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Commit | Line | Data |
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c34b1796 AL |
1 | //! Lints in the Rust compiler. |
2 | //! | |
3 | //! This contains lints which can feasibly be implemented as their own | |
ba9703b0 XL |
4 | //! AST visitor. Also see `rustc_session::lint::builtin`, which contains the |
5 | //! definitions of lints that are emitted directly inside the main compiler. | |
c34b1796 AL |
6 | //! |
7 | //! To add a new lint to rustc, declare it here using `declare_lint!()`. | |
8 | //! Then add code to emit the new lint in the appropriate circumstances. | |
9 | //! You can do that in an existing `LintPass` if it makes sense, or in a | |
10 | //! new `LintPass`, or using `Session::add_lint` elsewhere in the | |
11 | //! compiler. Only do the latter if the check can't be written cleanly as a | |
12 | //! `LintPass` (also, note that such lints will need to be defined in | |
ba9703b0 | 13 | //! `rustc_session::lint::builtin`, not here). |
c34b1796 | 14 | //! |
9fa01778 XL |
15 | //! If you define a new `EarlyLintPass`, you will also need to add it to the |
16 | //! `add_early_builtin!` or `add_early_builtin_with_new!` invocation in | |
17 | //! `lib.rs`. Use the former for unit-like structs and the latter for structs | |
18 | //! with a `pub fn new()`. | |
19 | //! | |
20 | //! If you define a new `LateLintPass`, you will also need to add it to the | |
21 | //! `late_lint_methods!` invocation in `lib.rs`. | |
c34b1796 | 22 | |
3dfed10e | 23 | use crate::{ |
1b1a35ee XL |
24 | types::{transparent_newtype_field, CItemKind}, |
25 | EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext, | |
3dfed10e | 26 | }; |
6a06907d | 27 | use rustc_ast::attr; |
74b04a01 XL |
28 | use rustc_ast::tokenstream::{TokenStream, TokenTree}; |
29 | use rustc_ast::visit::{FnCtxt, FnKind}; | |
3dfed10e | 30 | use rustc_ast::{self as ast, *}; |
74b04a01 | 31 | use rustc_ast_pretty::pprust::{self, expr_to_string}; |
f035d41b | 32 | use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
3dfed10e | 33 | use rustc_data_structures::stack::ensure_sufficient_stack; |
f035d41b | 34 | use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString}; |
3c0e092e | 35 | use rustc_feature::{deprecated_attributes, AttributeGate, BuiltinAttribute, GateIssue, Stability}; |
dfeec247 XL |
36 | use rustc_hir as hir; |
37 | use rustc_hir::def::{DefKind, Res}; | |
94222f64 | 38 | use rustc_hir::def_id::{DefId, LocalDefId, LocalDefIdSet, CRATE_DEF_ID}; |
f035d41b | 39 | use rustc_hir::{ForeignItemKind, GenericParamKind, PatKind}; |
6a06907d | 40 | use rustc_hir::{HirId, Node}; |
1b1a35ee | 41 | use rustc_index::vec::Idx; |
ba9703b0 | 42 | use rustc_middle::lint::LintDiagnosticBuilder; |
c295e0f8 | 43 | use rustc_middle::ty::layout::{LayoutError, LayoutOf}; |
1b1a35ee | 44 | use rustc_middle::ty::print::with_no_trimmed_paths; |
3dfed10e | 45 | use rustc_middle::ty::subst::{GenericArgKind, Subst}; |
5869c6ff | 46 | use rustc_middle::ty::Instance; |
c295e0f8 | 47 | use rustc_middle::ty::{self, Ty, TyCtxt}; |
94222f64 | 48 | use rustc_session::lint::{BuiltinLintDiagnostics, FutureIncompatibilityReason}; |
dfeec247 XL |
49 | use rustc_span::edition::Edition; |
50 | use rustc_span::source_map::Spanned; | |
f9f354fc | 51 | use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
94222f64 | 52 | use rustc_span::{BytePos, InnerSpan, MultiSpan, Span}; |
c295e0f8 | 53 | use rustc_target::abi::VariantIdx; |
ba9703b0 | 54 | use rustc_trait_selection::traits::misc::can_type_implement_copy; |
e9174d1e | 55 | |
dfeec247 | 56 | use crate::nonstandard_style::{method_context, MethodLateContext}; |
9fa01778 | 57 | |
dfeec247 | 58 | use std::fmt::Write; |
3dfed10e | 59 | use tracing::{debug, trace}; |
c34b1796 | 60 | |
ba9703b0 | 61 | // hardwired lints from librustc_middle |
dfeec247 | 62 | pub use rustc_session::lint::builtin::*; |
c34b1796 | 63 | |
b039eaaf | 64 | declare_lint! { |
1b1a35ee XL |
65 | /// The `while_true` lint detects `while true { }`. |
66 | /// | |
67 | /// ### Example | |
68 | /// | |
69 | /// ```rust,no_run | |
70 | /// while true { | |
71 | /// | |
72 | /// } | |
73 | /// ``` | |
74 | /// | |
75 | /// {{produces}} | |
76 | /// | |
77 | /// ### Explanation | |
78 | /// | |
79 | /// `while true` should be replaced with `loop`. A `loop` expression is | |
80 | /// the preferred way to write an infinite loop because it more directly | |
81 | /// expresses the intent of the loop. | |
b039eaaf SL |
82 | WHILE_TRUE, |
83 | Warn, | |
84 | "suggest using `loop { }` instead of `while true { }`" | |
85 | } | |
c34b1796 | 86 | |
532ac7d7 | 87 | declare_lint_pass!(WhileTrue => [WHILE_TRUE]); |
c34b1796 | 88 | |
416331ca XL |
89 | /// Traverse through any amount of parenthesis and return the first non-parens expression. |
90 | fn pierce_parens(mut expr: &ast::Expr) -> &ast::Expr { | |
e74abb32 | 91 | while let ast::ExprKind::Paren(sub) = &expr.kind { |
416331ca XL |
92 | expr = sub; |
93 | } | |
94 | expr | |
95 | } | |
96 | ||
97 | impl EarlyLintPass for WhileTrue { | |
98 | fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) { | |
5869c6ff | 99 | if let ast::ExprKind::While(cond, _, label) = &e.kind { |
e74abb32 XL |
100 | if let ast::ExprKind::Lit(ref lit) = pierce_parens(cond).kind { |
101 | if let ast::LitKind::Bool(true) = lit.kind { | |
e1599b0c | 102 | if !lit.span.from_expansion() { |
ea8adc8c | 103 | let msg = "denote infinite loops with `loop { ... }`"; |
5869c6ff | 104 | let condition_span = e.span.with_hi(cond.span.hi()); |
74b04a01 XL |
105 | cx.struct_span_lint(WHILE_TRUE, condition_span, |lint| { |
106 | lint.build(msg) | |
107 | .span_suggestion_short( | |
108 | condition_span, | |
109 | "use `loop`", | |
5869c6ff XL |
110 | format!( |
111 | "{}loop", | |
112 | label.map_or_else(String::new, |label| format!( | |
113 | "{}: ", | |
114 | label.ident, | |
115 | )) | |
116 | ), | |
74b04a01 XL |
117 | Applicability::MachineApplicable, |
118 | ) | |
119 | .emit(); | |
120 | }) | |
ea8adc8c | 121 | } |
b039eaaf | 122 | } |
c34b1796 AL |
123 | } |
124 | } | |
125 | } | |
126 | } | |
127 | ||
128 | declare_lint! { | |
1b1a35ee XL |
129 | /// The `box_pointers` lints use of the Box type. |
130 | /// | |
131 | /// ### Example | |
132 | /// | |
133 | /// ```rust,compile_fail | |
134 | /// #![deny(box_pointers)] | |
135 | /// struct Foo { | |
136 | /// x: Box<isize>, | |
137 | /// } | |
138 | /// ``` | |
139 | /// | |
140 | /// {{produces}} | |
141 | /// | |
142 | /// ### Explanation | |
143 | /// | |
144 | /// This lint is mostly historical, and not particularly useful. `Box<T>` | |
145 | /// used to be built into the language, and the only way to do heap | |
146 | /// allocation. Today's Rust can call into other allocators, etc. | |
b039eaaf SL |
147 | BOX_POINTERS, |
148 | Allow, | |
149 | "use of owned (Box type) heap memory" | |
c34b1796 AL |
150 | } |
151 | ||
532ac7d7 | 152 | declare_lint_pass!(BoxPointers => [BOX_POINTERS]); |
b039eaaf SL |
153 | |
154 | impl BoxPointers { | |
94222f64 XL |
155 | fn check_heap_type<'tcx>(&self, cx: &LateContext<'tcx>, span: Span, ty: Ty<'tcx>) { |
156 | for leaf in ty.walk(cx.tcx) { | |
ba9703b0 XL |
157 | if let GenericArgKind::Type(leaf_ty) = leaf.unpack() { |
158 | if leaf_ty.is_box() { | |
159 | cx.struct_span_lint(BOX_POINTERS, span, |lint| { | |
160 | lint.build(&format!("type uses owned (Box type) pointers: {}", ty)).emit() | |
161 | }); | |
162 | } | |
c34b1796 AL |
163 | } |
164 | } | |
165 | } | |
166 | } | |
167 | ||
f035d41b XL |
168 | impl<'tcx> LateLintPass<'tcx> for BoxPointers { |
169 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
e74abb32 | 170 | match it.kind { |
dfeec247 XL |
171 | hir::ItemKind::Fn(..) |
172 | | hir::ItemKind::TyAlias(..) | |
173 | | hir::ItemKind::Enum(..) | |
174 | | hir::ItemKind::Struct(..) | |
175 | | hir::ItemKind::Union(..) => { | |
6a06907d | 176 | self.check_heap_type(cx, it.span, cx.tcx.type_of(it.def_id)) |
c30ab7b3 | 177 | } |
dfeec247 | 178 | _ => (), |
d9579d0f | 179 | } |
d9579d0f | 180 | |
b039eaaf | 181 | // If it's a struct, we also have to check the fields' types |
e74abb32 | 182 | match it.kind { |
dfeec247 | 183 | hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => { |
b039eaaf | 184 | for struct_field in struct_def.fields() { |
416331ca | 185 | let def_id = cx.tcx.hir().local_def_id(struct_field.hir_id); |
dfeec247 | 186 | self.check_heap_type(cx, struct_field.span, cx.tcx.type_of(def_id)); |
b039eaaf | 187 | } |
d9579d0f | 188 | } |
c30ab7b3 | 189 | _ => (), |
d9579d0f AL |
190 | } |
191 | } | |
192 | ||
f035d41b | 193 | fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) { |
3dfed10e | 194 | let ty = cx.typeck_results().node_type(e.hir_id); |
b039eaaf | 195 | self.check_heap_type(cx, e.span, ty); |
c34b1796 AL |
196 | } |
197 | } | |
198 | ||
c34b1796 | 199 | declare_lint! { |
1b1a35ee XL |
200 | /// The `non_shorthand_field_patterns` lint detects using `Struct { x: x }` |
201 | /// instead of `Struct { x }` in a pattern. | |
202 | /// | |
203 | /// ### Example | |
204 | /// | |
205 | /// ```rust | |
206 | /// struct Point { | |
207 | /// x: i32, | |
208 | /// y: i32, | |
209 | /// } | |
210 | /// | |
211 | /// | |
212 | /// fn main() { | |
213 | /// let p = Point { | |
214 | /// x: 5, | |
215 | /// y: 5, | |
216 | /// }; | |
217 | /// | |
218 | /// match p { | |
219 | /// Point { x: x, y: y } => (), | |
220 | /// } | |
221 | /// } | |
222 | /// ``` | |
223 | /// | |
224 | /// {{produces}} | |
225 | /// | |
226 | /// ### Explanation | |
227 | /// | |
228 | /// The preferred style is to avoid the repetition of specifying both the | |
229 | /// field name and the binding name if both identifiers are the same. | |
c34b1796 AL |
230 | NON_SHORTHAND_FIELD_PATTERNS, |
231 | Warn, | |
abe05a73 | 232 | "using `Struct { x: x }` instead of `Struct { x }` in a pattern" |
c34b1796 AL |
233 | } |
234 | ||
532ac7d7 | 235 | declare_lint_pass!(NonShorthandFieldPatterns => [NON_SHORTHAND_FIELD_PATTERNS]); |
c34b1796 | 236 | |
f035d41b XL |
237 | impl<'tcx> LateLintPass<'tcx> for NonShorthandFieldPatterns { |
238 | fn check_pat(&mut self, cx: &LateContext<'_>, pat: &hir::Pat<'_>) { | |
dfeec247 XL |
239 | if let PatKind::Struct(ref qpath, field_pats, _) = pat.kind { |
240 | let variant = cx | |
3dfed10e | 241 | .typeck_results() |
dfeec247 XL |
242 | .pat_ty(pat) |
243 | .ty_adt_def() | |
244 | .expect("struct pattern type is not an ADT") | |
f035d41b | 245 | .variant_of_res(cx.qpath_res(qpath, pat.hir_id)); |
3157f602 | 246 | for fieldpat in field_pats { |
e1599b0c | 247 | if fieldpat.is_shorthand { |
3157f602 | 248 | continue; |
b039eaaf | 249 | } |
e1599b0c | 250 | if fieldpat.span.from_expansion() { |
83c7162d XL |
251 | // Don't lint if this is a macro expansion: macro authors |
252 | // shouldn't have to worry about this kind of style issue | |
253 | // (Issue #49588) | |
254 | continue; | |
255 | } | |
dfeec247 XL |
256 | if let PatKind::Binding(binding_annot, _, ident, None) = fieldpat.pat.kind { |
257 | if cx.tcx.find_field_index(ident, &variant) | |
3dfed10e | 258 | == Some(cx.tcx.field_index(fieldpat.hir_id, cx.typeck_results())) |
dfeec247 | 259 | { |
74b04a01 XL |
260 | cx.struct_span_lint(NON_SHORTHAND_FIELD_PATTERNS, fieldpat.span, |lint| { |
261 | let mut err = lint | |
262 | .build(&format!("the `{}:` in this pattern is redundant", ident)); | |
263 | let binding = match binding_annot { | |
264 | hir::BindingAnnotation::Unannotated => None, | |
265 | hir::BindingAnnotation::Mutable => Some("mut"), | |
266 | hir::BindingAnnotation::Ref => Some("ref"), | |
267 | hir::BindingAnnotation::RefMut => Some("ref mut"), | |
268 | }; | |
269 | let ident = if let Some(binding) = binding { | |
270 | format!("{} {}", binding, ident) | |
271 | } else { | |
272 | ident.to_string() | |
273 | }; | |
274 | err.span_suggestion( | |
275 | fieldpat.span, | |
276 | "use shorthand field pattern", | |
277 | ident, | |
278 | Applicability::MachineApplicable, | |
279 | ); | |
280 | err.emit(); | |
281 | }); | |
c34b1796 AL |
282 | } |
283 | } | |
284 | } | |
285 | } | |
286 | } | |
287 | } | |
288 | ||
c34b1796 | 289 | declare_lint! { |
1b1a35ee XL |
290 | /// The `unsafe_code` lint catches usage of `unsafe` code. |
291 | /// | |
292 | /// ### Example | |
293 | /// | |
294 | /// ```rust,compile_fail | |
295 | /// #![deny(unsafe_code)] | |
296 | /// fn main() { | |
297 | /// unsafe { | |
298 | /// | |
299 | /// } | |
300 | /// } | |
301 | /// ``` | |
302 | /// | |
303 | /// {{produces}} | |
304 | /// | |
305 | /// ### Explanation | |
306 | /// | |
307 | /// This lint is intended to restrict the usage of `unsafe`, which can be | |
308 | /// difficult to use correctly. | |
c34b1796 AL |
309 | UNSAFE_CODE, |
310 | Allow, | |
311 | "usage of `unsafe` code" | |
312 | } | |
313 | ||
532ac7d7 | 314 | declare_lint_pass!(UnsafeCode => [UNSAFE_CODE]); |
c34b1796 | 315 | |
3b2f2976 | 316 | impl UnsafeCode { |
74b04a01 XL |
317 | fn report_unsafe( |
318 | &self, | |
319 | cx: &EarlyContext<'_>, | |
320 | span: Span, | |
321 | decorate: impl for<'a> FnOnce(LintDiagnosticBuilder<'a>), | |
322 | ) { | |
dc9dc135 | 323 | // This comes from a macro that has `#[allow_internal_unsafe]`. |
3b2f2976 XL |
324 | if span.allows_unsafe() { |
325 | return; | |
326 | } | |
327 | ||
74b04a01 | 328 | cx.struct_span_lint(UNSAFE_CODE, span, decorate); |
3b2f2976 | 329 | } |
6a06907d XL |
330 | |
331 | fn report_overriden_symbol_name(&self, cx: &EarlyContext<'_>, span: Span, msg: &str) { | |
332 | self.report_unsafe(cx, span, |lint| { | |
333 | lint.build(msg) | |
334 | .note( | |
335 | "the linker's behavior with multiple libraries exporting duplicate symbol \ | |
336 | names is undefined and Rust cannot provide guarantees when you manually \ | |
337 | override them", | |
338 | ) | |
339 | .emit(); | |
340 | }) | |
341 | } | |
3b2f2976 XL |
342 | } |
343 | ||
0731742a | 344 | impl EarlyLintPass for UnsafeCode { |
9fa01778 | 345 | fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) { |
94222f64 | 346 | if attr.has_name(sym::allow_internal_unsafe) { |
74b04a01 XL |
347 | self.report_unsafe(cx, attr.span, |lint| { |
348 | lint.build( | |
349 | "`allow_internal_unsafe` allows defining \ | |
0731742a | 350 | macros using unsafe without triggering \ |
dfeec247 | 351 | the `unsafe_code` lint at their call site", |
74b04a01 XL |
352 | ) |
353 | .emit() | |
354 | }); | |
0731742a XL |
355 | } |
356 | } | |
357 | ||
9fa01778 | 358 | fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) { |
e74abb32 | 359 | if let ast::ExprKind::Block(ref blk, _) = e.kind { |
dc9dc135 | 360 | // Don't warn about generated blocks; that'll just pollute the output. |
0731742a | 361 | if blk.rules == ast::BlockCheckMode::Unsafe(ast::UserProvided) { |
74b04a01 XL |
362 | self.report_unsafe(cx, blk.span, |lint| { |
363 | lint.build("usage of an `unsafe` block").emit() | |
364 | }); | |
c34b1796 AL |
365 | } |
366 | } | |
367 | } | |
368 | ||
9fa01778 | 369 | fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) { |
e74abb32 | 370 | match it.kind { |
3c0e092e | 371 | ast::ItemKind::Trait(box ast::Trait { unsafety: ast::Unsafe::Yes(_), .. }) => self |
5869c6ff | 372 | .report_unsafe(cx, it.span, |lint| { |
74b04a01 | 373 | lint.build("declaration of an `unsafe` trait").emit() |
5869c6ff | 374 | }), |
c34b1796 | 375 | |
3c0e092e | 376 | ast::ItemKind::Impl(box ast::Impl { unsafety: ast::Unsafe::Yes(_), .. }) => self |
5869c6ff | 377 | .report_unsafe(cx, it.span, |lint| { |
74b04a01 | 378 | lint.build("implementation of an `unsafe` trait").emit() |
5869c6ff | 379 | }), |
c34b1796 | 380 | |
6a06907d XL |
381 | ast::ItemKind::Fn(..) => { |
382 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::no_mangle) { | |
383 | self.report_overriden_symbol_name( | |
384 | cx, | |
385 | attr.span, | |
386 | "declaration of a `no_mangle` function", | |
387 | ); | |
388 | } | |
389 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::export_name) { | |
390 | self.report_overriden_symbol_name( | |
391 | cx, | |
392 | attr.span, | |
393 | "declaration of a function with `export_name`", | |
394 | ); | |
395 | } | |
396 | } | |
397 | ||
398 | ast::ItemKind::Static(..) => { | |
399 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::no_mangle) { | |
400 | self.report_overriden_symbol_name( | |
401 | cx, | |
402 | attr.span, | |
403 | "declaration of a `no_mangle` static", | |
404 | ); | |
405 | } | |
406 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::export_name) { | |
407 | self.report_overriden_symbol_name( | |
408 | cx, | |
409 | attr.span, | |
410 | "declaration of a static with `export_name`", | |
411 | ); | |
412 | } | |
413 | } | |
414 | ||
ba9703b0 | 415 | _ => {} |
c34b1796 AL |
416 | } |
417 | } | |
418 | ||
94222f64 XL |
419 | fn check_impl_item(&mut self, cx: &EarlyContext<'_>, it: &ast::AssocItem) { |
420 | if let ast::AssocItemKind::Fn(..) = it.kind { | |
