1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Lints built in to rustc.
13 //! This is a sibling of `lint::context` in order to ensure that
14 //! lints implemented here use the same public API as lint plugins.
16 //! To add a new lint to rustc, declare it here using `declare_lint!()`.
17 //! Then add code to emit the new lint in the appropriate circumstances.
18 //! You can do that in an existing `LintPass` if it makes sense, or in
19 //! a new `LintPass`, or using `Session::add_lint` elsewhere in the
20 //! compiler. Only do the latter if the check can't be written cleanly
23 //! If you define a new `LintPass`, you will also need to add it to the
24 //! `add_builtin!` or `add_builtin_with_new!` invocation in `context.rs`.
25 //! Use the former for unit-like structs and the latter for structs with
28 use metadata::csearch;
30 use middle::trans::adt; // for `adt::is_ffi_safe`
31 use middle::typeck::astconv::ast_ty_to_ty;
32 use middle::typeck::infer;
33 use middle::{typeck, ty, def, pat_util, stability};
34 use util::ppaux::{ty_to_str};
35 use util::nodemap::NodeSet;
36 use lint::{Context, LintPass, LintArray};
39 use std::collections::HashMap;
51 use syntax::attr::AttrMetaMethods;
53 use syntax::codemap::Span;
54 use syntax::parse::token;
55 use syntax::{ast, ast_util, visit};
57 declare_lint!(WHILE_TRUE, Warn,
58 "suggest using `loop { }` instead of `while true { }`")
62 impl LintPass for WhileTrue {
63 fn get_lints(&self) -> LintArray {
64 lint_array!(WHILE_TRUE)
67 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
69 ast::ExprWhile(cond, _) => {
71 ast::ExprLit(lit) => {
73 ast::LitBool(true) => {
74 cx.span_lint(WHILE_TRUE, e.span,
75 "denote infinite loops with loop \
89 declare_lint!(UNNECESSARY_TYPECAST, Allow,
90 "detects unnecessary type casts, that can be removed")
92 pub struct UnusedCasts;
94 impl LintPass for UnusedCasts {
95 fn get_lints(&self) -> LintArray {
96 lint_array!(UNNECESSARY_TYPECAST)
99 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
101 ast::ExprCast(expr, ty) => {
102 let t_t = ast_ty_to_ty(cx, &infer::new_infer_ctxt(cx.tcx), &*ty);
103 if ty::get(ty::expr_ty(cx.tcx, &*expr)).sty == ty::get(t_t).sty {
104 cx.span_lint(UNNECESSARY_TYPECAST, ty.span, "unnecessary type cast");
112 declare_lint!(UNSIGNED_NEGATE, Warn,
113 "using an unary minus operator on unsigned type")
115 declare_lint!(TYPE_LIMITS, Warn,
116 "comparisons made useless by limits of the types involved")
118 declare_lint!(TYPE_OVERFLOW, Warn,
119 "literal out of range for its type")
121 pub struct TypeLimits {
122 /// Id of the last visited negated expression
123 negated_expr_id: ast::NodeId,
127 pub fn new() -> TypeLimits {
134 impl LintPass for TypeLimits {
135 fn get_lints(&self) -> LintArray {
136 lint_array!(UNSIGNED_NEGATE, TYPE_LIMITS, TYPE_OVERFLOW)
139 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
141 ast::ExprUnary(ast::UnNeg, expr) => {
143 ast::ExprLit(lit) => {
145 ast::LitUint(..) => {
146 cx.span_lint(UNSIGNED_NEGATE, e.span,
147 "negation of unsigned int literal may \
154 let t = ty::expr_ty(cx.tcx, &*expr);
155 match ty::get(t).sty {
157 cx.span_lint(UNSIGNED_NEGATE, e.span,
158 "negation of unsigned int variable may \
165 // propagate negation, if the negation itself isn't negated
166 if self.negated_expr_id != e.id {
167 self.negated_expr_id = expr.id;
170 ast::ExprParen(expr) if self.negated_expr_id == e.id => {
171 self.negated_expr_id = expr.id;
173 ast::ExprBinary(binop, l, r) => {
174 if is_comparison(binop) && !check_limits(cx.tcx, binop, &*l, &*r) {
175 cx.span_lint(TYPE_LIMITS, e.span,
176 "comparison is useless due to type limits");
179 ast::ExprLit(lit) => {
180 match ty::get(ty::expr_ty(cx.tcx, e)).sty {
182 let int_type = if t == ast::TyI {
183 cx.sess().targ_cfg.int_type
185 let (min, max) = int_ty_range(int_type);
186 let mut lit_val: i64 = match lit.node {
187 ast::LitInt(v, _) => v,
188 ast::LitUint(v, _) => v as i64,
189 ast::LitIntUnsuffixed(v) => v,
192 if self.negated_expr_id == e.id {
195 if lit_val < min || lit_val > max {
196 cx.span_lint(TYPE_OVERFLOW, e.span,
197 "literal out of range for its type");
201 let uint_type = if t == ast::TyU {
202 cx.sess().targ_cfg.uint_type
204 let (min, max) = uint_ty_range(uint_type);
205 let lit_val: u64 = match lit.node {
206 ast::LitByte(_v) => return, // _v is u8, within range by definition
207 ast::LitInt(v, _) => v as u64,
208 ast::LitUint(v, _) => v,
