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
27 use self::MethodContext::*;
29 use metadata::csearch;
31 use middle::subst::Substs;
32 use middle::ty::{mod, Ty};
33 use middle::{def, pat_util, stability};
34 use middle::const_eval::{eval_const_expr_partial, const_int, const_uint};
35 use util::ppaux::{ty_to_string};
36 use util::nodemap::{FnvHashMap, NodeSet};
37 use lint::{Context, LintPass, LintArray};
39 use std::{cmp, slice};
40 use std::collections::hash_map::Entry::{Occupied, Vacant};
41 use std::num::SignedInt;
42 use std::{i8, i16, i32, i64, u8, u16, u32, u64, f32, f64};
43 use syntax::{abi, ast, ast_map};
44 use syntax::ast_util::is_shift_binop;
45 use syntax::attr::{mod, AttrMetaMethods};
46 use syntax::codemap::{Span, DUMMY_SP};
47 use syntax::parse::token;
48 use syntax::ast::{TyI, TyU, TyI8, TyU8, TyI16, TyU16, TyI32, TyU32, TyI64, TyU64};
51 use syntax::visit::{mod, Visitor};
56 "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) {
68 if let ast::ExprWhile(ref cond, _, _) = e.node {
69 if let ast::ExprLit(ref lit) = cond.node {
70 if let ast::LitBool(true) = lit.node {
71 cx.span_lint(WHILE_TRUE, e.span,
72 "denote infinite loops with loop { ... }");
82 "detects unnecessary type casts that can be removed"
86 pub struct UnusedCasts;
88 impl LintPass for UnusedCasts {
89 fn get_lints(&self) -> LintArray {
90 lint_array!(UNUSED_TYPECASTS)
93 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
94 if let ast::ExprCast(ref expr, ref ty) = e.node {
95 let t_t = ty::expr_ty(cx.tcx, e);
96 if ty::expr_ty(cx.tcx, &**expr) == t_t {
97 cx.span_lint(UNUSED_TYPECASTS, ty.span, "unnecessary type cast");
106 "using an unary minus operator on unsigned type"
112 "comparisons made useless by limits of the types involved"
116 OVERFLOWING_LITERALS,
118 "literal out of range for its type"
124 "shift exceeds the type's number of bits"
128 pub struct TypeLimits {
129 /// Id of the last visited negated expression
130 negated_expr_id: ast::NodeId,
134 pub fn new() -> TypeLimits {
141 impl LintPass for TypeLimits {
142 fn get_lints(&self) -> LintArray {
143 lint_array!(UNSIGNED_NEGATION, UNUSED_COMPARISONS, OVERFLOWING_LITERALS,
147 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
149 ast::ExprUnary(ast::UnNeg, ref expr) => {
151 ast::ExprLit(ref lit) => {
153 ast::LitInt(_, ast::UnsignedIntLit(_)) => {
154 cx.span_lint(UNSIGNED_NEGATION, e.span,
155 "negation of unsigned int literal may \
162 let t = ty::expr_ty(cx.tcx, &**expr);
165 cx.span_lint(UNSIGNED_NEGATION, e.span,
166 "negation of unsigned int variable may \
173 // propagate negation, if the negation itself isn't negated
174 if self.negated_expr_id != e.id {
175 self.negated_expr_id = expr.id;
178 ast::ExprParen(ref expr) if self.negated_expr_id == e.id => {
179 self.negated_expr_id = expr.id;
181 ast::ExprBinary(binop, ref l, ref r) => {
182 if is_comparison(binop) && !check_limits(cx.tcx, binop, &**l, &**r) {
183 cx.span_lint(UNUSED_COMPARISONS, e.span,
184 "comparison is useless due to type limits");
187 if is_shift_binop(binop) {
188 let opt_ty_bits = match ty::expr_ty(cx.tcx, &**l).sty {
189 ty::ty_int(t) => Some(int_ty_bits(t, cx.sess().target.int_type)),
190 ty::ty_uint(t) => Some(uint_ty_bits(t, cx.sess().target.uint_type)),
194 if let Some(bits) = opt_ty_bits {
195 let exceeding = if let ast::ExprLit(ref lit) = r.node {
196 if let ast::LitInt(shift, _) = lit.node { shift >= bits }
199 match eval_const_expr_partial(cx.tcx, &**r) {
200 Ok(const_int(shift)) => { shift as u64 >= bits },
201 Ok(const_uint(shift)) => { shift >= bits },
206 cx.span_lint(EXCEEDING_BITSHIFTS, e.span,
207 "bitshift exceeds the type's number of bits");
212 ast::ExprLit(ref lit) => {
213 match ty::expr_ty(cx.tcx, e).sty {
216 ast::LitInt(v, ast::SignedIntLit(_, ast::Plus)) |
217 ast::LitInt(v, ast::UnsuffixedIntLit(ast::Plus)) => {
218 let int_type = if t == ast::TyI {
219 cx.sess().target.int_type
221 let (min, max) = int_ty_range(int_type);
222 let negative = self.negated_expr_id == e.id;
224 if (negative && v > (min.abs() as u64)) ||
225 (!negative && v > (max.abs() as u64)) {
226 cx.span_lint(OVERFLOWING_LITERALS, e.span,
227 "literal out of range for its type");
235 let uint_type = if t == ast::TyU {
236 cx.sess().target.uint_type
238 let (min, max) = uint_ty_range(uint_type);
239 let lit_val: u64 = match lit.node {
240 ast::LitByte(_v) => return, // _v is u8, within range by definition
241 ast::LitInt(v, _) => v,
