// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution. // // 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. // Copyright 2012-2015 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. // use crate::rustc::hir; use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass}; use crate::rustc::{declare_tool_lint, lint_array}; use crate::syntax::ast; use crate::syntax::source_map::Span; use crate::utils::span_lint; /// **What it does:** it lints if an exported function, method, trait method with default impl, /// or trait method impl is not `#[inline]`. /// /// **Why is this bad?** In general, it is not. Functions can be inlined across /// crates when that's profitable as long as any form of LTO is used. When LTO is disabled, /// functions that are not `#[inline]` cannot be inlined across crates. Certain types of crates /// might intend for most of the methods in their public API to be able to be inlined across /// crates even when LTO is disabled. For these types of crates, enabling this lint might make sense. /// It allows the crate to require all exported methods to be `#[inline]` by default, and then opt /// out for specific methods where this might not make sense. /// /// **Known problems:** None. /// /// **Example:** /// ```rust /// pub fn foo() {} // missing #[inline] /// fn ok() {} // ok /// #[inline] pub fn bar() {} // ok /// #[inline(always)] pub fn baz() {} // ok /// /// pub trait Bar { /// fn bar(); // ok /// fn def_bar() {} // missing #[inline] /// } /// /// struct Baz; /// impl Baz { /// fn priv() {} // ok /// } /// /// impl Bar for Baz { /// fn bar() {} // ok - Baz is not exported /// } /// /// pub struct PubBaz; /// impl PubBaz { /// fn priv() {} // ok /// pub not_ptriv() {} // missing #[inline] /// } /// /// impl Bar for PubBaz { /// fn bar() {} // missing #[inline] /// fn def_bar() {} // missing #[inline] /// } /// ``` declare_clippy_lint! { pub MISSING_INLINE_IN_PUBLIC_ITEMS, restriction, "detects missing #[inline] attribute for public callables (functions, trait methods, methods...)" } pub struct MissingInline; fn check_missing_inline_attrs(cx: &LateContext<'_, '_>, attrs: &[ast::Attribute], sp: Span, desc: &'static str) { let has_inline = attrs .iter() .any(|a| a.name() == "inline" ); if !has_inline { span_lint( cx, MISSING_INLINE_IN_PUBLIC_ITEMS, sp, &format!("missing `#[inline]` for {}", desc), ); } } fn is_executable<'a, 'tcx>(cx: &LateContext<'a, 'tcx>) -> bool { use crate::rustc::session::config::CrateType; cx.tcx.sess.crate_types.get().iter().any(|t: &CrateType| { match t { CrateType::Executable => true, _ => false, } }) } impl LintPass for MissingInline { fn get_lints(&self) -> LintArray { lint_array![MISSING_INLINE_IN_PUBLIC_ITEMS] } } impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingInline { fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, it: &'tcx hir::Item) { if is_executable(cx) { return; } if !cx.access_levels.is_exported(it.id) { return; } match it.node { hir::ItemKind::Fn(..) => { let desc = "a function"; check_missing_inline_attrs(cx, &it.attrs, it.span, desc); }, hir::ItemKind::Trait(ref _is_auto, ref _unsafe, ref _generics, ref _bounds, ref trait_items) => { // note: we need to check if the trait is exported so we can't use // `LateLintPass::check_trait_item` here. for tit in trait_items { let tit_ = cx.tcx.hir.trait_item(tit.id); match tit_.node { hir::TraitItemKind::Const(..) | hir::TraitItemKind::Type(..) => {}, hir::TraitItemKind::Method(..) => { if tit.defaultness.has_value() { // trait method with default body needs inline in case // an impl is not provided let desc = "a default trait method"; let item = cx.tcx.hir.expect_trait_item(tit.id.node_id); check_missing_inline_attrs(cx, &item.attrs, item.span, desc); } }, } } } hir::ItemKind::Const(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Mod(..) | hir::ItemKind::Static(..) | hir::ItemKind::Struct(..) | hir::ItemKind::TraitAlias(..) | hir::ItemKind::GlobalAsm(..) | hir::ItemKind::Ty(..) | hir::ItemKind::Union(..) | hir::ItemKind::Existential(..) | hir::ItemKind::ExternCrate(..) | hir::ItemKind::ForeignMod(..) | hir::ItemKind::Impl(..) | hir::ItemKind::Use(..) => {}, }; } fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx hir::ImplItem) { use crate::rustc::ty::{TraitContainer, ImplContainer}; if is_executable(cx) { return; } // If the item being implemented is not exported, then we don't need #[inline] if !cx.access_levels.is_exported(impl_item.id) { return; } let desc = match impl_item.node { hir::ImplItemKind::Method(..) => "a method", hir::ImplItemKind::Const(..) | hir::ImplItemKind::Type(_) | hir::ImplItemKind::Existential(_) => return, }; let def_id = cx.tcx.hir.local_def_id(impl_item.id); let trait_def_id = match cx.tcx.associated_item(def_id).container { TraitContainer(cid) => Some(cid), ImplContainer(cid) => cx.tcx.impl_trait_ref(cid).map(|t| t.def_id), }; if let Some(trait_def_id) = trait_def_id { if let Some(n) = cx.tcx.hir.as_local_node_id(trait_def_id) { if !cx.access_levels.is_exported(n) { // If a trait is being implemented for an item, and the // trait is not exported, we don't need #[inline] return; } } } check_missing_inline_attrs(cx, &impl_item.attrs, impl_item.span, desc); } }