209 ast::LitIntUnsuffixed(v) => v as u64,
212 if lit_val < min || lit_val > max {
213 cx.span_lint(TYPE_OVERFLOW, e.span,
214 "literal out of range for its type");
224 fn is_valid<T:cmp::PartialOrd>(binop: ast::BinOp, v: T,
225 min: T, max: T) -> bool {
227 ast::BiLt => v > min && v <= max,
228 ast::BiLe => v >= min && v < max,
229 ast::BiGt => v >= min && v < max,
230 ast::BiGe => v > min && v <= max,
231 ast::BiEq | ast::BiNe => v >= min && v <= max,
236 fn rev_binop(binop: ast::BinOp) -> ast::BinOp {
238 ast::BiLt => ast::BiGt,
239 ast::BiLe => ast::BiGe,
240 ast::BiGt => ast::BiLt,
241 ast::BiGe => ast::BiLe,
246 // for int & uint, be conservative with the warnings, so that the
247 // warnings are consistent between 32- and 64-bit platforms
248 fn int_ty_range(int_ty: ast::IntTy) -> (i64, i64) {
250 ast::TyI => (i64::MIN, i64::MAX),
251 ast::TyI8 => (i8::MIN as i64, i8::MAX as i64),
252 ast::TyI16 => (i16::MIN as i64, i16::MAX as i64),
253 ast::TyI32 => (i32::MIN as i64, i32::MAX as i64),
254 ast::TyI64 => (i64::MIN, i64::MAX)
258 fn uint_ty_range(uint_ty: ast::UintTy) -> (u64, u64) {
260 ast::TyU => (u64::MIN, u64::MAX),
261 ast::TyU8 => (u8::MIN as u64, u8::MAX as u64),
262 ast::TyU16 => (u16::MIN as u64, u16::MAX as u64),
263 ast::TyU32 => (u32::MIN as u64, u32::MAX as u64),
264 ast::TyU64 => (u64::MIN, u64::MAX)
268 fn check_limits(tcx: &ty::ctxt, binop: ast::BinOp,
269 l: &ast::Expr, r: &ast::Expr) -> bool {
270 let (lit, expr, swap) = match (&l.node, &r.node) {
271 (&ast::ExprLit(_), _) => (l, r, true),
272 (_, &ast::ExprLit(_)) => (r, l, false),
275 // Normalize the binop so that the literal is always on the RHS in
277 let norm_binop = if swap { rev_binop(binop) } else { binop };
278 match ty::get(ty::expr_ty(tcx, expr)).sty {
279 ty::ty_int(int_ty) => {
280 let (min, max) = int_ty_range(int_ty);
281 let lit_val: i64 = match lit.node {
282 ast::ExprLit(li) => match li.node {
283 ast::LitInt(v, _) => v,
284 ast::LitUint(v, _) => v as i64,
285 ast::LitIntUnsuffixed(v) => v,
290 is_valid(norm_binop, lit_val, min, max)
292 ty::ty_uint(uint_ty) => {
293 let (min, max): (u64, u64) = uint_ty_range(uint_ty);
294 let lit_val: u64 = match lit.node {
295 ast::ExprLit(li) => match li.node {
296 ast::LitInt(v, _) => v as u64,
297 ast::LitUint(v, _) => v,
298 ast::LitIntUnsuffixed(v) => v as u64,
303 is_valid(norm_binop, lit_val, min, max)
309 fn is_comparison(binop: ast::BinOp) -> bool {
311 ast::BiEq | ast::BiLt | ast::BiLe |
312 ast::BiNe | ast::BiGe | ast::BiGt => true,
319 declare_lint!(CTYPES, Warn,
320 "proper use of libc types in foreign modules")
324 impl LintPass for CTypes {
325 fn get_lints(&self) -> LintArray {
329 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
330 fn check_ty(cx: &Context, ty: &ast::Ty) {
332 ast::TyPath(_, _, id) => {
333 match cx.tcx.def_map.borrow().get_copy(&id) {
334 def::DefPrimTy(ast::TyInt(ast::TyI)) => {
335 cx.span_lint(CTYPES, ty.span,
336 "found rust type `int` in foreign module, while \
337 libc::c_int or libc::c_long should be used");
339 def::DefPrimTy(ast::TyUint(ast::TyU)) => {
340 cx.span_lint(CTYPES, ty.span,
341 "found rust type `uint` in foreign module, while \
342 libc::c_uint or libc::c_ulong should be used");
344 def::DefTy(def_id) => {
345 if !adt::is_ffi_safe(cx.tcx, def_id) {
346 cx.span_lint(CTYPES, ty.span,
347 "found enum type without foreign-function-safe \
348 representation annotation in foreign module");
349 // hmm... this message could be more helpful
355 ast::TyPtr(ref mt) => { check_ty(cx, &*mt.ty) }
360 fn check_foreign_fn(cx: &Context, decl: &ast::FnDecl) {
361 for input in decl.inputs.iter() {
362 check_ty(cx, &*input.ty);
364 check_ty(cx, &*decl.output)
368 ast::ItemForeignMod(ref nmod) if nmod.abi != abi::RustIntrinsic => {
369 for ni in nmod.items.iter() {
371 ast::ForeignItemFn(decl, _) => check_foreign_fn(cx, &*decl),
372 ast::ForeignItemStatic(t, _) => check_ty(cx, &*t)
376 _ => {/* nothing to do */ }
381 declare_lint!(MANAGED_HEAP_MEMORY, Allow,
382 "use of managed (@ type) heap memory")
384 declare_lint!(OWNED_HEAP_MEMORY, Allow,
385 "use of owned (Box type) heap memory")
387 declare_lint!(HEAP_MEMORY, Allow,
388 "use of any (Box type or @ type) heap memory")
390 pub struct HeapMemory;
393 fn check_heap_type(&self, cx: &Context, span: Span, ty: ty::t) {
396 ty::fold_ty(cx.tcx, ty, |t| {
397 match ty::get(t).sty {
402 ty::ty_closure(box ty::ClosureTy {
403 store: ty::UniqTraitStore,