244 if lit_val < min || lit_val > max {
245 cx.span_lint(OVERFLOWING_LITERALS, e.span,
246 "literal out of range for its type");
250 let (min, max) = float_ty_range(t);
251 let lit_val: f64 = match lit.node {
252 ast::LitFloat(ref v, _) |
253 ast::LitFloatUnsuffixed(ref v) => {
261 if lit_val < min || lit_val > max {
262 cx.span_lint(OVERFLOWING_LITERALS, e.span,
263 "literal out of range for its type");
272 fn is_valid<T:cmp::PartialOrd>(binop: ast::BinOp, v: T,
273 min: T, max: T) -> bool {
275 ast::BiLt => v > min && v <= max,
276 ast::BiLe => v >= min && v < max,
277 ast::BiGt => v >= min && v < max,
278 ast::BiGe => v > min && v <= max,
279 ast::BiEq | ast::BiNe => v >= min && v <= max,
284 fn rev_binop(binop: ast::BinOp) -> ast::BinOp {
286 ast::BiLt => ast::BiGt,
287 ast::BiLe => ast::BiGe,
288 ast::BiGt => ast::BiLt,
289 ast::BiGe => ast::BiLe,
294 // for int & uint, be conservative with the warnings, so that the
295 // warnings are consistent between 32- and 64-bit platforms
296 fn int_ty_range(int_ty: ast::IntTy) -> (i64, i64) {
298 ast::TyI => (i64::MIN, i64::MAX),
299 ast::TyI8 => (i8::MIN as i64, i8::MAX as i64),
300 ast::TyI16 => (i16::MIN as i64, i16::MAX as i64),
301 ast::TyI32 => (i32::MIN as i64, i32::MAX as i64),
302 ast::TyI64 => (i64::MIN, i64::MAX)
306 fn uint_ty_range(uint_ty: ast::UintTy) -> (u64, u64) {
308 ast::TyU => (u64::MIN, u64::MAX),
309 ast::TyU8 => (u8::MIN as u64, u8::MAX as u64),
310 ast::TyU16 => (u16::MIN as u64, u16::MAX as u64),
311 ast::TyU32 => (u32::MIN as u64, u32::MAX as u64),
312 ast::TyU64 => (u64::MIN, u64::MAX)
316 fn float_ty_range(float_ty: ast::FloatTy) -> (f64, f64) {
318 ast::TyF32 => (f32::MIN_VALUE as f64, f32::MAX_VALUE as f64),
319 ast::TyF64 => (f64::MIN_VALUE, f64::MAX_VALUE)
323 fn int_ty_bits(int_ty: ast::IntTy, target_int_ty: ast::IntTy) -> u64 {
325 ast::TyI => int_ty_bits(target_int_ty, target_int_ty),
326 ast::TyI8 => i8::BITS as u64,
327 ast::TyI16 => i16::BITS as u64,
328 ast::TyI32 => i32::BITS as u64,
329 ast::TyI64 => i64::BITS as u64
333 fn uint_ty_bits(uint_ty: ast::UintTy, target_uint_ty: ast::UintTy) -> u64 {
335 ast::TyU => uint_ty_bits(target_uint_ty, target_uint_ty),
336 ast::TyU8 => u8::BITS as u64,
337 ast::TyU16 => u16::BITS as u64,
338 ast::TyU32 => u32::BITS as u64,
339 ast::TyU64 => u64::BITS as u64
343 fn check_limits(tcx: &ty::ctxt, binop: ast::BinOp,
344 l: &ast::Expr, r: &ast::Expr) -> bool {
345 let (lit, expr, swap) = match (&l.node, &r.node) {
346 (&ast::ExprLit(_), _) => (l, r, true),
347 (_, &ast::ExprLit(_)) => (r, l, false),
350 // Normalize the binop so that the literal is always on the RHS in
352 let norm_binop = if swap { rev_binop(binop) } else { binop };
353 match ty::expr_ty(tcx, expr).sty {
354 ty::ty_int(int_ty) => {
355 let (min, max) = int_ty_range(int_ty);
356 let lit_val: i64 = match lit.node {
357 ast::ExprLit(ref li) => match li.node {
358 ast::LitInt(v, ast::SignedIntLit(_, ast::Plus)) |
359 ast::LitInt(v, ast::UnsuffixedIntLit(ast::Plus)) => v as i64,
360 ast::LitInt(v, ast::SignedIntLit(_, ast::Minus)) |
361 ast::LitInt(v, ast::UnsuffixedIntLit(ast::Minus)) => -(v as i64),
366 is_valid(norm_binop, lit_val, min, max)
368 ty::ty_uint(uint_ty) => {
369 let (min, max): (u64, u64) = uint_ty_range(uint_ty);
370 let lit_val: u64 = match lit.node {
371 ast::ExprLit(ref li) => match li.node {
372 ast::LitInt(v, _) => v,
377 is_valid(norm_binop, lit_val, min, max)
383 fn is_comparison(binop: ast::BinOp) -> bool {
385 ast::BiEq | ast::BiLt | ast::BiLe |
386 ast::BiNe | ast::BiGe | ast::BiGt => true,
396 "proper use of libc types in foreign modules"
399 struct ImproperCTypesVisitor<'a, 'tcx: 'a> {
400 cx: &'a Context<'a, 'tcx>
403 impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
404 fn check_def(&mut self, sp: Span, ty_id: ast::NodeId, path_id: ast::NodeId) {
405 match self.cx.tcx.def_map.borrow()[path_id].clone() {
406 def::DefPrimTy(ast::TyInt(ast::TyI)) => {
407 self.cx.span_lint(IMPROPER_CTYPES, sp,
408 "found rust type `int` in foreign module, while \
409 libc::c_int or libc::c_long should be used");
411 def::DefPrimTy(ast::TyUint(ast::TyU)) => {
412 self.cx.span_lint(IMPROPER_CTYPES, sp,
413 "found rust type `uint` in foreign module, while \
414 libc::c_uint or libc::c_ulong should be used");
417 let tty = match self.cx.tcx.ast_ty_to_ty_cache.borrow().get(&ty_id) {
418 Some(&ty::atttce_resolved(t)) => t,
419 _ => panic!("ast_ty_to_ty_cache was incomplete after typeck!")
