From 17fca8b4604bc4cf89ac06292f6475614984edc9 Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Thu, 8 Jun 2017 14:46:46 +0900 Subject: [PATCH 1/6] Check explicitly that tuple initializer is Sized. --- src/librustc/traits/error_reporting.rs | 3 +++ src/librustc/traits/mod.rs | 2 ++ src/librustc/traits/structural_impls.rs | 3 +++ src/librustc_typeck/check/mod.rs | 1 + src/test/compile-fail/unsized3.rs | 1 + 5 files changed, 10 insertions(+) diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs index e2e3d520d4777..35de536223a16 100644 --- a/src/librustc/traits/error_reporting.rs +++ b/src/librustc/traits/error_reporting.rs @@ -1097,6 +1097,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> { ObligationCauseCode::AssignmentLhsSized => { err.note("the left-hand-side of an assignment must have a statically known size"); } + ObligationCauseCode::TupleInitializerSized => { + err.note("tuples must have a statically known size to be initialized"); + } ObligationCauseCode::StructInitializerSized => { err.note("structs must have a statically known size to be initialized"); } diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs index c128438aea0d4..16c41c816b4eb 100644 --- a/src/librustc/traits/mod.rs +++ b/src/librustc/traits/mod.rs @@ -121,6 +121,8 @@ pub enum ObligationCauseCode<'tcx> { // Various cases where expressions must be sized/copy/etc: /// L = X implies that L is Sized AssignmentLhsSized, + /// (x1, .., xn) must be Sized + TupleInitializerSized, /// S { ... } must be Sized StructInitializerSized, /// Type of each variable must be Sized diff --git a/src/librustc/traits/structural_impls.rs b/src/librustc/traits/structural_impls.rs index 0d6df78c2ac5b..c4479e6903267 100644 --- a/src/librustc/traits/structural_impls.rs +++ b/src/librustc/traits/structural_impls.rs @@ -189,6 +189,7 @@ impl<'a, 'tcx> Lift<'tcx> for traits::ObligationCauseCode<'a> { tcx.lift(&ty).map(super::ObjectCastObligation) } super::AssignmentLhsSized => Some(super::AssignmentLhsSized), + super::TupleInitializerSized => Some(super::TupleInitializerSized), super::StructInitializerSized => Some(super::StructInitializerSized), super::VariableType(id) => Some(super::VariableType(id)), super::ReturnType(id) => Some(super::ReturnType(id)), @@ -476,6 +477,7 @@ impl<'tcx> TypeFoldable<'tcx> for traits::ObligationCauseCode<'tcx> { super::TupleElem | super::ItemObligation(_) | super::AssignmentLhsSized | + super::TupleInitializerSized | super::StructInitializerSized | super::VariableType(_) | super::ReturnType(_) | @@ -523,6 +525,7 @@ impl<'tcx> TypeFoldable<'tcx> for traits::ObligationCauseCode<'tcx> { super::TupleElem | super::ItemObligation(_) | super::AssignmentLhsSized | + super::TupleInitializerSized | super::StructInitializerSized | super::VariableType(_) | super::ReturnType(_) | diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 34cf1d7f96ba0..631158df47487 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -3854,6 +3854,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { if tuple.references_error() { tcx.types.err } else { + self.require_type_is_sized(tuple, expr.span, traits::TupleInitializerSized); tuple } } diff --git a/src/test/compile-fail/unsized3.rs b/src/test/compile-fail/unsized3.rs index 9b6ccf22c8da5..e96e0ea3aec36 100644 --- a/src/test/compile-fail/unsized3.rs +++ b/src/test/compile-fail/unsized3.rs @@ -54,6 +54,7 @@ fn f9(x1: Box>) { fn f10(x1: Box>) { f5(&(32, *x1)); //~^ ERROR `X: std::marker::Sized` is not satisfied + //~| ERROR `X: std::marker::Sized` is not satisfied } pub fn main() { From 23d1521684380a0a3099cb7439270cd650de36fb Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Thu, 8 Jun 2017 14:49:54 +0900 Subject: [PATCH 2/6] Add unsized tuple coercions. --- src/librustc/traits/error_reporting.rs | 2 +- src/librustc/traits/select.rs | 36 ++++++ src/librustc/ty/layout.rs | 10 +- src/librustc/ty/util.rs | 29 +++-- src/librustc_trans/glue.rs | 12 +- src/test/compile-fail/dst-bad-assign-3.rs | 48 ++++++++ src/test/compile-fail/dst-bad-coerce1.rs | 12 ++ src/test/compile-fail/dst-bad-coerce2.rs | 10 ++ src/test/compile-fail/dst-bad-coerce3.rs | 10 ++ src/test/compile-fail/dst-bad-coerce4.rs | 8 ++ src/test/compile-fail/dst-bad-deep-2.rs | 21 ++++ src/test/run-pass-valgrind/dst-dtor-1.rs | 3 +- src/test/run-pass-valgrind/dst-dtor-2.rs | 3 +- src/test/run-pass/dst-irrefutable-bind.rs | 10 ++ src/test/run-pass/dst-raw.rs | 32 ++++++ src/test/run-pass/dst-trait-tuple.rs | 110 +++++++++++++++++++ src/test/run-pass/dst-tuple-sole.rs | 83 ++++++++++++++ src/test/run-pass/dst-tuple.rs | 128 ++++++++++++++++++++++ 18 files changed, 549 insertions(+), 18 deletions(-) create mode 100644 src/test/compile-fail/dst-bad-assign-3.rs create mode 100644 src/test/compile-fail/dst-bad-deep-2.rs create mode 100644 src/test/run-pass/dst-trait-tuple.rs create mode 100644 src/test/run-pass/dst-tuple-sole.rs create mode 100644 src/test/run-pass/dst-tuple.rs diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs index 35de536223a16..0bf0e21baaf93 100644 --- a/src/librustc/traits/error_reporting.rs +++ b/src/librustc/traits/error_reporting.rs @@ -1060,7 +1060,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> { err.note("slice and array elements must have `Sized` type"); } ObligationCauseCode::TupleElem => { - err.note("tuple elements must have `Sized` type"); + err.note("only the last element of a tuple may have a dynamically sized type"); } ObligationCauseCode::ProjectionWf(data) => { err.note(&format!