415 let s = ty_to_str(cx.tcx, ty);
416 let m = format!("type uses owned (Box type) pointers: {}", s);
417 cx.span_lint(OWNED_HEAP_MEMORY, span, m.as_slice());
418 cx.span_lint(HEAP_MEMORY, span, m.as_slice());
422 let s = ty_to_str(cx.tcx, ty);
423 let m = format!("type uses managed (@ type) pointers: {}", s);
424 cx.span_lint(MANAGED_HEAP_MEMORY, span, m.as_slice());
425 cx.span_lint(HEAP_MEMORY, span, m.as_slice());
430 impl LintPass for HeapMemory {
431 fn get_lints(&self) -> LintArray {
432 lint_array!(MANAGED_HEAP_MEMORY, OWNED_HEAP_MEMORY, HEAP_MEMORY)
435 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
440 ast::ItemStruct(..) =>
441 self.check_heap_type(cx, it.span,
442 ty::node_id_to_type(cx.tcx, it.id)),
446 // If it's a struct, we also have to check the fields' types
448 ast::ItemStruct(struct_def, _) => {
449 for struct_field in struct_def.fields.iter() {
450 self.check_heap_type(cx, struct_field.span,
451 ty::node_id_to_type(cx.tcx, struct_field.node.id));
458 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
459 let ty = ty::expr_ty(cx.tcx, e);
460 self.check_heap_type(cx, e.span, ty);
464 declare_lint!(RAW_POINTER_DERIVING, Warn,
465 "uses of #[deriving] with raw pointers are rarely correct")
467 struct RawPtrDerivingVisitor<'a> {
471 impl<'a> visit::Visitor<()> for RawPtrDerivingVisitor<'a> {
472 fn visit_ty(&mut self, ty: &ast::Ty, _: ()) {
473 static MSG: &'static str = "use of `#[deriving]` with a raw pointer";
475 ast::TyPtr(..) => self.cx.span_lint(RAW_POINTER_DERIVING, ty.span, MSG),
478 visit::walk_ty(self, ty, ());
480 // explicit override to a no-op to reduce code bloat
481 fn visit_expr(&mut self, _: &ast::Expr, _: ()) {}
482 fn visit_block(&mut self, _: &ast::Block, _: ()) {}
485 pub struct RawPointerDeriving {
486 checked_raw_pointers: NodeSet,
489 impl RawPointerDeriving {
490 pub fn new() -> RawPointerDeriving {
492 checked_raw_pointers: NodeSet::new(),
497 impl LintPass for RawPointerDeriving {
498 fn get_lints(&self) -> LintArray {
499 lint_array!(RAW_POINTER_DERIVING)
502 fn check_item(&mut self, cx: &Context, item: &ast::Item) {
503 if !attr::contains_name(item.attrs.as_slice(), "automatically_derived") {
506 let did = match item.node {
507 ast::ItemImpl(..) => {
508 match ty::get(ty::node_id_to_type(cx.tcx, item.id)).sty {
509 ty::ty_enum(did, _) => did,
510 ty::ty_struct(did, _) => did,
516 if !ast_util::is_local(did) { return }
517 let item = match cx.tcx.map.find(did.node) {
518 Some(ast_map::NodeItem(item)) => item,
521 if !self.checked_raw_pointers.insert(item.id) { return }
523 ast::ItemStruct(..) | ast::ItemEnum(..) => {
524 let mut visitor = RawPtrDerivingVisitor { cx: cx };
525 visit::walk_item(&mut visitor, &*item, ());
532 declare_lint!(UNUSED_ATTRIBUTE, Warn,
533 "detects attributes that were not used by the compiler")
535 pub struct UnusedAttribute;
537 impl LintPass for UnusedAttribute {
538 fn get_lints(&self) -> LintArray {
539 lint_array!(UNUSED_ATTRIBUTE)
542 fn check_attribute(&mut self, cx: &Context, attr: &ast::Attribute) {
543 static ATTRIBUTE_WHITELIST: &'static [&'static str] = &'static [
544 // FIXME: #14408 whitelist docs since rustdoc looks at them
547 // FIXME: #14406 these are processed in trans, which happens after the
561 // not used anywhere (!?) but apparently we want to keep them around
566 // FIXME: #14407 these are only looked at on-demand so we can't
567 // guarantee they'll have already been checked
577 static CRATE_ATTRS: &'static [&'static str] = &'static [
591 for &name in ATTRIBUTE_WHITELIST.iter() {
592 if attr.check_name(name) {
597 if !attr::is_used(attr) {
598 cx.span_lint(UNUSED_ATTRIBUTE, attr.span, "unused attribute");
599 if CRATE_ATTRS.contains(&attr.name().get()) {
600 let msg = match attr.node.style {
601 ast::AttrOuter => "crate-level attribute should be an inner \
602 attribute: add an exclamation mark: #![foo]",
603 ast::AttrInner => "crate-level attribute should be in the \
606 cx.span_lint(UNUSED_ATTRIBUTE, attr.span, msg);
612 declare_lint!(PATH_STATEMENT, Warn,
613 "path statements with no effect")
615 pub struct PathStatement;
617 impl LintPass for PathStatement {
618 fn get_lints(&self) -> LintArray {
619 lint_array!(PATH_STATEMENT)
622 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
624 ast::StmtSemi(expr, _) => {
626 ast::ExprPath(_) => cx.span_lint(PATH_STATEMENT, s.span,
627 "path statement with no effect"),
636 declare_lint!(UNUSED_MUST_USE, Warn,
