// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Lints built in to rustc. //! //! This is a sibling of `lint::context` in order to ensure that //! lints implemented here use the same public API as lint plugins. //! //! To add a new lint to rustc, declare it here using `declare_lint!()`. //! Then add code to emit the new lint in the appropriate circumstances. //! You can do that in an existing `LintPass` if it makes sense, or in //! a new `LintPass`, or using `Session::add_lint` elsewhere in the //! compiler. Only do the latter if the check can't be written cleanly //! as a `LintPass`. //! //! If you define a new `LintPass`, you will also need to add it to the //! `add_builtin!` or `add_builtin_with_new!` invocation in `context.rs`. //! Use the former for unit-like structs and the latter for structs with //! a `pub fn new()`. use metadata::csearch; use middle::def::*; use middle::trans::adt; // for `adt::is_ffi_safe` use middle::typeck::astconv::ast_ty_to_ty; use middle::typeck::infer; use middle::{typeck, ty, def, pat_util, stability}; use util::ppaux::{ty_to_str}; use util::nodemap::NodeSet; use lint::{Context, LintPass, LintArray}; use std::cmp; use std::collections::HashMap; use std::i16; use std::i32; use std::i64; use std::i8; use std::u16; use std::u32; use std::u64; use std::u8; use std::gc::Gc; use syntax::abi; use syntax::ast_map; use syntax::attr::AttrMetaMethods; use syntax::attr; use syntax::codemap::Span; use syntax::parse::token; use syntax::{ast, ast_util, visit}; declare_lint!(WHILE_TRUE, Warn, "suggest using `loop { }` instead of `while true { }`") pub struct WhileTrue; impl LintPass for WhileTrue { fn get_lints(&self) -> LintArray { lint_array!(WHILE_TRUE) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { ast::ExprWhile(cond, _) => { match cond.node { ast::ExprLit(lit) => { match lit.node { ast::LitBool(true) => { cx.span_lint(WHILE_TRUE, e.span, "denote infinite loops with loop \ { ... }"); } _ => {} } } _ => () } } _ => () } } } declare_lint!(UNNECESSARY_TYPECAST, Allow, "detects unnecessary type casts, that can be removed") pub struct UnusedCasts; impl LintPass for UnusedCasts { fn get_lints(&self) -> LintArray { lint_array!(UNNECESSARY_TYPECAST) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { ast::ExprCast(expr, ty) => { let t_t = ast_ty_to_ty(cx, &infer::new_infer_ctxt(cx.tcx), &*ty); if ty::get(ty::expr_ty(cx.tcx, &*expr)).sty == ty::get(t_t).sty { cx.span_lint(UNNECESSARY_TYPECAST, ty.span, "unnecessary type cast"); } } _ => () } } } declare_lint!(UNSIGNED_NEGATE, Warn, "using an unary minus operator on unsigned type") declare_lint!(TYPE_LIMITS, Warn, "comparisons made useless by limits of the types involved") declare_lint!(TYPE_OVERFLOW, Warn, "literal out of range for its type") pub struct TypeLimits { /// Id of the last visited negated expression negated_expr_id: ast::NodeId, } impl TypeLimits { pub fn new() -> TypeLimits { TypeLimits { negated_expr_id: -1, } } } impl LintPass for TypeLimits { fn get_lints(&self) -> LintArray { lint_array!(UNSIGNED_NEGATE, TYPE_LIMITS, TYPE_OVERFLOW) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { ast::ExprUnary(ast::UnNeg, expr) => { match expr.node { ast::ExprLit(lit) => { match lit.node { ast::LitUint(..) => { cx.span_lint(UNSIGNED_NEGATE, e.span, "negation of unsigned int literal may \ be unintentional"); }, _ => () } }, _ => { let t = ty::expr_ty(cx.tcx, &*expr); match ty::get(t).sty { ty::ty_uint(_) => { cx.span_lint(UNSIGNED_NEGATE, e.span, "negation of unsigned int variable may \ be unintentional"); }, _ => () } } }; // propagate negation, if the negation itself isn't negated if self.negated_expr_id != e.id { self.negated_expr_id = expr.id; } }, ast::ExprParen(expr) if self.negated_expr_id == e.id => { self.negated_expr_id = expr.id; }, ast::ExprBinary(binop, l, r) => { if is_comparison(binop) && !check_limits(cx.tcx, binop, &*l, &*r) { cx.span_lint(TYPE_LIMITS, e.span, "comparison is useless due to type limits"); } }, ast::ExprLit(lit) => { match ty::get(ty::expr_ty(cx.tcx, e)).sty { ty::ty_int(t) => { let int_type = if t == ast::TyI { cx.sess().targ_cfg.int_type } else { t }; let (min, max) = int_ty_range(int_type); let mut lit_val: i64 = match lit.node { ast::LitInt(v, _) => v, ast::LitUint(v, _) => v as i64, ast::LitIntUnsuffixed(v) => v, _ => fail!