421 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::no_mangle) { | |
422 | self.report_overriden_symbol_name( | |
423 | cx, | |
424 | attr.span, | |
425 | "declaration of a `no_mangle` method", | |
426 | ); | |
427 | } | |
428 | if let Some(attr) = cx.sess().find_by_name(&it.attrs, sym::export_name) { | |
429 | self.report_overriden_symbol_name( | |
430 | cx, | |
431 | attr.span, | |
432 | "declaration of a method with `export_name`", | |
433 | ); | |
434 | } | |
435 | } | |
436 | } | |
437 | ||
74b04a01 XL |
438 | fn check_fn(&mut self, cx: &EarlyContext<'_>, fk: FnKind<'_>, span: Span, _: ast::NodeId) { |
439 | if let FnKind::Fn( | |
440 | ctxt, | |
441 | _, | |
442 | ast::FnSig { header: ast::FnHeader { unsafety: ast::Unsafe::Yes(_), .. }, .. }, | |
443 | _, | |
444 | body, | |
445 | ) = fk | |
446 | { | |
447 | let msg = match ctxt { | |
448 | FnCtxt::Foreign => return, | |
449 | FnCtxt::Free => "declaration of an `unsafe` function", | |
450 | FnCtxt::Assoc(_) if body.is_none() => "declaration of an `unsafe` method", | |
451 | FnCtxt::Assoc(_) => "implementation of an `unsafe` method", | |
452 | }; | |
453 | self.report_unsafe(cx, span, |lint| lint.build(msg).emit()); | |
c34b1796 AL |
454 | } |
455 | } | |
456 | } | |
457 | ||
c34b1796 | 458 | declare_lint! { |
1b1a35ee XL |
459 | /// The `missing_docs` lint detects missing documentation for public items. |
460 | /// | |
461 | /// ### Example | |
462 | /// | |
463 | /// ```rust,compile_fail | |
464 | /// #![deny(missing_docs)] | |
465 | /// pub fn foo() {} | |
466 | /// ``` | |
467 | /// | |
468 | /// {{produces}} | |
469 | /// | |
470 | /// ### Explanation | |
471 | /// | |
472 | /// This lint is intended to ensure that a library is well-documented. | |
473 | /// Items without documentation can be difficult for users to understand | |
474 | /// how to use properly. | |
475 | /// | |
476 | /// This lint is "allow" by default because it can be noisy, and not all | |
477 | /// projects may want to enforce everything to be documented. | |
94b46f34 | 478 | pub MISSING_DOCS, |
c34b1796 | 479 | Allow, |
8faf50e0 | 480 | "detects missing documentation for public members", |
e74abb32 | 481 | report_in_external_macro |
c34b1796 AL |
482 | } |
483 | ||
484 | pub struct MissingDoc { | |
9fa01778 | 485 | /// Stack of whether `#[doc(hidden)]` is set at each level which has lint attributes. |
c34b1796 AL |
486 | doc_hidden_stack: Vec<bool>, |
487 | ||
488 | /// Private traits or trait items that leaked through. Don't check their methods. | |
532ac7d7 | 489 | private_traits: FxHashSet<hir::HirId>, |
c34b1796 AL |
490 | } |
491 | ||
532ac7d7 XL |
492 | impl_lint_pass!(MissingDoc => [MISSING_DOCS]); |
493 | ||
94222f64 | 494 | fn has_doc(attr: &ast::Attribute) -> bool { |
dfeec247 XL |
495 | if attr.is_doc_comment() { |
496 | return true; | |
497 | } | |
498 | ||
94222f64 | 499 | if !attr.has_name(sym::doc) { |
0731742a XL |
500 | return false; |
501 | } | |
502 | ||
cdc7bbd5 | 503 | if attr.value_str().is_some() { |
0731742a XL |
504 | return true; |
505 | } | |
506 | ||
507 | if let Some(list) = attr.meta_item_list() { | |
508 | for meta in list { | |
17df50a5 | 509 | if meta.has_name(sym::hidden) { |
0731742a XL |
510 | return true; |
511 | } | |
512 | } | |
513 | } | |
514 | ||
515 | false | |
516 | } | |
517 | ||
c34b1796 AL |
518 | impl MissingDoc { |
519 | pub fn new() -> MissingDoc { | |
dfeec247 | 520 | MissingDoc { doc_hidden_stack: vec![false], private_traits: FxHashSet::default() } |
c34b1796 AL |
521 | } |
522 | ||
523 | fn doc_hidden(&self) -> bool { | |
524 | *self.doc_hidden_stack.last().expect("empty doc_hidden_stack") | |
525 | } | |
526 | ||
dfeec247 XL |
527 | fn check_missing_docs_attrs( |
528 | &self, | |
f035d41b | 529 | cx: &LateContext<'_>, |
94222f64 | 530 | def_id: LocalDefId, |
dfeec247 | 531 | sp: Span, |
ba9703b0 | 532 | article: &'static str, |
dfeec247 XL |
533 | desc: &'static str, |
534 | ) { | |
c34b1796 AL |
535 | // If we're building a test harness, then warning about |
536 | // documentation is probably not really relevant right now. | |
537 | if cx.sess().opts.test { | |
538 | return; | |
539 | } | |
540 | ||
541 | // `#[doc(hidden)]` disables missing_docs check. | |
542 | if self.doc_hidden() { | |
543 | return; | |
544 | } | |
545 | ||
546 | // Only check publicly-visible items, using the result from the privacy pass. | |
547 | // It's an option so the crate root can also use this function (it doesn't | |
dc9dc135 | 548 | // have a `NodeId`). |
94222f64 XL |
549 | if def_id != CRATE_DEF_ID { |
550 | if !cx.access_levels.is_exported(def_id) { | |
c34b1796 AL |
551 | return; |
552 | } | |
553 | } | |
554 | ||
94222f64 XL |
555 | let attrs = cx.tcx.get_attrs(def_id.to_def_id()); |
556 | let has_doc = attrs.iter().any(has_doc); | |
c34b1796 | 557 | if !has_doc { |
ba9703b0 XL |
558 | cx.struct_span_lint( |
559 | MISSING_DOCS, | |
560 | cx.tcx.sess.source_map().guess_head_span(sp), | |
561 | |lint| { | |
562 | lint.build(&format!("missing documentation for {} {}", article, desc)).emit() | |
563 | }, | |
564 | ); | |
c34b1796 AL |
565 | } |
566 | } | |
567 | } | |
568 | ||
f035d41b | 569 | impl<'tcx> LateLintPass<'tcx> for MissingDoc { |
94222f64 | 570 | fn enter_lint_attrs(&mut self, _cx: &LateContext<'_>, attrs: &[ast::Attribute]) { |
dfeec247 XL |
571 | let doc_hidden = self.doc_hidden() |
572 | || attrs.iter().any(|attr| { | |
94222f64 | 573 | attr.has_name(sym::doc) |
dfeec247 XL |
574 | && match attr.meta_item_list() { |
575 | None => false, | |
576 | Some(l) => attr::list_contains_name(&l, sym::hidden), | |
577 | } | |
578 | }); | |
c34b1796 AL |
579 | self.doc_hidden_stack.push(doc_hidden); |
580 | } | |
581 | ||
f035d41b | 582 | fn exit_lint_attrs(&mut self, _: &LateContext<'_>, _attrs: &[ast::Attribute]) { |
c34b1796 AL |
583 | self.doc_hidden_stack.pop().expect("empty doc_hidden_stack"); |
584 | } | |
585 | ||
c295e0f8 XL |
586 | fn check_crate(&mut self, cx: &LateContext<'_>) { |
587 | self.check_missing_docs_attrs( | |
588 | cx, | |
589 | CRATE_DEF_ID, | |
590 | cx.tcx.def_span(CRATE_DEF_ID), | |
591 | "the", | |
592 | "crate", | |
593 | ); | |
c34b1796 AL |
594 | } |
595 | ||
f035d41b | 596 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { |
ba9703b0 | 597 | match it.kind { |
dfeec247 | 598 | hir::ItemKind::Trait(.., trait_item_refs) => { |
dc9dc135 | 599 | // Issue #11592: traits are always considered exported, even when private. |
8faf50e0 | 600 | if let hir::VisibilityKind::Inherited = it.vis.node { |
6a06907d | 601 | self.private_traits.insert(it.hir_id()); |
32a655c1 | 602 | for trait_item_ref in trait_item_refs { |
6a06907d | 603 | self.private_traits.insert(trait_item_ref.id.hir_id()); |
c34b1796 | 604 | } |
c30ab7b3 | 605 | return; |
c34b1796 | 606 | } |
c30ab7b3 | 607 | } |
5869c6ff | 608 | hir::ItemKind::Impl(hir::Impl { of_trait: Some(ref trait_ref), items, .. }) => { |
dc9dc135 | 609 | // If the trait is private, add the impl items to `private_traits` so they don't get |
c34b1796 | 610 | // reported for missing docs. |
48663c56 | 611 | let real_trait = trait_ref.path.res.def_id(); |
f9f354fc | 612 | if let Some(def_id) = real_trait.as_local() { |
3dfed10e | 613 | let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id); |
ba9703b0 XL |
614 | if let Some(Node::Item(item)) = cx.tcx.hir().find(hir_id) { |
615 | if let hir::VisibilityKind::Inherited = item.vis.node { | |
616 | for impl_item_ref in items { | |
6a06907d | 617 | self.private_traits.insert(impl_item_ref.id.hir_id()); |
b039eaaf | 618 | } |
c30ab7b3 | 619 | } |
b039eaaf | 620 | } |
c34b1796 | 621 | } |
c30ab7b3 SL |
622 | return; |
623 | } | |
ba9703b0 XL |
624 | |
625 | hir::ItemKind::TyAlias(..) | |
626 | | hir::ItemKind::Fn(..) | |
94222f64 | 627 | | hir::ItemKind::Macro(..) |
ba9703b0 XL |
628 | | hir::ItemKind::Mod(..) |
629 | | hir::ItemKind::Enum(..) | |
630 | | hir::ItemKind::Struct(..) | |
631 | | hir::ItemKind::Union(..) | |
632 | | hir::ItemKind::Const(..) | |
633 | | hir::ItemKind::Static(..) => {} | |
634 | ||
c30ab7b3 | 635 | _ => return, |
c34b1796 AL |
636 | }; |
637 | ||
6a06907d | 638 | let (article, desc) = cx.tcx.article_and_description(it.def_id.to_def_id()); |
ba9703b0 | 639 | |
94222f64 | 640 | self.check_missing_docs_attrs(cx, it.def_id, it.span, article, desc); |
c34b1796 AL |
641 | } |
642 | ||
f035d41b | 643 | fn check_trait_item(&mut self, cx: &LateContext<'_>, trait_item: &hir::TraitItem<'_>) { |
6a06907d | 644 | if self.private_traits.contains(&trait_item.hir_id()) { |
c30ab7b3 SL |
645 | return; |
646 | } | |
c34b1796 | 647 | |
6a06907d | 648 | let (article, desc) = cx.tcx.article_and_description(trait_item.def_id.to_def_id()); |
c34b1796 | 649 | |
94222f64 | 650 | self.check_missing_docs_attrs(cx, trait_item.def_id, trait_item.span, article, desc); |
c34b1796 AL |
651 | } |
652 | ||
f035d41b | 653 | fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) { |
c34b1796 | 654 | // If the method is an impl for a trait, don't doc. |
6a06907d | 655 | if method_context(cx, impl_item.hir_id()) == MethodLateContext::TraitImpl { |
c34b1796 AL |
656 | return; |
657 | } | |
658 | ||
3c0e092e XL |
659 | // If the method is an impl for an item with docs_hidden, don't doc. |
660 | if method_context(cx, impl_item.hir_id()) == MethodLateContext::PlainImpl { | |
661 | let parent = cx.tcx.hir().get_parent_did(impl_item.hir_id()); | |
662 | let impl_ty = cx.tcx.type_of(parent); | |
663 | let outerdef = match impl_ty.kind() { | |
664 | ty::Adt(def, _) => Some(def.did), | |
665 | ty::Foreign(def_id) => Some(*def_id), | |
666 | _ => None, | |
667 | }; | |
668 | let is_hidden = match outerdef { | |
669 | Some(id) => cx.tcx.is_doc_hidden(id), | |
670 | None => false, | |
671 | }; | |
672 | if is_hidden { | |
673 | return; | |
674 | } | |
675 | } | |
676 | ||
6a06907d | 677 | let (article, desc) = cx.tcx.article_and_description(impl_item.def_id.to_def_id()); |
94222f64 | 678 | self.check_missing_docs_attrs(cx, impl_item.def_id, impl_item.span, article, desc); |
c34b1796 AL |
679 | } |
680 | ||
1b1a35ee | 681 | fn check_foreign_item(&mut self, cx: &LateContext<'_>, foreign_item: &hir::ForeignItem<'_>) { |
6a06907d | 682 | let (article, desc) = cx.tcx.article_and_description(foreign_item.def_id.to_def_id()); |
94222f64 | 683 | self.check_missing_docs_attrs(cx, foreign_item.def_id, foreign_item.span, article, desc); |
1b1a35ee XL |
684 | } |
685 | ||
6a06907d | 686 | fn check_field_def(&mut self, cx: &LateContext<'_>, sf: &hir::FieldDef<'_>) { |
54a0048b | 687 | if !sf.is_positional() { |
94222f64 XL |
688 | let def_id = cx.tcx.hir().local_def_id(sf.hir_id); |
689 | self.check_missing_docs_attrs(cx, def_id, sf.span, "a", "struct field") | |
c34b1796 AL |
690 | } |
691 | } | |
692 | ||
f035d41b | 693 | fn check_variant(&mut self, cx: &LateContext<'_>, v: &hir::Variant<'_>) { |
94222f64 | 694 | self.check_missing_docs_attrs(cx, cx.tcx.hir().local_def_id(v.id), v.span, "a", "variant"); |
c34b1796 AL |
695 | } |
696 | } | |
697 | ||
698 | declare_lint! { | |
1b1a35ee XL |
699 | /// The `missing_copy_implementations` lint detects potentially-forgotten |
700 | /// implementations of [`Copy`]. | |
701 | /// | |
702 | /// [`Copy`]: https://doc.rust-lang.org/std/marker/trait.Copy.html | |
703 | /// | |
704 | /// ### Example | |
705 | /// | |
706 | /// ```rust,compile_fail | |
707 | /// #![deny(missing_copy_implementations)] | |
708 | /// pub struct Foo { | |
709 | /// pub field: i32 | |
710 | /// } | |
711 | /// # fn main() {} | |
712 | /// ``` | |
713 | /// | |
714 | /// {{produces}} | |
715 | /// | |
716 | /// ### Explanation | |
717 | /// | |
718 | /// Historically (before 1.0), types were automatically marked as `Copy` | |
719 | /// if possible. This was changed so that it required an explicit opt-in | |
720 | /// by implementing the `Copy` trait. As part of this change, a lint was | |
721 | /// added to alert if a copyable type was not marked `Copy`. | |
722 | /// | |
723 | /// This lint is "allow" by default because this code isn't bad; it is | |
724 | /// common to write newtypes like this specifically so that a `Copy` type | |
725 | /// is no longer `Copy`. `Copy` types can result in unintended copies of | |
726 | /// large data which can impact performance. | |
c34b1796 AL |
727 | pub MISSING_COPY_IMPLEMENTATIONS, |
728 | Allow, | |
729 | "detects potentially-forgotten implementations of `Copy`" | |
730 | } | |
731 | ||
532ac7d7 | 732 | declare_lint_pass!(MissingCopyImplementations => [MISSING_COPY_IMPLEMENTATIONS]); |
c34b1796 | 733 | |
f035d41b XL |
734 | impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations { |
735 | fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) { | |
94222f64 | 736 | if !cx.access_levels.is_reachable(item.def_id) { |
c34b1796 AL |
737 | return; |
738 | } | |
e74abb32 | 739 | let (def, ty) = match item.kind { |
8faf50e0 | 740 | hir::ItemKind::Struct(_, ref ast_generics) => { |
ff7c6d11 | 741 | if !ast_generics.params.is_empty() { |
c34b1796 AL |
742 | return; |
743 | } | |
6a06907d | 744 | let def = cx.tcx.adt_def(item.def_id); |
c30ab7b3 | 745 | (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
9e0c209e | 746 | } |
8faf50e0 | 747 | hir::ItemKind::Union(_, ref ast_generics) => { |
ff7c6d11 | 748 | if !ast_generics.params.is_empty() { |
9e0c209e SL |
749 | return; |
750 | } | |
6a06907d | 751 | let def = cx.tcx.adt_def(item.def_id); |
c30ab7b3 | 752 | (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
c34b1796 | 753 | } |
8faf50e0 | 754 | hir::ItemKind::Enum(_, ref ast_generics) => { |
ff7c6d11 | 755 | if !ast_generics.params.is_empty() { |
c34b1796 AL |
756 | return; |
757 | } | |
6a06907d | 758 | let def = cx.tcx.adt_def(item.def_id); |
c30ab7b3 | 759 | (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
c34b1796 AL |
760 | } |
761 | _ => return, | |
762 | }; | |
8bb4bdeb | 763 | if def.has_dtor(cx.tcx) { |
c30ab7b3 SL |
764 | return; |
765 | } | |
0531ce1d | 766 | let param_env = ty::ParamEnv::empty(); |
f035d41b | 767 | if ty.is_copy_modulo_regions(cx.tcx.at(item.span), param_env) { |
c34b1796 AL |
768 | return; |
769 | } | |
dfeec247 | 770 | if can_type_implement_copy(cx.tcx, param_env, ty).is_ok() { |
74b04a01 XL |
771 | cx.struct_span_lint(MISSING_COPY_IMPLEMENTATIONS, item.span, |lint| { |
772 | lint.build( | |
773 | "type could implement `Copy`; consider adding `impl \ | |
dfeec247 | 774 | Copy`", |
74b04a01 XL |
775 | ) |
776 | .emit() | |
777 | }) | |
c34b1796 AL |
778 | } |
779 | } | |
780 | } | |
781 | ||
782 | declare_lint! { | |
1b1a35ee XL |
783 | /// The `missing_debug_implementations` lint detects missing |
784 | /// implementations of [`fmt::Debug`]. | |
785 | /// | |
786 | /// [`fmt::Debug`]: https://doc.rust-lang.org/std/fmt/trait.Debug.html | |
787 | /// | |
788 | /// ### Example | |
789 | /// | |
790 | /// ```rust,compile_fail | |
791 | /// #![deny(missing_debug_implementations)] | |
792 | /// pub struct Foo; | |
793 | /// # fn main() {} | |
794 | /// ``` | |
795 | /// | |
796 | /// {{produces}} | |
797 | /// | |
798 | /// ### Explanation | |
799 | /// | |
800 | /// Having a `Debug` implementation on all types can assist with | |
801 | /// debugging, as it provides a convenient way to format and display a | |
802 | /// value. Using the `#[derive(Debug)]` attribute will automatically | |
803 | /// generate a typical implementation, or a custom implementation can be | |
804 | /// added by manually implementing the `Debug` trait. | |
805 | /// | |
806 | /// This lint is "allow" by default because adding `Debug` to all types can | |
807 | /// have a negative impact on compile time and code size. It also requires | |
808 | /// boilerplate to be added to every type, which can be an impediment. | |
c34b1796 AL |
809 | MISSING_DEBUG_IMPLEMENTATIONS, |
810 | Allow, | |
74b04a01 | 811 | "detects missing implementations of Debug" |
c34b1796 AL |
812 | } |
813 | ||
48663c56 | 814 | #[derive(Default)] |
c34b1796 | 815 | pub struct MissingDebugImplementations { |
6a06907d | 816 | impling_types: Option<LocalDefIdSet>, |
c34b1796 AL |
817 | } |
818 | ||
532ac7d7 XL |
819 | impl_lint_pass!(MissingDebugImplementations => [MISSING_DEBUG_IMPLEMENTATIONS]); |
820 | ||
f035d41b XL |
821 | impl<'tcx> LateLintPass<'tcx> for MissingDebugImplementations { |
822 | fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) { | |
94222f64 | 823 | if !cx.access_levels.is_reachable(item.def_id) { |
c34b1796 AL |
824 | return; |
825 | } | |
826 | ||
e74abb32 | 827 | match item.kind { |
dfeec247 | 828 | hir::ItemKind::Struct(..) | hir::ItemKind::Union(..) | hir::ItemKind::Enum(..) => {} |
c34b1796 AL |
829 | _ => return, |
830 | } | |
831 | ||
c295e0f8 | 832 | let debug = match cx.tcx.get_diagnostic_item(sym::Debug) { |
c34b1796 AL |
833 | Some(debug) => debug, |
834 | None => return, | |
835 | }; | |
836 | ||
837 | if self.impling_types.is_none() { | |
6a06907d | 838 | let mut impls = LocalDefIdSet::default(); |