("required so that the projection `{}` is well-formed", diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs index a66b6b863541e..11169eefdaf87 100644 --- a/src/librustc/traits/select.rs +++ b/src/librustc/traits/select.rs @@ -1651,6 +1651,11 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> { def_id_a == def_id_b } + // (.., T) -> (.., U). + (&ty::TyTuple(tys_a, _), &ty::TyTuple(tys_b, _)) => { + tys_a.len() == tys_b.len() + } + _ => false }; @@ -2617,6 +2622,37 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> { &[inner_target])); } + // (.., T) -> (.., U). + (&ty::TyTuple(tys_a, _), &ty::TyTuple(tys_b, _)) => { + assert_eq!(tys_a.len(), tys_b.len()); + + // The last field of the tuple has to exist. + let (a_last, a_mid) = if let Some(x) = tys_a.split_last() { + x + } else { + return Err(Unimplemented); + }; + let b_last = tys_b.last().unwrap(); + + // Check that the source tuple with the target's + // last element is a subtype of the target. + let new_tuple = tcx.mk_tup(a_mid.iter().chain(Some(b_last)), false); + let InferOk { obligations, .. } = + self.infcx.at(&obligation.cause, obligation.param_env) + .eq(target, new_tuple) + .map_err(|_| Unimplemented)?; + self.inferred_obligations.extend(obligations); + + // Construct the nested T: Unsize predicate. + nested.push(tcx.predicate_for_trait_def( + obligation.param_env, + obligation.cause.clone(), + obligation.predicate.def_id(), + obligation.recursion_depth + 1, + a_last, + &[b_last])); + } + _ => bug!() }; diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs index 12af56d5c3dfa..e1aa89078a33b 100644 --- a/src/librustc/ty/layout.rs +++ b/src/librustc/ty/layout.rs @@ -1220,12 +1220,16 @@ impl<'a, 'tcx> Layout { } ty::TyTuple(tys, _) => { - // FIXME(camlorn): if we ever allow unsized tuples, this needs to be checked. - // See the univariant case below to learn how. + let kind = if tys.len() == 0 { + StructKind::AlwaysSizedUnivariant + } else { + StructKind::MaybeUnsizedUnivariant + }; + let st = Struct::new(dl, &tys.iter().map(|ty| ty.layout(tcx, param_env)) .collect::, _>>()?, - &ReprOptions::default(), StructKind::AlwaysSizedUnivariant, ty)?; + &ReprOptions::default(), kind, ty)?; Univariant { variant: st, non_zero: false } } diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs index 98ef7918fef82..df4bbad3859f4 100644 --- a/src/librustc/ty/util.rs +++ b/src/librustc/ty/util.rs @@ -317,15 +317,26 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> { target: Ty<'tcx>) -> (Ty<'tcx>, Ty<'tcx>) { let (mut a, mut b) = (source, target); - while let (&TyAdt(a_def, a_substs), &TyAdt(b_def, b_substs)) = (&a.sty, &b.sty) { - if a_def != b_def || !a_def.is_struct() { - break; - } - match a_def.struct_variant().fields.last() { - Some(f) => { - a = f.ty(self, a_substs); - b = f.ty(self, b_substs); - } + loop { + match (&a.sty, &b.sty) { + (&TyAdt(a_def, a_substs), &TyAdt(b_def, b_substs)) + if a_def == b_def && a_def.is_struct() => { + if let Some(f) = a_def.struct_variant().fields.last() { + a = f.ty(self, a_substs); + b = f.ty(self, b_substs); + } else { + break; + } + }, + (&TyTuple(a_tys, _), &TyTuple(b_tys, _)) + if a_tys.len() == b_tys.len() => { + if let Some(a_last) = a_tys.last() { + a = a_last; + b = b_tys.last().unwrap(); + } else { + break; + } + }, _ => break, } } diff --git a/src/librustc_trans/glue.rs b/src/librustc_trans/glue.rs index 367f0398fa838..c2f44c089a2d6 100644 --- a/src/librustc_trans/glue.rs +++ b/src/librustc_trans/glue.rs @@ -76,7 +76,7 @@ pub fn size_and_align_of_dst<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, t: Ty<'tcx>, inf } assert!(!info.is_null()); match t.sty { - ty::TyAdt(def, substs) => { + ty::TyAdt(..) | ty::TyTuple(..) => { let ccx = bcx.ccx; // First get the size of all statically known fields. // Don't use size_of because it also rounds up to alignment, which we @@ -101,8 +101,14 @@ pub fn size_and_align_of_dst<'a, 'tcx>(bcx: &Builder<'a, 'tcx>, t: Ty<'tcx>, inf // Recurse to get the size of the dynamically sized field (must be // the last field). - let last_field = def.struct_variant().fields.last().unwrap(); - let field_ty = monomorphize::field_ty(bcx.tcx(), substs, last_field); + let field_ty = match t.sty { + ty::TyAdt(def, substs) => { + let last_field = def.struct_variant().fields.last().unwrap(); + monomorphize::field_ty(bcx.tcx(), substs, last_field) + }, + ty::TyTuple(tys, _) => tys.last().unwrap(), + _ => unreachable!