() }; if self.negated_expr_id == e.id { lit_val *= -1; } if lit_val < min || lit_val > max { cx.span_lint(TYPE_OVERFLOW, e.span, "literal out of range for its type"); } }, ty::ty_uint(t) => { let uint_type = if t == ast::TyU { cx.sess().targ_cfg.uint_type } else { t }; let (min, max) = uint_ty_range(uint_type); let lit_val: u64 = match lit.node { ast::LitByte(_v) => return, // _v is u8, within range by definition ast::LitInt(v, _) => v as u64, ast::LitUint(v, _) => v, ast::LitIntUnsuffixed(v) => v as u64, _ => fail!() }; if lit_val < min || lit_val > max { cx.span_lint(TYPE_OVERFLOW, e.span, "literal out of range for its type"); } }, _ => () }; }, _ => () }; fn is_valid(binop: ast::BinOp, v: T, min: T, max: T) -> bool { match binop { ast::BiLt => v > min && v <= max, ast::BiLe => v >= min && v < max, ast::BiGt => v >= min && v < max, ast::BiGe => v > min && v <= max, ast::BiEq | ast::BiNe => v >= min && v <= max, _ => fail!() } } fn rev_binop(binop: ast::BinOp) -> ast::BinOp { match binop { ast::BiLt => ast::BiGt, ast::BiLe => ast::BiGe, ast::BiGt => ast::BiLt, ast::BiGe => ast::BiLe, _ => binop } } // for int & uint, be conservative with the warnings, so that the // warnings are consistent between 32- and 64-bit platforms fn int_ty_range(int_ty: ast::IntTy) -> (i64, i64) { match int_ty { ast::TyI => (i64::MIN, i64::MAX), ast::TyI8 => (i8::MIN as i64, i8::MAX as i64), ast::TyI16 => (i16::MIN as i64, i16::MAX as i64), ast::TyI32 => (i32::MIN as i64, i32::MAX as i64), ast::TyI64 => (i64::MIN, i64::MAX) } } fn uint_ty_range(uint_ty: ast::UintTy) -> (u64, u64) { match uint_ty { ast::TyU => (u64::MIN, u64::MAX), ast::TyU8 => (u8::MIN as u64, u8::MAX as u64), ast::TyU16 => (u16::MIN as u64, u16::MAX as u64), ast::TyU32 => (u32::MIN as u64, u32::MAX as u64), ast::TyU64 => (u64::MIN, u64::MAX) } } fn check_limits(tcx: &ty::ctxt, binop: ast::BinOp, l: &ast::Expr, r: &ast::Expr) -> bool { let (lit, expr, swap) = match (&l.node, &r.node) { (&ast::ExprLit(_), _) => (l, r, true), (_, &ast::ExprLit(_)) => (r, l, false), _ => return true }; // Normalize the binop so that the literal is always on the RHS in // the comparison let norm_binop = if swap { rev_binop(binop) } else { binop }; match ty::get(ty::expr_ty(tcx, expr)).sty { ty::ty_int(int_ty) => { let (min, max) = int_ty_range(int_ty); let lit_val: i64 = match lit.node { ast::ExprLit(li) => match li.node { ast::LitInt(v, _) => v, ast::LitUint(v, _) => v as i64, ast::LitIntUnsuffixed(v) => v, _ => return true }, _ => fail!() }; is_valid(norm_binop, lit_val, min, max) } ty::ty_uint(uint_ty) => { let (min, max): (u64, u64) = uint_ty_range(uint_ty); let lit_val: u64 = match lit.node { ast::ExprLit(li) => match li.node { ast::LitInt(v, _) => v as u64, ast::LitUint(v, _) => v, ast::LitIntUnsuffixed(v) => v as u64, _ => return true }, _ => fail!() }; is_valid(norm_binop, lit_val, min, max) } _ => true } } fn is_comparison(binop: ast::BinOp) -> bool { match binop { ast::BiEq | ast::BiLt | ast::BiLe | ast::BiNe | ast::BiGe | ast::BiGt => true, _ => false } } } } declare_lint!(CTYPES, Warn, "proper use of libc types in foreign modules") pub struct CTypes; impl LintPass for CTypes { fn get_lints(&self) -> LintArray { lint_array!