041b39d2 | 839 | cx.tcx.for_each_impl(debug, |d| { |
8faf50e0 | 840 | if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() { |
f9f354fc | 841 | if let Some(def_id) = ty_def.did.as_local() { |
6a06907d | 842 | impls.insert(def_id); |
d9579d0f | 843 | } |
c34b1796 | 844 | } |
d9579d0f AL |
845 | }); |
846 | ||
c34b1796 AL |
847 | self.impling_types = Some(impls); |
848 | debug!("{:?}", self.impling_types); | |
849 | } | |
850 | ||
6a06907d | 851 | if !self.impling_types.as_ref().unwrap().contains(&item.def_id) { |
74b04a01 XL |
852 | cx.struct_span_lint(MISSING_DEBUG_IMPLEMENTATIONS, item.span, |lint| { |
853 | lint.build(&format!( | |
854 | "type does not implement `{}`; consider adding `#[derive(Debug)]` \ | |
855 | or a manual implementation", | |
856 | cx.tcx.def_path_str(debug) | |
857 | )) | |
858 | .emit() | |
859 | }); | |
c34b1796 AL |
860 | } |
861 | } | |
862 | } | |
863 | ||
7cac9316 | 864 | declare_lint! { |
1b1a35ee XL |
865 | /// The `anonymous_parameters` lint detects anonymous parameters in trait |
866 | /// definitions. | |
867 | /// | |
868 | /// ### Example | |
869 | /// | |
870 | /// ```rust,edition2015,compile_fail | |
871 | /// #![deny(anonymous_parameters)] | |
872 | /// // edition 2015 | |
873 | /// pub trait Foo { | |
874 | /// fn foo(usize); | |
875 | /// } | |
876 | /// fn main() {} | |
877 | /// ``` | |
878 | /// | |
879 | /// {{produces}} | |
880 | /// | |
881 | /// ### Explanation | |
882 | /// | |
883 | /// This syntax is mostly a historical accident, and can be worked around | |
884 | /// quite easily by adding an `_` pattern or a descriptive identifier: | |
885 | /// | |
886 | /// ```rust | |
887 | /// trait Foo { | |
888 | /// fn foo(_: usize); | |
889 | /// } | |
890 | /// ``` | |
891 | /// | |
892 | /// This syntax is now a hard error in the 2018 edition. In the 2015 | |
cdc7bbd5 | 893 | /// edition, this lint is "warn" by default. This lint |
1b1a35ee XL |
894 | /// enables the [`cargo fix`] tool with the `--edition` flag to |
895 | /// automatically transition old code from the 2015 edition to 2018. The | |
cdc7bbd5 | 896 | /// tool will run this lint and automatically apply the |
1b1a35ee XL |
897 | /// suggested fix from the compiler (which is to add `_` to each |
898 | /// parameter). This provides a completely automated way to update old | |
899 | /// code for a new edition. See [issue #41686] for more details. | |
900 | /// | |
901 | /// [issue #41686]: https://github.com/rust-lang/rust/issues/41686 | |
902 | /// [`cargo fix`]: https://doc.rust-lang.org/cargo/commands/cargo-fix.html | |
7cac9316 | 903 | pub ANONYMOUS_PARAMETERS, |
cdc7bbd5 | 904 | Warn, |
e74abb32 XL |
905 | "detects anonymous parameters", |
906 | @future_incompatible = FutureIncompatibleInfo { | |
907 | reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>", | |
136023e0 | 908 | reason: FutureIncompatibilityReason::EditionError(Edition::Edition2018), |
e74abb32 | 909 | }; |
7cac9316 XL |
910 | } |
911 | ||
532ac7d7 XL |
912 | declare_lint_pass!( |
913 | /// Checks for use of anonymous parameters (RFC 1685). | |
914 | AnonymousParameters => [ANONYMOUS_PARAMETERS] | |
915 | ); | |
7cac9316 XL |
916 | |
917 | impl EarlyLintPass for AnonymousParameters { | |
dfeec247 | 918 | fn check_trait_item(&mut self, cx: &EarlyContext<'_>, it: &ast::AssocItem) { |
cdc7bbd5 XL |
919 | if cx.sess.edition() != Edition::Edition2015 { |
920 | // This is a hard error in future editions; avoid linting and erroring | |
921 | return; | |
922 | } | |
3c0e092e | 923 | if let ast::AssocItemKind::Fn(box Fn { ref sig, .. }) = it.kind { |
ba9703b0 XL |
924 | for arg in sig.decl.inputs.iter() { |
925 | if let ast::PatKind::Ident(_, ident, None) = arg.pat.kind { | |
5869c6ff | 926 | if ident.name == kw::Empty { |
ba9703b0 XL |
927 | cx.struct_span_lint(ANONYMOUS_PARAMETERS, arg.pat.span, |lint| { |
928 | let ty_snip = cx.sess.source_map().span_to_snippet(arg.ty.span); | |
929 | ||
930 | let (ty_snip, appl) = if let Ok(ref snip) = ty_snip { | |
931 | (snip.as_str(), Applicability::MachineApplicable) | |
932 | } else { | |
933 | ("<type>", Applicability::HasPlaceholders) | |
934 | }; | |
94b46f34 | 935 | |
ba9703b0 XL |
936 | lint.build( |
937 | "anonymous parameters are deprecated and will be \ | |
c295e0f8 | 938 | removed in the next edition", |
ba9703b0 XL |
939 | ) |
940 | .span_suggestion( | |
941 | arg.pat.span, | |
942 | "try naming the parameter or explicitly \ | |
74b04a01 | 943 | ignoring it", |
ba9703b0 XL |
944 | format!("_: {}", ty_snip), |
945 | appl, | |
946 | ) | |
947 | .emit(); | |
948 | }) | |
7cac9316 XL |
949 | } |
950 | } | |
dfeec247 | 951 | } |
7cac9316 XL |
952 | } |
953 | } | |
954 | } | |
955 | ||
9fa01778 | 956 | /// Check for use of attributes which have been deprecated. |
c30ab7b3 SL |
957 | #[derive(Clone)] |
958 | pub struct DeprecatedAttr { | |
959 | // This is not free to compute, so we want to keep it around, rather than | |
960 | // compute it for every attribute. | |
3c0e092e | 961 | depr_attrs: Vec<&'static BuiltinAttribute>, |
c30ab7b3 SL |
962 | } |
963 | ||
532ac7d7 XL |
964 | impl_lint_pass!(DeprecatedAttr => []); |
965 | ||
c30ab7b3 SL |
966 | impl DeprecatedAttr { |
967 | pub fn new() -> DeprecatedAttr { | |
dfeec247 | 968 | DeprecatedAttr { depr_attrs: deprecated_attributes() } |
c30ab7b3 SL |
969 | } |
970 | } | |
971 | ||
e1599b0c XL |
972 | fn lint_deprecated_attr( |
973 | cx: &EarlyContext<'_>, | |
974 | attr: &ast::Attribute, | |
975 | msg: &str, | |
976 | suggestion: Option<&str>, | |
977 | ) { | |
74b04a01 XL |
978 | cx.struct_span_lint(DEPRECATED, attr.span, |lint| { |
979 | lint.build(msg) | |
980 | .span_suggestion_short( | |
981 | attr.span, | |
982 | suggestion.unwrap_or("remove this attribute"), | |
983 | String::new(), | |
984 | Applicability::MachineApplicable, | |
985 | ) | |
986 | .emit(); | |
987 | }) | |
e1599b0c XL |
988 | } |
989 | ||
c30ab7b3 | 990 | impl EarlyLintPass for DeprecatedAttr { |
9fa01778 | 991 | fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) { |
3c0e092e XL |
992 | for BuiltinAttribute { name, gate, .. } in &self.depr_attrs { |
993 | if attr.ident().map(|ident| ident.name) == Some(*name) { | |
dfeec247 XL |
994 | if let &AttributeGate::Gated( |
995 | Stability::Deprecated(link, suggestion), | |
5869c6ff XL |
996 | name, |
997 | reason, | |
dfeec247 | 998 | _, |
3c0e092e | 999 | ) = gate |
dfeec247 XL |
1000 | { |
1001 | let msg = | |
1002 | format!("use of deprecated attribute `{}`: {}. See {}", name, reason, link); | |
e1599b0c | 1003 | lint_deprecated_attr(cx, attr, &msg, suggestion); |
c30ab7b3 SL |
1004 | } |
1005 | return; | |
1006 | } | |
1007 | } | |
94222f64 | 1008 | if attr.has_name(sym::no_start) || attr.has_name(sym::crate_id) { |
60c5eb7d | 1009 | let path_str = pprust::path_to_string(&attr.get_normal_item().path); |
e74abb32 | 1010 | let msg = format!("use of deprecated attribute `{}`: no longer used.", path_str); |
e1599b0c XL |
1011 | lint_deprecated_attr(cx, attr, &msg, None); |
1012 | } | |
c30ab7b3 SL |
1013 | } |
1014 | } | |
1015 | ||
74b04a01 | 1016 | fn warn_if_doc(cx: &EarlyContext<'_>, node_span: Span, node_kind: &str, attrs: &[ast::Attribute]) { |
136023e0 XL |
1017 | use rustc_ast::token::CommentKind; |
1018 | ||
74b04a01 | 1019 | let mut attrs = attrs.iter().peekable(); |
3b2f2976 | 1020 | |
74b04a01 XL |
1021 | // Accumulate a single span for sugared doc comments. |
1022 | let mut sugared_span: Option<Span> = None; | |
3b2f2976 | 1023 | |
74b04a01 | 1024 | while let Some(attr) = attrs.next() { |
136023e0 XL |
1025 | let is_doc_comment = attr.is_doc_comment(); |
1026 | if is_doc_comment { | |
74b04a01 | 1027 | sugared_span = |
29967ef6 | 1028 | Some(sugared_span.map_or(attr.span, |span| span.with_hi(attr.span.hi()))); |
74b04a01 | 1029 | } |
3b2f2976 | 1030 | |
cdc7bbd5 | 1031 | if attrs.peek().map_or(false, |next_attr| next_attr.is_doc_comment()) { |
74b04a01 XL |
1032 | continue; |
1033 | } | |
532ac7d7 | 1034 | |
1b1a35ee | 1035 | let span = sugared_span.take().unwrap_or(attr.span); |
532ac7d7 | 1036 | |
94222f64 | 1037 | if is_doc_comment || attr.has_name(sym::doc) { |
74b04a01 XL |
1038 | cx.struct_span_lint(UNUSED_DOC_COMMENTS, span, |lint| { |
1039 | let mut err = lint.build("unused doc comment"); | |
532ac7d7 XL |
1040 | err.span_label( |
1041 | node_span, | |
dfeec247 | 1042 | format!("rustdoc does not generate documentation for {}", node_kind), |
532ac7d7 | 1043 | ); |
136023e0 XL |
1044 | match attr.kind { |
1045 | AttrKind::DocComment(CommentKind::Line, _) | AttrKind::Normal(..) => { | |
1046 | err.help("use `//` for a plain comment"); | |
1047 | } | |
1048 | AttrKind::DocComment(CommentKind::Block, _) => { | |
1049 | err.help("use `/* */` for a plain comment"); | |
1050 | } | |
1051 | } | |
532ac7d7 | 1052 | err.emit(); |
74b04a01 | 1053 | }); |
3b2f2976 XL |
1054 | } |
1055 | } | |
1056 | } | |
1057 | ||
1058 | impl EarlyLintPass for UnusedDocComment { | |
532ac7d7 | 1059 | fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &ast::Stmt) { |
74b04a01 XL |
1060 | let kind = match stmt.kind { |
1061 | ast::StmtKind::Local(..) => "statements", | |
29967ef6 XL |
1062 | // Disabled pending discussion in #78306 |
1063 | ast::StmtKind::Item(..) => return, | |
532ac7d7 | 1064 | // expressions will be reported by `check_expr`. |
74b04a01 XL |
1065 | ast::StmtKind::Empty |
1066 | | ast::StmtKind::Semi(_) | |
1067 | | ast::StmtKind::Expr(_) | |
ba9703b0 | 1068 | | ast::StmtKind::MacCall(_) => return, |
532ac7d7 XL |
1069 | }; |
1070 | ||
74b04a01 | 1071 | warn_if_doc(cx, stmt.span, kind, stmt.kind.attrs()); |
3b2f2976 XL |
1072 | } |
1073 | ||
9fa01778 | 1074 | fn check_arm(&mut self, cx: &EarlyContext<'_>, arm: &ast::Arm) { |
e1599b0c | 1075 | let arm_span = arm.pat.span.with_hi(arm.body.span.hi()); |
74b04a01 | 1076 | warn_if_doc(cx, arm_span, "match arms", &arm.attrs); |
3b2f2976 XL |
1077 | } |
1078 | ||
9fa01778 | 1079 | fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) { |
74b04a01 | 1080 | warn_if_doc(cx, expr.span, "expressions", &expr.attrs); |
3b2f2976 XL |
1081 | } |
1082 | } | |
1083 | ||
c34b1796 | 1084 | declare_lint! { |
1b1a35ee XL |
1085 | /// The `no_mangle_const_items` lint detects any `const` items with the |
1086 | /// [`no_mangle` attribute]. | |
1087 | /// | |
1088 | /// [`no_mangle` attribute]: https://doc.rust-lang.org/reference/abi.html#the-no_mangle-attribute | |
1089 | /// | |
1090 | /// ### Example | |
1091 | /// | |
1092 | /// ```rust,compile_fail | |
1093 | /// #[no_mangle] | |
1094 | /// const FOO: i32 = 5; | |
1095 | /// ``` | |
1096 | /// | |
1097 | /// {{produces}} | |
1098 | /// | |
1099 | /// ### Explanation | |
1100 | /// | |
1101 | /// Constants do not have their symbols exported, and therefore, this | |
1102 | /// probably means you meant to use a [`static`], not a [`const`]. | |
1103 | /// | |
1104 | /// [`static`]: https://doc.rust-lang.org/reference/items/static-items.html | |
1105 | /// [`const`]: https://doc.rust-lang.org/reference/items/constant-items.html | |
c34b1796 AL |
1106 | NO_MANGLE_CONST_ITEMS, |
1107 | Deny, | |
1108 | "const items will not have their symbols exported" | |
1109 | } | |
1110 | ||
9cc50fc6 | 1111 | declare_lint! { |
1b1a35ee XL |
1112 | /// The `no_mangle_generic_items` lint detects generic items that must be |
1113 | /// mangled. | |
1114 | /// | |
1115 | /// ### Example | |
1116 | /// | |
1117 | /// ```rust | |
1118 | /// #[no_mangle] | |
1119 | /// fn foo<T>(t: T) { | |
1120 | /// | |
1121 | /// } | |
1122 | /// ``` | |
1123 | /// | |
1124 | /// {{produces}} | |
1125 | /// | |
1126 | /// ### Explanation | |
1127 | /// | |
136023e0 | 1128 | /// A function with generics must have its symbol mangled to accommodate |
1b1a35ee XL |
1129 | /// the generic parameter. The [`no_mangle` attribute] has no effect in |
1130 | /// this situation, and should be removed. | |
1131 | /// | |
1132 | /// [`no_mangle` attribute]: https://doc.rust-lang.org/reference/abi.html#the-no_mangle-attribute | |
9cc50fc6 SL |
1133 | NO_MANGLE_GENERIC_ITEMS, |
1134 | Warn, | |
1135 | "generic items must be mangled" | |
1136 | } | |
1137 | ||
532ac7d7 | 1138 | declare_lint_pass!(InvalidNoMangleItems => [NO_MANGLE_CONST_ITEMS, NO_MANGLE_GENERIC_ITEMS]); |
c34b1796 | 1139 | |
f035d41b XL |
1140 | impl<'tcx> LateLintPass<'tcx> for InvalidNoMangleItems { |
1141 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
6a06907d | 1142 | let attrs = cx.tcx.hir().attrs(it.hir_id()); |
94222f64 XL |
1143 | let check_no_mangle_on_generic_fn = |no_mangle_attr: &ast::Attribute, |
1144 | impl_generics: Option<&hir::Generics<'_>>, | |
1145 | generics: &hir::Generics<'_>, | |
1146 | span| { | |
1147 | for param in | |
1148 | generics.params.iter().chain(impl_generics.map(|g| g.params).into_iter().flatten()) | |
1149 | { | |
1150 | match param.kind { | |
1151 | GenericParamKind::Lifetime { .. } => {} | |
1152 | GenericParamKind::Type { .. } | GenericParamKind::Const { .. } => { | |
1153 | cx.struct_span_lint(NO_MANGLE_GENERIC_ITEMS, span, |lint| { | |
1154 | lint.build("functions generic over types or consts must be mangled") | |
1155 | .span_suggestion_short( | |
1156 | no_mangle_attr.span, | |
1157 | "remove this attribute", | |
1158 | String::new(), | |
1159 | // Use of `#[no_mangle]` suggests FFI intent; correct | |
1160 | // fix may be to monomorphize source by hand | |
1161 | Applicability::MaybeIncorrect, | |
1162 | ) | |
1163 | .emit(); | |
1164 | }); | |
1165 | break; | |
1166 | } | |
1167 | } | |
1168 | } | |
1169 | }; | |
e74abb32 | 1170 | match it.kind { |
8faf50e0 | 1171 | hir::ItemKind::Fn(.., ref generics, _) => { |
6a06907d | 1172 | if let Some(no_mangle_attr) = cx.sess().find_by_name(attrs, sym::no_mangle) { |
94222f64 | 1173 | check_no_mangle_on_generic_fn(no_mangle_attr, None, generics, it.span); |
c34b1796 | 1174 | } |
c30ab7b3 | 1175 | } |
8faf50e0 | 1176 | hir::ItemKind::Const(..) => { |
6a06907d | 1177 | if cx.sess().contains_name(attrs, sym::no_mangle) { |
c34b1796 AL |
1178 | // Const items do not refer to a particular location in memory, and therefore |
1179 | // don't have anything to attach a symbol to | |
74b04a01 XL |
1180 | cx.struct_span_lint(NO_MANGLE_CONST_ITEMS, it.span, |lint| { |
1181 | let msg = "const items should never be `#[no_mangle]`"; | |
1182 | let mut err = lint.build(msg); | |
1183 | ||
1184 | // account for "pub const" (#45562) | |
1185 | let start = cx | |
1186 | .tcx | |
1187 | .sess | |
1188 | .source_map() | |
1189 | .span_to_snippet(it.span) | |
1190 | .map(|snippet| snippet.find("const").unwrap_or(0)) | |
1191 | .unwrap_or(0) as u32; | |
1192 | // `const` is 5 chars | |
1193 | let const_span = it.span.with_hi(BytePos(it.span.lo().0 + start + 5)); | |
1194 | err.span_suggestion( | |
1195 | const_span, | |
1196 | "try a static value", | |
1197 | "pub static".to_owned(), | |
1198 | Applicability::MachineApplicable, | |
1199 | ); | |
1200 | err.emit(); | |
1201 | }); | |
c34b1796 AL |
1202 | } |
1203 | } | |
94222f64 XL |
1204 | hir::ItemKind::Impl(hir::Impl { ref generics, items, .. }) => { |
1205 | for it in items { | |
1206 | if let hir::AssocItemKind::Fn { .. } = it.kind { | |
1207 | if let Some(no_mangle_attr) = cx | |
1208 | .sess() | |
1209 | .find_by_name(cx.tcx.hir().attrs(it.id.hir_id()), sym::no_mangle) | |
1210 | { | |
1211 | check_no_mangle_on_generic_fn( | |
1212 | no_mangle_attr, | |
1213 | Some(generics), | |
1214 | cx.tcx.hir().get_generics(it.id.def_id.to_def_id()).unwrap(), | |
1215 | it.span, | |
1216 | ); | |
1217 | } | |
1218 | } | |
1219 | } | |
1220 | } | |
c30ab7b3 | 1221 | _ => {} |
c34b1796 AL |
1222 | } |
1223 | } | |
1224 | } | |
1225 | ||
bd371182 | 1226 | declare_lint! { |
1b1a35ee XL |
1227 | /// The `mutable_transmutes` lint catches transmuting from `&T` to `&mut |
1228 | /// T` because it is [undefined behavior]. | |
1229 | /// | |
1230 | /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | |
1231 | /// | |
1232 | /// ### Example | |
1233 | /// | |
1234 | /// ```rust,compile_fail | |
1235 | /// unsafe { | |
1236 | /// let y = std::mem::transmute::<&i32, &mut i32>(&5); | |
1237 | /// } | |
1238 | /// ``` | |
1239 | /// | |
1240 | /// {{produces}} | |
1241 | /// | |
1242 | /// ### Explanation | |
1243 | /// | |
1244 | /// Certain assumptions are made about aliasing of data, and this transmute | |
1245 | /// violates those assumptions. Consider using [`UnsafeCell`] instead. | |
1246 | /// | |
1247 | /// [`UnsafeCell`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html | |
bd371182 AL |
1248 | MUTABLE_TRANSMUTES, |
1249 | Deny, | |
1250 | "mutating transmuted &mut T from &T may cause undefined behavior" | |
1251 | } | |
1252 | ||
532ac7d7 | 1253 | declare_lint_pass!(MutableTransmutes => [MUTABLE_TRANSMUTES]); |
bd371182 | 1254 | |
f035d41b XL |
1255 | impl<'tcx> LateLintPass<'tcx> for MutableTransmutes { |
1256 | fn check_expr(&mut self, cx: &LateContext<'_>, expr: &hir::Expr<'_>) { | |
83c7162d | 1257 | use rustc_target::spec::abi::Abi::RustIntrinsic; |
