From ef1a40d5fec8678c4ae51cf2dcbed96934182b8c Mon Sep 17 00:00:00 2001 From: Matthew Jasper Date: Fri, 12 Oct 2018 15:16:29 +0100 Subject: [PATCH] Propagate bounds from generators --- .../borrow_check/nll/region_infer/mod.rs | 12 ++++------- .../borrow_check/nll/type_check/mod.rs | 15 ++++++------- .../borrow_check/nll/universal_regions.rs | 4 ++-- .../generator-region-requirements.ast.stderr | 12 +++++++++++ .../generator-region-requirements.nll.stderr | 12 +++++++++++ .../generator-region-requirements.rs | 21 +++++++++++++++++++ 6 files changed, 57 insertions(+), 19 deletions(-) create mode 100644 src/test/ui/generator/generator-region-requirements.ast.stderr create mode 100644 src/test/ui/generator/generator-region-requirements.nll.stderr create mode 100644 src/test/ui/generator/generator-region-requirements.rs diff --git a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs index dd8a7f19a63..0fabcfe4564 100644 --- a/src/librustc_mir/borrow_check/nll/region_infer/mod.rs +++ b/src/librustc_mir/borrow_check/nll/region_infer/mod.rs @@ -1268,7 +1268,7 @@ pub trait ClosureRegionRequirementsExt<'gcx, 'tcx> { tcx: TyCtxt<'_, 'gcx, 'tcx>, location: Location, closure_def_id: DefId, - closure_substs: ty::ClosureSubsts<'tcx>, + closure_substs: &'tcx ty::subst::Substs<'tcx>, ) -> Vec>; fn subst_closure_mapping( @@ -1299,23 +1299,19 @@ impl<'gcx, 'tcx> ClosureRegionRequirementsExt<'gcx, 'tcx> for ClosureRegionRequi tcx: TyCtxt<'_, 'gcx, 'tcx>, location: Location, closure_def_id: DefId, - closure_substs: ty::ClosureSubsts<'tcx>, + closure_substs: &'tcx ty::subst::Substs<'tcx>, ) -> Vec> { debug!( "apply_requirements(location={:?}, closure_def_id={:?}, closure_substs={:?})", location, closure_def_id, closure_substs ); - // Get Tu. - let user_closure_ty = tcx.mk_closure(closure_def_id, closure_substs); - debug!("apply_requirements: user_closure_ty={:?}", user_closure_ty); - - // Extract the values of the free regions in `user_closure_ty` + // Extract the values of the free regions in `closure_substs` // into a vector. These are the regions that we will be // relating to one another. let closure_mapping = &UniversalRegions::closure_mapping( tcx, - user_closure_ty, + closure_substs, self.num_external_vids, tcx.closure_base_def_id(closure_def_id), ); diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs index 1e79bc272e4..c5758cde949 100644 --- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs +++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs @@ -42,7 +42,7 @@ use rustc::traits::query::type_op::custom::CustomTypeOp; use rustc::traits::query::{Fallible, NoSolution}; use rustc::traits::{ObligationCause, PredicateObligations}; use rustc::ty::fold::TypeFoldable; -use rustc::ty::subst::{Subst, UnpackedKind}; +use rustc::ty::subst::{Subst, Substs, UnpackedKind}; use rustc::ty::{self, RegionVid, ToPolyTraitRef, Ty, TyCtxt, TyKind}; use std::rc::Rc; use std::{fmt, iter}; @@ -2075,12 +2075,9 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> { // desugaring. A closure gets desugared to a struct, and // these extra requirements are basically like where // clauses on the struct. - AggregateKind::Closure(def_id, substs) => { - self.prove_closure_bounds(tcx, *def_id, *substs, location) - } - - AggregateKind::Generator(def_id, substs, _) => { - tcx.predicates_of(*def_id).instantiate(tcx, substs.substs) + AggregateKind::Closure(def_id, ty::ClosureSubsts { substs }) + | AggregateKind::Generator(def_id, ty::GeneratorSubsts { substs }, _) => { + self.prove_closure_bounds(tcx, *def_id, substs, location) } AggregateKind::Array(_) | AggregateKind::Tuple => ty::InstantiatedPredicates::empty(), @@ -2096,7 +2093,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> { &mut self, tcx: TyCtxt<'a, 'gcx, 'tcx>, def_id: DefId, - substs: ty::ClosureSubsts<'tcx>, + substs: &'tcx Substs<'tcx>, location: Location, ) -> ty::InstantiatedPredicates<'tcx> { if let Some(closure_region_requirements) = @@ -2155,7 +2152,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> { ); } - tcx.predicates_of(def_id).instantiate(tcx, substs.substs) + tcx.predicates_of(def_id).instantiate(tcx, substs) } fn prove_trait_ref( diff --git a/src/librustc_mir/borrow_check/nll/universal_regions.rs b/src/librustc_mir/borrow_check/nll/universal_regions.rs index eb6f1a0677b..c54a4f96b7d 100644 --- a/src/librustc_mir/borrow_check/nll/universal_regions.rs +++ b/src/librustc_mir/borrow_check/nll/universal_regions.rs @@ -232,13 +232,13 @@ impl<'tcx> UniversalRegions<'tcx> { /// `V[1]: V[2]`. pub fn closure_mapping( tcx: TyCtxt<'_, '_, 'tcx>, - closure_ty: Ty<'tcx>, + closure_substs: &'tcx Substs<'tcx>, expected_num_vars: usize, closure_base_def_id: DefId, ) -> IndexVec> { let mut region_mapping = IndexVec::with_capacity(expected_num_vars); region_mapping.push(tcx.types.re_static); - tcx.for_each_free_region(&closure_ty, |fr| { + tcx.for_each_free_region(&closure_substs, |fr| { region_mapping.push(fr); }); diff --git a/src/test/ui/generator/generator-region-requirements.ast.stderr b/src/test/ui/generator/generator-region-requirements.ast.stderr new file mode 100644 index 00000000000..6a423aea7ec --- /dev/null +++ b/src/test/ui/generator/generator-region-requirements.ast.stderr @@ -0,0 +1,12 @@ +error[E0621]: explicit lifetime required in the type of `x` + --> $DIR/generator-region-requirements.rs:15:51 + | +LL | fn dangle(x: &mut i32) -> &'static mut i32 { + | -------- help: add explicit lifetime `'static` to the type of `x`: `&'static mut i32` +... +LL | GeneratorState::Complete(c) => return c, + | ^ lifetime `'static` required + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0621`. diff --git a/src/test/ui/generator/generator-region-requirements.nll.stderr b/src/test/ui/generator/generator-region-requirements.nll.stderr new file mode 100644 index 00000000000..5d1050dc352 --- /dev/null +++ b/src/test/ui/generator/generator-region-requirements.nll.stderr @@ -0,0 +1,12 @@ +error[E0621]: explicit lifetime required in the type of `x` + --> $DIR/generator-region-requirements.rs:11:9 + | +LL | fn dangle(x: &mut i32) -> &'static mut i32 { + | -------- help: add explicit lifetime `'static` to the type of `x`: `&'static mut i32` +... +LL | x + | ^ lifetime `'static` required + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0621`. diff --git a/src/test/ui/generator/generator-region-requirements.rs b/src/test/ui/generator/generator-region-requirements.rs new file mode 100644 index 00000000000..59e7841309c --- /dev/null +++ b/src/test/ui/generator/generator-region-requirements.rs @@ -0,0 +1,21 @@ +// revisions: ast nll +// ignore-compare-mode-nll + +#![feature(generators, generator_trait)] +#![cfg_attr(nll, feature(nll))] +use std::ops::{Generator, GeneratorState}; + +fn dangle(x: &mut i32) -> &'static mut i32 { + let mut g = || { + yield; + x + }; + loop { + match unsafe { g.resume() } { + GeneratorState::Complete(c) => return c, + GeneratorState::Yielded(_) => (), + } + } +} + +fn main() {}