637 "unused result of a type flagged as #[must_use]")
639 declare_lint!(UNUSED_RESULT, Allow,
640 "unused result of an expression in a statement")
642 pub struct UnusedResult;
644 impl LintPass for UnusedResult {
645 fn get_lints(&self) -> LintArray {
646 lint_array!(UNUSED_MUST_USE, UNUSED_RESULT)
649 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
650 let expr = match s.node {
651 ast::StmtSemi(expr, _) => expr,
654 let t = ty::expr_ty(cx.tcx, &*expr);
655 match ty::get(t).sty {
656 ty::ty_nil | ty::ty_bot | ty::ty_bool => return,
660 ast::ExprRet(..) => return,
664 let t = ty::expr_ty(cx.tcx, &*expr);
665 let mut warned = false;
666 match ty::get(t).sty {
667 ty::ty_struct(did, _) |
668 ty::ty_enum(did, _) => {
669 if ast_util::is_local(did) {
670 match cx.tcx.map.get(did.node) {
671 ast_map::NodeItem(it) => {
672 if attr::contains_name(it.attrs.as_slice(),
674 cx.span_lint(UNUSED_MUST_USE, s.span,
675 "unused result which must be used");
682 csearch::get_item_attrs(&cx.sess().cstore, did, |attrs| {
683 if attr::contains_name(attrs.as_slice(), "must_use") {
684 cx.span_lint(UNUSED_MUST_USE, s.span,
685 "unused result which must be used");
694 cx.span_lint(UNUSED_RESULT, s.span, "unused result");
699 declare_lint!(NON_CAMEL_CASE_TYPES, Warn,
700 "types, variants and traits should have camel case names")
702 pub struct NonCamelCaseTypes;
704 impl LintPass for NonCamelCaseTypes {
705 fn get_lints(&self) -> LintArray {
706 lint_array!(NON_CAMEL_CASE_TYPES)
709 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
710 fn is_camel_case(ident: ast::Ident) -> bool {
711 let ident = token::get_ident(ident);
712 assert!(!ident.get().is_empty());
713 let ident = ident.get().trim_chars('_');
715 // start with a non-lowercase letter rather than non-uppercase
716 // ones (some scripts don't have a concept of upper/lowercase)
717 !ident.char_at(0).is_lowercase() && !ident.contains_char('_')
720 fn to_camel_case(s: &str) -> String {
721 s.split('_').flat_map(|word| word.chars().enumerate().map(|(i, c)|
722 if i == 0 { c.to_uppercase() }
727 fn check_case(cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
728 let s = token::get_ident(ident);
730 if !is_camel_case(ident) {
731 cx.span_lint(NON_CAMEL_CASE_TYPES, span,
732 format!("{} `{}` should have a camel case name such as `{}`",
733 sort, s, to_camel_case(s.get())).as_slice());
738 ast::ItemTy(..) | ast::ItemStruct(..) => {
739 check_case(cx, "type", it.ident, it.span)
741 ast::ItemTrait(..) => {
742 check_case(cx, "trait", it.ident, it.span)
744 ast::ItemEnum(ref enum_definition, _) => {
745 check_case(cx, "type", it.ident, it.span);
746 for variant in enum_definition.variants.iter() {
747 check_case(cx, "variant", variant.node.name, variant.span);
755 #[deriving(PartialEq)]
762 fn method_context(cx: &Context, m: &ast::Method) -> MethodContext {
763 let did = ast::DefId {
764 krate: ast::LOCAL_CRATE,
768 match cx.tcx.methods.borrow().find_copy(&did) {
769 None => cx.sess().span_bug(m.span, "missing method descriptor?!"),
772 ty::TraitContainer(..) => TraitDefaultImpl,
773 ty::ImplContainer(cid) => {
774 match ty::impl_trait_ref(cx.tcx, cid) {
775 Some(..) => TraitImpl,
784 declare_lint!(NON_SNAKE_CASE_FUNCTIONS, Warn,
785 "methods and functions should have snake case names")
787 pub struct NonSnakeCaseFunctions;
789 impl NonSnakeCaseFunctions {
790 fn check_snake_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
791 fn is_snake_case(ident: ast::Ident) -> bool {
792 let ident = token::get_ident(ident);
793 assert!(!ident.get().is_empty());
794 let ident = ident.get().trim_chars('_');
796 let mut allow_underscore = true;
797 ident.chars().all(|c| {
798 allow_underscore = match c {
799 c if c.is_lowercase() || c.is_digit() => true,
800 '_' if allow_underscore => false,
807 fn to_snake_case(str: &str) -> String {
808 let mut words = vec![];
809 for s in str.split('_') {
810 let mut buf = String::new();
811 if s.is_empty() { continue; }
812 for ch in s.chars() {
813 if !buf.is_empty() && ch.is_uppercase() {
817 buf.push_char(ch.to_lowercase());
824 let s = token::get_ident(ident);
826 if !is_snake_case(ident) {
827 cx.span_lint(NON_SNAKE_CASE_FUNCTIONS, span,
828 format!("{} `{}` should have a snake case name such as `{}`",
829 sort, s, to_snake_case(s.get())).as_slice());
834 impl LintPass for NonSnakeCaseFunctions {
835 fn get_lints(&self) -> LintArray {
836 lint_array!(NON_SNAKE_CASE_FUNCTIONS)
839 fn check_fn(&mut self, cx: &Context,