(), + }; let (unsized_size, unsized_align) = size_and_align_of_dst(bcx, field_ty, info); // FIXME (#26403, #27023): We should be adding padding diff --git a/src/test/compile-fail/dst-bad-assign-3.rs b/src/test/compile-fail/dst-bad-assign-3.rs new file mode 100644 index 0000000000000..3c089edf00130 --- /dev/null +++ b/src/test/compile-fail/dst-bad-assign-3.rs @@ -0,0 +1,48 @@ +// Copyright 2014 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. + +// Forbid assignment into a dynamically sized type. + +type Fat = (isize, &'static str, T); +//~^ WARNING trait bounds are not (yet) enforced + +#[derive(PartialEq,Eq)] +struct Bar; + +#[derive(PartialEq,Eq)] +struct Bar1 { + f: isize +} + +trait ToBar { + fn to_bar(&self) -> Bar; + fn to_val(&self) -> isize; +} + +impl ToBar for Bar1 { + fn to_bar(&self) -> Bar { + Bar + } + fn to_val(&self) -> isize { + self.f + } +} + +pub fn main() { + // Assignment. + let f5: &mut Fat = &mut (5, "some str", Bar1 {f :42}); + let z: Box = Box::new(Bar1 {f: 36}); + f5.2 = Bar1 {f: 36}; + //~^ ERROR mismatched types + //~| expected type `ToBar` + //~| found type `Bar1` + //~| expected trait ToBar, found struct `Bar1` + //~| ERROR `ToBar: std::marker::Sized` is not satisfied +} diff --git a/src/test/compile-fail/dst-bad-coerce1.rs b/src/test/compile-fail/dst-bad-coerce1.rs index 9a3ea54a3a455..722ff8f25d610 100644 --- a/src/test/compile-fail/dst-bad-coerce1.rs +++ b/src/test/compile-fail/dst-bad-coerce1.rs @@ -29,4 +29,16 @@ pub fn main() { let f2: &Fat = &f1; let f3: &Fat = f2; //~^ ERROR `Foo: Bar` is not satisfied + + // Tuple with a vec of isize. + let f1 = ([1, 2, 3],); + let f2: &([isize; 3],) = &f1; + let f3: &([usize],) = f2; + //~^ ERROR mismatched types + + // Tuple with a trait. + let f1 = (Foo,); + let f2: &(Foo,) = &f1; + let f3: &(Bar,) = f2; + //~^ ERROR `Foo: Bar` is not satisfied } diff --git a/src/test/compile-fail/dst-bad-coerce2.rs b/src/test/compile-fail/dst-bad-coerce2.rs index 160197368d6d9..9e92f649b2d56 100644 --- a/src/test/compile-fail/dst-bad-coerce2.rs +++ b/src/test/compile-fail/dst-bad-coerce2.rs @@ -28,4 +28,14 @@ pub fn main() { let f1 = Fat { ptr: Foo }; let f2: &Fat = &f1; let f3: &mut Fat = f2; //~ ERROR mismatched types + + // Tuple with a vec of ints. + let f1 = ([1, 2, 3],); + let f2: &([isize; 3],) = &f1; + let f3: &mut ([isize],) = f2; //~ ERROR mismatched types + + // Tuple with a trait. + let f1 = (Foo,); + let f2: &(Foo,) = &f1; + let f3: &mut (Bar,) = f2; //~ ERROR mismatched types } diff --git a/src/test/compile-fail/dst-bad-coerce3.rs b/src/test/compile-fail/dst-bad-coerce3.rs index 7bad3bd69d3b0..4dedae9331bc3 100644 --- a/src/test/compile-fail/dst-bad-coerce3.rs +++ b/src/test/compile-fail/dst-bad-coerce3.rs @@ -28,6 +28,16 @@ fn baz<'a>() { let f1 = Fat { ptr: Foo }; let f2: &Fat = &f1; //~ ERROR `f1` does not live long enough let f3: &'a Fat = f2; + + // Tuple with a vec of ints. + let f1 = ([1, 2, 3],); + let f2: &([isize; 3],) = &f1; //~ ERROR `f1` does not live long enough + let f3: &'a ([isize],) = f2; + + // Tuple with a trait. + let f1 = (Foo,); + let f2: &(Foo,) = &f1; //~ ERROR `f1` does not live long enough + let f3: &'a (Bar,) = f2; } pub fn main() { diff --git a/src/test/compile-fail/dst-bad-coerce4.rs b/src/test/compile-fail/dst-bad-coerce4.rs index 9d4d56cf79190..2e78108a8dea0 100644 --- a/src/test/compile-fail/dst-bad-coerce4.rs +++ b/src/test/compile-fail/dst-bad-coerce4.rs @@ -22,4 +22,12 @@ pub fn main() { //~| expected type `&Fat<[isize; 3]>` //~| found type `&Fat<[isize]>` //~| expected array of 3 elements, found slice + + // Tuple with a vec of isizes. + let f1: &([isize],) = &([1, 2, 3],); + let f2: &([isize; 3],) = f1; + //~^ ERROR mismatched types + //~| expected type `&([isize; 3],)` + //~| found type `&([isize],)` + //~| expected array of 3 elements, found slice } diff --git a/src/test/compile-fail/dst-bad-deep-2.rs b/src/test/compile-fail/dst-bad-deep-2.rs new file mode 100644 index 0000000000000..831afd27153ae --- /dev/null +++ b/src/test/compile-fail/dst-bad-deep-2.rs @@ -0,0 +1,21 @@ +// Copyright 2014 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. + +// Try to initialise a DST struct where the lost information is deeply nested. +// This is an error because it requires an unsized rvalue. This is a problem +// because it would require stack allocation of an unsized temporary (*g in the +// test). + +pub fn main() { + let f: ([isize; 3],) = ([5, 6, 7],); + let g: &([isize],) = &f; + let h: &(([isize],),) = &(*g,); + //~^ ERROR `[isize]: std::marker::Sized` is not satisfied +} diff --git a/src/test/run-pass-valgrind/dst-dtor-1.rs b/src/test/run-pass-valgrind/dst-dtor-1.rs index 4af642a106c15..00bfebb3f1e24 100644 --- a/src/test/run-pass-valgrind/dst-dtor-1.rs +++ b/src/test/run-pass-valgrind/dst-dtor-1.rs @@ -28,7 +28,8 @@ struct Fat { pub fn main() { { - let _x: Box> = Box::>::new(Fat { f: Foo }); + let _x: Box<(i32, Fat)> = + Box::<(i32, Fat)>::new((42, Fat { f: Foo })); } unsafe { assert!