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532ac7d7 XL |
1 | //! Some lints that are only useful in the compiler or crates that use compiler internals, such as |
2 | //! Clippy. | |
3 | ||
dfeec247 | 4 | use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext}; |
f9f354fc | 5 | use rustc_ast::ast::{Item, ItemKind}; |
532ac7d7 | 6 | use rustc_data_structures::fx::FxHashMap; |
dfeec247 XL |
7 | use rustc_errors::Applicability; |
8 | use rustc_hir::{GenericArg, HirId, MutTy, Mutability, Path, PathSegment, QPath, Ty, TyKind}; | |
9 | use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass}; | |
10 | use rustc_span::hygiene::{ExpnKind, MacroKind}; | |
f9f354fc | 11 | use rustc_span::symbol::{sym, Ident, Symbol}; |
532ac7d7 | 12 | |
416331ca XL |
13 | declare_tool_lint! { |
14 | pub rustc::DEFAULT_HASH_TYPES, | |
532ac7d7 | 15 | Allow, |
dfeec247 XL |
16 | "forbid HashMap and HashSet and suggest the FxHash* variants", |
17 | report_in_external_macro: true | |
532ac7d7 XL |
18 | } |
19 | ||
20 | pub struct DefaultHashTypes { | |
dc9dc135 | 21 | map: FxHashMap<Symbol, Symbol>, |
532ac7d7 XL |
22 | } |
23 | ||
24 | impl DefaultHashTypes { | |
dc9dc135 | 25 | // we are allowed to use `HashMap` and `HashSet` as identifiers for implementing the lint itself |
e1599b0c | 26 | #[allow(rustc::default_hash_types)] |
532ac7d7 XL |
27 | pub fn new() -> Self { |
28 | let mut map = FxHashMap::default(); | |
dc9dc135 XL |
29 | map.insert(sym::HashMap, sym::FxHashMap); |
30 | map.insert(sym::HashSet, sym::FxHashSet); | |
532ac7d7 XL |
31 | Self { map } |
32 | } | |
33 | } | |
34 | ||
35 | impl_lint_pass!(DefaultHashTypes => [DEFAULT_HASH_TYPES]); | |
36 | ||
37 | impl EarlyLintPass for DefaultHashTypes { | |
38 | fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) { | |
dc9dc135 | 39 | if let Some(replace) = self.map.get(&ident.name) { |
74b04a01 XL |
40 | cx.struct_span_lint(DEFAULT_HASH_TYPES, ident.span, |lint| { |
41 | // FIXME: We can avoid a copy here. Would require us to take String instead of &str. | |
42 | let msg = format!("Prefer {} over {}, it has better performance", replace, ident); | |
43 | lint.build(&msg) | |
44 | .span_suggestion( | |
45 | ident.span, | |
46 | "use", | |
47 | replace.to_string(), | |
48 | Applicability::MaybeIncorrect, // FxHashMap, ... needs another import | |
49 | ) | |
50 | .note(&format!( | |
51 | "a `use rustc_data_structures::fx::{}` may be necessary", | |
52 | replace | |
53 | )) | |
54 | .emit(); | |
55 | }); | |
532ac7d7 XL |
56 | } |
57 | } | |
58 | } | |
59 | ||
416331ca XL |
60 | declare_tool_lint! { |
61 | pub rustc::USAGE_OF_TY_TYKIND, | |
532ac7d7 | 62 | Allow, |
dfeec247 XL |
63 | "usage of `ty::TyKind` outside of the `ty::sty` module", |
64 | report_in_external_macro: true | |
532ac7d7 XL |
65 | } |
66 | ||
416331ca XL |
67 | declare_tool_lint! { |
68 | pub rustc::TY_PASS_BY_REFERENCE, | |
48663c56 | 69 | Allow, |
dfeec247 XL |
70 | "passing `Ty` or `TyCtxt` by reference", |
71 | report_in_external_macro: true | |
48663c56 XL |
72 | } |
73 | ||
416331ca XL |
74 | declare_tool_lint! { |
75 | pub rustc::USAGE_OF_QUALIFIED_TY, | |