840 fk: &visit::FnKind, _: &ast::FnDecl,
841 _: &ast::Block, span: Span, _: ast::NodeId) {
843 visit::FkMethod(ident, _, m) => match method_context(cx, m) {
845 => self.check_snake_case(cx, "method", ident, span),
847 => self.check_snake_case(cx, "trait method", ident, span),
850 visit::FkItemFn(ident, _, _, _)
851 => self.check_snake_case(cx, "function", ident, span),
856 fn check_ty_method(&mut self, cx: &Context, t: &ast::TypeMethod) {
857 self.check_snake_case(cx, "trait method", t.ident, t.span);
861 declare_lint!(NON_UPPERCASE_STATICS, Allow,
862 "static constants should have uppercase identifiers")
864 pub struct NonUppercaseStatics;
866 impl LintPass for NonUppercaseStatics {
867 fn get_lints(&self) -> LintArray {
868 lint_array!(NON_UPPERCASE_STATICS)
871 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
873 // only check static constants
874 ast::ItemStatic(_, ast::MutImmutable, _) => {
875 let s = token::get_ident(it.ident);
876 // check for lowercase letters rather than non-uppercase
877 // ones (some scripts don't have a concept of
879 if s.get().chars().any(|c| c.is_lowercase()) {
880 cx.span_lint(NON_UPPERCASE_STATICS, it.span,
881 format!("static constant `{}` should have an uppercase name \
883 s.get(), s.get().chars().map(|c| c.to_uppercase())
884 .collect::<String>().as_slice()).as_slice());
892 declare_lint!(NON_UPPERCASE_PATTERN_STATICS, Warn,
893 "static constants in match patterns should be all caps")
895 pub struct NonUppercasePatternStatics;
897 impl LintPass for NonUppercasePatternStatics {
898 fn get_lints(&self) -> LintArray {
899 lint_array!(NON_UPPERCASE_PATTERN_STATICS)
902 fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
903 // Lint for constants that look like binding identifiers (#7526)
904 match (&p.node, cx.tcx.def_map.borrow().find(&p.id)) {
905 (&ast::PatIdent(_, ref path, _), Some(&def::DefStatic(_, false))) => {
906 // last identifier alone is right choice for this lint.
907 let ident = path.segments.last().unwrap().identifier;
908 let s = token::get_ident(ident);
909 if s.get().chars().any(|c| c.is_lowercase()) {
910 cx.span_lint(NON_UPPERCASE_PATTERN_STATICS, path.span,
911 format!("static constant in pattern `{}` should have an uppercase \
913 s.get(), s.get().chars().map(|c| c.to_uppercase())
914 .collect::<String>().as_slice()).as_slice());
922 declare_lint!(UPPERCASE_VARIABLES, Warn,
923 "variable and structure field names should start with a lowercase character")
925 pub struct UppercaseVariables;
927 impl LintPass for UppercaseVariables {
928 fn get_lints(&self) -> LintArray {
929 lint_array!(UPPERCASE_VARIABLES)
932 fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
934 &ast::PatIdent(_, ref path, _) => {
935 match cx.tcx.def_map.borrow().find(&p.id) {
936 Some(&def::DefLocal(_, _)) | Some(&def::DefBinding(_, _)) |
937 Some(&def::DefArg(_, _)) => {
938 // last identifier alone is right choice for this lint.
939 let ident = path.segments.last().unwrap().identifier;
940 let s = token::get_ident(ident);
941 if s.get().len() > 0 && s.get().char_at(0).is_uppercase() {
942 cx.span_lint(UPPERCASE_VARIABLES, path.span,
943 "variable names should start with \
944 a lowercase character");
954 fn check_struct_def(&mut self, cx: &Context, s: &ast::StructDef,
955 _: ast::Ident, _: &ast::Generics, _: ast::NodeId) {
956 for sf in s.fields.iter() {
958 ast::StructField_ { kind: ast::NamedField(ident, _), .. } => {
959 let s = token::get_ident(ident);
960 if s.get().char_at(0).is_uppercase() {
961 cx.span_lint(UPPERCASE_VARIABLES, sf.span,
962 "structure field names should start with \
963 a lowercase character");
972 declare_lint!(UNNECESSARY_PARENS, Warn,
973 "`if`, `match`, `while` and `return` do not need parentheses")
975 pub struct UnnecessaryParens;
977 impl UnnecessaryParens {
978 fn check_unnecessary_parens_core(&self, cx: &Context, value: &ast::Expr, msg: &str,
979 struct_lit_needs_parens: bool) {
981 ast::ExprParen(ref inner) => {
982 let necessary = struct_lit_needs_parens && contains_exterior_struct_lit(&**inner);
984 cx.span_lint(UNNECESSARY_PARENS, value.span,
985 format!("unnecessary parentheses around {}",
992 /// Expressions that syntatically contain an "exterior" struct
993 /// literal i.e. not surrounded by any parens or other
994 /// delimiters, e.g. `X { y: 1 }`, `X { y: 1 }.method()`, `foo
995 /// == X { y: 1 }` and `X { y: 1 } == foo` all do, but `(X {
996 /// y: 1 }) == foo` does not.