ba9703b0 | 1258 | if let Some((&ty::Ref(_, _, from_mt), &ty::Ref(_, _, to_mt))) = |
1b1a35ee | 1259 | get_transmute_from_to(cx, expr).map(|(ty1, ty2)| (ty1.kind(), ty2.kind())) |
ba9703b0 XL |
1260 | { |
1261 | if to_mt == hir::Mutability::Mut && from_mt == hir::Mutability::Not { | |
1262 | let msg = "mutating transmuted &mut T from &T may cause undefined behavior, \ | |
74b04a01 | 1263 | consider instead using an UnsafeCell"; |
ba9703b0 | 1264 | cx.struct_span_lint(MUTABLE_TRANSMUTES, expr.span, |lint| lint.build(msg).emit()); |
bd371182 | 1265 | } |
bd371182 AL |
1266 | } |
1267 | ||
f035d41b XL |
1268 | fn get_transmute_from_to<'tcx>( |
1269 | cx: &LateContext<'tcx>, | |
dfeec247 XL |
1270 | expr: &hir::Expr<'_>, |
1271 | ) -> Option<(Ty<'tcx>, Ty<'tcx>)> { | |
e74abb32 | 1272 | let def = if let hir::ExprKind::Path(ref qpath) = expr.kind { |
f035d41b | 1273 | cx.qpath_res(qpath, expr.hir_id) |
476ff2be SL |
1274 | } else { |
1275 | return None; | |
1276 | }; | |
48663c56 | 1277 | if let Res::Def(DefKind::Fn, did) = def { |
bd371182 AL |
1278 | if !def_id_is_transmute(cx, did) { |
1279 | return None; | |
1280 | } | |
3dfed10e | 1281 | let sig = cx.typeck_results().node_type(expr.hir_id).fn_sig(cx.tcx); |
041b39d2 | 1282 | let from = sig.inputs().skip_binder()[0]; |
f035d41b | 1283 | let to = sig.output().skip_binder(); |
532ac7d7 | 1284 | return Some((from, to)); |
bd371182 AL |
1285 | } |
1286 | None | |
1287 | } | |
1288 | ||
f035d41b | 1289 | fn def_id_is_transmute(cx: &LateContext<'_>, def_id: DefId) -> bool { |
dfeec247 XL |
1290 | cx.tcx.fn_sig(def_id).abi() == RustIntrinsic |
1291 | && cx.tcx.item_name(def_id) == sym::transmute | |
bd371182 AL |
1292 | } |
1293 | } | |
1294 | } | |
1295 | ||
c34b1796 | 1296 | declare_lint! { |
1b1a35ee | 1297 | /// The `unstable_features` is deprecated and should no longer be used. |
c34b1796 AL |
1298 | UNSTABLE_FEATURES, |
1299 | Allow, | |
62682a34 | 1300 | "enabling unstable features (deprecated. do not use)" |
c34b1796 AL |
1301 | } |
1302 | ||
532ac7d7 XL |
1303 | declare_lint_pass!( |
1304 | /// Forbids using the `#[feature(...)]` attribute | |
1305 | UnstableFeatures => [UNSTABLE_FEATURES] | |
1306 | ); | |
b039eaaf | 1307 | |
f035d41b | 1308 | impl<'tcx> LateLintPass<'tcx> for UnstableFeatures { |
3dfed10e | 1309 | fn check_attribute(&mut self, cx: &LateContext<'_>, attr: &ast::Attribute) { |
94222f64 | 1310 | if attr.has_name(sym::feature) { |
cc61c64b | 1311 | if let Some(items) = attr.meta_item_list() { |
62682a34 | 1312 | for item in items { |
3dfed10e | 1313 | cx.struct_span_lint(UNSTABLE_FEATURES, item.span(), |lint| { |
74b04a01 XL |
1314 | lint.build("unstable feature").emit() |
1315 | }); | |
62682a34 SL |
1316 | } |
1317 | } | |
c34b1796 AL |
1318 | } |
1319 | } | |
1320 | } | |
bd371182 | 1321 | |
abe05a73 | 1322 | declare_lint! { |
1b1a35ee XL |
1323 | /// The `unreachable_pub` lint triggers for `pub` items not reachable from |
1324 | /// the crate root. | |
1325 | /// | |
1326 | /// ### Example | |
1327 | /// | |
1328 | /// ```rust,compile_fail | |
1329 | /// #![deny(unreachable_pub)] | |
1330 | /// mod foo { | |
1331 | /// pub mod bar { | |
1332 | /// | |
1333 | /// } | |
1334 | /// } | |
1335 | /// ``` | |
1336 | /// | |
1337 | /// {{produces}} | |
1338 | /// | |
1339 | /// ### Explanation | |
1340 | /// | |
1341 | /// A bare `pub` visibility may be misleading if the item is not actually | |
1342 | /// publicly exported from the crate. The `pub(crate)` visibility is | |
1343 | /// recommended to be used instead, which more clearly expresses the intent | |
1344 | /// that the item is only visible within its own crate. | |
1345 | /// | |
1346 | /// This lint is "allow" by default because it will trigger for a large | |
1347 | /// amount existing Rust code, and has some false-positives. Eventually it | |
1348 | /// is desired for this to become warn-by-default. | |
0531ce1d | 1349 | pub UNREACHABLE_PUB, |
abe05a73 XL |
1350 | Allow, |
1351 | "`pub` items not reachable from crate root" | |
1352 | } | |
1353 | ||
532ac7d7 XL |
1354 | declare_lint_pass!( |
1355 | /// Lint for items marked `pub` that aren't reachable from other crates. | |
1356 | UnreachablePub => [UNREACHABLE_PUB] | |
1357 | ); | |
abe05a73 XL |
1358 | |
1359 | impl UnreachablePub { | |
dfeec247 XL |
1360 | fn perform_lint( |
1361 | &self, | |
f035d41b | 1362 | cx: &LateContext<'_>, |
dfeec247 | 1363 | what: &str, |
94222f64 | 1364 | def_id: LocalDefId, |
dfeec247 XL |
1365 | vis: &hir::Visibility<'_>, |
1366 | span: Span, | |
1367 | exportable: bool, | |
1368 | ) { | |
8faf50e0 XL |
1369 | let mut applicability = Applicability::MachineApplicable; |
1370 | match vis.node { | |
94222f64 | 1371 | hir::VisibilityKind::Public if !cx.access_levels.is_reachable(def_id) => { |
e1599b0c | 1372 | if span.from_expansion() { |
8faf50e0 XL |
1373 | applicability = Applicability::MaybeIncorrect; |
1374 | } | |
ba9703b0 | 1375 | let def_span = cx.tcx.sess.source_map().guess_head_span(span); |
74b04a01 XL |
1376 | cx.struct_span_lint(UNREACHABLE_PUB, def_span, |lint| { |
1377 | let mut err = lint.build(&format!("unreachable `pub` {}", what)); | |
1378 | let replacement = if cx.tcx.features().crate_visibility_modifier { | |
1379 | "crate" | |
1380 | } else { | |
1381 | "pub(crate)" | |
1382 | } | |
1383 | .to_owned(); | |
8faf50e0 | 1384 | |
74b04a01 XL |
1385 | err.span_suggestion( |
1386 | vis.span, | |
1387 | "consider restricting its visibility", | |
1388 | replacement, | |
1389 | applicability, | |
1390 | ); | |
1391 | if exportable { | |
1392 | err.help("or consider exporting it for use by other crates"); | |
1393 | } | |
1394 | err.emit(); | |
1395 | }); | |
dfeec247 | 1396 | } |
8faf50e0 | 1397 | _ => {} |
abe05a73 XL |
1398 | } |
1399 | } | |
1400 | } | |
1401 | ||
f035d41b XL |
1402 | impl<'tcx> LateLintPass<'tcx> for UnreachablePub { |
1403 | fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) { | |
94222f64 | 1404 | self.perform_lint(cx, "item", item.def_id, &item.vis, item.span, true); |
abe05a73 XL |
1405 | } |
1406 | ||
f035d41b | 1407 | fn check_foreign_item(&mut self, cx: &LateContext<'_>, foreign_item: &hir::ForeignItem<'tcx>) { |
dfeec247 XL |
1408 | self.perform_lint( |
1409 | cx, | |
1410 | "item", | |
94222f64 | 1411 | foreign_item.def_id, |
dfeec247 XL |
1412 | &foreign_item.vis, |
1413 | foreign_item.span, | |
1414 | true, | |
1415 | ); | |
abe05a73 XL |
1416 | } |
1417 | ||
6a06907d | 1418 | fn check_field_def(&mut self, cx: &LateContext<'_>, field: &hir::FieldDef<'_>) { |
94222f64 XL |
1419 | let def_id = cx.tcx.hir().local_def_id(field.hir_id); |
1420 | self.perform_lint(cx, "field", def_id, &field.vis, field.span, false); | |
abe05a73 XL |
1421 | } |
1422 | ||
f035d41b | 1423 | fn check_impl_item(&mut self, cx: &LateContext<'_>, impl_item: &hir::ImplItem<'_>) { |
94222f64 | 1424 | self.perform_lint(cx, "item", impl_item.def_id, &impl_item.vis, impl_item.span, false); |
abe05a73 XL |
1425 | } |
1426 | } | |
0531ce1d | 1427 | |
0531ce1d | 1428 | declare_lint! { |
1b1a35ee XL |
1429 | /// The `type_alias_bounds` lint detects bounds in type aliases. |
1430 | /// | |
1431 | /// ### Example | |
1432 | /// | |
1433 | /// ```rust | |
1434 | /// type SendVec<T: Send> = Vec<T>; | |
1435 | /// ``` | |
1436 | /// | |
1437 | /// {{produces}} | |
1438 | /// | |
1439 | /// ### Explanation | |
1440 | /// | |
1441 | /// The trait bounds in a type alias are currently ignored, and should not | |
1442 | /// be included to avoid confusion. This was previously allowed | |
1443 | /// unintentionally; this may become a hard error in the future. | |
0531ce1d XL |
1444 | TYPE_ALIAS_BOUNDS, |
1445 | Warn, | |
1446 | "bounds in type aliases are not enforced" | |
1447 | } | |
1448 | ||
532ac7d7 XL |
1449 | declare_lint_pass!( |
1450 | /// Lint for trait and lifetime bounds in type aliases being mostly ignored. | |
1451 | /// They are relevant when using associated types, but otherwise neither checked | |
1452 | /// at definition site nor enforced at use site. | |
1453 | TypeAliasBounds => [TYPE_ALIAS_BOUNDS] | |
1454 | ); | |
0531ce1d XL |
1455 | |
1456 | impl TypeAliasBounds { | |
dfeec247 | 1457 | fn is_type_variable_assoc(qpath: &hir::QPath<'_>) -> bool { |
0531ce1d XL |
1458 | match *qpath { |
1459 | hir::QPath::TypeRelative(ref ty, _) => { | |
1460 | // If this is a type variable, we found a `T::Assoc`. | |
e74abb32 | 1461 | match ty.kind { |
29967ef6 XL |
1462 | hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => { |
1463 | matches!(path.res, Res::Def(DefKind::TyParam, _)) | |
1464 | } | |
dfeec247 | 1465 | _ => false, |
0531ce1d XL |
1466 | } |
1467 | } | |
3dfed10e | 1468 | hir::QPath::Resolved(..) | hir::QPath::LangItem(..) => false, |
0531ce1d XL |
1469 | } |
1470 | } | |
1471 | ||
dfeec247 | 1472 | fn suggest_changing_assoc_types(ty: &hir::Ty<'_>, err: &mut DiagnosticBuilder<'_>) { |
0531ce1d XL |
1473 | // Access to associates types should use `<T as Bound>::Assoc`, which does not need a |
1474 | // bound. Let's see if this type does that. | |
1475 | ||
1476 | // We use a HIR visitor to walk the type. | |
dfeec247 | 1477 | use rustc_hir::intravisit::{self, Visitor}; |
dc9dc135 | 1478 | struct WalkAssocTypes<'a, 'db> { |
dfeec247 | 1479 | err: &'a mut DiagnosticBuilder<'db>, |
0531ce1d XL |
1480 | } |
1481 | impl<'a, 'db, 'v> Visitor<'v> for WalkAssocTypes<'a, 'db> { | |
ba9703b0 | 1482 | type Map = intravisit::ErasedMap<'v>; |
dfeec247 | 1483 | |
ba9703b0 | 1484 | fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { |
0531ce1d XL |
1485 | intravisit::NestedVisitorMap::None |
1486 | } | |
1487 | ||
dfeec247 | 1488 | fn visit_qpath(&mut self, qpath: &'v hir::QPath<'v>, id: hir::HirId, span: Span) { |
0531ce1d | 1489 | if TypeAliasBounds::is_type_variable_assoc(qpath) { |
dfeec247 XL |
1490 | self.err.span_help( |
1491 | span, | |
0531ce1d | 1492 | "use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to \ |
dfeec247 XL |
1493 | associated types in type aliases", |
1494 | ); | |
0531ce1d XL |
1495 | } |
1496 | intravisit::walk_qpath(self, qpath, id, span) | |
1497 | } | |
1498 | } | |
1499 | ||
1500 | // Let's go for a walk! | |
1501 | let mut visitor = WalkAssocTypes { err }; | |
1502 | visitor.visit_ty(ty); | |
1503 | } | |
1504 | } | |
1505 | ||
f035d41b XL |
1506 | impl<'tcx> LateLintPass<'tcx> for TypeAliasBounds { |
1507 | fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) { | |
e74abb32 | 1508 | let (ty, type_alias_generics) = match item.kind { |
416331ca | 1509 | hir::ItemKind::TyAlias(ref ty, ref generics) => (&*ty, generics), |
0531ce1d XL |
1510 | _ => return, |
1511 | }; | |
f035d41b XL |
1512 | if let hir::TyKind::OpaqueDef(..) = ty.kind { |
1513 | // Bounds are respected for `type X = impl Trait` | |
1514 | return; | |
1515 | } | |
0531ce1d XL |
1516 | let mut suggested_changing_assoc_types = false; |
1517 | // There must not be a where clause | |
1518 | if !type_alias_generics.where_clause.predicates.is_empty() { | |
74b04a01 | 1519 | cx.lint( |
dfeec247 | 1520 | TYPE_ALIAS_BOUNDS, |
74b04a01 XL |
1521 | |lint| { |
1522 | let mut err = lint.build("where clauses are not enforced in type aliases"); | |
1523 | let spans: Vec<_> = type_alias_generics | |
1524 | .where_clause | |
1525 | .predicates | |
1526 | .iter() | |
1527 | .map(|pred| pred.span()) | |
1528 | .collect(); | |
1529 | err.set_span(spans); | |
1530 | err.span_suggestion( | |
1531 | type_alias_generics.where_clause.span_for_predicates_or_empty_place(), | |
1532 | "the clause will not be checked when the type alias is used, and should be removed", | |
1533 | String::new(), | |
1534 | Applicability::MachineApplicable, | |
1535 | ); | |
1536 | if !suggested_changing_assoc_types { | |
1537 | TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err); | |
1538 | suggested_changing_assoc_types = true; | |
1539 | } | |
1540 | err.emit(); | |
1541 | }, | |
e74abb32 | 1542 | ); |
0531ce1d XL |
1543 | } |
1544 | // The parameters must not have bounds | |
1545 | for param in type_alias_generics.params.iter() { | |
8faf50e0 | 1546 | let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect(); |
dfeec247 XL |
1547 | let suggestion = spans |
1548 | .iter() | |
1549 | .map(|sp| { | |
1550 | let start = param.span.between(*sp); // Include the `:` in `T: Bound`. | |
1551 | (start.to(*sp), String::new()) | |
1552 | }) | |
1553 | .collect(); | |
0531ce1d | 1554 | if !spans.is_empty() { |
74b04a01 XL |
1555 | cx.struct_span_lint(TYPE_ALIAS_BOUNDS, spans, |lint| { |
1556 | let mut err = | |
1557 | lint.build("bounds on generic parameters are not enforced in type aliases"); | |
1558 | let msg = "the bound will not be checked when the type alias is used, \ | |
1559 | and should be removed"; | |
1560 | err.multipart_suggestion(&msg, suggestion, Applicability::MachineApplicable); | |
1561 | if !suggested_changing_assoc_types { | |
1562 | TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err); | |
1563 | suggested_changing_assoc_types = true; | |
1564 | } | |
1565 | err.emit(); | |
1566 | }); | |
0531ce1d XL |
1567 | } |
1568 | } | |
1569 | } | |
1570 | } | |
1571 | ||
532ac7d7 XL |
1572 | declare_lint_pass!( |
1573 | /// Lint constants that are erroneous. | |
1574 | /// Without this lint, we might not get any diagnostic if the constant is | |
1575 | /// unused within this crate, even though downstream crates can't use it | |
1576 | /// without producing an error. | |
1577 | UnusedBrokenConst => [] | |
1578 | ); | |
9fa01778 | 1579 | |
f035d41b XL |
1580 | impl<'tcx> LateLintPass<'tcx> for UnusedBrokenConst { |
1581 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
e74abb32 | 1582 | match it.kind { |
8faf50e0 | 1583 | hir::ItemKind::Const(_, body_id) => { |
1b1a35ee XL |
1584 | let def_id = cx.tcx.hir().body_owner_def_id(body_id).to_def_id(); |
1585 | // trigger the query once for all constants since that will already report the errors | |
1586 | // FIXME: Use ensure here | |
1587 | let _ = cx.tcx.const_eval_poly(def_id); | |
dfeec247 | 1588 | } |
8faf50e0 | 1589 | hir::ItemKind::Static(_, _, body_id) => { |
1b1a35ee XL |
1590 | let def_id = cx.tcx.hir().body_owner_def_id(body_id).to_def_id(); |
1591 | // FIXME: Use ensure here | |
1592 | let _ = cx.tcx.eval_static_initializer(def_id); | |
dfeec247 XL |
1593 | } |
1594 | _ => {} | |
0531ce1d XL |
1595 | } |
1596 | } | |
1597 | } | |
94b46f34 | 1598 | |
94b46f34 | 1599 | declare_lint! { |
1b1a35ee XL |
1600 | /// The `trivial_bounds` lint detects trait bounds that don't depend on |
1601 | /// any type parameters. | |
1602 | /// | |
1603 | /// ### Example | |
1604 | /// | |
1605 | /// ```rust | |
1606 | /// #![feature(trivial_bounds)] | |
1607 | /// pub struct A where i32: Copy; | |
1608 | /// ``` | |
1609 | /// | |
1610 | /// {{produces}} | |
1611 | /// | |
1612 | /// ### Explanation | |
1613 | /// | |
1614 | /// Usually you would not write a trait bound that you know is always | |
1615 | /// true, or never true. However, when using macros, the macro may not | |
1616 | /// know whether or not the constraint would hold or not at the time when | |
1617 | /// generating the code. Currently, the compiler does not alert you if the | |
1618 | /// constraint is always true, and generates an error if it is never true. | |
1619 | /// The `trivial_bounds` feature changes this to be a warning in both | |
1620 | /// cases, giving macros more freedom and flexibility to generate code, | |
1621 | /// while still providing a signal when writing non-macro code that | |
1622 | /// something is amiss. | |
1623 | /// | |
1624 | /// See [RFC 2056] for more details. This feature is currently only | |
1625 | /// available on the nightly channel, see [tracking issue #48214]. | |
1626 | /// | |
1627 | /// [RFC 2056]: https://github.com/rust-lang/rfcs/blob/master/text/2056-allow-trivial-where-clause-constraints.md | |
1628 | /// [tracking issue #48214]: https://github.com/rust-lang/rust/issues/48214 | |
94b46f34 XL |
1629 | TRIVIAL_BOUNDS, |
1630 | Warn, | |
1631 | "these bounds don't depend on an type parameters" | |
1632 | } | |
1633 | ||
532ac7d7 XL |
1634 | declare_lint_pass!( |
1635 | /// Lint for trait and lifetime bounds that don't depend on type parameters | |
1636 | /// which either do nothing, or stop the item from being used. | |
1637 | TrivialConstraints => [TRIVIAL_BOUNDS] | |
1638 | ); | |
94b46f34 | 1639 | |
f035d41b XL |
1640 | impl<'tcx> LateLintPass<'tcx> for TrivialConstraints { |
1641 | fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) { | |
ba9703b0 | 1642 | use rustc_middle::ty::fold::TypeFoldable; |
5869c6ff | 1643 | use rustc_middle::ty::PredicateKind::*; |
94b46f34 | 1644 | |
94b46f34 | 1645 | if cx.tcx.features().trivial_bounds { |
6a06907d | 1646 | let predicates = cx.tcx.predicates_of(item.def_id); |
e74abb32 | 1647 | for &(predicate, span) in predicates.predicates { |
5869c6ff | 1648 | let predicate_kind_name = match predicate.kind().skip_binder() { |
