From 0b969a9d68b29fa53fb0595beb319036210d9e73 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Wed, 11 Jul 2018 14:25:29 -0700 Subject: [PATCH] rustc: Lint against `#[macro_use]` in 2018 idioms This commit adds a lint to the compiler to warn against the `#[macro_use]` directive as part of the `rust_2018_idioms` lint. This lint is turned off by default and is only enabled when the `use_extern_macros` feature is also enabled. The lint here isn't fully fleshed out as it's just a simple warning rather than suggestions of how to actually import the macro, but hopefully it's a good base to start from! cc #52043 --- src/librustc/lint/builtin.rs | 8 ++++++ src/librustc_lint/lib.rs | 2 ++ src/librustc_resolve/check_unused.rs | 17 +++++++++++- .../auxiliary/macro-use-warned-against.rs | 12 +++++++++ .../auxiliary/macro-use-warned-against2.rs | 10 +++++++ .../ui/rust-2018/macro-use-warned-against.rs | 25 ++++++++++++++++++ .../rust-2018/macro-use-warned-against.stderr | 26 +++++++++++++++++++ 7 files changed, 99 insertions(+), 1 deletion(-) create mode 100644 src/test/ui/rust-2018/auxiliary/macro-use-warned-against.rs create mode 100644 src/test/ui/rust-2018/auxiliary/macro-use-warned-against2.rs create mode 100644 src/test/ui/rust-2018/macro-use-warned-against.rs create mode 100644 src/test/ui/rust-2018/macro-use-warned-against.stderr diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs index efc2d9311c1..a46b3120622 100644 --- a/src/librustc/lint/builtin.rs +++ b/src/librustc/lint/builtin.rs @@ -322,6 +322,13 @@ declare_lint! { "detects proc macro derives using inaccessible names from parent modules" } +declare_lint! { + pub MACRO_USE_EXTERN_CRATE, + Allow, + "the `#[macro_use]` attribute is now deprecated in favor of using macros \ + via the module system" +} + /// Does nothing as a lint pass, but registers some `Lint`s /// which are used by other parts of the compiler. #[derive(Copy, Clone)] @@ -379,6 +386,7 @@ impl LintPass for HardwiredLints { INTRA_DOC_LINK_RESOLUTION_FAILURE, WHERE_CLAUSES_OBJECT_SAFETY, PROC_MACRO_DERIVE_RESOLUTION_FALLBACK, + MACRO_USE_EXTERN_CRATE, ) } } diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs index 359b056b5a2..5348a47eed6 100644 --- a/src/librustc_lint/lib.rs +++ b/src/librustc_lint/lib.rs @@ -43,6 +43,7 @@ extern crate syntax_pos; use rustc::lint; use rustc::lint::{LateContext, LateLintPass, LintPass, LintArray}; use rustc::lint::builtin::{BARE_TRAIT_OBJECTS, ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE}; +use rustc::lint::builtin::MACRO_USE_EXTERN_CRATE; use rustc::session; use rustc::util; use rustc::hir; @@ -179,6 +180,7 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) { BARE_TRAIT_OBJECTS, UNREACHABLE_PUB, UNUSED_EXTERN_CRATES, + MACRO_USE_EXTERN_CRATE, ELLIPSIS_INCLUSIVE_RANGE_PATTERNS); // Guidelines for creating a future incompatibility lint: diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs index 0c4b9a546cb..ef24a201e0f 100644 --- a/src/librustc_resolve/check_unused.rs +++ b/src/librustc_resolve/check_unused.rs @@ -129,7 +129,22 @@ pub fn check_crate(resolver: &mut Resolver, krate: &ast::Crate) { match directive.subclass { _ if directive.used.get() || directive.vis.get() == ty::Visibility::Public || - directive.span.is_dummy() => {} + directive.span.is_dummy() => { + if let ImportDirectiveSubclass::MacroUse = directive.subclass { + if resolver.session.features_untracked().use_extern_macros && + !directive.span.is_dummy() { + resolver.session.buffer_lint( + lint::builtin::MACRO_USE_EXTERN_CRATE, + directive.id, + directive.span, + "deprecated `#[macro_use]` directive used to \ + import macros should be replaced at use sites \ + with a `use` statement to import the macro \ + instead", + ); + } + } + } ImportDirectiveSubclass::ExternCrate(_) => { resolver.maybe_unused_extern_crates.push((directive.id, directive.span)); } diff --git a/src/test/ui/rust-2018/auxiliary/macro-use-warned-against.rs b/src/test/ui/rust-2018/auxiliary/macro-use-warned-against.rs new file mode 100644 index 00000000000..9487fd808cd --- /dev/null +++ b/src/test/ui/rust-2018/auxiliary/macro-use-warned-against.rs @@ -0,0 +1,12 @@ +// Copyright 2012-2014 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. + +#[macro_export] +macro_rules! foo { () => () } diff --git a/src/test/ui/rust-2018/auxiliary/macro-use-warned-against2.rs b/src/test/ui/rust-2018/auxiliary/macro-use-warned-against2.rs new file mode 100644 index 00000000000..6391db85dc5 --- /dev/null +++ b/src/test/ui/rust-2018/auxiliary/macro-use-warned-against2.rs @@ -0,0 +1,10 @@ +// 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. + diff --git a/src/test/ui/rust-2018/macro-use-warned-against.rs b/src/test/ui/rust-2018/macro-use-warned-against.rs new file mode 100644 index 00000000000..f7a6b560280 --- /dev/null +++ b/src/test/ui/rust-2018/macro-use-warned-against.rs @@ -0,0 +1,25 @@ +// 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. + +// aux-build:macro-use-warned-against.rs +// aux-build:macro-use-warned-against2.rs +// compile-pass + +#![warn(rust_2018_idioms, unused)] +#![feature(use_extern_macros)] + +#[macro_use] //~ WARN should be replaced at use sites with a `use` statement +extern crate macro_use_warned_against; +#[macro_use] //~ WARN unused `#[macro_use]` +extern crate macro_use_warned_against2; + +fn main() { + foo!(); +} diff --git a/src/test/ui/rust-2018/macro-use-warned-against.stderr b/src/test/ui/rust-2018/macro-use-warned-against.stderr new file mode 100644 index 00000000000..bebad31510f --- /dev/null +++ b/src/test/ui/rust-2018/macro-use-warned-against.stderr @@ -0,0 +1,26 @@ +warning: deprecated `#[macro_use]` directive used to import macros should be replaced at use sites with a `use` statement to import the macro instead + --> $DIR/macro-use-warned-against.rs:18:1 + | +LL | #[macro_use] //~ WARN should be replaced at use sites with a `use` statement + | ^^^^^^^^^^^^ + | +note: lint level defined here + --> $DIR/macro-use-warned-against.rs:15:9 + | +LL | #![warn(rust_2018_idioms, unused)] + | ^^^^^^^^^^^^^^^^ + = note: #[warn(macro_use_extern_crate)] implied by #[warn(rust_2018_idioms)] + +warning: unused `#[macro_use]` import + --> $DIR/macro-use-warned-against.rs:20:1 + | +LL | #[macro_use] //~ WARN unused `#[macro_use]` + | ^^^^^^^^^^^^ + | +note: lint level defined here + --> $DIR/macro-use-warned-against.rs:15:27 + | +LL | #![warn(rust_2018_idioms, unused)] + | ^^^^^^ + = note: #[warn(unused_imports)] implied by #[warn(unused)] +