997 fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
999 ast::ExprStruct(..) => true,
1001 ast::ExprAssign(ref lhs, ref rhs) |
1002 ast::ExprAssignOp(_, ref lhs, ref rhs) |
1003 ast::ExprBinary(_, ref lhs, ref rhs) => {
1004 // X { y: 1 } + X { y: 2 }
1005 contains_exterior_struct_lit(&**lhs) ||
1006 contains_exterior_struct_lit(&**rhs)
1008 ast::ExprUnary(_, ref x) |
1009 ast::ExprCast(ref x, _) |
1010 ast::ExprField(ref x, _, _) |
1011 ast::ExprIndex(ref x, _) => {
1012 // &X { y: 1 }, X { y: 1 }.y
1013 contains_exterior_struct_lit(&**x)
1016 ast::ExprMethodCall(_, _, ref exprs) => {
1017 // X { y: 1 }.bar(...)
1018 contains_exterior_struct_lit(&**exprs.get(0))
1027 impl LintPass for UnnecessaryParens {
1028 fn get_lints(&self) -> LintArray {
1029 lint_array!(UNNECESSARY_PARENS)
1032 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1033 let (value, msg, struct_lit_needs_parens) = match e.node {
1034 ast::ExprIf(cond, _, _) => (cond, "`if` condition", true),
1035 ast::ExprWhile(cond, _) => (cond, "`while` condition", true),
1036 ast::ExprMatch(head, _) => (head, "`match` head expression", true),
1037 ast::ExprRet(Some(value)) => (value, "`return` value", false),
1038 ast::ExprAssign(_, value) => (value, "assigned value", false),
1039 ast::ExprAssignOp(_, _, value) => (value, "assigned value", false),
1042 self.check_unnecessary_parens_core(cx, &*value, msg, struct_lit_needs_parens);
1045 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
1046 let (value, msg) = match s.node {
1047 ast::StmtDecl(decl, _) => match decl.node {
1048 ast::DeclLocal(local) => match local.init {
1049 Some(value) => (value, "assigned value"),
1056 self.check_unnecessary_parens_core(cx, &*value, msg, false);
1060 declare_lint!(UNUSED_UNSAFE, Warn,
1061 "unnecessary use of an `unsafe` block")
1063 pub struct UnusedUnsafe;
1065 impl LintPass for UnusedUnsafe {
1066 fn get_lints(&self) -> LintArray {
1067 lint_array!(UNUSED_UNSAFE)
1070 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1072 // Don't warn about generated blocks, that'll just pollute the output.
1073 ast::ExprBlock(ref blk) => {
1074 if blk.rules == ast::UnsafeBlock(ast::UserProvided) &&
1075 !cx.tcx.used_unsafe.borrow().contains(&blk.id) {
1076 cx.span_lint(UNUSED_UNSAFE, blk.span, "unnecessary `unsafe` block");
1084 declare_lint!(UNSAFE_BLOCK, Allow,
1085 "usage of an `unsafe` block")
1087 pub struct UnsafeBlock;
1089 impl LintPass for UnsafeBlock {
1090 fn get_lints(&self) -> LintArray {
1091 lint_array!(UNSAFE_BLOCK)
1094 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1096 // Don't warn about generated blocks, that'll just pollute the output.
1097 ast::ExprBlock(ref blk) if blk.rules == ast::UnsafeBlock(ast::UserProvided) => {
1098 cx.span_lint(UNSAFE_BLOCK, blk.span, "usage of an `unsafe` block");
1105 declare_lint!(UNUSED_MUT, Warn,
1106 "detect mut variables which don't need to be mutable")
1108 pub struct UnusedMut;
1111 fn check_unused_mut_pat(&self, cx: &Context, pats: &[Gc<ast::Pat>]) {
1112 // collect all mutable pattern and group their NodeIDs by their Identifier to
1113 // avoid false warnings in match arms with multiple patterns
1114 let mut mutables = HashMap::new();
1115 for &p in pats.iter() {
1116 pat_util::pat_bindings(&cx.tcx.def_map, &*p, |mode, id, _, path| {
1118 ast::BindByValue(ast::MutMutable) => {
1119 if path.segments.len() != 1 {
1120 cx.sess().span_bug(p.span,
1121 "mutable binding that doesn't consist \
1122 of exactly one segment");
1124 let ident = path.segments.get(0).identifier;
1125 if !token::get_ident(ident).get().starts_with("_") {
1126 mutables.insert_or_update_with(ident.name as uint,
1127 vec!(id), |_, old| { old.push(id); });
1136 let used_mutables = cx.tcx.used_mut_nodes.borrow();
1137 for (_, v) in mutables.iter() {
1138 if !v.iter().any(|e| used_mutables.contains(e)) {
1139 cx.span_lint(UNUSED_MUT, cx.tcx.map.span(*v.get(0)),
1140 "variable does not need to be mutable");
1146 impl LintPass for UnusedMut {
1147 fn get_lints(&self) -> LintArray {
1148 lint_array!(UNUSED_MUT)
1151 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1153 ast::ExprMatch(_, ref arms) => {
1154 for a in arms.iter() {
1155 self.check_unused_mut_pat(cx, a.pats.as_slice())
1162 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
1164 ast::StmtDecl(d, _) => {
1166 ast::DeclLocal(l) => {
1167 self.check_unused_mut_pat(cx, &[l.pat]);
1176 fn check_fn(&mut self, cx: &Context,
1177 _: &visit::FnKind, decl: &ast::FnDecl,
1178 _: &ast::Block, _: Span, _: ast::NodeId) {
1179 for a in decl.inputs.iter() {
1180 self.check_unused_mut_pat(cx, &[a.pat]);
1190 declare_lint!(UNNECESSARY_ALLOCATION, Warn,
1191 "detects unnecessary allocations that can be eliminated")
1193 pub struct UnnecessaryAllocation;
1195 impl LintPass for UnnecessaryAllocation {
1196 fn get_lints(&self) -> LintArray {
1197 lint_array!(UNNECESSARY_ALLOCATION)
1200 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1201 // Warn if string and vector literals with sigils, or boxing expressions,
1202 // are immediately borrowed.