c295e0f8 | 1649 | Trait(..) => "trait", |
94b46f34 | 1650 | TypeOutlives(..) | |
c295e0f8 | 1651 | RegionOutlives(..) => "lifetime", |
94b46f34 XL |
1652 | |
1653 | // Ignore projections, as they can only be global | |
1654 | // if the trait bound is global | |
1655 | Projection(..) | | |
1656 | // Ignore bounds that a user can't type | |
1657 | WellFormed(..) | | |
1658 | ObjectSafe(..) | | |
1659 | ClosureKind(..) | | |
1660 | Subtype(..) | | |
94222f64 | 1661 | Coerce(..) | |
f9f354fc | 1662 | ConstEvaluatable(..) | |
1b1a35ee XL |
1663 | ConstEquate(..) | |
1664 | TypeWellFormedFromEnv(..) => continue, | |
94b46f34 | 1665 | }; |
94222f64 | 1666 | if predicate.is_global(cx.tcx) { |
74b04a01 XL |
1667 | cx.struct_span_lint(TRIVIAL_BOUNDS, span, |lint| { |
1668 | lint.build(&format!( | |
dfeec247 XL |
1669 | "{} bound {} does not depend on any type \ |
1670 | or lifetime parameters", | |
1671 | predicate_kind_name, predicate | |
74b04a01 XL |
1672 | )) |
1673 | .emit() | |
1674 | }); | |
94b46f34 XL |
1675 | } |
1676 | } | |
1677 | } | |
1678 | } | |
1679 | } | |
1680 | ||
532ac7d7 XL |
1681 | declare_lint_pass!( |
1682 | /// Does nothing as a lint pass, but registers some `Lint`s | |
1683 | /// which are used by other parts of the compiler. | |
1684 | SoftLints => [ | |
1685 | WHILE_TRUE, | |
1686 | BOX_POINTERS, | |
1687 | NON_SHORTHAND_FIELD_PATTERNS, | |
1688 | UNSAFE_CODE, | |
1689 | MISSING_DOCS, | |
1690 | MISSING_COPY_IMPLEMENTATIONS, | |
1691 | MISSING_DEBUG_IMPLEMENTATIONS, | |
1692 | ANONYMOUS_PARAMETERS, | |
1693 | UNUSED_DOC_COMMENTS, | |
532ac7d7 XL |
1694 | NO_MANGLE_CONST_ITEMS, |
1695 | NO_MANGLE_GENERIC_ITEMS, | |
1696 | MUTABLE_TRANSMUTES, | |
1697 | UNSTABLE_FEATURES, | |
532ac7d7 XL |
1698 | UNREACHABLE_PUB, |
1699 | TYPE_ALIAS_BOUNDS, | |
1700 | TRIVIAL_BOUNDS | |
1701 | ] | |
1702 | ); | |
8faf50e0 XL |
1703 | |
1704 | declare_lint! { | |
1b1a35ee XL |
1705 | /// The `ellipsis_inclusive_range_patterns` lint detects the [`...` range |
1706 | /// pattern], which is deprecated. | |
1707 | /// | |
1708 | /// [`...` range pattern]: https://doc.rust-lang.org/reference/patterns.html#range-patterns | |
1709 | /// | |
1710 | /// ### Example | |
1711 | /// | |
c295e0f8 | 1712 | /// ```rust,edition2018 |
1b1a35ee XL |
1713 | /// let x = 123; |
1714 | /// match x { | |
1715 | /// 0...100 => {} | |
1716 | /// _ => {} | |
1717 | /// } | |
1718 | /// ``` | |
1719 | /// | |
1720 | /// {{produces}} | |
1721 | /// | |
1722 | /// ### Explanation | |
1723 | /// | |
1724 | /// The `...` range pattern syntax was changed to `..=` to avoid potential | |
1725 | /// confusion with the [`..` range expression]. Use the new form instead. | |
1726 | /// | |
1727 | /// [`..` range expression]: https://doc.rust-lang.org/reference/expressions/range-expr.html | |
8faf50e0 | 1728 | pub ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, |
dc9dc135 | 1729 | Warn, |
17df50a5 XL |
1730 | "`...` range patterns are deprecated", |
1731 | @future_incompatible = FutureIncompatibleInfo { | |
94222f64 | 1732 | reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>", |
136023e0 | 1733 | reason: FutureIncompatibilityReason::EditionError(Edition::Edition2021), |
17df50a5 | 1734 | }; |
8faf50e0 XL |
1735 | } |
1736 | ||
48663c56 XL |
1737 | #[derive(Default)] |
1738 | pub struct EllipsisInclusiveRangePatterns { | |
1739 | /// If `Some(_)`, suppress all subsequent pattern | |
1740 | /// warnings for better diagnostics. | |
1741 | node_id: Option<ast::NodeId>, | |
1742 | } | |
1743 | ||
1744 | impl_lint_pass!(EllipsisInclusiveRangePatterns => [ELLIPSIS_INCLUSIVE_RANGE_PATTERNS]); | |
8faf50e0 XL |
1745 | |
1746 | impl EarlyLintPass for EllipsisInclusiveRangePatterns { | |
48663c56 XL |
1747 | fn check_pat(&mut self, cx: &EarlyContext<'_>, pat: &ast::Pat) { |
1748 | if self.node_id.is_some() { | |
1749 | // Don't recursively warn about patterns inside range endpoints. | |
dfeec247 | 1750 | return; |
48663c56 XL |
1751 | } |
1752 | ||
3dfed10e | 1753 | use self::ast::{PatKind, RangeSyntax::DotDotDot}; |
13cf67c4 XL |
1754 | |
1755 | /// If `pat` is a `...` pattern, return the start and end of the range, as well as the span | |
1756 | /// corresponding to the ellipsis. | |
dfeec247 | 1757 | fn matches_ellipsis_pat(pat: &ast::Pat) -> Option<(Option<&Expr>, &Expr, Span)> { |
e74abb32 | 1758 | match &pat.kind { |
dfeec247 XL |
1759 | PatKind::Range( |
1760 | a, | |
1761 | Some(b), | |
1762 | Spanned { span, node: RangeEnd::Included(DotDotDot) }, | |
1763 | ) => Some((a.as_deref(), b, *span)), | |
13cf67c4 XL |
1764 | _ => None, |
1765 | } | |
1766 | } | |
8faf50e0 | 1767 | |
e74abb32 | 1768 | let (parenthesise, endpoints) = match &pat.kind { |
13cf67c4 XL |
1769 | PatKind::Ref(subpat, _) => (true, matches_ellipsis_pat(&subpat)), |
1770 | _ => (false, matches_ellipsis_pat(pat)), | |
1771 | }; | |
1772 | ||
1773 | if let Some((start, end, join)) = endpoints { | |
8faf50e0 | 1774 | let msg = "`...` range patterns are deprecated"; |
13cf67c4 XL |
1775 | let suggestion = "use `..=` for an inclusive range"; |
1776 | if parenthesise { | |
48663c56 | 1777 | self.node_id = Some(pat.id); |
17df50a5 XL |
1778 | let end = expr_to_string(&end); |
1779 | let replace = match start { | |
1780 | Some(start) => format!("&({}..={})", expr_to_string(&start), end), | |
1781 | None => format!("&(..={})", end), | |
1782 | }; | |
1783 | if join.edition() >= Edition::Edition2021 { | |
1784 | let mut err = | |
1785 | rustc_errors::struct_span_err!(cx.sess, pat.span, E0783, "{}", msg,); | |
1786 | err.span_suggestion( | |
1787 | pat.span, | |
1788 | suggestion, | |
1789 | replace, | |
1790 | Applicability::MachineApplicable, | |
1791 | ) | |
1792 | .emit(); | |
1793 | } else { | |
1794 | cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, pat.span, |lint| { | |
1795 | lint.build(msg) | |
1796 | .span_suggestion( | |
1797 | pat.span, | |
1798 | suggestion, | |
1799 | replace, | |
1800 | Applicability::MachineApplicable, | |
1801 | ) | |
1802 | .emit(); | |
1803 | }); | |
1804 | } | |
13cf67c4 | 1805 | } else { |
17df50a5 XL |
1806 | let replace = "..=".to_owned(); |
1807 | if join.edition() >= Edition::Edition2021 { | |
1808 | let mut err = | |
1809 | rustc_errors::struct_span_err!(cx.sess, pat.span, E0783, "{}", msg,); | |
1810 | err.span_suggestion_short( | |
1811 | join, | |
1812 | suggestion, | |
1813 | replace, | |
1814 | Applicability::MachineApplicable, | |
1815 | ) | |
1816 | .emit(); | |
1817 | } else { | |
1818 | cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, join, |lint| { | |
1819 | lint.build(msg) | |
1820 | .span_suggestion_short( | |
1821 | join, | |
1822 | suggestion, | |
1823 | replace, | |
1824 | Applicability::MachineApplicable, | |
1825 | ) | |
1826 | .emit(); | |
1827 | }); | |
1828 | } | |
13cf67c4 | 1829 | }; |
8faf50e0 XL |
1830 | } |
1831 | } | |
48663c56 XL |
1832 | |
1833 | fn check_pat_post(&mut self, _cx: &EarlyContext<'_>, pat: &ast::Pat) { | |
1834 | if let Some(node_id) = self.node_id { | |
1835 | if pat.id == node_id { | |
1836 | self.node_id = None | |
1837 | } | |
1838 | } | |
1839 | } | |
8faf50e0 XL |
1840 | } |
1841 | ||
1842 | declare_lint! { | |
1b1a35ee XL |
1843 | /// The `unnameable_test_items` lint detects [`#[test]`][test] functions |
1844 | /// that are not able to be run by the test harness because they are in a | |
1845 | /// position where they are not nameable. | |
1846 | /// | |
1847 | /// [test]: https://doc.rust-lang.org/reference/attributes/testing.html#the-test-attribute | |
1848 | /// | |
1849 | /// ### Example | |
1850 | /// | |
1851 | /// ```rust,test | |
1852 | /// fn main() { | |
1853 | /// #[test] | |
1854 | /// fn foo() { | |
1855 | /// // This test will not fail because it does not run. | |
1856 | /// assert_eq!(1, 2); | |
1857 | /// } | |
1858 | /// } | |
1859 | /// ``` | |
1860 | /// | |
1861 | /// {{produces}} | |
1862 | /// | |
1863 | /// ### Explanation | |
1864 | /// | |
1865 | /// In order for the test harness to run a test, the test function must be | |
1866 | /// located in a position where it can be accessed from the crate root. | |
1867 | /// This generally means it must be defined in a module, and not anywhere | |
1868 | /// else such as inside another function. The compiler previously allowed | |
1869 | /// this without an error, so a lint was added as an alert that a test is | |
1870 | /// not being used. Whether or not this should be allowed has not yet been | |
1871 | /// decided, see [RFC 2471] and [issue #36629]. | |
1872 | /// | |
1873 | /// [RFC 2471]: https://github.com/rust-lang/rfcs/pull/2471#issuecomment-397414443 | |
1874 | /// [issue #36629]: https://github.com/rust-lang/rust/issues/36629 | |
b7449926 | 1875 | UNNAMEABLE_TEST_ITEMS, |
8faf50e0 | 1876 | Warn, |
416331ca | 1877 | "detects an item that cannot be named being marked as `#[test_case]`", |
e74abb32 | 1878 | report_in_external_macro |
8faf50e0 XL |
1879 | } |
1880 | ||
b7449926 | 1881 | pub struct UnnameableTestItems { |
6a06907d | 1882 | boundary: Option<LocalDefId>, // Id of the item under which things are not nameable |
b7449926 XL |
1883 | items_nameable: bool, |
1884 | } | |
8faf50e0 | 1885 | |
532ac7d7 XL |
1886 | impl_lint_pass!(UnnameableTestItems => [UNNAMEABLE_TEST_ITEMS]); |
1887 | ||
b7449926 XL |
1888 | impl UnnameableTestItems { |
1889 | pub fn new() -> Self { | |
ba9703b0 | 1890 | Self { boundary: None, items_nameable: true } |
b7449926 XL |
1891 | } |
1892 | } | |
1893 | ||
f035d41b XL |
1894 | impl<'tcx> LateLintPass<'tcx> for UnnameableTestItems { |
1895 | fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) { | |
b7449926 | 1896 | if self.items_nameable { |
dfeec247 XL |
1897 | if let hir::ItemKind::Mod(..) = it.kind { |
1898 | } else { | |
b7449926 | 1899 | self.items_nameable = false; |
6a06907d | 1900 | self.boundary = Some(it.def_id); |
8faf50e0 | 1901 | } |
b7449926 XL |
1902 | return; |
1903 | } | |
1904 | ||
6a06907d XL |
1905 | let attrs = cx.tcx.hir().attrs(it.hir_id()); |
1906 | if let Some(attr) = cx.sess().find_by_name(attrs, sym::rustc_test_marker) { | |
74b04a01 XL |
1907 | cx.struct_span_lint(UNNAMEABLE_TEST_ITEMS, attr.span, |lint| { |
1908 | lint.build("cannot test inner items").emit() | |
1909 | }); | |
b7449926 XL |
1910 | } |
1911 | } | |
1912 | ||
f035d41b | 1913 | fn check_item_post(&mut self, _cx: &LateContext<'_>, it: &hir::Item<'_>) { |
6a06907d | 1914 | if !self.items_nameable && self.boundary == Some(it.def_id) { |
b7449926 XL |
1915 | self.items_nameable = true; |
1916 | } | |
8faf50e0 XL |
1917 | } |
1918 | } | |
1919 | ||
1920 | declare_lint! { | |
1b1a35ee XL |
1921 | /// The `keyword_idents` lint detects edition keywords being used as an |
1922 | /// identifier. | |
1923 | /// | |
1924 | /// ### Example | |
1925 | /// | |
1926 | /// ```rust,edition2015,compile_fail | |
1927 | /// #![deny(keyword_idents)] | |
1928 | /// // edition 2015 | |
1929 | /// fn dyn() {} | |
1930 | /// ``` | |
1931 | /// | |
1932 | /// {{produces}} | |
1933 | /// | |
1934 | /// ### Explanation | |
1935 | /// | |
1936 | /// Rust [editions] allow the language to evolve without breaking | |
1937 | /// backwards compatibility. This lint catches code that uses new keywords | |
1938 | /// that are added to the language that are used as identifiers (such as a | |
1939 | /// variable name, function name, etc.). If you switch the compiler to a | |
1940 | /// new edition without updating the code, then it will fail to compile if | |
1941 | /// you are using a new keyword as an identifier. | |
1942 | /// | |
1943 | /// You can manually change the identifiers to a non-keyword, or use a | |
1944 | /// [raw identifier], for example `r#dyn`, to transition to a new edition. | |
1945 | /// | |
1946 | /// This lint solves the problem automatically. It is "allow" by default | |
1947 | /// because the code is perfectly valid in older editions. The [`cargo | |
1948 | /// fix`] tool with the `--edition` flag will switch this lint to "warn" | |
1949 | /// and automatically apply the suggested fix from the compiler (which is | |
1950 | /// to use a raw identifier). This provides a completely automated way to | |
1951 | /// update old code for a new edition. | |
1952 | /// | |
1953 | /// [editions]: https://doc.rust-lang.org/edition-guide/ | |
1954 | /// [raw identifier]: https://doc.rust-lang.org/reference/identifiers.html | |
1955 | /// [`cargo fix`]: https://doc.rust-lang.org/cargo/commands/cargo-fix.html | |
b7449926 | 1956 | pub KEYWORD_IDENTS, |
8faf50e0 | 1957 | Allow, |
e74abb32 XL |
1958 | "detects edition keywords being used as an identifier", |
1959 | @future_incompatible = FutureIncompatibleInfo { | |
1960 | reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>", | |
136023e0 | 1961 | reason: FutureIncompatibilityReason::EditionError(Edition::Edition2018), |
e74abb32 | 1962 | }; |
8faf50e0 XL |
1963 | } |
1964 | ||
532ac7d7 XL |
1965 | declare_lint_pass!( |
1966 | /// Check for uses of edition keywords used as an identifier. | |
1967 | KeywordIdents => [KEYWORD_IDENTS] | |
1968 | ); | |
8faf50e0 | 1969 | |
532ac7d7 | 1970 | struct UnderMacro(bool); |
8faf50e0 | 1971 | |
b7449926 | 1972 | impl KeywordIdents { |
9fa01778 | 1973 | fn check_tokens(&mut self, cx: &EarlyContext<'_>, tokens: TokenStream) { |
8faf50e0 XL |
1974 | for tt in tokens.into_trees() { |
1975 | match tt { | |
dc9dc135 | 1976 | // Only report non-raw idents. |
dfeec247 XL |
1977 | TokenTree::Token(token) => { |
1978 | if let Some((ident, false)) = token.ident() { | |
1979 | self.check_ident_token(cx, UnderMacro(true), ident); | |
1980 | } | |
8faf50e0 | 1981 | } |
dfeec247 | 1982 | TokenTree::Delimited(_, _, tts) => self.check_tokens(cx, tts), |
8faf50e0 XL |
1983 | } |
1984 | } | |
1985 | } | |
8faf50e0 | 1986 | |
dfeec247 XL |
1987 | fn check_ident_token( |
1988 | &mut self, | |
1989 | cx: &EarlyContext<'_>, | |
1990 | UnderMacro(under_macro): UnderMacro, | |
f9f354fc | 1991 | ident: Ident, |
dfeec247 | 1992 | ) { |
48663c56 | 1993 | let next_edition = match cx.sess.edition() { |
b7449926 | 1994 | Edition::Edition2015 => { |
dc9dc135 XL |
1995 | match ident.name { |
1996 | kw::Async | kw::Await | kw::Try => Edition::Edition2018, | |
532ac7d7 XL |
1997 | |
1998 | // rust-lang/rust#56327: Conservatively do not | |
1999 | // attempt to report occurrences of `dyn` within | |
2000 | // macro definitions or invocations, because `dyn` | |
2001 | // can legitimately occur as a contextual keyword | |
2002 | // in 2015 code denoting its 2018 meaning, and we | |
2003 | // do not want rustfix to inject bugs into working | |
2004 | // code by rewriting such occurrences. | |
2005 | // | |
2006 | // But if we see `dyn` outside of a macro, we know | |
2007 | // its precise role in the parsed AST and thus are | |
2008 | // assured this is truly an attempt to use it as | |
2009 | // an identifier. | |
dc9dc135 | 2010 | kw::Dyn if !under_macro => Edition::Edition2018, |
532ac7d7 | 2011 | |
b7449926 XL |
2012 | _ => return, |
2013 | } | |
2014 | } | |
2015 | ||
0731742a | 2016 | // There are no new keywords yet for the 2018 edition and beyond. |
48663c56 | 2017 | _ => return, |
b7449926 XL |
2018 | }; |
2019 | ||
dc9dc135 | 2020 | // Don't lint `r#foo`. |
48663c56 | 2021 | if cx.sess.parse_sess.raw_identifier_spans.borrow().contains(&ident.span) { |
b7449926 | 2022 | return; |
8faf50e0 | 2023 | } |
b7449926 | 2024 | |
74b04a01 XL |
2025 | cx.struct_span_lint(KEYWORD_IDENTS, ident.span, |lint| { |
2026 | lint.build(&format!("`{}` is a keyword in the {} edition", ident, next_edition)) | |
2027 | .span_suggestion( | |
2028 | ident.span, | |
2029 | "you can use a raw identifier to stay compatible", | |
2030 | format!("r#{}", ident), | |
2031 | Applicability::MachineApplicable, | |
2032 | ) | |
2033 | .emit() | |
2034 | }); | |
8faf50e0 XL |
2035 | } |
2036 | } | |
0bf4aa26 | 2037 | |
532ac7d7 XL |
2038 | impl EarlyLintPass for KeywordIdents { |
2039 | fn check_mac_def(&mut self, cx: &EarlyContext<'_>, mac_def: &ast::MacroDef, _id: ast::NodeId) { | |
60c5eb7d | 2040 | self.check_tokens(cx, mac_def.body.inner_tokens()); |
9fa01778 | 2041 | } |
ba9703b0 | 2042 | fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &ast::MacCall) { |
60c5eb7d | 2043 | self.check_tokens(cx, mac.args.inner_tokens()); |
532ac7d7 | 2044 | } |
f9f354fc | 2045 | fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) { |
532ac7d7 | 2046 | self.check_ident_token(cx, UnderMacro(false), ident); |
0bf4aa26 XL |
2047 | } |
2048 | } | |
2049 | ||
532ac7d7 XL |
2050 | declare_lint_pass!(ExplicitOutlivesRequirements => [EXPLICIT_OUTLIVES_REQUIREMENTS]); |
2051 | ||
0bf4aa26 | 2052 | impl ExplicitOutlivesRequirements { |
dc9dc135 | 2053 | fn lifetimes_outliving_lifetime<'tcx>( |
e74abb32 | 2054 | inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
dc9dc135 XL |
2055 | index: u32, |
2056 | ) -> Vec<ty::Region<'tcx>> { | |
dfeec247 XL |
2057 | inferred_outlives |
2058 | .iter() | |
