index 00000000000..4b53e116789 --- /dev/null +++ b/src/test/run-pass/const-trait-to-trait.rs @@ -0,0 +1,31 @@ +// Copyright 2015 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. + +// Issue #24644 - block causes a &Trait -> &Trait coercion: +trait Trait {} + +struct Bar; +impl Trait for Bar {} + +fn main() { + let x: &[&Trait] = &[{ &Bar }]; +} + +// Issue #25748 - the cast causes an &Encoding -> &Encoding coercion: +pub struct UTF8Encoding; +pub const UTF_8: &'static UTF8Encoding = &UTF8Encoding; +pub trait Encoding {} +impl Encoding for UTF8Encoding {} +pub fn f() -> &'static Encoding { UTF_8 as &'static Encoding } + +// Root of the problem: &Trait -> &Trait coercions: +const FOO: &'static Trait = &Bar; +const BAR: &'static Trait = FOO; +fn foo() { let _x = BAR; } |