48663c56 | 76 | Allow, |
dfeec247 XL |
77 | "using `ty::{Ty,TyCtxt}` instead of importing it", |
78 | report_in_external_macro: true | |
48663c56 XL |
79 | } |
80 | ||
81 | declare_lint_pass!(TyTyKind => [ | |
82 | USAGE_OF_TY_TYKIND, | |
83 | TY_PASS_BY_REFERENCE, | |
84 | USAGE_OF_QUALIFIED_TY, | |
85 | ]); | |
532ac7d7 | 86 | |
48663c56 | 87 | impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TyTyKind { |
dfeec247 | 88 | fn check_path(&mut self, cx: &LateContext<'_, '_>, path: &'tcx Path<'tcx>, _: HirId) { |
532ac7d7 XL |
89 | let segments = path.segments.iter().rev().skip(1).rev(); |
90 | ||
91 | if let Some(last) = segments.last() { | |
92 | let span = path.span.with_hi(last.ident.span.hi()); | |
93 | if lint_ty_kind_usage(cx, last) { | |
74b04a01 XL |
94 | cx.struct_span_lint(USAGE_OF_TY_TYKIND, span, |lint| { |
95 | lint.build("usage of `ty::TyKind::<kind>`") | |
96 | .span_suggestion( | |
97 | span, | |
98 | "try using ty::<kind> directly", | |
99 | "ty".to_string(), | |
100 | Applicability::MaybeIncorrect, // ty maybe needs an import | |
101 | ) | |
102 | .emit(); | |
103 | }) | |
532ac7d7 XL |
104 | } |
105 | } | |
106 | } | |
107 | ||
dfeec247 | 108 | fn check_ty(&mut self, cx: &LateContext<'_, '_>, ty: &'tcx Ty<'tcx>) { |
e74abb32 | 109 | match &ty.kind { |
48663c56 XL |
110 | TyKind::Path(qpath) => { |
111 | if let QPath::Resolved(_, path) = qpath { | |
112 | if let Some(last) = path.segments.iter().last() { | |
113 | if lint_ty_kind_usage(cx, last) { | |
74b04a01 XL |
114 | cx.struct_span_lint(USAGE_OF_TY_TYKIND, path.span, |lint| { |
115 | lint.build("usage of `ty::TyKind`") | |
116 | .help("try using `Ty` instead") | |
117 | .emit(); | |
118 | }) | |
48663c56 | 119 | } else { |
e1599b0c | 120 | if ty.span.from_expansion() { |
48663c56 XL |
121 | return; |
122 | } | |
123 | if let Some(t) = is_ty_or_ty_ctxt(cx, ty) { | |
124 | if path.segments.len() > 1 { | |
74b04a01 XL |
125 | cx.struct_span_lint(USAGE_OF_QUALIFIED_TY, path.span, |lint| { |
126 | lint.build(&format!("usage of qualified `ty::{}`", t)) | |
127 | .span_suggestion( | |
128 | path.span, | |
129 | "try using it unqualified", | |
130 | t, | |
131 | // The import probably needs to be changed | |
132 | Applicability::MaybeIncorrect, | |
133 | ) | |
134 | .emit(); | |
135 | }) | |
48663c56 XL |
136 | } |
137 | } | |
138 | } | |
139 | } | |
140 | } | |
141 | } | |
dfeec247 | 142 | TyKind::Rptr(_, MutTy { ty: inner_ty, mutbl: Mutability::Not }) => { |
ba9703b0 | 143 | if let Some(impl_did) = cx.tcx.impl_of_method(ty.hir_id.owner.to_def_id()) { |
48663c56 XL |
144 | if cx.tcx.impl_trait_ref(impl_did).is_some() { |
145 | return; | |
532ac7d7 XL |
146 | } |
147 | } | |
48663c56 | 148 | if let Some(t) = is_ty_or_ty_ctxt(cx, &inner_ty) { |
74b04a01 XL |
149 | cx.struct_span_lint(TY_PASS_BY_REFERENCE, ty.span, |lint| { |
150 | lint.build(&format!("passing `{}` by reference", t)) | |
151 | .span_suggestion( | |
152 | ty.span, | |
153 | "try passing by value", | |
154 | t, | |
155 | // Changing type of function argument | |
156 | Applicability::MaybeIncorrect, | |
157 | ) | |
158 | .emit(); | |
159 | }) | |