5869c6ff XL |
2059 | .filter_map(|(pred, _)| match pred.kind().skip_binder() { |
2060 | ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => match a { | |
3dfed10e XL |
2061 | ty::ReEarlyBound(ebr) if ebr.index == index => Some(b), |
2062 | _ => None, | |
2063 | }, | |
dfeec247 XL |
2064 | _ => None, |
2065 | }) | |
2066 | .collect() | |
dc9dc135 | 2067 | } |
0bf4aa26 | 2068 | |
dc9dc135 | 2069 | fn lifetimes_outliving_type<'tcx>( |
e74abb32 | 2070 | inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
dc9dc135 XL |
2071 | index: u32, |
2072 | ) -> Vec<ty::Region<'tcx>> { | |
dfeec247 XL |
2073 | inferred_outlives |
2074 | .iter() | |
5869c6ff XL |
2075 | .filter_map(|(pred, _)| match pred.kind().skip_binder() { |
2076 | ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(a, b)) => { | |
3dfed10e | 2077 | a.is_param(index).then_some(b) |
0bf4aa26 | 2078 | } |
dfeec247 XL |
2079 | _ => None, |
2080 | }) | |
2081 | .collect() | |
dc9dc135 XL |
2082 | } |
2083 | ||
2084 | fn collect_outlived_lifetimes<'tcx>( | |
2085 | &self, | |
dfeec247 | 2086 | param: &'tcx hir::GenericParam<'tcx>, |
dc9dc135 | 2087 | tcx: TyCtxt<'tcx>, |
e74abb32 | 2088 | inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
dc9dc135 XL |
2089 | ty_generics: &'tcx ty::Generics, |
2090 | ) -> Vec<ty::Region<'tcx>> { | |
f9f354fc XL |
2091 | let index = |
2092 | ty_generics.param_def_id_to_index[&tcx.hir().local_def_id(param.hir_id).to_def_id()]; | |
dc9dc135 XL |
2093 | |
2094 | match param.kind { | |
2095 | hir::GenericParamKind::Lifetime { .. } => { | |
2096 | Self::lifetimes_outliving_lifetime(inferred_outlives, index) | |
2097 | } | |
2098 | hir::GenericParamKind::Type { .. } => { | |
2099 | Self::lifetimes_outliving_type(inferred_outlives, index) | |
0bf4aa26 | 2100 | } |
dc9dc135 | 2101 | hir::GenericParamKind::Const { .. } => Vec::new(), |
0bf4aa26 | 2102 | } |
dc9dc135 XL |
2103 | } |
2104 | ||
dc9dc135 XL |
2105 | fn collect_outlives_bound_spans<'tcx>( |
2106 | &self, | |
2107 | tcx: TyCtxt<'tcx>, | |
dfeec247 | 2108 | bounds: &hir::GenericBounds<'_>, |
dc9dc135 XL |
2109 | inferred_outlives: &[ty::Region<'tcx>], |
2110 | infer_static: bool, | |
2111 | ) -> Vec<(usize, Span)> { | |
ba9703b0 | 2112 | use rustc_middle::middle::resolve_lifetime::Region; |
dc9dc135 XL |
2113 | |
2114 | bounds | |
2115 | .iter() | |
2116 | .enumerate() | |
2117 | .filter_map(|(i, bound)| { | |
2118 | if let hir::GenericBound::Outlives(lifetime) = bound { | |
2119 | let is_inferred = match tcx.named_region(lifetime.hir_id) { | |
1b1a35ee XL |
2120 | Some(Region::Static) if infer_static => { |
2121 | inferred_outlives.iter().any(|r| matches!(r, ty::ReStatic)) | |
2122 | } | |
dfeec247 XL |
2123 | Some(Region::EarlyBound(index, ..)) => inferred_outlives.iter().any(|r| { |
2124 | if let ty::ReEarlyBound(ebr) = r { ebr.index == index } else { false } | |
2125 | }), | |
dc9dc135 XL |
2126 | _ => false, |
2127 | }; | |
60c5eb7d | 2128 | is_inferred.then_some((i, bound.span())) |
dc9dc135 XL |
2129 | } else { |
2130 | None | |
2131 | } | |
2132 | }) | |
2133 | .collect() | |
0bf4aa26 XL |
2134 | } |
2135 | ||
2136 | fn consolidate_outlives_bound_spans( | |
2137 | &self, | |
2138 | lo: Span, | |
dfeec247 XL |
2139 | bounds: &hir::GenericBounds<'_>, |
2140 | bound_spans: Vec<(usize, Span)>, | |
0bf4aa26 XL |
2141 | ) -> Vec<Span> { |
2142 | if bounds.is_empty() { | |
2143 | return Vec::new(); | |
2144 | } | |
2145 | if bound_spans.len() == bounds.len() { | |
dfeec247 | 2146 | let (_, last_bound_span) = bound_spans[bound_spans.len() - 1]; |
0bf4aa26 XL |
2147 | // If all bounds are inferable, we want to delete the colon, so |
2148 | // start from just after the parameter (span passed as argument) | |
2149 | vec![lo.to(last_bound_span)] | |
2150 | } else { | |
2151 | let mut merged = Vec::new(); | |
2152 | let mut last_merged_i = None; | |
2153 | ||
2154 | let mut from_start = true; | |
2155 | for (i, bound_span) in bound_spans { | |
2156 | match last_merged_i { | |
dc9dc135 | 2157 | // If the first bound is inferable, our span should also eat the leading `+`. |
0bf4aa26 XL |
2158 | None if i == 0 => { |
2159 | merged.push(bound_span.to(bounds[1].span().shrink_to_lo())); | |
2160 | last_merged_i = Some(0); | |
dfeec247 | 2161 | } |
0bf4aa26 | 2162 | // If consecutive bounds are inferable, merge their spans |
dfeec247 | 2163 | Some(h) if i == h + 1 => { |
0bf4aa26 XL |
2164 | if let Some(tail) = merged.last_mut() { |
2165 | // Also eat the trailing `+` if the first | |
2166 | // more-than-one bound is inferable | |
2167 | let to_span = if from_start && i < bounds.len() { | |
dfeec247 | 2168 | bounds[i + 1].span().shrink_to_lo() |
0bf4aa26 XL |
2169 | } else { |
2170 | bound_span | |
2171 | }; | |
2172 | *tail = tail.to(to_span); | |
2173 | last_merged_i = Some(i); | |
2174 | } else { | |
2175 | bug!("another bound-span visited earlier"); | |
2176 | } | |
dfeec247 | 2177 | } |
0bf4aa26 XL |
2178 | _ => { |
2179 | // When we find a non-inferable bound, subsequent inferable bounds | |
2180 | // won't be consecutive from the start (and we'll eat the leading | |
2181 | // `+` rather than the trailing one) | |
2182 | from_start = false; | |
dfeec247 | 2183 | merged.push(bounds[i - 1].span().shrink_to_hi().to(bound_span)); |
0bf4aa26 XL |
2184 | last_merged_i = Some(i); |
2185 | } | |
2186 | } | |
2187 | } | |
2188 | merged | |
2189 | } | |
2190 | } | |
2191 | } | |
2192 | ||
f035d41b XL |
2193 | impl<'tcx> LateLintPass<'tcx> for ExplicitOutlivesRequirements { |
2194 | fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) { | |
ba9703b0 | 2195 | use rustc_middle::middle::resolve_lifetime::Region; |
dc9dc135 | 2196 | |
0bf4aa26 | 2197 | let infer_static = cx.tcx.features().infer_static_outlives_requirements; |
6a06907d | 2198 | let def_id = item.def_id; |
dc9dc135 | 2199 | if let hir::ItemKind::Struct(_, ref hir_generics) |
dfeec247 XL |
2200 | | hir::ItemKind::Enum(_, ref hir_generics) |
2201 | | hir::ItemKind::Union(_, ref hir_generics) = item.kind | |
dc9dc135 XL |
2202 | { |
2203 | let inferred_outlives = cx.tcx.inferred_outlives_of(def_id); | |
2204 | if inferred_outlives.is_empty() { | |
2205 | return; | |
2206 | } | |
2207 | ||
2208 | let ty_generics = cx.tcx.generics_of(def_id); | |
2209 | ||
0bf4aa26 XL |
2210 | let mut bound_count = 0; |
2211 | let mut lint_spans = Vec::new(); | |
2212 | ||
dfeec247 | 2213 | for param in hir_generics.params { |
1b1a35ee XL |
2214 | let has_lifetime_bounds = param |
2215 | .bounds | |
2216 | .iter() | |
2217 | .any(|bound| matches!(bound, hir::GenericBound::Outlives(_))); | |
dc9dc135 XL |
2218 | if !has_lifetime_bounds { |
2219 | continue; | |
2220 | } | |
2221 | ||
dfeec247 XL |
2222 | let relevant_lifetimes = |
2223 | self.collect_outlived_lifetimes(param, cx.tcx, inferred_outlives, ty_generics); | |
dc9dc135 XL |
2224 | if relevant_lifetimes.is_empty() { |
2225 | continue; | |
2226 | } | |
2227 | ||
0bf4aa26 | 2228 | let bound_spans = self.collect_outlives_bound_spans( |
dfeec247 XL |
2229 | cx.tcx, |
2230 | ¶m.bounds, | |
2231 | &relevant_lifetimes, | |
2232 | infer_static, | |
0bf4aa26 XL |
2233 | ); |
2234 | bound_count += bound_spans.len(); | |
dfeec247 XL |
2235 | lint_spans.extend(self.consolidate_outlives_bound_spans( |
2236 | param.span.shrink_to_hi(), | |
2237 | ¶m.bounds, | |
2238 | bound_spans, | |
2239 | )); | |
0bf4aa26 XL |
2240 | } |
2241 | ||
2242 | let mut where_lint_spans = Vec::new(); | |
2243 | let mut dropped_predicate_count = 0; | |
dc9dc135 XL |
2244 | let num_predicates = hir_generics.where_clause.predicates.len(); |
2245 | for (i, where_predicate) in hir_generics.where_clause.predicates.iter().enumerate() { | |
2246 | let (relevant_lifetimes, bounds, span) = match where_predicate { | |
2247 | hir::WherePredicate::RegionPredicate(predicate) => { | |
dfeec247 XL |
2248 | if let Some(Region::EarlyBound(index, ..)) = |
2249 | cx.tcx.named_region(predicate.lifetime.hir_id) | |
dc9dc135 XL |
2250 | { |
2251 | ( | |
2252 | Self::lifetimes_outliving_lifetime(inferred_outlives, index), | |
0bf4aa26 | 2253 | &predicate.bounds, |
dc9dc135 | 2254 | predicate.span, |
0bf4aa26 | 2255 | ) |
dc9dc135 XL |
2256 | } else { |
2257 | continue; | |
2258 | } | |
0bf4aa26 | 2259 | } |
dc9dc135 XL |
2260 | hir::WherePredicate::BoundPredicate(predicate) => { |
2261 | // FIXME we can also infer bounds on associated types, | |
2262 | // and should check for them here. | |
e74abb32 | 2263 | match predicate.bounded_ty.kind { |
dfeec247 | 2264 | hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => { |
dc9dc135 XL |
2265 | if let Res::Def(DefKind::TyParam, def_id) = path.res { |
2266 | let index = ty_generics.param_def_id_to_index[&def_id]; | |
2267 | ( | |
2268 | Self::lifetimes_outliving_type(inferred_outlives, index), | |
2269 | &predicate.bounds, | |
2270 | predicate.span, | |
2271 | ) | |
2272 | } else { | |
2273 | continue; | |
2274 | } | |
dfeec247 XL |
2275 | } |
2276 | _ => { | |
2277 | continue; | |
2278 | } | |
dc9dc135 XL |
2279 | } |
2280 | } | |
2281 | _ => continue, | |
2282 | }; | |
2283 | if relevant_lifetimes.is_empty() { | |
2284 | continue; | |
2285 | } | |
2286 | ||
2287 | let bound_spans = self.collect_outlives_bound_spans( | |
dfeec247 XL |
2288 | cx.tcx, |
2289 | bounds, | |
2290 | &relevant_lifetimes, | |
2291 | infer_static, | |
dc9dc135 XL |
2292 | ); |
2293 | bound_count += bound_spans.len(); | |
2294 | ||
2295 | let drop_predicate = bound_spans.len() == bounds.len(); | |
2296 | if drop_predicate { | |
2297 | dropped_predicate_count += 1; | |
2298 | } | |
2299 | ||
2300 | // If all the bounds on a predicate were inferable and there are | |
2301 | // further predicates, we want to eat the trailing comma. | |
2302 | if drop_predicate && i + 1 < num_predicates { | |
2303 | let next_predicate_span = hir_generics.where_clause.predicates[i + 1].span(); | |
dfeec247 | 2304 | where_lint_spans.push(span.to(next_predicate_span.shrink_to_lo())); |
dc9dc135 | 2305 | } else { |
dfeec247 XL |
2306 | where_lint_spans.extend(self.consolidate_outlives_bound_spans( |
2307 | span.shrink_to_lo(), | |
2308 | bounds, | |
2309 | bound_spans, | |
2310 | )); | |
0bf4aa26 XL |
2311 | } |
2312 | } | |
2313 | ||
2314 | // If all predicates are inferable, drop the entire clause | |
2315 | // (including the `where`) | |
2316 | if num_predicates > 0 && dropped_predicate_count == num_predicates { | |
dfeec247 XL |
2317 | let where_span = hir_generics |
2318 | .where_clause | |
2319 | .span() | |
dc9dc135 XL |
2320 | .expect("span of (nonempty) where clause should exist"); |
2321 | // Extend the where clause back to the closing `>` of the | |
2322 | // generics, except for tuple struct, which have the `where` | |
2323 | // after the fields of the struct. | |
dfeec247 XL |
2324 | let full_where_span = |
2325 | if let hir::ItemKind::Struct(hir::VariantData::Tuple(..), _) = item.kind { | |
2326 | where_span | |
2327 | } else { | |
2328 | hir_generics.span.shrink_to_hi().to(where_span) | |
2329 | }; | |
2330 | lint_spans.push(full_where_span); | |
0bf4aa26 XL |
2331 | } else { |
2332 | lint_spans.extend(where_lint_spans); | |
2333 | } | |
2334 | ||
2335 | if !lint_spans.is_empty() { | |
74b04a01 XL |
2336 | cx.struct_span_lint(EXPLICIT_OUTLIVES_REQUIREMENTS, lint_spans.clone(), |lint| { |
2337 | lint.build("outlives requirements can be inferred") | |
2338 | .multipart_suggestion( | |
2339 | if bound_count == 1 { | |
2340 | "remove this bound" | |
2341 | } else { | |
2342 | "remove these bounds" | |
2343 | }, | |
2344 | lint_spans | |
2345 | .into_iter() | |
2346 | .map(|span| (span, "".to_owned())) | |
2347 | .collect::<Vec<_>>(), | |
2348 | Applicability::MachineApplicable, | |
2349 | ) | |
2350 | .emit(); | |
2351 | }); | |
0bf4aa26 | 2352 | } |
0bf4aa26 XL |
2353 | } |
2354 | } | |
0bf4aa26 | 2355 | } |
416331ca XL |
2356 | |
2357 | declare_lint! { | |
1b1a35ee XL |
2358 | /// The `incomplete_features` lint detects unstable features enabled with |
2359 | /// the [`feature` attribute] that may function improperly in some or all | |
2360 | /// cases. | |
2361 | /// | |
2362 | /// [`feature` attribute]: https://doc.rust-lang.org/nightly/unstable-book/ | |
2363 | /// | |
2364 | /// ### Example | |
2365 | /// | |
2366 | /// ```rust | |
94222f64 | 2367 | /// #![feature(generic_const_exprs)] |
1b1a35ee XL |
2368 | /// ``` |
2369 | /// | |
2370 | /// {{produces}} | |
2371 | /// | |
2372 | /// ### Explanation | |
2373 | /// | |
2374 | /// Although it is encouraged for people to experiment with unstable | |
2375 | /// features, some of them are known to be incomplete or faulty. This lint | |
2376 | /// is a signal that the feature has not yet been finished, and you may | |
2377 | /// experience problems with it. | |
416331ca XL |
2378 | pub INCOMPLETE_FEATURES, |
2379 | Warn, | |
2380 | "incomplete features that may function improperly in some or all cases" | |
2381 | } | |
2382 | ||
2383 | declare_lint_pass!( | |
cdc7bbd5 | 2384 | /// Check for used feature gates in `INCOMPLETE_FEATURES` in `rustc_feature/src/active.rs`. |
416331ca XL |
2385 | IncompleteFeatures => [INCOMPLETE_FEATURES] |
2386 | ); | |
2387 | ||
2388 | impl EarlyLintPass for IncompleteFeatures { | |
2389 | fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) { | |
2390 | let features = cx.sess.features_untracked(); | |
dfeec247 XL |
2391 | features |
2392 | .declared_lang_features | |
2393 | .iter() | |
2394 | .map(|(name, span, _)| (name, span)) | |
416331ca | 2395 | .chain(features.declared_lib_features.iter().map(|(name, span)| (name, span))) |
136023e0 | 2396 | .filter(|(&name, _)| features.incomplete(name)) |
f9f354fc | 2397 | .for_each(|(&name, &span)| { |
74b04a01 | 2398 | cx.struct_span_lint(INCOMPLETE_FEATURES, span, |lint| { |
f9f354fc XL |
2399 | let mut builder = lint.build(&format!( |
2400 | "the feature `{}` is incomplete and may not be safe to use \ | |
2401 | and/or cause compiler crashes", | |
416331ca | 2402 | name, |
f9f354fc XL |
2403 | )); |
2404 | if let Some(n) = rustc_feature::find_feature_issue(name, GateIssue::Language) { | |
2405 | builder.note(&format!( | |
2406 | "see issue #{} <https://github.com/rust-lang/rust/issues/{}> \ | |
2407 | for more information", | |
2408 | n, n, | |
2409 | )); | |
2410 | } | |
29967ef6 XL |
2411 | if HAS_MIN_FEATURES.contains(&name) { |
2412 | builder.help(&format!( | |
2413 | "consider using `min_{}` instead, which is more stable and complete", | |
2414 | name, | |
2415 | )); | |
2416 | } | |
f9f354fc | 2417 | builder.emit(); |
74b04a01 | 2418 | }) |
416331ca XL |
2419 | }); |
2420 | } | |
2421 | } | |
2422 | ||
5869c6ff | 2423 | const HAS_MIN_FEATURES: &[Symbol] = &[sym::specialization]; |
29967ef6 | 2424 | |
416331ca | 2425 | declare_lint! { |
1b1a35ee | 2426 | /// The `invalid_value` lint detects creating a value that is not valid, |
17df50a5 | 2427 | /// such as a null reference. |
1b1a35ee XL |
2428 | /// |
2429 | /// ### Example | |
2430 | /// | |
2431 | /// ```rust,no_run | |
2432 | /// # #![allow(unused)] | |
2433 | /// unsafe { | |
2434 | /// let x: &'static i32 = std::mem::zeroed(); | |
2435 | /// } | |
2436 | /// ``` | |
2437 | /// | |
2438 | /// {{produces}} | |
2439 | /// | |
2440 | /// ### Explanation | |
2441 | /// | |
2442 | /// In some situations the compiler can detect that the code is creating | |
2443 | /// an invalid value, which should be avoided. | |
2444 | /// | |
2445 | /// In particular, this lint will check for improper use of | |
2446 | /// [`mem::zeroed`], [`mem::uninitialized`], [`mem::transmute`], and | |
2447 | /// [`MaybeUninit::assume_init`] that can cause [undefined behavior]. The | |
2448 | /// lint should provide extra information to indicate what the problem is | |
2449 | /// and a possible solution. | |
2450 | /// | |
2451 | /// [`mem::zeroed`]: https://doc.rust-lang.org/std/mem/fn.zeroed.html | |
2452 | /// [`mem::uninitialized`]: https://doc.rust-lang.org/std/mem/fn.uninitialized.html | |
2453 | /// [`mem::transmute`]: https://doc.rust-lang.org/std/mem/fn.transmute.html | |
2454 | /// [`MaybeUninit::assume_init`]: https://doc.rust-lang.org/std/mem/union.MaybeUninit.html#method.assume_init | |
2455 | /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | |
416331ca XL |
2456 | pub INVALID_VALUE, |
2457 | Warn, | |
17df50a5 | 2458 | "an invalid value is being created (such as a null reference)" |
416331ca XL |
2459 | } |
2460 | ||
2461 | declare_lint_pass!(InvalidValue => [INVALID_VALUE]); | |
2462 | ||
f035d41b XL |
2463 | impl<'tcx> LateLintPass<'tcx> for InvalidValue { |
2464 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &hir::Expr<'_>) { | |
e1599b0c | 2465 | #[derive(Debug, Copy, Clone, PartialEq)] |
dfeec247 XL |
2466 | enum InitKind { |
2467 | Zeroed, | |
2468 | Uninit, | |
fc512014 | 2469 | } |
416331ca XL |
2470 | |
2471 | /// Information about why a type cannot be initialized this way. | |
2472 | /// Contains an error message and optionally a span to point at. | |
