diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs index d43da5392ab8ed197b7b7da046850a2704411233..446ef6bd32876b63dce95e1b156cf90a05b5cb54 100644 --- a/src/librustc_mir/monomorphize/collector.rs +++ b/src/librustc_mir/monomorphize/collector.rs @@ -1068,7 +1068,6 @@ fn create_mono_items_for_default_impls<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id_to_string(tcx, impl_def_id)); if let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) { - let callee_substs = tcx.erase_regions(&trait_ref.substs); let overridden_methods: FxHashSet<_> = impl_item_refs.iter() .map(|iiref| iiref.name) @@ -1082,10 +1081,15 @@ fn create_mono_items_for_default_impls<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, continue; } + let substs = Substs::for_item(tcx, + method.def_id, + |_, _| tcx.types.re_erased, + |def, _| trait_ref.substs.type_for_def(def)); + let instance = ty::Instance::resolve(tcx, ty::ParamEnv::reveal_all(), method.def_id, - callee_substs).unwrap(); + substs).unwrap(); let mono_item = create_fn_mono_item(instance); if mono_item.is_instantiable(tcx) diff --git a/src/test/compile-fail/issue-47309.rs b/src/test/compile-fail/issue-47309.rs new file mode 100644 index 0000000000000000000000000000000000000000..7141bd62dc0d2f5362eeb6965352b67d36667e72 --- /dev/null +++ b/src/test/compile-fail/issue-47309.rs @@ -0,0 +1,31 @@ +// Copyright 2018 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. + +// Make sure that the mono-item collector does not crash when trying to +// instantiate a default impl of a method with lifetime parameters. +// See https://github.com/rust-lang/rust/issues/47309 + +// compile-flags:-Clink-dead-code +// must-compile-successfully + +#![crate_type="rlib"] + +pub trait EnvFuture { + type Item; + + fn boxed_result<'a>(self) where Self: Sized, Self::Item: 'a, { + } +} + +struct Foo; + +impl<'a> EnvFuture for &'a Foo { + type Item = (); +}