48663c56 | 160 | } |
532ac7d7 | 161 | } |
48663c56 | 162 | _ => {} |
532ac7d7 XL |
163 | } |
164 | } | |
165 | } | |
166 | ||
dfeec247 | 167 | fn lint_ty_kind_usage(cx: &LateContext<'_, '_>, segment: &PathSegment<'_>) -> bool { |
e1599b0c XL |
168 | if let Some(res) = segment.res { |
169 | if let Some(did) = res.opt_def_id() { | |
170 | return cx.tcx.is_diagnostic_item(sym::TyKind, did); | |
532ac7d7 XL |
171 | } |
172 | } | |
173 | ||
174 | false | |
175 | } | |
48663c56 | 176 | |
dfeec247 | 177 | fn is_ty_or_ty_ctxt(cx: &LateContext<'_, '_>, ty: &Ty<'_>) -> Option<String> { |
ba9703b0 XL |
178 | if let TyKind::Path(qpath) = &ty.kind { |
179 | if let QPath::Resolved(_, path) = qpath { | |
180 | let did = path.res.opt_def_id()?; | |
181 | if cx.tcx.is_diagnostic_item(sym::Ty, did) { | |
182 | return Some(format!("Ty{}", gen_args(path.segments.last().unwrap()))); | |
183 | } else if cx.tcx.is_diagnostic_item(sym::TyCtxt, did) { | |
184 | return Some(format!("TyCtxt{}", gen_args(path.segments.last().unwrap()))); | |
48663c56 XL |
185 | } |
186 | } | |
48663c56 XL |
187 | } |
188 | ||
189 | None | |
190 | } | |
191 | ||
dfeec247 | 192 | fn gen_args(segment: &PathSegment<'_>) -> String { |
48663c56 XL |
193 | if let Some(args) = &segment.args { |
194 | let lifetimes = args | |
195 | .args | |
196 | .iter() | |
197 | .filter_map(|arg| { | |
198 | if let GenericArg::Lifetime(lt) = arg { | |
199 | Some(lt.name.ident().to_string()) | |
200 | } else { | |
201 | None | |
202 | } | |
203 | }) | |
204 | .collect::<Vec<_>>(); | |
205 | ||
206 | if !lifetimes.is_empty() { | |
207 | return format!("<{}>", lifetimes.join(", ")); | |
208 | } | |
209 | } | |
210 | ||
211 | String::new() | |
212 | } | |
416331ca XL |
213 | |
214 | declare_tool_lint! { | |
215 | pub rustc::LINT_PASS_IMPL_WITHOUT_MACRO, | |
216 | Allow, | |
217 | "`impl LintPass` without the `declare_lint_pass!` or `impl_lint_pass!` macros" | |
218 | } | |
219 | ||
220 | declare_lint_pass!(LintPassImpl => [LINT_PASS_IMPL_WITHOUT_MACRO]); | |
221 | ||
222 | impl EarlyLintPass for LintPassImpl { | |
223 | fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) { | |
dfeec247 | 224 | if let ItemKind::Impl { of_trait: Some(lint_pass), .. } = &item.kind { |
416331ca XL |
225 | if let Some(last) = lint_pass.path.segments.last() { |
226 | if last.ident.name == sym::LintPass { | |
e1599b0c XL |
227 | let expn_data = lint_pass.path.span.ctxt().outer_expn_data(); |
228 | let call_site = expn_data.call_site; | |
dfeec247 XL |
229 | if expn_data.kind != ExpnKind::Macro(MacroKind::Bang, sym::impl_lint_pass) |
230 | && call_site.ctxt().outer_expn_data().kind | |
231 | != ExpnKind::Macro(MacroKind::Bang, sym::declare_lint_pass) | |
232 | { | |
e1599b0c XL |
233 | cx.struct_span_lint( |
234 | LINT_PASS_IMPL_WITHOUT_MACRO, | |
235 | lint_pass.path.span, | |
74b04a01 XL |
236 | |lint| { |
237 | lint.build("implementing `LintPass` by hand") | |
238 | .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead") | |
239 | .emit(); | |
240 | }, | |
e1599b0c | 241 | ) |
416331ca XL |
242 | } |
243 | } | |
244 | } | |
245 | } | |
246 | } | |
247 | } |