422 if !ty::is_ffi_safe(self.cx.tcx, tty) {
423 self.cx.span_lint(IMPROPER_CTYPES, sp,
424 "found type without foreign-function-safe
425 representation annotation in foreign module, consider \
426 adding a #[repr(...)] attribute to the type");
434 impl<'a, 'tcx, 'v> Visitor<'v> for ImproperCTypesVisitor<'a, 'tcx> {
435 fn visit_ty(&mut self, ty: &ast::Ty) {
437 ast::TyPath(_, id) => self.check_def(ty.span, ty.id, id),
440 visit::walk_ty(self, ty);
445 pub struct ImproperCTypes;
447 impl LintPass for ImproperCTypes {
448 fn get_lints(&self) -> LintArray {
449 lint_array!(IMPROPER_CTYPES)
452 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
453 fn check_ty(cx: &Context, ty: &ast::Ty) {
454 let mut vis = ImproperCTypesVisitor { cx: cx };
458 fn check_foreign_fn(cx: &Context, decl: &ast::FnDecl) {
459 for input in decl.inputs.iter() {
460 check_ty(cx, &*input.ty);
462 if let ast::Return(ref ret_ty) = decl.output {
463 check_ty(cx, &**ret_ty);
468 ast::ItemForeignMod(ref nmod) if nmod.abi != abi::RustIntrinsic => {
469 for ni in nmod.items.iter() {
471 ast::ForeignItemFn(ref decl, _) => check_foreign_fn(cx, &**decl),
472 ast::ForeignItemStatic(ref t, _) => check_ty(cx, &**t)
484 "use of owned (Box type) heap memory"
488 pub struct BoxPointers;
491 fn check_heap_type<'a, 'tcx>(&self, cx: &Context<'a, 'tcx>,
492 span: Span, ty: Ty<'tcx>) {
494 ty::fold_ty(cx.tcx, ty, |t| {
497 ty::ty_closure(box ty::ClosureTy {
498 store: ty::UniqTraitStore,
510 let s = ty_to_string(cx.tcx, ty);
511 let m = format!("type uses owned (Box type) pointers: {}", s);
512 cx.span_lint(BOX_POINTERS, span, m[]);
517 impl LintPass for BoxPointers {
518 fn get_lints(&self) -> LintArray {
519 lint_array!(BOX_POINTERS)
522 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
527 ast::ItemStruct(..) =>
528 self.check_heap_type(cx, it.span,
529 ty::node_id_to_type(cx.tcx, it.id)),
533 // If it's a struct, we also have to check the fields' types
535 ast::ItemStruct(ref struct_def, _) => {
536 for struct_field in struct_def.fields.iter() {
537 self.check_heap_type(cx, struct_field.span,
538 ty::node_id_to_type(cx.tcx, struct_field.node.id));
545 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
546 let ty = ty::expr_ty(cx.tcx, e);
547 self.check_heap_type(cx, e.span, ty);
552 RAW_POINTER_DERIVING,
554 "uses of #[deriving] with raw pointers are rarely correct"
557 struct RawPtrDerivingVisitor<'a, 'tcx: 'a> {
558 cx: &'a Context<'a, 'tcx>
561 impl<'a, 'tcx, 'v> Visitor<'v> for RawPtrDerivingVisitor<'a, 'tcx> {
562 fn visit_ty(&mut self, ty: &ast::Ty) {
563 static MSG: &'static str = "use of `#[deriving]` with a raw pointer";
564 if let ast::TyPtr(..) = ty.node {
565 self.cx.span_lint(RAW_POINTER_DERIVING, ty.span, MSG);
567 visit::walk_ty(self, ty);
569 // explicit override to a no-op to reduce code bloat
570 fn visit_expr(&mut self, _: &ast::Expr) {}
571 fn visit_block(&mut self, _: &ast::Block) {}
574 pub struct RawPointerDeriving {
575 checked_raw_pointers: NodeSet,
578 impl RawPointerDeriving {
579 pub fn new() -> RawPointerDeriving {
581 checked_raw_pointers: NodeSet::new(),
586 impl LintPass for RawPointerDeriving {
587 fn get_lints(&self) -> LintArray {
588 lint_array!(RAW_POINTER_DERIVING)
591 fn check_item(&mut self, cx: &Context, item: &ast::Item) {
592 if !attr::contains_name(item.attrs[], "automatically_derived") {
595 let did = match item.node {
596 ast::ItemImpl(..) => {
597 match ty::node_id_to_type(cx.tcx, item.id).sty {
598 ty::ty_enum(did, _) => did,
599 ty::ty_struct(did, _) => did,
605 if !ast_util::is_local(did) { return }
606 let item = match cx.tcx.map.find(did.node) {
607 Some(ast_map::NodeItem(item)) => item,
610 if !self.checked_raw_pointers.insert(item.id) { return }
612 ast::ItemStruct(..) | ast::ItemEnum(..) => {
613 let mut visitor = RawPtrDerivingVisitor { cx: cx };
614 visit::walk_item(&mut visitor, &*item);
624 "detects attributes that were not used by the compiler"
628 pub struct UnusedAttributes;
630 impl LintPass for UnusedAttributes {
631 fn get_lints(&self) -> LintArray {
632 lint_array!(UNUSED_ATTRIBUTES)
635 fn check_attribute(&mut self, cx: &Context, attr: &ast::Attribute) {
636 static ATTRIBUTE_WHITELIST: &'static [&'static str] = &[
637 // FIXME: #14408 whitelist docs since rustdoc looks at them
640 // FIXME: #14406 these are processed in trans, which happens after the
657 "omit_gdb_pretty_printer_section",
658 "unsafe_no_drop_flag",
663 // FIXME: #14407 these are only looked at on-demand so we can't
664 // guarantee they'll have already been checked
674 static CRATE_ATTRS: &'static [&'static str] = &[
684 for &name in ATTRIBUTE_WHITELIST.iter() {
685 if attr.check_name(name) {
690 if !attr::is_used(attr) {
691 cx.span_lint(UNUSED_ATTRIBUTES, attr.span, "unused attribute");
692 if CRATE_ATTRS.contains(&attr.name().get()) {
693 let msg = match attr.node.style {
694 ast::AttrOuter => "crate-level attribute should be an inner \
695 attribute: add an exclamation mark: #![foo]",
696 ast::AttrInner => "crate-level attribute should be in the \
699 cx.span_lint(UNUSED_ATTRIBUTES, attr.span, msg);
708 "path statements with no effect"
712 pub struct PathStatements;
714 impl LintPass for PathStatements {
715 fn get_lints(&self) -> LintArray {
716 lint_array!(PATH_STATEMENTS)
719 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
721 ast::StmtSemi(ref expr, _) => {
723 ast::ExprPath(_) => cx.span_lint(PATH_STATEMENTS, s.span,
724 "path statement with no effect"),
736 "unused result of a type flagged as #[must_use]"
742 "unused result of an expression in a statement"
746 pub struct UnusedResults;
748 impl LintPass for UnusedResults {
749 fn get_lints(&self) -> LintArray {
750 lint_array!(UNUSED_MUST_USE, UNUSED_RESULTS)
753 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
754 let expr = match s.node {
755 ast::StmtSemi(ref expr, _) => &**expr,
759 if let ast::ExprRet(..) = expr.node {
763 let t = ty::expr_ty(cx.tcx, expr);
764 let mut warned = false;
766 ty::ty_tup(ref tys) if tys.is_empty() => return,
767 ty::ty_bool => return,
768 ty::ty_struct(did, _) |
769 ty::ty_enum(did, _) => {
770 if ast_util::is_local(did) {
771 if let ast_map::NodeItem(it) = cx.tcx.map.get(did.node) {
772 warned |= check_must_use(cx, it.attrs[], s.span);
775 csearch::get_item_attrs(&cx.sess().cstore, did, |attrs| {
776 warned |= check_must_use(cx, attrs[], s.span);
783 cx.span_lint(UNUSED_RESULTS, s.span, "unused result");
786 fn check_must_use(cx: &Context, attrs: &[ast::Attribute], sp: Span) -> bool {
787 for attr in attrs.iter() {
788 if attr.check_name("must_use") {
789 let mut msg = "unused result which must be used".to_string();
790 // check for #[must_use="..."]