(DROP_RAN); diff --git a/src/test/run-pass-valgrind/dst-dtor-2.rs b/src/test/run-pass-valgrind/dst-dtor-2.rs index 283b8202b35d0..fa0c6c0322539 100644 --- a/src/test/run-pass-valgrind/dst-dtor-2.rs +++ b/src/test/run-pass-valgrind/dst-dtor-2.rs @@ -25,7 +25,8 @@ struct Fat { pub fn main() { { - let _x: Box> = Box::>::new(Fat { f: [Foo, Foo, Foo] }); + let _x: Box<(Fat<[Foo]>,)> = + Box::<(Fat<[Foo; 3]>,)>::new((Fat { f: [Foo, Foo, Foo] },)); } unsafe { assert_eq!(DROP_RAN, 3); diff --git a/src/test/run-pass/dst-irrefutable-bind.rs b/src/test/run-pass/dst-irrefutable-bind.rs index 9f8067f372aef..bd6ad9207adcd 100644 --- a/src/test/run-pass/dst-irrefutable-bind.rs +++ b/src/test/run-pass/dst-irrefutable-bind.rs @@ -21,4 +21,14 @@ fn main() { let slice = &[1,2,3]; let x = Test(&slice); let Test(&_slice) = x; + + + let x = (10, [1,2,3]); + let x : &(i32, [i32]) = &x; + + let & ref _y = x; + + let slice = &[1,2,3]; + let x = (10, &slice); + let (_, &_slice) = x; } diff --git a/src/test/run-pass/dst-raw.rs b/src/test/run-pass/dst-raw.rs index 3a74626b0299f..c82cbd75044fb 100644 --- a/src/test/run-pass/dst-raw.rs +++ b/src/test/run-pass/dst-raw.rs @@ -45,6 +45,14 @@ pub fn main() { }; assert_eq!(r, 42); + // raw DST tuple + let p = (A { f: 42 },); + let o: *const (Trait,) = &p; + let r = unsafe { + (&*o).0.foo() + }; + assert_eq!(r, 42); + // raw slice let a: *const [_] = &[1, 2, 3]; unsafe { @@ -72,6 +80,15 @@ pub fn main() { assert_eq!(len, 3); } + // raw DST tuple with slice + let c: *const ([_],) = &([1, 2, 3],); + unsafe { + let b = (&*c).0[0]; + assert_eq!(b, 1); + let len = (&*c).0.len(); + assert_eq!(len, 3); + } + // all of the above with *mut let mut x = A { f: 42 }; let z: *mut Trait = &mut x; @@ -87,6 +104,13 @@ pub fn main() { }; assert_eq!(r, 42); + let mut p = (A { f: 42 },); + let o: *mut (Trait,) = &mut p; + let r = unsafe { + (&*o).0.foo() + }; + assert_eq!(r, 42); + let a: *mut [_] = &mut [1, 2, 3]; unsafe { let b = (*a)[2]; @@ -110,4 +134,12 @@ pub fn main() { let len = (&*c).f.len(); assert_eq!(len, 3); } + + let c: *mut ([_],) = &mut ([1, 2, 3],); + unsafe { + let b = (&*c).0[0]; + assert_eq!(b, 1); + let len = (&*c).0.len(); + assert_eq!(len, 3); + } } diff --git a/src/test/run-pass/dst-trait-tuple.rs b/src/test/run-pass/dst-trait-tuple.rs new file mode 100644 index 0000000000000..ab60e95c74e81 --- /dev/null +++ b/src/test/run-pass/dst-trait-tuple.rs @@ -0,0 +1,110 @@ +// Copyright 2014 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. + + +#![allow(unused_features)] +#![feature(box_syntax)] + +type Fat = (isize, &'static str, T); + +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +struct Bar; + +#[derive(Copy, Clone, PartialEq, Eq)] +struct Bar1 { + f: isize +} + +trait ToBar { + fn to_bar(&self) -> Bar; + fn to_val(&self) -> isize; +} + +impl ToBar for Bar { + fn to_bar(&self) -> Bar { + *self + } + fn to_val(&self) -> isize { + 0 + } +} +impl ToBar for Bar1 { + fn to_bar(&self) -> Bar { + Bar + } + fn to_val(&self) -> isize { + self.f + } +} + +// x is a fat pointer +fn foo(x: &Fat) { + assert_eq!(x.0, 5); + assert_eq!(x.1, "some str"); + assert_eq!(x.2.to_bar(), Bar); + assert_eq!(x.2.to_val(), 42); + + let y = &x.2; + assert_eq!(y.to_bar(), Bar); + assert_eq!(y.to_val(), 42); +} + +fn bar(x: &ToBar) { + assert_eq!(x.to_bar(), Bar); + assert_eq!(x.to_val(), 42); +} + +fn baz(x: &Fat>) { + assert_eq!(x.0, 5); + assert_eq!(x.1, "some str"); + assert_eq!((x.2).0, 8); + assert_eq!((x.2).1, "deep str"); + assert_eq!((x.2).2.to_bar(), Bar); + assert_eq!((x.2).2.to_val(), 42); + + let y = &(x.2).2; + assert_eq!(y.to_bar(), Bar); + assert_eq!(y.to_val(), 42); + +} + +pub fn main() { + let f1 = (5, "some str", Bar1 {f :42}); + foo(&f1); + let f2 = &f1; + foo(f2); + let f3: &Fat = f2; + foo(f3); + let f4: &Fat = &f1; + foo(f4); + let f5: &Fat = &(5, "some str", Bar1 {f :42}); + foo(f5); + + // Zero size object. + let f6: &Fat = &(5, "some str", Bar); + assert_eq!(f6.2.to_bar(), Bar); + + // &* + // + let f7: Box = Box::new(Bar1 {f :42}); + bar(&*f7); + + // Deep nesting + let f1 = (5, "some str", (8, "deep str", Bar1 {f :42})); + baz(&f1); + let f2 = &f1; + baz(f2); + let f3: &Fat> = f2; + baz(f3); + let f4: &Fat> = &f1; + baz(f4); + let f5: &Fat> = &(5, "some str", (8, "deep str", Bar1 {f :42})); + baz(f5); +} diff --git a/src/test/run-pass/dst-tuple-sole.rs b/src/test/run-pass/dst-tuple-sole.rs new file mode 100644 index 0000000000000..d3901a7555fd7 --- /dev/null +++ b/src/test/run-pass/dst-tuple-sole.rs @@ -0,0 +1,83 @@ +// Copyright 2014 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. + +// As dst-tuple.rs, but the unsized field is the only field in the tuple. + + +type Fat = (T,); + +// x is a fat pointer +fn foo(x: &Fat<[isize]>) { + let y = &x.0; + assert_eq!