diff options
| -rw-r--r-- | src/librustc_passes/consts.rs | 46 | ||||
| -rw-r--r-- | src/test/compile-fail/issue-44373.rs | 16 | ||||
| -rw-r--r-- | src/test/run-pass/issue-44373.rs | 18 |
3 files changed, 76 insertions, 4 deletions
diff --git a/src/librustc_passes/consts.rs b/src/librustc_passes/consts.rs index 6f2c448ceb6..547d63fc3d4 100644 --- a/src/librustc_passes/consts.rs +++ b/src/librustc_passes/consts.rs @@ -56,6 +56,7 @@ use std::cmp::Ordering; struct CheckCrateVisitor<'a, 'tcx: 'a> { tcx: TyCtxt<'a, 'tcx, 'tcx>, in_fn: bool, + in_static: bool, promotable: bool, mut_rvalue_borrows: NodeSet, param_env: ty::ParamEnv<'tcx>, @@ -128,10 +129,16 @@ impl<'a, 'tcx> Visitor<'tcx> for CheckCrateVisitor<'a, 'tcx> { let outer_param_env = self.param_env; let outer_identity_substs = self.identity_substs; - self.in_fn = match MirSource::from_node(self.tcx, item_id) { - MirSource::Fn(_) => true, - _ => false + self.in_fn = false; + self.in_static = false; + + match MirSource::from_node(self.tcx, item_id) { + MirSource::Fn(_) => self.in_fn = true, + MirSource::Static(_, _) => self.in_static = true, + _ => {} }; + + self.tables = self.tcx.typeck_tables_of(item_def_id); self.param_env = self.tcx.param_env(item_def_id); self.identity_substs = Substs::identity_for_item(self.tcx, item_def_id); @@ -327,7 +334,37 @@ fn check_expr<'a, 'tcx>(v: &mut CheckCrateVisitor<'a, 'tcx>, e: &hir::Expr, node let def = v.tables.qpath_def(qpath, e.hir_id); match def { Def::VariantCtor(..) | Def::StructCtor(..) | - Def::Fn(..) | Def::Method(..) => {} + Def::Fn(..) | Def::Method(..) => {} + + // References to a static that are themselves within a static + // are inherently promotable with the exception + // of "#[thread_loca]" statics, which may not + // outlive the current function + Def::Static(did, _) => { + + if v.in_static { + let mut thread_local = false; + + for attr in &v.tcx.get_attrs(did)[..] { + if attr.check_name("thread_local") { + debug!("Reference to Static(id={:?}) is unpromotable \ + due to a #[thread_local] attribute", did); + v.promotable = false; + thread_local = true; + break; + } + } + + if !thread_local { + debug!("Allowing promotion of reference to Static(id={:?})", did); + } + } else { + debug!("Reference to Static(id={:?}) is unpromotable as it is not \ + referenced from a static", did); + v.promotable = false; + + } + } Def::Const(did) | Def::AssociatedConst(did) => { @@ -481,6 +518,7 @@ pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) { tcx, tables: &ty::TypeckTables::empty(None), in_fn: false, + in_static: false, promotable: false, mut_rvalue_borrows: NodeSet(), param_env: ty::ParamEnv::empty(Reveal::UserFacing), diff --git a/src/test/compile-fail/issue-44373.rs b/src/test/compile-fail/issue-44373.rs new file mode 100644 index 00000000000..d744ad11c5c --- /dev/null +++ b/src/test/compile-fail/issue-44373.rs @@ -0,0 +1,16 @@ +// 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 <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. + + +static FOO: u32 = 50; + +fn main() { + let _val: &'static [&'static u32] = &[&FOO]; //~ ERROR borrowed value does not live long enough +} diff --git a/src/test/run-pass/issue-44373.rs b/src/test/run-pass/issue-44373.rs new file mode 100644 index 00000000000..06627e2ad93 --- /dev/null +++ b/src/test/run-pass/issue-44373.rs @@ -0,0 +1,18 @@ +// 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 <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. + +struct Foo(bool); + +struct Container(&'static [&'static Foo]); + +static FOO: Foo = Foo(true); +static CONTAINER: Container = Container(&[&FOO]); + +fn main() {} |