791 match attr.value_str() {
795 msg.push_str(s.get());
798 cx.span_lint(UNUSED_MUST_USE, sp, msg[]);
808 pub NON_CAMEL_CASE_TYPES,
810 "types, variants, traits and type parameters should have camel case names"
814 pub struct NonCamelCaseTypes;
816 impl NonCamelCaseTypes {
817 fn check_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
818 fn is_camel_case(ident: ast::Ident) -> bool {
819 let ident = token::get_ident(ident);
820 if ident.get().is_empty() { return true; }
821 let ident = ident.get().trim_matches('_');
823 // start with a non-lowercase letter rather than non-uppercase
824 // ones (some scripts don't have a concept of upper/lowercase)
825 ident.len() > 0 && !ident.char_at(0).is_lowercase() && !ident.contains_char('_')
828 fn to_camel_case(s: &str) -> String {
829 s.split('_').flat_map(|word| word.chars().enumerate().map(|(i, c)|
830 if i == 0 { c.to_uppercase() }
835 let s = token::get_ident(ident);
837 if !is_camel_case(ident) {
838 let c = to_camel_case(s.get());
839 let m = if c.is_empty() {
840 format!("{} `{}` should have a camel case name such as `CamelCase`", sort, s)
842 format!("{} `{}` should have a camel case name such as `{}`", sort, s, c)
844 cx.span_lint(NON_CAMEL_CASE_TYPES, span, m[]);
849 impl LintPass for NonCamelCaseTypes {
850 fn get_lints(&self) -> LintArray {
851 lint_array!(NON_CAMEL_CASE_TYPES)
854 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
855 let has_extern_repr = it.attrs.iter().map(|attr| {
856 attr::find_repr_attrs(cx.tcx.sess.diagnostic(), attr).iter()
857 .any(|r| r == &attr::ReprExtern)
859 if has_extern_repr { return }
862 ast::ItemTy(..) | ast::ItemStruct(..) => {
863 self.check_case(cx, "type", it.ident, it.span)
865 ast::ItemTrait(..) => {
866 self.check_case(cx, "trait", it.ident, it.span)
868 ast::ItemEnum(ref enum_definition, _) => {
869 if has_extern_repr { return }
870 self.check_case(cx, "type", it.ident, it.span);
871 for variant in enum_definition.variants.iter() {
872 self.check_case(cx, "variant", variant.node.name, variant.span);
879 fn check_generics(&mut self, cx: &Context, it: &ast::Generics) {
880 for gen in it.ty_params.iter() {
881 self.check_case(cx, "type parameter", gen.ident, gen.span);
886 #[deriving(PartialEq)]
893 fn method_context(cx: &Context, m: &ast::Method) -> MethodContext {
894 let did = ast::DefId {
895 krate: ast::LOCAL_CRATE,
899 match cx.tcx.impl_or_trait_items.borrow().get(&did).cloned() {
900 None => cx.sess().span_bug(m.span, "missing method descriptor?!"),
903 ty::MethodTraitItem(md) => {
905 ty::TraitContainer(..) => TraitDefaultImpl,
906 ty::ImplContainer(cid) => {
907 match ty::impl_trait_ref(cx.tcx, cid) {
908 Some(..) => TraitImpl,
914 ty::TypeTraitItem(typedef) => {
915 match typedef.container {
916 ty::TraitContainer(..) => TraitDefaultImpl,
917 ty::ImplContainer(cid) => {
918 match ty::impl_trait_ref(cx.tcx, cid) {
919 Some(..) => TraitImpl,
933 "methods, functions, lifetime parameters and modules should have snake case names"
937 pub struct NonSnakeCase;
940 fn check_snake_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
941 fn is_snake_case(ident: ast::Ident) -> bool {
942 let ident = token::get_ident(ident);
943 if ident.get().is_empty() { return true; }
944 let ident = ident.get().trim_left_matches('\'');
945 let ident = ident.trim_matches('_');
947 let mut allow_underscore = true;
948 ident.chars().all(|c| {
949 allow_underscore = match c {
950 c if c.is_lowercase() || c.is_numeric() => true,
951 '_' if allow_underscore => false,
958 fn to_snake_case(str: &str) -> String {
959 let mut words = vec![];
960 for s in str.split('_') {
961 let mut last_upper = false;
962 let mut buf = String::new();
963 if s.is_empty() { continue; }
964 for ch in s.chars() {
965 if !buf.is_empty() && buf != "'"
971 last_upper = ch.is_uppercase();
972 buf.push(ch.to_lowercase());
979 let s = token::get_ident(ident);
981 if !is_snake_case(ident) {
982 cx.span_lint(NON_SNAKE_CASE, span,
983 format!("{} `{}` should have a snake case name such as `{}`",
984 sort, s, to_snake_case(s.get()))[]);
989 impl LintPass for NonSnakeCase {
990 fn get_lints(&self) -> LintArray {
991 lint_array!(NON_SNAKE_CASE)
994 fn check_fn(&mut self, cx: &Context,
