diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs index ba17df4cdca4b..7773891b5d066 100644 --- a/src/librustc_lint/unused.rs +++ b/src/librustc_lint/unused.rs @@ -146,7 +146,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults { let t = cx.tables.expr_ty(&expr); let ty_warned = match t.sty { - ty::TyAdt(def, _) => check_must_use(cx, def.did, s.span, ""), + ty::TyTuple(ref tys, _) if tys.is_empty() => return, + ty::TyNever => return, + ty::TyAdt(def, _) => { + if def.variants.is_empty() { + return; + } else { + check_must_use(cx, def.did, s.span, "") + } + }, _ => false, }; diff --git a/src/test/ui/issue-43806.rs b/src/test/ui/issue-43806.rs new file mode 100644 index 0000000000000..7757a503c7e87 --- /dev/null +++ b/src/test/ui/issue-43806.rs @@ -0,0 +1,33 @@ +// 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. + +// run-pass + +#![deny(unused_results)] + +enum Void {} + +fn foo() {} + +fn bar() -> ! { + loop {} +} + +fn baz() -> Void { + loop {} +} + +fn qux() { + foo(); + bar(); + baz(); +} + +fn main() {}