2473 | type InitError = (String, Option<Span>); | |
2474 | ||
e1599b0c | 2475 | /// Test if this constant is all-0. |
dfeec247 | 2476 | fn is_zero(expr: &hir::Expr<'_>) -> bool { |
e1599b0c | 2477 | use hir::ExprKind::*; |
3dfed10e | 2478 | use rustc_ast::LitKind::*; |
e74abb32 | 2479 | match &expr.kind { |
dfeec247 | 2480 | Lit(lit) => { |
e1599b0c XL |
2481 | if let Int(i, _) = lit.node { |
2482 | i == 0 | |
2483 | } else { | |
2484 | false | |
dfeec247 XL |
2485 | } |
2486 | } | |
2487 | Tup(tup) => tup.iter().all(is_zero), | |
2488 | _ => false, | |
e1599b0c XL |
2489 | } |
2490 | } | |
2491 | ||
2492 | /// Determine if this expression is a "dangerous initialization". | |
f035d41b | 2493 | fn is_dangerous_init(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<InitKind> { |
e74abb32 | 2494 | if let hir::ExprKind::Call(ref path_expr, ref args) = expr.kind { |
60c5eb7d | 2495 | // Find calls to `mem::{uninitialized,zeroed}` methods. |
e74abb32 | 2496 | if let hir::ExprKind::Path(ref qpath) = path_expr.kind { |
f035d41b | 2497 | let def_id = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id()?; |
c295e0f8 XL |
2498 | match cx.tcx.get_diagnostic_name(def_id) { |
2499 | Some(sym::mem_zeroed) => return Some(InitKind::Zeroed), | |
2500 | Some(sym::mem_uninitialized) => return Some(InitKind::Uninit), | |
2501 | Some(sym::transmute) if is_zero(&args[0]) => return Some(InitKind::Zeroed), | |
2502 | _ => {} | |
e1599b0c | 2503 | } |
60c5eb7d | 2504 | } |
f035d41b | 2505 | } else if let hir::ExprKind::MethodCall(_, _, ref args, _) = expr.kind { |
60c5eb7d | 2506 | // Find problematic calls to `MaybeUninit::assume_init`. |
3dfed10e | 2507 | let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id)?; |
60c5eb7d XL |
2508 | if cx.tcx.is_diagnostic_item(sym::assume_init, def_id) { |
2509 | // This is a call to *some* method named `assume_init`. | |
2510 | // See if the `self` parameter is one of the dangerous constructors. | |
2511 | if let hir::ExprKind::Call(ref path_expr, _) = args[0].kind { | |
2512 | if let hir::ExprKind::Path(ref qpath) = path_expr.kind { | |
f035d41b | 2513 | let def_id = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id()?; |
c295e0f8 XL |
2514 | match cx.tcx.get_diagnostic_name(def_id) { |
2515 | Some(sym::maybe_uninit_zeroed) => return Some(InitKind::Zeroed), | |
2516 | Some(sym::maybe_uninit_uninit) => return Some(InitKind::Uninit), | |
2517 | _ => {} | |
60c5eb7d XL |
2518 | } |
2519 | } | |
2520 | } | |
e1599b0c XL |
2521 | } |
2522 | } | |
2523 | ||
2524 | None | |
2525 | } | |
2526 | ||
3dfed10e XL |
2527 | /// Test if this enum has several actually "existing" variants. |
2528 | /// Zero-sized uninhabited variants do not always have a tag assigned and thus do not "exist". | |
2529 | fn is_multi_variant(adt: &ty::AdtDef) -> bool { | |
2530 | // As an approximation, we only count dataless variants. Those are definitely inhabited. | |
2531 | let existing_variants = adt.variants.iter().filter(|v| v.fields.is_empty()).count(); | |
2532 | existing_variants > 1 | |
2533 | } | |
2534 | ||
416331ca XL |
2535 | /// Return `Some` only if we are sure this type does *not* |
2536 | /// allow zero initialization. | |
e1599b0c XL |
2537 | fn ty_find_init_error<'tcx>( |
2538 | tcx: TyCtxt<'tcx>, | |
2539 | ty: Ty<'tcx>, | |
2540 | init: InitKind, | |
2541 | ) -> Option<InitError> { | |
ba9703b0 | 2542 | use rustc_middle::ty::TyKind::*; |
1b1a35ee | 2543 | match ty.kind() { |
416331ca | 2544 | // Primitive types that don't like 0 as a value. |
74b04a01 XL |
2545 | Ref(..) => Some(("references must be non-null".to_string(), None)), |
2546 | Adt(..) if ty.is_box() => Some(("`Box` must be non-null".to_string(), None)), | |
2547 | FnPtr(..) => Some(("function pointers must be non-null".to_string(), None)), | |
2548 | Never => Some(("the `!` type has no valid value".to_string(), None)), | |
1b1a35ee | 2549 | RawPtr(tm) if matches!(tm.ty.kind(), Dynamic(..)) => |
dfeec247 XL |
2550 | // raw ptr to dyn Trait |
2551 | { | |
74b04a01 | 2552 | Some(("the vtable of a wide raw pointer must be non-null".to_string(), None)) |
dfeec247 | 2553 | } |
e1599b0c | 2554 | // Primitive types with other constraints. |
dfeec247 | 2555 | Bool if init == InitKind::Uninit => { |
74b04a01 | 2556 | Some(("booleans must be either `true` or `false`".to_string(), None)) |
dfeec247 XL |
2557 | } |
2558 | Char if init == InitKind::Uninit => { | |
74b04a01 | 2559 | Some(("characters must be a valid Unicode codepoint".to_string(), None)) |
dfeec247 | 2560 | } |
e1599b0c | 2561 | // Recurse and checks for some compound types. |
416331ca | 2562 | Adt(adt_def, substs) if !adt_def.is_union() => { |
3dfed10e | 2563 | // First check if this ADT has a layout attribute (like `NonNull` and friends). |
e1599b0c XL |
2564 | use std::ops::Bound; |
2565 | match tcx.layout_scalar_valid_range(adt_def.did) { | |
2566 | // We exploit here that `layout_scalar_valid_range` will never | |
2567 | // return `Bound::Excluded`. (And we have tests checking that we | |
2568 | // handle the attribute correctly.) | |
dfeec247 XL |
2569 | (Bound::Included(lo), _) if lo > 0 => { |
2570 | return Some((format!("`{}` must be non-null", ty), None)); | |
2571 | } | |
e1599b0c | 2572 | (Bound::Included(_), _) | (_, Bound::Included(_)) |
dfeec247 XL |
2573 | if init == InitKind::Uninit => |
2574 | { | |
e1599b0c | 2575 | return Some(( |
dfeec247 XL |
2576 | format!( |
2577 | "`{}` must be initialized inside its custom valid range", | |
2578 | ty, | |
2579 | ), | |
e1599b0c | 2580 | None, |
dfeec247 XL |
2581 | )); |
2582 | } | |
e1599b0c XL |
2583 | _ => {} |
2584 | } | |
2585 | // Now, recurse. | |
416331ca | 2586 | match adt_def.variants.len() { |
74b04a01 | 2587 | 0 => Some(("enums with no variants have no valid value".to_string(), None)), |
416331ca XL |
2588 | 1 => { |
2589 | // Struct, or enum with exactly one variant. | |
2590 | // Proceed recursively, check all fields. | |
2591 | let variant = &adt_def.variants[VariantIdx::from_u32(0)]; | |
2592 | variant.fields.iter().find_map(|field| { | |
dfeec247 XL |
2593 | ty_find_init_error(tcx, field.ty(tcx, substs), init).map( |
2594 | |(mut msg, span)| { | |
2595 | if span.is_none() { | |
2596 | // Point to this field, should be helpful for figuring | |
2597 | // out where the source of the error is. | |
2598 | let span = tcx.def_span(field.did); | |
2599 | write!( | |
2600 | &mut msg, | |
2601 | " (in this {} field)", | |
2602 | adt_def.descr() | |
2603 | ) | |
2604 | .unwrap(); | |
2605 | (msg, Some(span)) | |
2606 | } else { | |
2607 | // Just forward. | |
2608 | (msg, span) | |
2609 | } | |
2610 | }, | |
2611 | ) | |
416331ca XL |
2612 | }) |
2613 | } | |
3dfed10e XL |
2614 | // Multi-variant enum. |
2615 | _ => { | |
2616 | if init == InitKind::Uninit && is_multi_variant(adt_def) { | |
2617 | let span = tcx.def_span(adt_def.did); | |
2618 | Some(( | |
2619 | "enums have to be initialized to a variant".to_string(), | |
2620 | Some(span), | |
2621 | )) | |
2622 | } else { | |
2623 | // In principle, for zero-initialization we could figure out which variant corresponds | |
2624 | // to tag 0, and check that... but for now we just accept all zero-initializations. | |
2625 | None | |
2626 | } | |
2627 | } | |
416331ca XL |
2628 | } |
2629 | } | |
2630 | Tuple(..) => { | |
2631 | // Proceed recursively, check all fields. | |
e1599b0c | 2632 | ty.tuple_fields().find_map(|field| ty_find_init_error(tcx, field, init)) |
416331ca | 2633 | } |
416331ca XL |
2634 | // Conservative fallback. |
2635 | _ => None, | |
2636 | } | |
2637 | } | |
2638 | ||
e1599b0c XL |
2639 | if let Some(init) = is_dangerous_init(cx, expr) { |
2640 | // This conjures an instance of a type out of nothing, | |
2641 | // using zeroed or uninitialized memory. | |
2642 | // We are extremely conservative with what we warn about. | |
3dfed10e | 2643 | let conjured_ty = cx.typeck_results().expr_ty(expr); |
1b1a35ee XL |
2644 | if let Some((msg, span)) = |
2645 | with_no_trimmed_paths(|| ty_find_init_error(cx.tcx, conjured_ty, init)) | |
2646 | { | |
74b04a01 XL |
2647 | cx.struct_span_lint(INVALID_VALUE, expr.span, |lint| { |
2648 | let mut err = lint.build(&format!( | |
e1599b0c XL |
2649 | "the type `{}` does not permit {}", |
2650 | conjured_ty, | |
2651 | match init { | |
2652 | InitKind::Zeroed => "zero-initialization", | |
2653 | InitKind::Uninit => "being left uninitialized", | |
2654 | }, | |
74b04a01 XL |
2655 | )); |
2656 | err.span_label(expr.span, "this code causes undefined behavior when executed"); | |
2657 | err.span_label( | |
2658 | expr.span, | |
2659 | "help: use `MaybeUninit<T>` instead, \ | |
2660 | and only call `assume_init` after initialization is done", | |
2661 | ); | |
2662 | if let Some(span) = span { | |
2663 | err.span_note(span, &msg); | |
2664 | } else { | |
2665 | err.note(&msg); | |
2666 | } | |
2667 | err.emit(); | |
2668 | }); | |
416331ca XL |
2669 | } |
2670 | } | |
2671 | } | |
2672 | } | |
f035d41b XL |
2673 | |
2674 | declare_lint! { | |
1b1a35ee XL |
2675 | /// The `clashing_extern_declarations` lint detects when an `extern fn` |
2676 | /// has been declared with the same name but different types. | |
2677 | /// | |
2678 | /// ### Example | |
2679 | /// | |
2680 | /// ```rust | |
2681 | /// mod m { | |
2682 | /// extern "C" { | |
2683 | /// fn foo(); | |
2684 | /// } | |
2685 | /// } | |
2686 | /// | |
2687 | /// extern "C" { | |
2688 | /// fn foo(_: u32); | |
2689 | /// } | |
2690 | /// ``` | |
2691 | /// | |
2692 | /// {{produces}} | |
2693 | /// | |
2694 | /// ### Explanation | |
2695 | /// | |
2696 | /// Because two symbols of the same name cannot be resolved to two | |
2697 | /// different functions at link time, and one function cannot possibly | |
2698 | /// have two types, a clashing extern declaration is almost certainly a | |
2699 | /// mistake. Check to make sure that the `extern` definitions are correct | |
2700 | /// and equivalent, and possibly consider unifying them in one location. | |
2701 | /// | |
2702 | /// This lint does not run between crates because a project may have | |
2703 | /// dependencies which both rely on the same extern function, but declare | |
2704 | /// it in a different (but valid) way. For example, they may both declare | |
2705 | /// an opaque type for one or more of the arguments (which would end up | |
2706 | /// distinct types), or use types that are valid conversions in the | |
2707 | /// language the `extern fn` is defined in. In these cases, the compiler | |
2708 | /// can't say that the clashing declaration is incorrect. | |
f035d41b | 2709 | pub CLASHING_EXTERN_DECLARATIONS, |
3dfed10e | 2710 | Warn, |
f035d41b XL |
2711 | "detects when an extern fn has been declared with the same name but different types" |
2712 | } | |
2713 | ||
2714 | pub struct ClashingExternDeclarations { | |
5869c6ff XL |
2715 | /// Map of function symbol name to the first-seen hir id for that symbol name.. If seen_decls |
2716 | /// contains an entry for key K, it means a symbol with name K has been seen by this lint and | |
2717 | /// the symbol should be reported as a clashing declaration. | |
2718 | // FIXME: Technically, we could just store a &'tcx str here without issue; however, the | |
2719 | // `impl_lint_pass` macro doesn't currently support lints parametric over a lifetime. | |
f035d41b XL |
2720 | seen_decls: FxHashMap<Symbol, HirId>, |
2721 | } | |
2722 | ||
2723 | /// Differentiate between whether the name for an extern decl came from the link_name attribute or | |
2724 | /// just from declaration itself. This is important because we don't want to report clashes on | |
2725 | /// symbol name if they don't actually clash because one or the other links against a symbol with a | |
2726 | /// different name. | |
2727 | enum SymbolName { | |
2728 | /// The name of the symbol + the span of the annotation which introduced the link name. | |
2729 | Link(Symbol, Span), | |
2730 | /// No link name, so just the name of the symbol. | |
2731 | Normal(Symbol), | |
2732 | } | |
2733 | ||
2734 | impl SymbolName { | |
2735 | fn get_name(&self) -> Symbol { | |
2736 | match self { | |
2737 | SymbolName::Link(s, _) | SymbolName::Normal(s) => *s, | |
2738 | } | |
2739 | } | |
2740 | } | |
2741 | ||
2742 | impl ClashingExternDeclarations { | |
2743 | crate fn new() -> Self { | |
2744 | ClashingExternDeclarations { seen_decls: FxHashMap::default() } | |
2745 | } | |
2746 | /// Insert a new foreign item into the seen set. If a symbol with the same name already exists | |
2747 | /// for the item, return its HirId without updating the set. | |
2748 | fn insert(&mut self, tcx: TyCtxt<'_>, fi: &hir::ForeignItem<'_>) -> Option<HirId> { | |
6a06907d | 2749 | let did = fi.def_id.to_def_id(); |
5869c6ff XL |
2750 | let instance = Instance::new(did, ty::List::identity_for_item(tcx, did)); |
2751 | let name = Symbol::intern(tcx.symbol_name(instance).name); | |
2752 | if let Some(&hir_id) = self.seen_decls.get(&name) { | |
f035d41b XL |
2753 | // Avoid updating the map with the new entry when we do find a collision. We want to |
2754 | // make sure we're always pointing to the first definition as the previous declaration. | |
2755 | // This lets us avoid emitting "knock-on" diagnostics. | |
5869c6ff | 2756 | Some(hir_id) |
f035d41b | 2757 | } else { |
6a06907d | 2758 | self.seen_decls.insert(name, fi.hir_id()) |
f035d41b XL |
2759 | } |
2760 | } | |
2761 | ||
2762 | /// Get the name of the symbol that's linked against for a given extern declaration. That is, | |
2763 | /// the name specified in a #[link_name = ...] attribute if one was specified, else, just the | |
2764 | /// symbol's name. | |
2765 | fn name_of_extern_decl(tcx: TyCtxt<'_>, fi: &hir::ForeignItem<'_>) -> SymbolName { | |
f035d41b | 2766 | if let Some((overridden_link_name, overridden_link_name_span)) = |
6a06907d | 2767 | tcx.codegen_fn_attrs(fi.def_id).link_name.map(|overridden_link_name| { |
f035d41b XL |
2768 | // FIXME: Instead of searching through the attributes again to get span |
2769 | // information, we could have codegen_fn_attrs also give span information back for | |
2770 | // where the attribute was defined. However, until this is found to be a | |
2771 | // bottleneck, this does just fine. | |
2772 | ( | |
2773 | overridden_link_name, | |
6a06907d | 2774 | tcx.get_attrs(fi.def_id.to_def_id()) |
f035d41b | 2775 | .iter() |
94222f64 | 2776 | .find(|at| at.has_name(sym::link_name)) |
f035d41b XL |
2777 | .unwrap() |
2778 | .span, | |
2779 | ) | |
2780 | }) | |
2781 | { | |
2782 | SymbolName::Link(overridden_link_name, overridden_link_name_span) | |
2783 | } else { | |
2784 | SymbolName::Normal(fi.ident.name) | |
2785 | } | |
2786 | } | |
2787 | ||
2788 | /// Checks whether two types are structurally the same enough that the declarations shouldn't | |
2789 | /// clash. We need this so we don't emit a lint when two modules both declare an extern struct, | |
2790 | /// with the same members (as the declarations shouldn't clash). | |
3dfed10e XL |
2791 | fn structurally_same_type<'tcx>( |
2792 | cx: &LateContext<'tcx>, | |
2793 | a: Ty<'tcx>, | |
2794 | b: Ty<'tcx>, | |
2795 | ckind: CItemKind, | |
2796 | ) -> bool { | |
2797 | fn structurally_same_type_impl<'tcx>( | |
2798 | seen_types: &mut FxHashSet<(Ty<'tcx>, Ty<'tcx>)>, | |
2799 | cx: &LateContext<'tcx>, | |
2800 | a: Ty<'tcx>, | |
2801 | b: Ty<'tcx>, | |
2802 | ckind: CItemKind, | |
2803 | ) -> bool { | |
2804 | debug!("structurally_same_type_impl(cx, a = {:?}, b = {:?})", a, b); | |
1b1a35ee XL |
2805 | let tcx = cx.tcx; |
2806 | ||
2807 | // Given a transparent newtype, reach through and grab the inner | |
2808 | // type unless the newtype makes the type non-null. | |
2809 | let non_transparent_ty = |ty: Ty<'tcx>| -> Ty<'tcx> { | |
2810 | let mut ty = ty; | |
2811 | loop { | |
2812 | if let ty::Adt(def, substs) = *ty.kind() { | |
2813 | let is_transparent = def.subst(tcx, substs).repr.transparent(); | |
2814 | let is_non_null = crate::types::nonnull_optimization_guaranteed(tcx, &def); | |
2815 | debug!( | |
2816 | "non_transparent_ty({:?}) -- type is transparent? {}, type is non-null? {}", | |
2817 | ty, is_transparent, is_non_null | |
2818 | ); | |
2819 | if is_transparent && !is_non_null { | |
2820 | debug_assert!(def.variants.len() == 1); | |
2821 | let v = &def.variants[VariantIdx::new(0)]; | |
2822 | ty = transparent_newtype_field(tcx, v) | |
2823 | .expect( | |
2824 | "single-variant transparent structure with zero-sized field", | |
2825 | ) | |
2826 | .ty(tcx, substs); | |
2827 | continue; | |
2828 | } | |
2829 | } | |
2830 | debug!("non_transparent_ty -> {:?}", ty); | |
2831 | return ty; | |
2832 | } | |
2833 | }; | |
2834 | ||
2835 | let a = non_transparent_ty(a); | |
2836 | let b = non_transparent_ty(b); | |
2837 | ||
3dfed10e XL |
2838 | if !seen_types.insert((a, b)) { |
2839 | // We've encountered a cycle. There's no point going any further -- the types are | |