995 fk: visit::FnKind, _: &ast::FnDecl,
996 _: &ast::Block, span: Span, _: ast::NodeId) {
998 visit::FkMethod(ident, _, m) => match method_context(cx, m) {
1000 => self.check_snake_case(cx, "method", ident, span),
1002 => self.check_snake_case(cx, "trait method", ident, span),
1005 visit::FkItemFn(ident, _, _, _)
1006 => self.check_snake_case(cx, "function", ident, span),
1011 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
1012 if let ast::ItemMod(_) = it.node {
1013 self.check_snake_case(cx, "module", it.ident, it.span);
1017 fn check_ty_method(&mut self, cx: &Context, t: &ast::TypeMethod) {
1018 self.check_snake_case(cx, "trait method", t.ident, t.span);
1021 fn check_lifetime_def(&mut self, cx: &Context, t: &ast::LifetimeDef) {
1022 self.check_snake_case(cx, "lifetime", t.lifetime.name.ident(), t.lifetime.span);
1025 fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
1026 if let &ast::PatIdent(_, ref path1, _) = &p.node {
1027 if let Some(&def::DefLocal(_)) = cx.tcx.def_map.borrow().get(&p.id) {
1028 self.check_snake_case(cx, "variable", path1.node, p.span);
1033 fn check_struct_def(&mut self, cx: &Context, s: &ast::StructDef,
1034 _: ast::Ident, _: &ast::Generics, _: ast::NodeId) {
1035 for sf in s.fields.iter() {
1036 if let ast::StructField_ { kind: ast::NamedField(ident, _), .. } = sf.node {
1037 self.check_snake_case(cx, "structure field", ident, sf.span);
1044 pub NON_UPPER_CASE_GLOBALS,
1046 "static constants should have uppercase identifiers"
1050 pub struct NonUpperCaseGlobals;
1052 impl LintPass for NonUpperCaseGlobals {
1053 fn get_lints(&self) -> LintArray {
1054 lint_array!(NON_UPPER_CASE_GLOBALS)
1057 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
1059 // only check static constants
1060 ast::ItemStatic(_, ast::MutImmutable, _) |
1061 ast::ItemConst(..) => {
1062 let s = token::get_ident(it.ident);
1063 // check for lowercase letters rather than non-uppercase
1064 // ones (some scripts don't have a concept of
1066 if s.get().chars().any(|c| c.is_lowercase()) {
1067 cx.span_lint(NON_UPPER_CASE_GLOBALS, it.span,
1068 format!("static constant `{}` should have an uppercase name \
1070 s.get(), s.get().chars().map(|c| c.to_uppercase())
1071 .collect::<String>()[])[]);
1078 fn check_pat(&mut self, cx: &Context, p: &ast::Pat) {
1079 // Lint for constants that look like binding identifiers (#7526)
1080 match (&p.node, cx.tcx.def_map.borrow().get(&p.id)) {
1081 (&ast::PatIdent(_, ref path1, _), Some(&def::DefConst(..))) => {
1082 let s = token::get_ident(path1.node);
1083 if s.get().chars().any(|c| c.is_lowercase()) {
1084 cx.span_lint(NON_UPPER_CASE_GLOBALS, path1.span,
1085 format!("static constant in pattern `{}` should have an uppercase \
1087 s.get(), s.get().chars().map(|c| c.to_uppercase())
1088 .collect::<String>()[])[]);
1099 "`if`, `match`, `while` and `return` do not need parentheses"
1103 pub struct UnusedParens;
1106 fn check_unused_parens_core(&self, cx: &Context, value: &ast::Expr, msg: &str,
1107 struct_lit_needs_parens: bool) {
1108 if let ast::ExprParen(ref inner) = value.node {
1109 let necessary = struct_lit_needs_parens && contains_exterior_struct_lit(&**inner);
1111 cx.span_lint(UNUSED_PARENS, value.span,
1112 format!("unnecessary parentheses around {}",
1117 /// Expressions that syntactically contain an "exterior" struct
1118 /// literal i.e. not surrounded by any parens or other
1119 /// delimiters, e.g. `X { y: 1 }`, `X { y: 1 }.method()`, `foo
1120 /// == X { y: 1 }` and `X { y: 1 } == foo` all do, but `(X {
1121 /// y: 1 }) == foo` does not.
1122 fn contains_exterior_struct_lit(value: &ast::Expr) -> bool {
1124 ast::ExprStruct(..) => true,
1126 ast::ExprAssign(ref lhs, ref rhs) |
1127 ast::ExprAssignOp(_, ref lhs, ref rhs) |
1128 ast::ExprBinary(_, ref lhs, ref rhs) => {
1129 // X { y: 1 } + X { y: 2 }
1130 contains_exterior_struct_lit(&**lhs) ||
1131 contains_exterior_struct_lit(&**rhs)
1133 ast::ExprUnary(_, ref x) |
1134 ast::ExprCast(ref x, _) |
1135 ast::ExprField(ref x, _) |
1136 ast::ExprTupField(ref x, _) |
1137 ast::ExprIndex(ref x, _) => {
1138 // &X { y: 1 }, X { y: 1 }.y
1139 contains_exterior_struct_lit(&**x)
1142 ast::ExprMethodCall(_, _, ref exprs) => {
1143 // X { y: 1 }.bar(...)