1203 let allocation = match e.node {
1204 ast::ExprVstore(e2, ast::ExprVstoreUniq) => {
1206 ast::ExprLit(lit) if ast_util::lit_is_str(lit) => {
1209 ast::ExprVec(..) => VectorAllocation,
1213 ast::ExprUnary(ast::UnUniq, _) |
1214 ast::ExprUnary(ast::UnBox, _) => BoxAllocation,
1219 match cx.tcx.adjustments.borrow().find(&e.id) {
1220 Some(adjustment) => {
1222 ty::AutoDerefRef(ty::AutoDerefRef { autoref, .. }) => {
1223 match (allocation, autoref) {
1224 (VectorAllocation, Some(ty::AutoBorrowVec(..))) => {
1225 cx.span_lint(UNNECESSARY_ALLOCATION, e.span,
1226 "unnecessary allocation, the sigil can be removed");
1229 Some(ty::AutoPtr(_, ast::MutImmutable))) => {
1230 cx.span_lint(UNNECESSARY_ALLOCATION, e.span,
1231 "unnecessary allocation, use & instead");
1234 Some(ty::AutoPtr(_, ast::MutMutable))) => {
1235 cx.span_lint(UNNECESSARY_ALLOCATION, e.span,
1236 "unnecessary allocation, use &mut instead");
1249 declare_lint!(MISSING_DOC, Allow,
1250 "detects missing documentation for public members")
1252 pub struct MissingDoc {
1253 /// Stack of IDs of struct definitions.
1254 struct_def_stack: Vec<ast::NodeId>,
1256 /// Stack of whether #[doc(hidden)] is set
1257 /// at each level which has lint attributes.
1258 doc_hidden_stack: Vec<bool>,
1262 pub fn new() -> MissingDoc {
1264 struct_def_stack: vec!(),
1265 doc_hidden_stack: vec!(false),
1269 fn doc_hidden(&self) -> bool {
1270 *self.doc_hidden_stack.last().expect("empty doc_hidden_stack")
1273 fn check_missing_doc_attrs(&self,
1275 id: Option<ast::NodeId>,
1276 attrs: &[ast::Attribute],
1278 desc: &'static str) {
1279 // If we're building a test harness, then warning about
1280 // documentation is probably not really relevant right now.
1281 if cx.sess().opts.test { return }
1283 // `#[doc(hidden)]` disables missing_doc check.
1284 if self.doc_hidden() { return }
1286 // Only check publicly-visible items, using the result from the privacy pass.
1287 // It's an option so the crate root can also use this function (it doesn't
1290 Some(ref id) if !cx.exported_items.contains(id) => return,
1294 let has_doc = attrs.iter().any(|a| {
1295 match a.node.value.node {
1296 ast::MetaNameValue(ref name, _) if name.equiv(&("doc")) => true,
1301 cx.span_lint(MISSING_DOC, sp,
1302 format!("missing documentation for {}", desc).as_slice());
1307 impl LintPass for MissingDoc {
1308 fn get_lints(&self) -> LintArray {
1309 lint_array!(MISSING_DOC)
1312 fn enter_lint_attrs(&mut self, _: &Context, attrs: &[ast::Attribute]) {
1313 let doc_hidden = self.doc_hidden() || attrs.iter().any(|attr| {
1314 attr.check_name("doc") && match attr.meta_item_list() {
1316 Some(l) => attr::contains_name(l.as_slice(), "hidden"),
1319 self.doc_hidden_stack.push(doc_hidden);
1322 fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) {
1323 self.doc_hidden_stack.pop().expect("empty doc_hidden_stack");
1326 fn check_struct_def(&mut self, _: &Context,
1327 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
1328 self.struct_def_stack.push(id);
1331 fn check_struct_def_post(&mut self, _: &Context,
1332 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
1333 let popped = self.struct_def_stack.pop().expect("empty struct_def_stack");
1334 assert!(popped == id);
1337 fn check_crate(&mut self, cx: &Context, krate: &ast::Crate) {
1338 self.check_missing_doc_attrs(cx, None, krate.attrs.as_slice(),
1339 krate.span, "crate");
1342 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
1343 let desc = match it.node {
1344 ast::ItemFn(..) => "a function",
1345 ast::ItemMod(..) => "a module",
1346 ast::ItemEnum(..) => "an enum",
1347 ast::ItemStruct(..) => "a struct",
1348 ast::ItemTrait(..) => "a trait",
1351 self.check_missing_doc_attrs(cx, Some(it.id), it.attrs.as_slice(),
1355 fn check_fn(&mut self, cx: &Context,
1356 fk: &visit::FnKind, _: &ast::FnDecl,
1357 _: &ast::Block, _: Span, _: ast::NodeId) {
1359 visit::FkMethod(_, _, m) => {
1360 // If the method is an impl for a trait, don't doc.
1361 if method_context(cx, m) == TraitImpl { return; }
1363 // Otherwise, doc according to privacy. This will also check
1364 // doc for default methods defined on traits.
