1 use clippy_utils
::diagnostics
::span_lint
;
4 use rustc_lint
::{self, LateContext, LateLintPass, LintContext}
;
5 use rustc_session
::{declare_lint_pass, declare_tool_lint}
;
6 use rustc_span
::source_map
::Span
;
11 /// It lints if an exported function, method, trait method with default impl,
12 /// or trait method impl is not `#[inline]`.
14 /// ### Why is this bad?
15 /// In general, it is not. Functions can be inlined across
16 /// crates when that's profitable as long as any form of LTO is used. When LTO is disabled,
17 /// functions that are not `#[inline]` cannot be inlined across crates. Certain types of crates
18 /// might intend for most of the methods in their public API to be able to be inlined across
19 /// crates even when LTO is disabled. For these types of crates, enabling this lint might make
20 /// sense. It allows the crate to require all exported methods to be `#[inline]` by default, and
21 /// then opt out for specific methods where this might not make sense.
25 /// pub fn foo() {} // missing #[inline]
27 /// #[inline] pub fn bar() {} // ok
28 /// #[inline(always)] pub fn baz() {} // ok
32 /// fn def_bar() {} // missing #[inline]
37 /// fn private() {} // ok
40 /// impl Bar for Baz {
41 /// fn bar() {} // ok - Baz is not exported
44 /// pub struct PubBaz;
46 /// fn private() {} // ok
47 /// pub fn not_ptrivate() {} // missing #[inline]
50 /// impl Bar for PubBaz {
51 /// fn bar() {} // missing #[inline]
52 /// fn def_bar() {} // missing #[inline]
55 #[clippy::version = "pre 1.29.0"]
56 pub MISSING_INLINE_IN_PUBLIC_ITEMS
,
58 "detects missing `#[inline]` attribute for public callables (functions, trait methods, methods...)"
61 fn check_missing_inline_attrs(cx
: &LateContext
<'_
>, attrs
: &[ast
::Attribute
], sp
: Span
, desc
: &'
static str) {
62 let has_inline
= attrs
.iter().any(|a
| a
.has_name(sym
::inline
));
66 MISSING_INLINE_IN_PUBLIC_ITEMS
,
68 &format
!("missing `#[inline]` for {}", desc
),
73 fn is_executable_or_proc_macro(cx
: &LateContext
<'_
>) -> bool
{
74 use rustc_session
::config
::CrateType
;
80 .any(|t
: &CrateType
| matches
!(t
, CrateType
::Executable
| CrateType
::ProcMacro
))
83 declare_lint_pass
!(MissingInline
=> [MISSING_INLINE_IN_PUBLIC_ITEMS
]);
85 impl<'tcx
> LateLintPass
<'tcx
> for MissingInline
{
86 fn check_item(&mut self, cx
: &LateContext
<'tcx
>, it
: &'tcx hir
::Item
<'_
>) {
87 if rustc_middle
::lint
::in_external_macro(cx
.sess(), it
.span
) || is_executable_or_proc_macro(cx
) {
91 if !cx
.access_levels
.is_exported(it
.def_id
) {
95 hir
::ItemKind
::Fn(..) => {
96 let desc
= "a function";
97 let attrs
= cx
.tcx
.hir().attrs(it
.hir_id());
98 check_missing_inline_attrs(cx
, attrs
, it
.span
, desc
);
100 hir
::ItemKind
::Trait(ref _is_auto
, ref _unsafe
, ref _generics
, _bounds
, trait_items
) => {
101 // note: we need to check if the trait is exported so we can't use
102 // `LateLintPass::check_trait_item` here.
103 for tit
in trait_items
{
104 let tit_
= cx
.tcx
.hir().trait_item(tit
.id
);
106 hir
::TraitItemKind
::Const(..) | hir
::TraitItemKind
::Type(..) => {}
,
107 hir
::TraitItemKind
::Fn(..) => {
108 if tit
.defaultness
.has_value() {
109 // trait method with default body needs inline in case
110 // an impl is not provided
111 let desc
= "a default trait method";
112 let item
= cx
.tcx
.hir().trait_item(tit
.id
);
113 let attrs
= cx
.tcx
.hir().attrs(item
.hir_id());
114 check_missing_inline_attrs(cx
, attrs
, item
.span
, desc
);
120 hir
::ItemKind
::Const(..)
121 | hir
::ItemKind
::Enum(..)
122 | hir
::ItemKind
::Macro(..)
123 | hir
::ItemKind
::Mod(..)
124 | hir
::ItemKind
::Static(..)
125 | hir
::ItemKind
::Struct(..)
126 | hir
::ItemKind
::TraitAlias(..)
127 | hir
::ItemKind
::GlobalAsm(..)
128 | hir
::ItemKind
::TyAlias(..)
129 | hir
::ItemKind
::Union(..)
130 | hir
::ItemKind
::OpaqueTy(..)
131 | hir
::ItemKind
::ExternCrate(..)
132 | hir
::ItemKind
::ForeignMod { .. }
133 | hir
::ItemKind
::Impl { .. }
134 | hir
::ItemKind
::Use(..) => {}
,
138 fn check_impl_item(&mut self, cx
: &LateContext
<'tcx
>, impl_item
: &'tcx hir
::ImplItem
<'_
>) {
139 use rustc_middle
::ty
::{ImplContainer, TraitContainer}
;
140 if rustc_middle
::lint
::in_external_macro(cx
.sess(), impl_item
.span
) || is_executable_or_proc_macro(cx
) {
144 // If the item being implemented is not exported, then we don't need #[inline]
145 if !cx
.access_levels
.is_exported(impl_item
.def_id
) {
149 let desc
= match impl_item
.kind
{
150 hir
::ImplItemKind
::Fn(..) => "a method",
151 hir
::ImplItemKind
::Const(..) | hir
::ImplItemKind
::TyAlias(_
) => return,
154 let trait_def_id
= match cx
.tcx
.associated_item(impl_item
.def_id
).container
{
155 TraitContainer(cid
) => Some(cid
),
156 ImplContainer(cid
) => cx
.tcx
.impl_trait_ref(cid
).map(|t
| t
.def_id
),
159 if let Some(trait_def_id
) = trait_def_id
{
160 if trait_def_id
.is_local() && !cx
.access_levels
.is_exported(impl_item
.def_id
) {
161 // If a trait is being implemented for an item, and the
162 // trait is not exported, we don't need #[inline]
167 let attrs
= cx
.tcx
.hir().attrs(impl_item
.hir_id());
168 check_missing_inline_attrs(cx
, attrs
, impl_item
.span
, desc
);