1144 contains_exterior_struct_lit(&*exprs[0])
1153 impl LintPass for UnusedParens {
1154 fn get_lints(&self) -> LintArray {
1155 lint_array!(UNUSED_PARENS)
1158 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1159 let (value, msg, struct_lit_needs_parens) = match e.node {
1160 ast::ExprIf(ref cond, _, _) => (cond, "`if` condition", true),
1161 ast::ExprWhile(ref cond, _, _) => (cond, "`while` condition", true),
1162 ast::ExprMatch(ref head, _, source) => match source {
1163 ast::MatchSource::Normal => (head, "`match` head expression", true),
1164 ast::MatchSource::IfLetDesugar { .. } => (head, "`if let` head expression", true),
1165 ast::MatchSource::WhileLetDesugar => (head, "`while let` head expression", true),
1167 ast::ExprRet(Some(ref value)) => (value, "`return` value", false),
1168 ast::ExprAssign(_, ref value) => (value, "assigned value", false),
1169 ast::ExprAssignOp(_, _, ref value) => (value, "assigned value", false),
1172 self.check_unused_parens_core(cx, &**value, msg, struct_lit_needs_parens);
1175 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
1176 let (value, msg) = match s.node {
1177 ast::StmtDecl(ref decl, _) => match decl.node {
1178 ast::DeclLocal(ref local) => match local.init {
1179 Some(ref value) => (value, "assigned value"),
1186 self.check_unused_parens_core(cx, &**value, msg, false);
1191 UNUSED_IMPORT_BRACES,
1193 "unnecessary braces around an imported item"
1197 pub struct UnusedImportBraces;
1199 impl LintPass for UnusedImportBraces {
1200 fn get_lints(&self) -> LintArray {
1201 lint_array!(UNUSED_IMPORT_BRACES)
1204 fn check_view_item(&mut self, cx: &Context, view_item: &ast::ViewItem) {
1205 match view_item.node {
1206 ast::ViewItemUse(ref view_path) => {
1207 match view_path.node {
1208 ast::ViewPathList(_, ref items, _) => {
1209 if items.len() == 1 {
1210 match items[0].node {
1211 ast::PathListIdent {ref name, ..} => {
1212 let m = format!("braces around {} is unnecessary",
1213 token::get_ident(*name).get());
1214 cx.span_lint(UNUSED_IMPORT_BRACES, view_item.span,
1230 NON_SHORTHAND_FIELD_PATTERNS,
1232 "using `Struct { x: x }` instead of `Struct { x }`"
1236 pub struct NonShorthandFieldPatterns;
1238 impl LintPass for NonShorthandFieldPatterns {
1239 fn get_lints(&self) -> LintArray {
1240 lint_array!(NON_SHORTHAND_FIELD_PATTERNS)
1243 fn check_pat(&mut self, cx: &Context, pat: &ast::Pat) {
1244 let def_map = cx.tcx.def_map.borrow();
1245 if let ast::PatStruct(_, ref v, _) = pat.node {
1246 for fieldpat in v.iter()
1247 .filter(|fieldpat| !fieldpat.node.is_shorthand)
1248 .filter(|fieldpat| def_map.get(&fieldpat.node.pat.id)
1249 == Some(&def::DefLocal(fieldpat.node.pat.id))) {
1250 if let ast::PatIdent(_, ident, None) = fieldpat.node.pat.node {
1251 if ident.node.as_str() == fieldpat.node.ident.as_str() {
1252 cx.span_lint(NON_SHORTHAND_FIELD_PATTERNS, fieldpat.span,
1253 format!("the `{}:` in this pattern is redundant and can \
1254 be removed", ident.node.as_str())[])
1265 "unnecessary use of an `unsafe` block"
1269 pub struct UnusedUnsafe;
1271 impl LintPass for UnusedUnsafe {
1272 fn get_lints(&self) -> LintArray {
1273 lint_array!(UNUSED_UNSAFE)
1276 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1277 if let ast::ExprBlock(ref blk) = e.node {
1278 // Don't warn about generated blocks, that'll just pollute the output.
1279 if blk.rules == ast::UnsafeBlock(ast::UserProvided) &&
1280 !cx.tcx.used_unsafe.borrow().contains(&blk.id) {
1281 cx.span_lint(UNUSED_UNSAFE, blk.span, "unnecessary `unsafe` block");
1290 "usage of an `unsafe` block"
1294 pub struct UnsafeBlocks;
1296 impl LintPass for UnsafeBlocks {
1297 fn get_lints(&self) -> LintArray {
1298 lint_array!(UNSAFE_BLOCKS)
1301 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1302 if let ast::ExprBlock(ref blk) = e.node {
1303 // Don't warn about generated blocks, that'll just pollute the output.
1304 if blk.rules == ast::UnsafeBlock(ast::UserProvided) {
1305 cx.span_lint(UNSAFE_BLOCKS, blk.span, "usage of an `unsafe` block");
1314 "detect mut variables which don't need to be mutable"
1318 pub struct UnusedMut;
1321 fn check_unused_mut_pat(&self, cx: &Context, pats: &[P<ast::Pat>]) {
1322 // collect all mutable pattern and group their NodeIDs by their Identifier to
1323 // avoid false warnings in match arms with multiple patterns
1325 let mut mutables = FnvHashMap::new();
1326 for p in pats.iter() {
1327 pat_util::pat_bindings(&cx.tcx.def_map, &**p, |mode, id, _, path1| {
1328 let ident = path1.node;
1329 if let ast::BindByValue(ast::MutMutable) = mode {
1330 if !token::get_ident(ident).get().starts_with("_") {
1331 match mutables.entry(ident.name.uint()) {
1332 Vacant(entry) => { entry.set(vec![id]); },
1333 Occupied(mut entry) => { entry.get_mut().push(id); },
1340 let used_mutables = cx.tcx.used_mut_nodes.borrow();
1341 for (_, v) in mutables.iter() {
1342 if !v.iter().any(|e| used_mutables.contains(e)) {
1343 cx.span_lint(UNUSED_MUT, cx.tcx.map.span(v[0]),
1344 "variable does not need to be mutable");
1350 impl LintPass for UnusedMut {
1351 fn get_lints(&self) -> LintArray {
1352 lint_array!(UNUSED_MUT)
1355 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1356 if let ast::ExprMatch(_, ref arms, _) = e.node {
1357 for a in arms.iter() {
1358 self.check_unused_mut_pat(cx, a.pats[])
1363 fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) {
1364 if let ast::StmtDecl(ref d, _) = s.node {
1365 if let ast::DeclLocal(ref l) = d.node {
1366 self.check_unused_mut_pat(cx, slice::ref_slice(&l.pat));
1371 fn check_fn(&mut self, cx: &Context,
1372 _: visit::FnKind, decl: &ast::FnDecl,
1373 _: &ast::Block, _: Span, _: ast::NodeId) {
1374 for a in decl.inputs.iter() {
1375 self.check_unused_mut_pat(cx, slice::ref_slice(&a.pat));
1383 "detects unnecessary allocations that can be eliminated"
1387 pub struct UnusedAllocation;
1389 impl LintPass for UnusedAllocation {
1390 fn get_lints(&self) -> LintArray {
1391 lint_array!(UNUSED_ALLOCATION)
1394 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1396 ast::ExprUnary(ast::UnUniq, _) => (),
1400 if let Some(adjustment) = cx.tcx.adjustments.borrow().get(&e.id) {
1401 if let ty::AdjustDerefRef(ty::AutoDerefRef { ref autoref, .. }) = *adjustment {
1403 &Some(ty::AutoPtr(_, ast::MutImmutable, None)) => {
1404 cx.span_lint(UNUSED_ALLOCATION, e.span,
1405 "unnecessary allocation, use & instead");
1407 &Some(ty::AutoPtr(_, ast::MutMutable, None)) => {
1408 cx.span_lint(UNUSED_ALLOCATION, e.span,
1409 "unnecessary allocation, use &mut instead");
1421 "detects missing documentation for public members"
1424 pub struct MissingDoc {
1425 /// Stack of IDs of struct definitions.
1426 struct_def_stack: Vec<ast::NodeId>,
1428 /// True if inside variant definition
1431 /// Stack of whether #[doc(hidden)] is set
1432 /// at each level which has lint attributes.