2840 | // structurally the same. | |
2841 | return true; | |
2842 | } | |
2843 | let tcx = cx.tcx; | |
2844 | if a == b || rustc_middle::ty::TyS::same_type(a, b) { | |
2845 | // All nominally-same types are structurally same, too. | |
2846 | true | |
2847 | } else { | |
2848 | // Do a full, depth-first comparison between the two. | |
2849 | use rustc_middle::ty::TyKind::*; | |
1b1a35ee XL |
2850 | let a_kind = a.kind(); |
2851 | let b_kind = b.kind(); | |
2852 | ||
2853 | let compare_layouts = |a, b| -> Result<bool, LayoutError<'tcx>> { | |
2854 | debug!("compare_layouts({:?}, {:?})", a, b); | |
2855 | let a_layout = &cx.layout_of(a)?.layout.abi; | |
2856 | let b_layout = &cx.layout_of(b)?.layout.abi; | |
2857 | debug!( | |
2858 | "comparing layouts: {:?} == {:?} = {}", | |
2859 | a_layout, | |
2860 | b_layout, | |
2861 | a_layout == b_layout | |
2862 | ); | |
2863 | Ok(a_layout == b_layout) | |
3dfed10e XL |
2864 | }; |
2865 | ||
2866 | #[allow(rustc::usage_of_ty_tykind)] | |
2867 | let is_primitive_or_pointer = |kind: &ty::TyKind<'_>| { | |
2868 | kind.is_primitive() || matches!(kind, RawPtr(..) | Ref(..)) | |
2869 | }; | |
2870 | ||
2871 | ensure_sufficient_stack(|| { | |
2872 | match (a_kind, b_kind) { | |
2873 | (Adt(a_def, a_substs), Adt(b_def, b_substs)) => { | |
2874 | let a = a.subst(cx.tcx, a_substs); | |
2875 | let b = b.subst(cx.tcx, b_substs); | |
2876 | debug!("Comparing {:?} and {:?}", a, b); | |
2877 | ||
1b1a35ee XL |
2878 | // We can immediately rule out these types as structurally same if |
2879 | // their layouts differ. | |
2880 | match compare_layouts(a, b) { | |
2881 | Ok(false) => return false, | |
2882 | _ => (), // otherwise, continue onto the full, fields comparison | |
2883 | } | |
2884 | ||
3dfed10e XL |
2885 | // Grab a flattened representation of all fields. |
2886 | let a_fields = a_def.variants.iter().flat_map(|v| v.fields.iter()); | |
2887 | let b_fields = b_def.variants.iter().flat_map(|v| v.fields.iter()); | |
1b1a35ee XL |
2888 | |
2889 | // Perform a structural comparison for each field. | |
2890 | a_fields.eq_by( | |
3dfed10e XL |
2891 | b_fields, |
2892 | |&ty::FieldDef { did: a_did, .. }, | |
2893 | &ty::FieldDef { did: b_did, .. }| { | |
2894 | structurally_same_type_impl( | |
2895 | seen_types, | |
2896 | cx, | |
2897 | tcx.type_of(a_did), | |
2898 | tcx.type_of(b_did), | |
2899 | ckind, | |
2900 | ) | |
2901 | }, | |
2902 | ) | |
2903 | } | |
2904 | (Array(a_ty, a_const), Array(b_ty, b_const)) => { | |
2905 | // For arrays, we also check the constness of the type. | |
2906 | a_const.val == b_const.val | |
2907 | && structurally_same_type_impl(seen_types, cx, a_ty, b_ty, ckind) | |
2908 | } | |
2909 | (Slice(a_ty), Slice(b_ty)) => { | |
2910 | structurally_same_type_impl(seen_types, cx, a_ty, b_ty, ckind) | |
2911 | } | |
2912 | (RawPtr(a_tymut), RawPtr(b_tymut)) => { | |
2913 | a_tymut.mutbl == b_tymut.mutbl | |
2914 | && structurally_same_type_impl( | |
2915 | seen_types, | |
2916 | cx, | |
2917 | &a_tymut.ty, | |
2918 | &b_tymut.ty, | |
2919 | ckind, | |
2920 | ) | |
2921 | } | |
2922 | (Ref(_a_region, a_ty, a_mut), Ref(_b_region, b_ty, b_mut)) => { | |
2923 | // For structural sameness, we don't need the region to be same. | |
2924 | a_mut == b_mut | |
2925 | && structurally_same_type_impl(seen_types, cx, a_ty, b_ty, ckind) | |
2926 | } | |
2927 | (FnDef(..), FnDef(..)) => { | |
2928 | let a_poly_sig = a.fn_sig(tcx); | |
2929 | let b_poly_sig = b.fn_sig(tcx); | |
2930 | ||
2931 | // As we don't compare regions, skip_binder is fine. | |
2932 | let a_sig = a_poly_sig.skip_binder(); | |
2933 | let b_sig = b_poly_sig.skip_binder(); | |
2934 | ||
2935 | (a_sig.abi, a_sig.unsafety, a_sig.c_variadic) | |
2936 | == (b_sig.abi, b_sig.unsafety, b_sig.c_variadic) | |
2937 | && a_sig.inputs().iter().eq_by(b_sig.inputs().iter(), |a, b| { | |
2938 | structurally_same_type_impl(seen_types, cx, a, b, ckind) | |
2939 | }) | |
2940 | && structurally_same_type_impl( | |
2941 | seen_types, | |
2942 | cx, | |
2943 | a_sig.output(), | |
2944 | b_sig.output(), | |
2945 | ckind, | |
2946 | ) | |
2947 | } | |
2948 | (Tuple(a_substs), Tuple(b_substs)) => { | |
2949 | a_substs.types().eq_by(b_substs.types(), |a_ty, b_ty| { | |
2950 | structurally_same_type_impl(seen_types, cx, a_ty, b_ty, ckind) | |
2951 | }) | |
2952 | } | |
2953 | // For these, it's not quite as easy to define structural-sameness quite so easily. | |
2954 | // For the purposes of this lint, take the conservative approach and mark them as | |
2955 | // not structurally same. | |
2956 | (Dynamic(..), Dynamic(..)) | |
2957 | | (Error(..), Error(..)) | |
2958 | | (Closure(..), Closure(..)) | |
2959 | | (Generator(..), Generator(..)) | |
2960 | | (GeneratorWitness(..), GeneratorWitness(..)) | |
2961 | | (Projection(..), Projection(..)) | |
2962 | | (Opaque(..), Opaque(..)) => false, | |
2963 | ||
2964 | // These definitely should have been caught above. | |
2965 | (Bool, Bool) | (Char, Char) | (Never, Never) | (Str, Str) => unreachable!(), | |
2966 | ||
2967 | // An Adt and a primitive or pointer type. This can be FFI-safe if non-null | |
2968 | // enum layout optimisation is being applied. | |
2969 | (Adt(..), other_kind) | (other_kind, Adt(..)) | |
2970 | if is_primitive_or_pointer(other_kind) => | |
2971 | { | |
2972 | let (primitive, adt) = | |
1b1a35ee | 2973 | if is_primitive_or_pointer(a.kind()) { (a, b) } else { (b, a) }; |
3dfed10e XL |
2974 | if let Some(ty) = crate::types::repr_nullable_ptr(cx, adt, ckind) { |
2975 | ty == primitive | |
2976 | } else { | |
1b1a35ee | 2977 | compare_layouts(a, b).unwrap_or(false) |
3dfed10e XL |
2978 | } |
2979 | } | |
2980 | // Otherwise, just compare the layouts. This may fail to lint for some | |
2981 | // incompatible types, but at the very least, will stop reads into | |
2982 | // uninitialised memory. | |
1b1a35ee | 2983 | _ => compare_layouts(a, b).unwrap_or(false), |
3dfed10e XL |
2984 | } |
2985 | }) | |
f035d41b XL |
2986 | } |
2987 | } | |
3dfed10e XL |
2988 | let mut seen_types = FxHashSet::default(); |
2989 | structurally_same_type_impl(&mut seen_types, cx, a, b, ckind) | |
f035d41b XL |
2990 | } |
2991 | } | |
2992 | ||
2993 | impl_lint_pass!(ClashingExternDeclarations => [CLASHING_EXTERN_DECLARATIONS]); | |
2994 | ||
2995 | impl<'tcx> LateLintPass<'tcx> for ClashingExternDeclarations { | |
2996 | fn check_foreign_item(&mut self, cx: &LateContext<'tcx>, this_fi: &hir::ForeignItem<'_>) { | |
2997 | trace!("ClashingExternDeclarations: check_foreign_item: {:?}", this_fi); | |
2998 | if let ForeignItemKind::Fn(..) = this_fi.kind { | |
29967ef6 | 2999 | let tcx = cx.tcx; |
f035d41b XL |
3000 | if let Some(existing_hid) = self.insert(tcx, this_fi) { |
3001 | let existing_decl_ty = tcx.type_of(tcx.hir().local_def_id(existing_hid)); | |
6a06907d | 3002 | let this_decl_ty = tcx.type_of(this_fi.def_id); |
f035d41b XL |
3003 | debug!( |
3004 | "ClashingExternDeclarations: Comparing existing {:?}: {:?} to this {:?}: {:?}", | |
6a06907d | 3005 | existing_hid, existing_decl_ty, this_fi.def_id, this_decl_ty |
f035d41b XL |
3006 | ); |
3007 | // Check that the declarations match. | |
3dfed10e XL |
3008 | if !Self::structurally_same_type( |
3009 | cx, | |
3010 | existing_decl_ty, | |
3011 | this_decl_ty, | |
3012 | CItemKind::Declaration, | |
3013 | ) { | |
f035d41b XL |
3014 | let orig_fi = tcx.hir().expect_foreign_item(existing_hid); |
3015 | let orig = Self::name_of_extern_decl(tcx, orig_fi); | |
3016 | ||
3017 | // We want to ensure that we use spans for both decls that include where the | |
3018 | // name was defined, whether that was from the link_name attribute or not. | |
3019 | let get_relevant_span = | |
3020 | |fi: &hir::ForeignItem<'_>| match Self::name_of_extern_decl(tcx, fi) { | |
3021 | SymbolName::Normal(_) => fi.span, | |
3022 | SymbolName::Link(_, annot_span) => fi.span.to(annot_span), | |
3023 | }; | |
3024 | // Finally, emit the diagnostic. | |
3025 | tcx.struct_span_lint_hir( | |
3026 | CLASHING_EXTERN_DECLARATIONS, | |
6a06907d | 3027 | this_fi.hir_id(), |
f035d41b XL |
3028 | get_relevant_span(this_fi), |
3029 | |lint| { | |
3030 | let mut expected_str = DiagnosticStyledString::new(); | |
3031 | expected_str.push(existing_decl_ty.fn_sig(tcx).to_string(), false); | |
3032 | let mut found_str = DiagnosticStyledString::new(); | |
3033 | found_str.push(this_decl_ty.fn_sig(tcx).to_string(), true); | |
3034 | ||
3035 | lint.build(&format!( | |
3036 | "`{}` redeclare{} with a different signature", | |
3037 | this_fi.ident.name, | |
3038 | if orig.get_name() == this_fi.ident.name { | |
3039 | "d".to_string() | |
3040 | } else { | |
3041 | format!("s `{}`", orig.get_name()) | |
3042 | } | |
3043 | )) | |
3044 | .span_label( | |
3045 | get_relevant_span(orig_fi), | |
3046 | &format!("`{}` previously declared here", orig.get_name()), | |
3047 | ) | |
3048 | .span_label( | |
3049 | get_relevant_span(this_fi), | |
3050 | "this signature doesn't match the previous declaration", | |
3051 | ) | |
3052 | .note_expected_found(&"", expected_str, &"", found_str) | |
3053 | .emit() | |
3054 | }, | |
3055 | ); | |
3056 | } | |
3057 | } | |
3058 | } | |
3059 | } | |
3060 | } | |
cdc7bbd5 XL |
3061 | |
3062 | declare_lint! { | |
3063 | /// The `deref_nullptr` lint detects when an null pointer is dereferenced, | |
3064 | /// which causes [undefined behavior]. | |
3065 | /// | |
3066 | /// ### Example | |
3067 | /// | |
3068 | /// ```rust,no_run | |
3069 | /// # #![allow(unused)] | |
3070 | /// use std::ptr; | |
3071 | /// unsafe { | |
3072 | /// let x = &*ptr::null::<i32>(); | |
3073 | /// let x = ptr::addr_of!(*ptr::null::<i32>()); | |
3074 | /// let x = *(0 as *const i32); | |
3075 | /// } | |
3076 | /// ``` | |
3077 | /// | |
3078 | /// {{produces}} | |
3079 | /// | |
3080 | /// ### Explanation | |
3081 | /// | |
3082 | /// Dereferencing a null pointer causes [undefined behavior] even as a place expression, | |
3083 | /// like `&*(0 as *const i32)` or `addr_of!(*(0 as *const i32))`. | |
3084 | /// | |
3085 | /// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | |
3086 | pub DEREF_NULLPTR, | |
3087 | Warn, | |
3088 | "detects when an null pointer is dereferenced" | |
3089 | } | |
3090 | ||
3091 | declare_lint_pass!(DerefNullPtr => [DEREF_NULLPTR]); | |
3092 | ||
3093 | impl<'tcx> LateLintPass<'tcx> for DerefNullPtr { | |
3094 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &hir::Expr<'_>) { | |
3095 | /// test if expression is a null ptr | |
3096 | fn is_null_ptr(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> bool { | |
3097 | match &expr.kind { | |
3098 | rustc_hir::ExprKind::Cast(ref expr, ref ty) => { | |
3099 | if let rustc_hir::TyKind::Ptr(_) = ty.kind { | |
3100 | return is_zero(expr) || is_null_ptr(cx, expr); | |
3101 | } | |
3102 | } | |
3103 | // check for call to `core::ptr::null` or `core::ptr::null_mut` | |
3104 | rustc_hir::ExprKind::Call(ref path, _) => { | |
3105 | if let rustc_hir::ExprKind::Path(ref qpath) = path.kind { | |
3106 | if let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() { | |
c295e0f8 XL |
3107 | return matches!( |
3108 | cx.tcx.get_diagnostic_name(def_id), | |
3109 | Some(sym::ptr_null | sym::ptr_null_mut) | |
3110 | ); | |
cdc7bbd5 XL |
3111 | } |
3112 | } | |
3113 | } | |
3114 | _ => {} | |
3115 | } | |
3116 | false | |
3117 | } | |
3118 | ||
3119 | /// test if expression is the literal `0` | |
3120 | fn is_zero(expr: &hir::Expr<'_>) -> bool { | |
3121 | match &expr.kind { | |
3122 | rustc_hir::ExprKind::Lit(ref lit) => { | |
3123 | if let LitKind::Int(a, _) = lit.node { | |
3124 | return a == 0; | |
3125 | } | |
3126 | } | |
3127 | _ => {} | |
3128 | } | |
3129 | false | |
3130 | } | |
3131 | ||
3c0e092e XL |
3132 | if let rustc_hir::ExprKind::Unary(rustc_hir::UnOp::Deref, expr_deref) = expr.kind { |
3133 | if is_null_ptr(cx, expr_deref) { | |
3134 | cx.struct_span_lint(DEREF_NULLPTR, expr.span, |lint| { | |
3135 | let mut err = lint.build("dereferencing a null pointer"); | |
3136 | err.span_label(expr.span, "this code causes undefined behavior when executed"); | |
3137 | err.emit(); | |
3138 | }); | |
cdc7bbd5 XL |
3139 | } |
3140 | } | |
3141 | } | |
3142 | } | |
94222f64 XL |
3143 | |
3144 | declare_lint! { | |
3145 | /// The `named_asm_labels` lint detects the use of named labels in the | |
3146 | /// inline `asm!` macro. | |
3147 | /// | |
3148 | /// ### Example | |
3149 | /// | |
3150 | /// ```rust,compile_fail | |
3151 | /// #![feature(asm)] | |
3152 | /// fn main() { | |
3153 | /// unsafe { | |
3154 | /// asm!("foo: bar"); | |
3155 | /// } | |
3156 | /// } | |
3157 | /// ``` | |
3158 | /// | |
3159 | /// {{produces}} | |
3160 | /// | |
3161 | /// ### Explanation | |
3162 | /// | |
3163 | /// LLVM is allowed to duplicate inline assembly blocks for any | |
3164 | /// reason, for example when it is in a function that gets inlined. Because | |
3165 | /// of this, GNU assembler [local labels] *must* be used instead of labels | |
3166 | /// with a name. Using named labels might cause assembler or linker errors. | |
3167 | /// | |
3168 | /// See the [unstable book] for more details. | |
3169 | /// | |
3170 | /// [local labels]: https://sourceware.org/binutils/docs/as/Symbol-Names.html#Local-Labels | |
3171 | /// [unstable book]: https://doc.rust-lang.org/nightly/unstable-book/library-features/asm.html#labels | |
3172 | pub NAMED_ASM_LABELS, | |
3173 | Deny, | |
3174 | "named labels in inline assembly", | |
3175 | } | |
3176 | ||
3177 | declare_lint_pass!(NamedAsmLabels => [NAMED_ASM_LABELS]); | |
3178 | ||
3179 | impl<'tcx> LateLintPass<'tcx> for NamedAsmLabels { | |
3180 | fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>) { | |
3181 | if let hir::Expr { | |
3182 | kind: hir::ExprKind::InlineAsm(hir::InlineAsm { template_strs, .. }), | |
3183 | .. | |
3184 | } = expr | |
3185 | { | |
3186 | for (template_sym, template_snippet, template_span) in template_strs.iter() { | |
3187 | let template_str = &template_sym.as_str(); | |
3188 | let find_label_span = |needle: &str| -> Option<Span> { | |
3189 | if let Some(template_snippet) = template_snippet { | |
3190 | let snippet = template_snippet.as_str(); | |
3191 | if let Some(pos) = snippet.find(needle) { | |
3192 | let end = pos | |
3c0e092e | 3193 | + snippet[pos..] |
94222f64 XL |
3194 | .find(|c| c == ':') |
3195 | .unwrap_or(snippet[pos..].len() - 1); | |
3196 | let inner = InnerSpan::new(pos, end); | |
3197 | return Some(template_span.from_inner(inner)); | |
3198 | } | |
3199 | } | |
3200 | ||
3201 | None | |
3202 | }; | |
3203 | ||
3204 | let mut found_labels = Vec::new(); | |
3205 | ||
3206 | // A semicolon might not actually be specified as a separator for all targets, but it seems like LLVM accepts it always | |
3207 | let statements = template_str.split(|c| matches!(c, '\n' | ';')); | |
3208 | for statement in statements { | |
3209 | // If there's a comment, trim it from the statement | |
3210 | let statement = statement.find("//").map_or(statement, |idx| &statement[..idx]); | |
3211 | let mut start_idx = 0; | |
3212 | for (idx, _) in statement.match_indices(':') { | |
3213 | let possible_label = statement[start_idx..idx].trim(); | |
3214 | let mut chars = possible_label.chars(); | |
3215 | if let Some(c) = chars.next() { | |
3216 | // A label starts with an alphabetic character or . or _ and continues with alphanumeric characters, _, or $ | |
3217 | if (c.is_alphabetic() || matches!(c, '.' | '_')) | |
3218 | && chars.all(|c| c.is_alphanumeric() || matches!(c, '_' | '$')) | |
3219 | { | |
3220 | found_labels.push(possible_label); | |
3221 | } else { | |
3222 | // If we encounter a non-label, there cannot be any further labels, so stop checking | |
3223 | break; | |
3224 | } | |
3225 | } else { | |
3226 | // Empty string means a leading ':' in this section, which is not a label | |
3227 | break; | |
3228 | } | |
3229 | ||
3230 | start_idx = idx + 1; | |
3231 | } | |
3232 | } | |
3233 | ||
3234 | debug!("NamedAsmLabels::check_expr(): found_labels: {:#?}", &found_labels); | |
3235 | ||
3236 | if found_labels.len() > 0 { | |
3237 | let spans = found_labels | |
3238 | .into_iter() | |
3239 | .filter_map(|label| find_label_span(label)) | |
3240 | .collect::<Vec<Span>>(); | |
3241 | // If there were labels but we couldn't find a span, combine the warnings and use the template span | |
3242 | let target_spans: MultiSpan = | |
3243 | if spans.len() > 0 { spans.into() } else { (*template_span).into() }; | |
3244 | ||
3245 | cx.lookup_with_diagnostics( | |
3246 | NAMED_ASM_LABELS, | |
3247 | Some(target_spans), | |
3248 | |diag| { | |
3249 | let mut err = | |
3250 | diag.build("avoid using named labels in inline assembly"); | |
3251 | err.emit(); | |
3252 | }, | |
3253 | BuiltinLintDiagnostics::NamedAsmLabel( | |
3254 | "only local labels of the form `<number>:` should be used in inline asm" | |
3255 | .to_string(), | |
3256 | ), | |
3257 | ); | |
3258 | } | |
3259 | } | |
3260 | } | |
3261 | } | |
3262 | } |