(x.0.len(), 3); + assert_eq!(y[0], 1); + assert_eq!(x.0[1], 2); +} + +fn foo2(x: &Fat<[T]>) { + let y = &x.0; + let bar = Bar; + assert_eq!(x.0.len(), 3); + assert_eq!(y[0].to_bar(), bar); + assert_eq!(x.0[1].to_bar(), bar); +} + +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +struct Bar; + +trait ToBar { + fn to_bar(&self) -> Bar; +} + +impl ToBar for Bar { + fn to_bar(&self) -> Bar { + *self + } +} + +pub fn main() { + // With a vec of ints. + let f1 = ([1, 2, 3],); + foo(&f1); + let f2 = &f1; + foo(f2); + let f3: &Fat<[isize]> = f2; + foo(f3); + let f4: &Fat<[isize]> = &f1; + foo(f4); + let f5: &Fat<[isize]> = &([1, 2, 3],); + foo(f5); + + // With a vec of Bars. + let bar = Bar; + let f1 = ([bar, bar, bar],); + foo2(&f1); + let f2 = &f1; + foo2(f2); + let f3: &Fat<[Bar]> = f2; + foo2(f3); + let f4: &Fat<[Bar]> = &f1; + foo2(f4); + let f5: &Fat<[Bar]> = &([bar, bar, bar],); + foo2(f5); + + // Assignment. + let f5: &mut Fat<[isize]> = &mut ([1, 2, 3],); + f5.0[1] = 34; + assert_eq!(f5.0[0], 1); + assert_eq!(f5.0[1], 34); + assert_eq!(f5.0[2], 3); + + // Zero size vec. + let f5: &Fat<[isize]> = &([],); + assert!(f5.0.is_empty()); + let f5: &Fat<[Bar]> = &([],); + assert!(f5.0.is_empty()); +} diff --git a/src/test/run-pass/dst-tuple.rs b/src/test/run-pass/dst-tuple.rs new file mode 100644 index 0000000000000..130294feb6ca5 --- /dev/null +++ b/src/test/run-pass/dst-tuple.rs @@ -0,0 +1,128 @@ +// Copyright 2014 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. + + +#![allow(unknown_features)] +#![feature(box_syntax)] + +type Fat = (isize, &'static str, T); + +// x is a fat pointer +fn foo(x: &Fat<[isize]>) { + let y = &x.2; + assert_eq!(x.2.len(), 3); + assert_eq!(y[0], 1); + assert_eq!(x.2[1], 2); + assert_eq!(x.0, 5); + assert_eq!(x.1, "some str"); +} + +fn foo2(x: &Fat<[T]>) { + let y = &x.2; + let bar = Bar; + assert_eq!(x.2.len(), 3); + assert_eq!(y[0].to_bar(), bar); + assert_eq!(x.2[1].to_bar(), bar); + assert_eq!(x.0, 5); + assert_eq!(x.1, "some str"); +} + +fn foo3(x: &Fat>) { + let y = &(x.2).2; + assert_eq!(x.0, 5); + assert_eq!(x.1, "some str"); + assert_eq!((x.2).0, 8); + assert_eq!((x.2).1, "deep str"); + assert_eq!((x.2).2.len(), 3); + assert_eq!(y[0], 1); + assert_eq!((x.2).2[1], 2); +} + + +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +struct Bar; + +trait ToBar { + fn to_bar(&self) -> Bar; +} + +impl ToBar for Bar { + fn to_bar(&self) -> Bar { + *self + } +} + +pub fn main() { + // With a vec of ints. + let f1 = (5, "some str", [1, 2, 3]); + foo(&f1); + let f2 = &f1; + foo(f2); + let f3: &Fat<[isize]> = f2; + foo(f3); + let f4: &Fat<[isize]> = &f1; + foo(f4); + let f5: &Fat<[isize]> = &(5, "some str", [1, 2, 3]); + foo(f5); + + // With a vec of Bars. + let bar = Bar; + let f1 = (5, "some str", [bar, bar, bar]); + foo2(&f1); + let f2 = &f1; + foo2(f2); + let f3: &Fat<[Bar]> = f2; + foo2(f3); + let f4: &Fat<[Bar]> = &f1; + foo2(f4); + let f5: &Fat<[Bar]> = &(5, "some str", [bar, bar, bar]); + foo2(f5); + + // Assignment. + let f5: &mut Fat<[isize]> = &mut (5, "some str", [1, 2, 3]); + f5.2[1] = 34; + assert_eq!(f5.2[0], 1); + assert_eq!(f5.2[1], 34); + assert_eq!(f5.2[2], 3); + + // Zero size vec. + let f5: &Fat<[isize]> = &(5, "some str", []); + assert!(f5.2.is_empty()); + let f5: &Fat<[Bar]> = &(5, "some str", []); + assert!(f5.2.is_empty()); + + // Deeply nested. + let f1 = (5, "some str", (8, "deep str", [1, 2, 3])); + foo3(&f1); + let f2 = &f1; + foo3(f2); + let f3: &Fat> = f2; + foo3(f3); + let f4: &Fat> = &f1; + foo3(f4); + let f5: &Fat> = &(5, "some str", (8, "deep str", [1, 2, 3])); + foo3(f5); + + // Box. + let f1 = Box::new([1, 2, 3]); + assert_eq!((*f1)[1], 2); + let f2: Box<[isize]> = f1; + assert_eq!((*f2)[1], 2); + + // Nested Box. + let f1 : Box> = box (5, "some str", [1, 2, 3]); + foo(&*f1); + let f2 : Box> = f1; + foo(&*f2); + + let f3 : Box> = + Box::>::new((5, "some str", [1, 2, 3])); + foo(&*f3); +} From b0bf1b46820d74c30a725a7ea332305098bf3def Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Wed, 14 Jun 2017 12:27:51 +0900 Subject: [PATCH 3/6] Split dst-dtor-{1,2} tests into four. --- src/test/run-pass-valgrind/dst-dtor-1.rs | 3 +-- src/test/run-pass-valgrind/dst-dtor-2.rs | 3 +-- src/test/run-pass-valgrind/dst-dtor-3.rs | 32 ++++++++++++++++++++++++ src/test/run-pass-valgrind/dst-dtor-4.rs | 29 +++++++++++++++++++++ 4 files changed, 63 insertions(+), 4 deletions(-) create mode 100644 src/test/run-pass-valgrind/dst-dtor-3.rs create mode 100644 src/test/run-pass-valgrind/dst-dtor-4.rs diff --git a/src/test/run-pass-valgrind/dst-dtor-1.rs b/src/test/run-pass-valgrind/dst-dtor-1.rs index 00bfebb3f1e24..4af642a106c15 100644 --- a/src/test/run-pass-valgrind/dst-dtor-1.rs +++ b/src/test/run-pass-valgrind/dst-dtor-1.rs @@ -28,8 +28,7 @@ struct Fat { pub fn main() { { - let _x: Box<(i32, Fat)> = - Box::<(i32, Fat)>::new((42, Fat { f: Foo })); + let _x: Box> = Box::>::new(Fat { f: Foo }); } unsafe { assert!