1433 doc_hidden_stack: Vec<bool>,
1437 pub fn new() -> MissingDoc {
1439 struct_def_stack: vec!(),
1441 doc_hidden_stack: vec!(false),
1445 fn doc_hidden(&self) -> bool {
1446 *self.doc_hidden_stack.last().expect("empty doc_hidden_stack")
1449 fn check_missing_docs_attrs(&self,
1451 id: Option<ast::NodeId>,
1452 attrs: &[ast::Attribute],
1454 desc: &'static str) {
1455 // If we're building a test harness, then warning about
1456 // documentation is probably not really relevant right now.
1457 if cx.sess().opts.test { return }
1459 // `#[doc(hidden)]` disables missing_docs check.
1460 if self.doc_hidden() { return }
1462 // Only check publicly-visible items, using the result from the privacy pass.
1463 // It's an option so the crate root can also use this function (it doesn't
1465 if let Some(ref id) = id {
1466 if !cx.exported_items.contains(id) {
1471 let has_doc = attrs.iter().any(|a| {
1472 match a.node.value.node {
1473 ast::MetaNameValue(ref name, _) if *name == "doc" => true,
1478 cx.span_lint(MISSING_DOCS, sp,
1479 format!("missing documentation for {}", desc)[]);
1484 impl LintPass for MissingDoc {
1485 fn get_lints(&self) -> LintArray {
1486 lint_array!(MISSING_DOCS)
1489 fn enter_lint_attrs(&mut self, _: &Context, attrs: &[ast::Attribute]) {
1490 let doc_hidden = self.doc_hidden() || attrs.iter().any(|attr| {
1491 attr.check_name("doc") && match attr.meta_item_list() {
1493 Some(l) => attr::contains_name(l[], "hidden"),
1496 self.doc_hidden_stack.push(doc_hidden);
1499 fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) {
1500 self.doc_hidden_stack.pop().expect("empty doc_hidden_stack");
1503 fn check_struct_def(&mut self, _: &Context,
1504 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
1505 self.struct_def_stack.push(id);
1508 fn check_struct_def_post(&mut self, _: &Context,
1509 _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) {
1510 let popped = self.struct_def_stack.pop().expect("empty struct_def_stack");
1511 assert!(popped == id);
1514 fn check_crate(&mut self, cx: &Context, krate: &ast::Crate) {
1515 self.check_missing_docs_attrs(cx, None, krate.attrs[],
1516 krate.span, "crate");
1519 fn check_item(&mut self, cx: &Context, it: &ast::Item) {
1520 let desc = match it.node {
1521 ast::ItemFn(..) => "a function",
1522 ast::ItemMod(..) => "a module",
1523 ast::ItemEnum(..) => "an enum",
1524 ast::ItemStruct(..) => "a struct",
1525 ast::ItemTrait(..) => "a trait",
1526 ast::ItemTy(..) => "a type alias",
1529 self.check_missing_docs_attrs(cx, Some(it.id), it.attrs[],
1533 fn check_fn(&mut self, cx: &Context,
1534 fk: visit::FnKind, _: &ast::FnDecl,
1535 _: &ast::Block, _: Span, _: ast::NodeId) {
1536 if let visit::FkMethod(_, _, m) = fk {
1537 // If the method is an impl for a trait, don't doc.
1538 if method_context(cx, m) == TraitImpl { return; }
1540 // Otherwise, doc according to privacy. This will also check
1541 // doc for default methods defined on traits.
1542 self.check_missing_docs_attrs(cx, Some(m.id), m.attrs[],
1543 m.span, "a method");
1547 fn check_ty_method(&mut self, cx: &Context, tm: &ast::TypeMethod) {
1548 self.check_missing_docs_attrs(cx, Some(tm.id), tm.attrs[],
1549 tm.span, "a type method");
1552 fn check_struct_field(&mut self, cx: &Context, sf: &ast::StructField) {
1553 if let ast::NamedField(_, vis) = sf.node.kind {
1554 if vis == ast::Public || self.in_variant {
1555 let cur_struct_def = *self.struct_def_stack.last()
1556 .expect("empty struct_def_stack");
1557 self.check_missing_docs_attrs(cx, Some(cur_struct_def),
1558 sf.node.attrs[], sf.span,
1564 fn check_variant(&mut self, cx: &Context, v: &ast::Variant, _: &ast::Generics) {
1565 self.check_missing_docs_attrs(cx, Some(v.node.id), v.node.attrs[],
1566 v.span, "a variant");
1567 assert!(!self.in_variant);
1568 self.in_variant = true;
1571 fn check_variant_post(&mut self, _: &Context, _: &ast::Variant, _: &ast::Generics) {
1572 assert!(self.in_variant);
1573 self.in_variant = false;
1578 pub struct MissingCopyImplementations;
1580 impl LintPass for MissingCopyImplementations {
1581 fn get_lints(&self) -> LintArray {
1582 lint_array!(MISSING_COPY_IMPLEMENTATIONS)
1585 fn check_item(&mut self, cx: &Context, item: &ast::Item) {
1586 if !cx.exported_items.contains(&item.id) {
1590 .destructor_for_type
1592 .contains_key(&ast_util::local_def(item.id)) {
1595 let ty = match item.node {
1596 ast::ItemStruct(_, ref ast_generics) => {
1597 if ast_generics.is_parameterized() {
1600 ty::mk_struct(cx.tcx,
1601 ast_util::local_def(item.id),
1602 cx.tcx.mk_substs(Substs::empty()))
1604 ast::ItemEnum(_, ref ast_generics) => {
1605 if ast_generics.is_parameterized() {
1609 ast_util::local_def(item.id),
1610 cx.tcx.mk_substs(Substs::empty()))
1614 let parameter_environment = ty::empty_parameter_environment();
1615 if !ty::type_moves_by_default(cx.tcx,
1617 ¶meter_environment) {
1620 if ty::can_type_implement_copy(cx.tcx,
1622 ¶meter_environment).is_ok() {
1623 cx.span_lint(MISSING_COPY_IMPLEMENTATIONS,
1625 "type could implement `Copy`; consider adding `impl \
1634 "detects use of #[deprecated] items"
1637 // FIXME #6875: Change to Warn after std library stabilization is complete
1641 "detects use of #[experimental] items"
1647 "detects use of #[unstable] items (incl. items with no stability attribute)"
1650 /// Checks for use of items with `#[deprecated]`, `#[experimental]` and
1651 /// `#[unstable]` attributes, or no stability attribute.
