diff options
| -rw-r--r-- | src/librustc/middle/ty/sty.rs | 8 | ||||
| -rw-r--r-- | src/librustc_trans/trans/expr.rs | 2 | ||||
| -rw-r--r-- | src/librustc_typeck/coherence/mod.rs | 9 | ||||
| -rw-r--r-- | src/test/compile-fail/issue-26905.rs | 34 | ||||
| -rw-r--r-- | src/test/run-pass/issue-26905.rs | 31 |
5 files changed, 82 insertions, 2 deletions
diff --git a/src/librustc/middle/ty/sty.rs b/src/librustc/middle/ty/sty.rs index 2d578fd0ea5..44f97a6b9e3 100644 --- a/src/librustc/middle/ty/sty.rs +++ b/src/librustc/middle/ty/sty.rs @@ -899,6 +899,14 @@ impl<'tcx> TyS<'tcx> { } } + pub fn is_phantom_data(&self) -> bool { + if let TyStruct(def, _) = self.sty { + def.is_phantom_data() + } else { + false + } + } + pub fn is_bool(&self) -> bool { self.sty == TyBool } pub fn is_param(&self, space: subst::ParamSpace, index: u32) -> bool { diff --git a/src/librustc_trans/trans/expr.rs b/src/librustc_trans/trans/expr.rs index d8397b3c017..5b0dae23807 100644 --- a/src/librustc_trans/trans/expr.rs +++ b/src/librustc_trans/trans/expr.rs @@ -533,7 +533,7 @@ fn coerce_unsized<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, Rvalue::new(ByRef))); } else { // Otherwise, simply copy the data from the source. - assert_eq!(src_ty, target_ty); + assert!(src_ty.is_phantom_data() || src_ty == target_ty); memcpy_ty(bcx, ll_target, ll_source, src_ty); } } diff --git a/src/librustc_typeck/coherence/mod.rs b/src/librustc_typeck/coherence/mod.rs index 9ba6f1398e4..d5164af56b3 100644 --- a/src/librustc_typeck/coherence/mod.rs +++ b/src/librustc_typeck/coherence/mod.rs @@ -480,9 +480,16 @@ impl<'a, 'tcx> CoherenceChecker<'a, 'tcx> { let fields = &def_a.struct_variant().fields; let diff_fields = fields.iter().enumerate().filter_map(|(i, f)| { let (a, b) = (f.ty(tcx, substs_a), f.ty(tcx, substs_b)); - if infcx.sub_types(false, origin, b, a).is_ok() { + + if f.unsubst_ty().is_phantom_data() { + // Ignore PhantomData fields + None + } else if infcx.sub_types(false, origin, b, a).is_ok() { + // Ignore fields that aren't significantly changed None } else { + // Collect up all fields that were significantly changed + // i.e. those that contain T in coerce_unsized T -> U Some((i, a, b)) } }).collect::<Vec<_>>(); diff --git a/src/test/compile-fail/issue-26905.rs b/src/test/compile-fail/issue-26905.rs new file mode 100644 index 00000000000..3b8fac832a4 --- /dev/null +++ b/src/test/compile-fail/issue-26905.rs @@ -0,0 +1,34 @@ +// 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. + +#![feature(unsize, coerce_unsized)] + +// Verfies that non-PhantomData ZSTs still cause coercions to fail. +// They might have additional semantics that we don't want to bulldoze. + +use std::marker::{Unsize, PhantomData}; +use std::ops::CoerceUnsized; + +struct NotPhantomData<T: ?Sized>(PhantomData<T>); + +struct MyRc<T: ?Sized> { + _ptr: *const T, + _boo: NotPhantomData<T>, +} + +impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<MyRc<U>> for MyRc<T>{ } //~ERROR + +fn main() { + let data = [1, 2, 3]; + let iter = data.iter(); + let x = MyRc { _ptr: &iter, _boo: NotPhantomData(PhantomData) }; + let _y: MyRc<Iterator<Item=&u32>> = x; +} + diff --git a/src/test/run-pass/issue-26905.rs b/src/test/run-pass/issue-26905.rs new file mode 100644 index 00000000000..0ad193bb28c --- /dev/null +++ b/src/test/run-pass/issue-26905.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. + +#![feature(unsize, coerce_unsized)] + +// Verfies that PhantomData is ignored for DST coercions + +use std::marker::{Unsize, PhantomData}; +use std::ops::CoerceUnsized; + +struct MyRc<T: ?Sized> { + _ptr: *const T, + _boo: PhantomData<T>, +} + +impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<MyRc<U>> for MyRc<T>{ } + +fn main() { + let data = [1, 2, 3]; + let iter = data.iter(); + let x = MyRc { _ptr: &iter, _boo: PhantomData }; + let _y: MyRc<Iterator<Item=&u32>> = x; +} + |