(DROP_RAN); diff --git a/src/test/run-pass-valgrind/dst-dtor-2.rs b/src/test/run-pass-valgrind/dst-dtor-2.rs index fa0c6c0322539..283b8202b35d0 100644 --- a/src/test/run-pass-valgrind/dst-dtor-2.rs +++ b/src/test/run-pass-valgrind/dst-dtor-2.rs @@ -25,8 +25,7 @@ struct Fat { pub fn main() { { - let _x: Box<(Fat<[Foo]>,)> = - Box::<(Fat<[Foo; 3]>,)>::new((Fat { f: [Foo, Foo, Foo] },)); + let _x: Box> = Box::>::new(Fat { f: [Foo, Foo, Foo] }); } unsafe { assert_eq!(DROP_RAN, 3); diff --git a/src/test/run-pass-valgrind/dst-dtor-3.rs b/src/test/run-pass-valgrind/dst-dtor-3.rs new file mode 100644 index 0000000000000..b21f6434b5402 --- /dev/null +++ b/src/test/run-pass-valgrind/dst-dtor-3.rs @@ -0,0 +1,32 @@ +// Copyright 2014 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. + +// no-prefer-dynamic + +static mut DROP_RAN: bool = false; + +struct Foo; +impl Drop for Foo { + fn drop(&mut self) { + unsafe { DROP_RAN = true; } + } +} + +trait Trait { fn dummy(&self) { } } +impl Trait for Foo {} + +pub fn main() { + { + let _x: Box<(i32, Trait)> = Box::<(i32, Foo)>::new((42, Foo)); + } + unsafe { + assert!(DROP_RAN); + } +} diff --git a/src/test/run-pass-valgrind/dst-dtor-4.rs b/src/test/run-pass-valgrind/dst-dtor-4.rs new file mode 100644 index 0000000000000..810589de7708b --- /dev/null +++ b/src/test/run-pass-valgrind/dst-dtor-4.rs @@ -0,0 +1,29 @@ +// Copyright 2014 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. + +// no-prefer-dynamic + +static mut DROP_RAN: isize = 0; + +struct Foo; +impl Drop for Foo { + fn drop(&mut self) { + unsafe { DROP_RAN += 1; } + } +} + +pub fn main() { + { + let _x: Box<(i32, [Foo])> = Box::<(i32, [Foo; 3])>::new((42, [Foo, Foo, Foo])); + } + unsafe { + assert_eq!(DROP_RAN, 3); + } +} From 03660b647690c3dea12a20468f9f798bacd14d82 Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Sat, 24 Jun 2017 16:20:27 +0900 Subject: [PATCH 4/6] Move unsized_tuple_coercion behind a feature gate. --- .../unsized-tuple-coercion.md | 27 +++++++++++++++++++ src/librustc_typeck/check/coercion.rs | 21 ++++++++++++++- src/libsyntax/feature_gate.rs | 6 +++++ src/test/compile-fail/dst-bad-assign-3.rs | 2 ++ src/test/compile-fail/dst-bad-coerce1.rs | 2 ++ src/test/compile-fail/dst-bad-coerce3.rs | 2 ++ src/test/compile-fail/dst-bad-coerce4.rs | 2 ++ src/test/compile-fail/dst-bad-deep-2.rs | 2 ++ .../feature-gate-unsized_tuple_coercion.rs | 14 ++++++++++ src/test/run-pass-valgrind/dst-dtor-3.rs | 2 ++ src/test/run-pass-valgrind/dst-dtor-4.rs | 2 ++ src/test/run-pass/dst-irrefutable-bind.rs | 2 ++ src/test/run-pass/dst-raw.rs | 2 ++ src/test/run-pass/dst-trait-tuple.rs | 1 + src/test/run-pass/dst-tuple-sole.rs | 2 ++ src/test/run-pass/dst-tuple.rs | 1 + 16 files changed, 89 insertions(+), 1 deletion(-) create mode 100644 src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md create mode 100644 src/test/compile-fail/feature-gate-unsized_tuple_coercion.rs diff --git a/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md b/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md new file mode 100644 index 0000000000000..c243737e1be53 --- /dev/null +++ b/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md @@ -0,0 +1,27 @@ +# `unsized_tuple_coercion` + +The tracking issue for this feature is: [#XXXXX] + +[#XXXXX]: https://github.com/rust-lang/rust/issues/XXXXX + +------------------------ + +This is a part of [RFC0401]. According to the RFC, there should be an implementation like this: + +```rust +impl<..., T, U: ?Sized> Unsized<(..., U)> for (..., T) where T: Unsized {} +``` + +This implementation is currently gated behind `#[feature(unsized_tuple_coercion)]` to avoid insta-stability. Therefore you can use it like this: + +```rust +#![feature(unsized_tuple_coercion)] + +fn main() { + let x : ([i32; 3], [i32; 3]) = ([1, 2, 3], [4, 5, 6]); + let y : &([i32; 3], [i32]) = &x; + assert_eq!(y.1[0], 4); +} +``` + +[RFC0401]: https://github.com/rust-lang/rfcs/blob/master/text/0401-coercions.md diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs index 81aa59e956abf..968e893b9a00b 100644 --- a/src/librustc_typeck/check/coercion.rs +++ b/src/librustc_typeck/check/coercion.rs @@ -76,6 +76,7 @@ use rustc::ty::relate::RelateResult; use rustc::ty::subst::Subst; use errors::DiagnosticBuilder; use syntax::abi; +use syntax::feature_gate; use syntax::ptr::P; use syntax_pos; @@ -520,6 +521,8 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> { coerce_source, &[coerce_target])); + let mut has_unsized_tuple_coercion = false; + // Keep resolving `CoerceUnsized` and `Unsize` predicates to avoid // emitting a coercion in cases like `Foo<$1>` -> `Foo<$2>`, where // inference might unify those two inner type variables later. @@ -527,7 +530,15 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> { while let Some(obligation) = queue.pop_front() { debug!