1653 pub struct Stability;
1656 fn lint(&self, cx: &Context, id: ast::DefId, span: Span) {
1657 let stability = stability::lookup(cx.tcx, id);
1658 let cross_crate = !ast_util::is_local(id);
1660 // stability attributes are promises made across crates; only
1661 // check DEPRECATED for crate-local usage.
1662 let (lint, label) = match stability {
1663 // no stability attributes == Unstable
1664 None if cross_crate => (UNSTABLE, "unmarked"),
1665 Some(attr::Stability { level: attr::Unstable, .. }) if cross_crate =>
1666 (UNSTABLE, "unstable"),
1667 Some(attr::Stability { level: attr::Experimental, .. }) if cross_crate =>
1668 (EXPERIMENTAL, "experimental"),
1669 Some(attr::Stability { level: attr::Deprecated, .. }) =>
1670 (DEPRECATED, "deprecated"),
1674 let msg = match stability {
1675 Some(attr::Stability { text: Some(ref s), .. }) => {
1676 format!("use of {} item: {}", label, *s)
1678 _ => format!("use of {} item", label)
1681 cx.span_lint(lint, span, msg[]);
1684 fn is_internal(&self, cx: &Context, span: Span) -> bool {
1685 // first, check if the given expression was generated by a macro or not
1686 // we need to go back the expn_info tree to check only the arguments
1687 // of the initial macro call, not the nested ones.
1688 let mut expnid = span.expn_id;
1689 let mut is_internal = false;
1690 while cx.tcx.sess.codemap().with_expn_info(expnid, |expninfo| {
1693 // save the parent expn_id for next loop iteration
1694 expnid = info.call_site.expn_id;
1695 if info.callee.span.is_none() {
1696 // it's a compiler built-in, we *really* don't want to mess with it
1697 // so we skip it, unless it was called by a regular macro, in which case
1698 // we will handle the caller macro next turn
1700 true // continue looping
1702 // was this expression from the current macro arguments ?
1703 is_internal = !( span.lo > info.call_site.lo &&
1704 span.hi < info.call_site.hi );
1705 true // continue looping
1708 _ => false // stop looping
1710 }) { /* empty while loop body */ }
1715 impl LintPass for Stability {
1716 fn get_lints(&self) -> LintArray {
1717 lint_array!(DEPRECATED, EXPERIMENTAL, UNSTABLE)
1720 fn check_view_item(&mut self, cx: &Context, item: &ast::ViewItem) {
1721 // compiler-generated `extern crate` statements have a dummy span.
1722 if item.span == DUMMY_SP { return }
1724 let id = match item.node {
1725 ast::ViewItemExternCrate(_, _, id) => id,
1726 ast::ViewItemUse(..) => return,
1728 let cnum = match cx.tcx.sess.cstore.find_extern_mod_stmt_cnum(id) {
1732 let id = ast::DefId { krate: cnum, node: ast::CRATE_NODE_ID };
1733 self.lint(cx, id, item.span);
1736 fn check_expr(&mut self, cx: &Context, e: &ast::Expr) {
1737 if self.is_internal(cx, e.span) { return; }
1739 let mut span = e.span;
1741 let id = match e.node {
1742 ast::ExprPath(..) | ast::ExprStruct(..) => {
1743 match cx.tcx.def_map.borrow().get(&e.id) {
1744 Some(&def) => def.def_id(),
1748 ast::ExprMethodCall(i, _, _) => {
1750 let method_call = ty::MethodCall::expr(e.id);
1751 match cx.tcx.method_map.borrow().get(&method_call) {
1753 match method.origin {
1754 ty::MethodStatic(def_id) => {
1757 ty::MethodStaticUnboxedClosure(def_id) => {
1760 ty::MethodTypeParam(ty::MethodParam {
1765 ty::MethodTraitObject(ty::MethodObject {
1770 ty::trait_item(cx.tcx, trait_ref.def_id, index).def_id()
1779 self.lint(cx, id, span);
1782 fn check_item(&mut self, cx: &Context, item: &ast::Item) {
1783 if self.is_internal(cx, item.span) { return }
1786 ast::ItemTrait(_, _, ref supertraits, _) => {
1787 for t in supertraits.iter() {
1788 if let ast::TraitTyParamBound(ref t, _) = *t {
1789 let id = ty::trait_ref_to_def_id(cx.tcx, &t.trait_ref);
1790 self.lint(cx, id, t.trait_ref.path.span);
1794 ast::ItemImpl(_, _, Some(ref t), _, _) => {
1795 let id = ty::trait_ref_to_def_id(cx.tcx, t);
1796 self.lint(cx, id, t.path.span);
1806 "imports that are never used"
1810 pub UNUSED_EXTERN_CRATES,
1812 "extern crates that are never used"
1816 pub UNUSED_QUALIFICATIONS,
1818 "detects unnecessarily qualified names"
1824 "unrecognized lint attribute"
1828 pub UNUSED_VARIABLES,
1830 "detect variables which are not used in any way"
1834 pub UNUSED_ASSIGNMENTS,
1836 "detect assignments that will never be read"
1842 "detect unused, unexported items"
1846 pub UNREACHABLE_CODE,
1848 "detects unreachable code paths"
1854 "mass-change the level for lints which produce warnings"
1858 pub UNKNOWN_FEATURES,
1860 "unknown features found in crate-level #[feature] directives"
1864 pub UNKNOWN_CRATE_TYPES,
1866 "unknown crate type found in #[crate_type] directive"
1870 pub VARIANT_SIZE_DIFFERENCES,
1872 "detects enums with widely varying variant sizes"
1876 pub FAT_PTR_TRANSMUTES,
1878 "detects transmutes of fat pointers"
1882 pub MISSING_COPY_IMPLEMENTATIONS,
1884 "detects potentially-forgotten implementations of `Copy`"
1887 /// Does nothing as a lint pass, but registers some `Lint`s
1888 /// which are used by other parts of the compiler.
1890 pub struct HardwiredLints;
1892 impl LintPass for HardwiredLints {
1893 fn get_lints(&self) -> LintArray {
1896 UNUSED_EXTERN_CRATES,
1897 UNUSED_QUALIFICATIONS,
1905 UNKNOWN_CRATE_TYPES,
1906 VARIANT_SIZE_DIFFERENCES,