1365 self.check_missing_doc_attrs(cx, Some(m.id), m.attrs.as_slice(),
1366 m.span, "a method");
1372 fn check_ty_method(&mut self, cx: &Context, tm: &ast::TypeMethod) {
1373 self.check_missing_doc_attrs(cx, Some(tm.id), tm.attrs.as_slice(),
1374 tm.span, "a type method");
1377 fn check_struct_field(&mut self, cx: &Context, sf: &ast::StructField) {
1378 match sf.node.kind {
1379 ast::NamedField(_, vis) if vis == ast::Public => {
1380 let cur_struct_def = *self.struct_def_stack.last()
1381 .expect("empty struct_def_stack");
1382 self.check_missing_doc_attrs(cx, Some(cur_struct_def),
1383 sf.node.attrs.as_slice(), sf.span,
1390 fn check_variant(&mut self, cx: &Context, v: &ast::Variant, _: &ast::Generics) {
1391 self.check_missing_doc_attrs(cx, Some(v.node.id), v.node.attrs.as_slice(),
1392 v.span, "a variant");
1396 declare_lint!(DEPRECATED, Warn,
1397 "detects use of #[deprecated] items")
1399 // FIXME #6875: Change to Warn after std library stabilization is complete
1400 declare_lint!(EXPERIMENTAL, Allow,
1401 "detects use of #[experimental] items")
1403 declare_lint!(UNSTABLE, Allow,
1404 "detects use of #[unstable] items (incl. items with no stability attribute)")
1406 /// Checks for use of items with `#[deprecated]`, `#[experimental]` and
1407 /// `#[unstable]` attributes, or no stability attribute.
1408 pub struct Stability;
1410 impl LintPass for Stability {
1411 fn get_lints(&self) -> LintArray {
1412 lint_array!(DEPRECATED, EXPERIMENTAL, UNSTABLE)
1415 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1416 let id = match e.node {
1417 ast::ExprPath(..) | ast::ExprStruct(..) => {
1418 match cx.tcx.def_map.borrow().find(&e.id) {
1419 Some(&def) => def.def_id(),
1423 ast::ExprMethodCall(..) => {
1424 let method_call = typeck::MethodCall::expr(e.id);
1425 match cx.tcx.method_map.borrow().find(&method_call) {
1427 match method.origin {
1428 typeck::MethodStatic(def_id) => {
1431 typeck::MethodParam(typeck::MethodParam {
1436 | typeck::MethodObject(typeck::MethodObject {
1440 }) => ty::trait_method(cx.tcx, trait_id, index).def_id
1449 // stability attributes are promises made across crates; do not
1450 // check anything for crate-local usage.
1451 if ast_util::is_local(id) { return }
1453 let stability = stability::lookup(cx.tcx, id);
1454 let (lint, label) = match stability {
1455 // no stability attributes == Unstable
1456 None => (UNSTABLE, "unmarked"),
1457 Some(attr::Stability { level: attr::Unstable, .. }) =>
1458 (UNSTABLE, "unstable"),
1459 Some(attr::Stability { level: attr::Experimental, .. }) =>
1460 (EXPERIMENTAL, "experimental"),
1461 Some(attr::Stability { level: attr::Deprecated, .. }) =>
1462 (DEPRECATED, "deprecated"),
1466 let msg = match stability {
1467 Some(attr::Stability { text: Some(ref s), .. }) => {
1468 format!("use of {} item: {}", label, *s)
1470 _ => format!("use of {} item", label)
1473 cx.span_lint(lint, e.span, msg.as_slice());
1477 declare_lint!(pub UNUSED_IMPORTS, Warn,
1478 "imports that are never used")
1480 declare_lint!(pub UNNECESSARY_QUALIFICATION, Allow,
1481 "detects unnecessarily qualified names")
1483 declare_lint!(pub UNRECOGNIZED_LINT, Warn,
1484 "unrecognized lint attribute")
1486 declare_lint!(pub UNUSED_VARIABLE, Warn,
1487 "detect variables which are not used in any way")
1489 declare_lint!(pub DEAD_ASSIGNMENT, Warn,
1490 "detect assignments that will never be read")
1492 declare_lint!(pub DEAD_CODE, Warn,
1493 "detect piece of code that will never be used")
1495 declare_lint!(pub VISIBLE_PRIVATE_TYPES, Warn,
1496 "detect use of private types in exported type signatures")
1498 declare_lint!(pub UNREACHABLE_CODE, Warn,
1499 "detects unreachable code")
1501 declare_lint!(pub WARNINGS, Warn,
1502 "mass-change the level for lints which produce warnings")
1504 declare_lint!(pub UNKNOWN_FEATURES, Deny,
1505 "unknown features found in crate-level #[feature] directives")
1507 declare_lint!(pub UNKNOWN_CRATE_TYPE, Deny,
1508 "unknown crate type found in #[crate_type] directive")
1510 declare_lint!(pub VARIANT_SIZE_DIFFERENCE, Allow,
1511 "detects enums with widely varying variant sizes")
1513 /// Does nothing as a lint pass, but registers some `Lint`s
1514 /// which are used by other parts of the compiler.
1515 pub struct HardwiredLints;
1517 impl LintPass for HardwiredLints {
1518 fn get_lints(&self) -> LintArray {
1521 UNNECESSARY_QUALIFICATION,
1526 VISIBLE_PRIVATE_TYPES,
1531 VARIANT_SIZE_DIFFERENCE