("coerce_unsized resolve step: {:?}", obligation); let trait_ref = match obligation.predicate { - ty::Predicate::Trait(ref tr) if traits.contains(&tr.def_id()) => tr.clone(), + ty::Predicate::Trait(ref tr) if traits.contains(&tr.def_id()) => { + if unsize_did == tr.def_id() { + if let ty::TyTuple(..) = tr.0.input_types().nth(1).unwrap().sty { + debug!("coerce_unsized: found unsized tuple coercion"); + has_unsized_tuple_coercion = true; + } + } + tr.clone() + } _ => { coercion.obligations.push(obligation); continue; @@ -557,6 +568,14 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> { } } + if has_unsized_tuple_coercion && !self.tcx.sess.features.borrow().unsized_tuple_coercion { + feature_gate::emit_feature_err(&self.tcx.sess.parse_sess, + "unsized_tuple_coercion", + self.cause.span, + feature_gate::GateIssue::Language, + feature_gate::EXPLAIN_UNSIZED_TUPLE_COERCION); + } + Ok(coercion) } diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index 74bf19b841e88..5de9062de7487 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -357,6 +357,9 @@ declare_features! ( // Allows a test to fail without failing the whole suite (active, allow_fail, "1.19.0", Some(42219)), + + // Allows unsized tuple coercion. + (active, unsized_tuple_coercion, "1.20.0", None), ); declare_features! ( @@ -1041,6 +1044,9 @@ pub const EXPLAIN_VIS_MATCHER: &'static str = pub const EXPLAIN_PLACEMENT_IN: &'static str = "placement-in expression syntax is experimental and subject to change."; +pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &'static str = + "Unsized tuple coercion is not stable enough for use and is subject to change"; + struct PostExpansionVisitor<'a> { context: &'a Context<'a>, } diff --git a/src/test/compile-fail/dst-bad-assign-3.rs b/src/test/compile-fail/dst-bad-assign-3.rs index 3c089edf00130..1c3bad5ba5643 100644 --- a/src/test/compile-fail/dst-bad-assign-3.rs +++ b/src/test/compile-fail/dst-bad-assign-3.rs @@ -10,6 +10,8 @@ // Forbid assignment into a dynamically sized type. +#![feature(unsized_tuple_coercion)] + type Fat = (isize, &'static str, T); //~^ WARNING trait bounds are not (yet) enforced diff --git a/src/test/compile-fail/dst-bad-coerce1.rs b/src/test/compile-fail/dst-bad-coerce1.rs index 722ff8f25d610..b0de84a530072 100644 --- a/src/test/compile-fail/dst-bad-coerce1.rs +++ b/src/test/compile-fail/dst-bad-coerce1.rs @@ -10,6 +10,8 @@ // Attempt to change the type as well as unsizing. +#![feature(unsized_tuple_coercion)] + struct Fat { ptr: T } diff --git a/src/test/compile-fail/dst-bad-coerce3.rs b/src/test/compile-fail/dst-bad-coerce3.rs index 4dedae9331bc3..35a147c15bb43 100644 --- a/src/test/compile-fail/dst-bad-coerce3.rs +++ b/src/test/compile-fail/dst-bad-coerce3.rs @@ -10,6 +10,8 @@ // Attempt to extend the lifetime as well as unsizing. +#![feature(unsized_tuple_coercion)] + struct Fat { ptr: T } diff --git a/src/test/compile-fail/dst-bad-coerce4.rs b/src/test/compile-fail/dst-bad-coerce4.rs index 2e78108a8dea0..874b7588ff9bb 100644 --- a/src/test/compile-fail/dst-bad-coerce4.rs +++ b/src/test/compile-fail/dst-bad-coerce4.rs @@ -10,6 +10,8 @@ // Attempt to coerce from unsized to sized. +#![feature(unsized_tuple_coercion)] + struct Fat { ptr: T } diff --git a/src/test/compile-fail/dst-bad-deep-2.rs b/src/test/compile-fail/dst-bad-deep-2.rs index 831afd27153ae..0c812b1d815ab 100644 --- a/src/test/compile-fail/dst-bad-deep-2.rs +++ b/src/test/compile-fail/dst-bad-deep-2.rs @@ -13,6 +13,8 @@ // because it would require stack allocation of an unsized temporary (*g in the // test). +#![feature(unsized_tuple_coercion)] + pub fn main() { let f: ([isize; 3],) = ([5, 6, 7],); let g: &([isize],) = &f; diff --git a/src/test/compile-fail/feature-gate-unsized_tuple_coercion.rs b/src/test/compile-fail/feature-gate-unsized_tuple_coercion.rs new file mode 100644 index 0000000000000..4ddde01126363 --- /dev/null +++ b/src/test/compile-fail/feature-gate-unsized_tuple_coercion.rs @@ -0,0 +1,14 @@ +// Copyright 2017 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. + +fn main() { + let _ : &(Send,) = &((),); + //~^ ERROR Unsized tuple coercion is not stable enough +} diff --git a/src/test/run-pass-valgrind/dst-dtor-3.rs b/src/test/run-pass-valgrind/dst-dtor-3.rs index b21f6434b5402..1ae66a28a849e 100644 --- a/src/test/run-pass-valgrind/dst-dtor-3.rs +++ b/src/test/run-pass-valgrind/dst-dtor-3.rs @@ -10,6 +10,8 @@ // no-prefer-dynamic +#![feature(unsized_tuple_coercion)] + static mut DROP_RAN: bool = false; struct Foo; diff --git a/src/test/run-pass-valgrind/dst-dtor-4.rs b/src/test/run-pass-valgrind/dst-dtor-4.rs index 810589de7708b..e416f25bc03a0 100644 --- a/src/test/run-pass-valgrind/dst-dtor-4.rs +++ b/src/test/run-pass-valgrind/dst-dtor-4.rs @@ -10,6 +10,8 @@ // no-prefer-dynamic +#![feature(unsized_tuple_coercion)] + static mut DROP_RAN: isize = 0; struct Foo; diff --git a/src/test/run-pass/dst-irrefutable-bind.rs b/src/test/run-pass/dst-irrefutable-bind.rs index bd6ad9207adcd..b1d6c732e7fbb 100644 --- a/src/test/run-pass/dst-irrefutable-bind.rs +++ b/src/test/run-pass/dst-irrefutable-bind.rs @@ -8,6 +8,8 @@ // option. This file may not be copied, modified, or distributed // except according to those terms. +#![feature(unsized_tuple_coercion)] + struct Test(T); fn main() { diff --git a/src/test/run-pass/dst-raw.rs b/src/test/run-pass/dst-raw.rs index c82cbd75044fb..9ebfbee8a3302 100644 --- a/src/test/run-pass/dst-raw.rs +++ b/src/test/run-pass/dst-raw.rs @@ -11,6 +11,8 @@ // Test DST raw pointers +#![feature(unsized_tuple_coercion)] + trait Trait { fn foo(&self) -> isize; } diff --git a/src/test/run-pass/dst-trait-tuple.rs b/src/test/run-pass/dst-trait-tuple.rs index ab60e95c74e81..9803e26f5f859 100644 --- a/src/test/run-pass/dst-trait-tuple.rs +++ b/src/test/run-pass/dst-trait-tuple.rs @@ -11,6 +11,7 @@ #![allow(unused_features)] #![feature(box_syntax)] +#![feature(unsized_tuple_coercion)] type Fat = (isize, &'static str, T); diff --git a/src/test/run-pass/dst-tuple-sole.rs b/src/test/run-pass/dst-tuple-sole.rs index d3901a7555fd7..a788e25218eb4 100644 --- a/src/test/run-pass/dst-tuple-sole.rs +++ b/src/test/run-pass/dst-tuple-sole.rs @@ -11,6 +11,8 @@ // As dst-tuple.rs, but the unsized field is the only field in the tuple. +#![feature(unsized_tuple_coercion)] + type Fat = (T,); // x is a fat pointer diff --git a/src/test/run-pass/dst-tuple.rs b/src/test/run-pass/dst-tuple.rs index 130294feb6ca5..2f5b28495b8ae 100644 --- a/src/test/run-pass/dst-tuple.rs +++ b/src/test/run-pass/dst-tuple.rs @@ -11,6 +11,7 @@ #![allow(unknown_features)] #![feature(box_syntax)] +#![feature(unsized_tuple_coercion)] type Fat = (isize, &'static str, T); From 141265dfe8eb345d3218c771db957a93d6c7f000 Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Sun, 25 Jun 2017 07:32:00 +0900 Subject: [PATCH 5/6] Give a tracking-issue number for unsized tuple coercion. --- .../src/language-features/unsized-tuple-coercion.md | 4 ++-- src/libsyntax/feature_gate.rs | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md b/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md index c243737e1be53..200a9c19462ca 100644 --- a/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md +++ b/src/doc/unstable-book/src/language-features/unsized-tuple-coercion.md @@ -1,8 +1,8 @@ # `unsized_tuple_coercion` -The tracking issue for this feature is: [#XXXXX] +The tracking issue for this feature is: [#42877] -[#XXXXX]: https://github.com/rust-lang/rust/issues/XXXXX +[#42877]: https://github.com/rust-lang/rust/issues/42877 ------------------------ diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs index 5de9062de7487..df8ee189d21b3 100644 --- a/src/libsyntax/feature_gate.rs +++ b/src/libsyntax/feature_gate.rs @@ -359,7 +359,7 @@ declare_features! ( (active, allow_fail, "1.19.0", Some(42219)), // Allows unsized tuple coercion. - (active, unsized_tuple_coercion, "1.20.0", None), + (active, unsized_tuple_coercion, "1.20.0", Some(42877)), ); declare_features! ( From 94862c601be15a8edd93539244177f5a9145374d Mon Sep 17 00:00:00 2001 From: Masaki Hara Date: Thu, 29 Jun 2017 20:00:31 +0900 Subject: [PATCH 6/6] Correct comments about unsizing regarding #40319. --- src/librustc/traits/select.rs | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs index 11169eefdaf87..856fea7c2c437 100644 --- a/src/librustc/traits/select.rs +++ b/src/librustc/traits/select.rs @@ -2596,8 +2596,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> { let inner_source = field.subst(tcx, substs_a); let inner_target = field.subst(tcx, substs_b); - // Check that the source structure with the target's - // type parameters is a subtype of the target. + // Check that the source struct with the target's + // unsized parameters is equal to the target. let params = substs_a.iter().enumerate().map(|(i, &k)| { if ty_params.contains(i) { Kind::from(substs_b.type_at(i)) @@ -2635,7 +2635,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> { let b_last = tys_b.last().unwrap(); // Check that the source tuple with the target's - // last element is a subtype of the target. + // last element is equal to the target. let new_tuple = tcx.mk_tup(a_mid.iter().chain(Some(b_last)), false); let InferOk { obligations, .. } = self.infcx.at(&obligation.cause, obligation.param_env)