(CTYPES) } fn check_item(&mut self, cx: &Context, it: &ast::Item) { fn check_ty(cx: &Context, ty: &ast::Ty) { match ty.node { ast::TyPath(_, _, id) => { match cx.tcx.def_map.borrow().get_copy(&id) { def::DefPrimTy(ast::TyInt(ast::TyI)) => { cx.span_lint(CTYPES, ty.span, "found rust type `int` in foreign module, while \ libc::c_int or libc::c_long should be used"); } def::DefPrimTy(ast::TyUint(ast::TyU)) => { cx.span_lint(CTYPES, ty.span, "found rust type `uint` in foreign module, while \ libc::c_uint or libc::c_ulong should be used"); } def::DefTy(def_id) => { if !adt::is_ffi_safe(cx.tcx, def_id) { cx.span_lint(CTYPES, ty.span, "found enum type without foreign-function-safe \ representation annotation in foreign module"); // hmm... this message could be more helpful } } _ => () } } ast::TyPtr(ref mt) => { check_ty(cx, &*mt.ty) } _ => {} } } fn check_foreign_fn(cx: &Context, decl: &ast::FnDecl) { for input in decl.inputs.iter() { check_ty(cx, &*input.ty); } check_ty(cx, &*decl.output) } match it.node { ast::ItemForeignMod(ref nmod) if nmod.abi != abi::RustIntrinsic => { for ni in nmod.items.iter() { match ni.node { ast::ForeignItemFn(decl, _) => check_foreign_fn(cx, &*decl), ast::ForeignItemStatic(t, _) => check_ty(cx, &*t) } } } _ => {/* nothing to do */ } } } } declare_lint!(MANAGED_HEAP_MEMORY, Allow, "use of managed (@ type) heap memory") declare_lint!(OWNED_HEAP_MEMORY, Allow, "use of owned (Box type) heap memory") declare_lint!(HEAP_MEMORY, Allow, "use of any (Box type or @ type) heap memory") pub struct HeapMemory; impl HeapMemory { fn check_heap_type(&self, cx: &Context, span: Span, ty: ty::t) { let mut n_box = 0i; let mut n_uniq = 0i; ty::fold_ty(cx.tcx, ty, |t| { match ty::get(t).sty { ty::ty_box(_) => { n_box += 1; } ty::ty_uniq(_) | ty::ty_closure(box ty::ClosureTy { store: ty::UniqTraitStore, .. }) => { n_uniq += 1; } _ => () }; t }); if n_uniq > 0 { let s = ty_to_str(cx.tcx, ty); let m = format!("type uses owned (Box type) pointers: {}", s); cx.span_lint(OWNED_HEAP_MEMORY, span, m.as_slice()); cx.span_lint(HEAP_MEMORY, span, m.as_slice()); } if n_box > 0 { let s = ty_to_str(cx.tcx, ty); let m = format!("type uses managed (@ type) pointers: {}", s); cx.span_lint(MANAGED_HEAP_MEMORY, span, m.as_slice()); cx.span_lint(HEAP_MEMORY, span, m.as_slice()); } } } impl LintPass for HeapMemory { fn get_lints(&self) -> LintArray { lint_array!(MANAGED_HEAP_MEMORY, OWNED_HEAP_MEMORY, HEAP_MEMORY) } fn check_item(&mut self, cx: &Context, it: &ast::Item) { match it.node { ast::ItemFn(..) | ast::ItemTy(..) | ast::ItemEnum(..) | ast::ItemStruct(..) => self.check_heap_type(cx, it.span, ty::node_id_to_type(cx.tcx, it.id)), _ => () } // If it's a struct, we also have to check the fields' types match it.node { ast::ItemStruct(struct_def, _) => { for struct_field in struct_def.fields.iter() { self.check_heap_type(cx, struct_field.span, ty::node_id_to_type(cx.tcx, struct_field.node.id)); } } _ => () } } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { let ty = ty::expr_ty(cx.tcx, e); self.check_heap_type(cx, e.span, ty); } } declare_lint!(RAW_POINTER_DERIVING, Warn, "uses of #[deriving] with raw pointers are rarely correct") struct RawPtrDerivingVisitor<'a> { cx: &'a Context<'a> } impl<'a> visit::Visitor<()> for RawPtrDerivingVisitor<'a> { fn visit_ty(&mut self, ty: &ast::Ty, _: ()) { static MSG: &'static str = "use of `#[deriving]` with a raw pointer"; match ty.node { ast::TyPtr(..) => self.cx.span_lint(RAW_POINTER_DERIVING, ty.span, MSG), _ => {} } visit::walk_ty(self, ty, ()); } // explicit override to a no-op to reduce code bloat fn visit_expr(&mut self, _: &ast::Expr, _: ()) {} fn visit_block(&mut self, _: &ast::Block, _: ()) {} } pub struct RawPointerDeriving { checked_raw_pointers: NodeSet, } impl RawPointerDeriving { pub fn new() -> RawPointerDeriving { RawPointerDeriving { checked_raw_pointers: NodeSet::new(), } } } impl LintPass for RawPointerDeriving { fn get_lints(&self) -> LintArray { lint_array!(RAW_POINTER_DERIVING) } fn check_item(&mut self, cx: &Context, item: &ast::Item) { if !attr::contains_name(item.attrs.as_slice(), "automatically_derived") { return } let did = match item.node { ast::ItemImpl(..) => { match ty::get(ty::node_id_to_type(cx.tcx, item.id)).sty { ty::ty_enum(did, _) => did, ty::ty_struct(did, _) => did, _ => return, } } _ => return, }; if !ast_util::is_local(did) { return } let item = match cx.tcx.map.find(did.node) { Some(ast_map::NodeItem(item)) => item, _ => return, }; if !self.checked_raw_pointers.insert(item.id) { return } match item.node { ast::ItemStruct(..) | ast::ItemEnum(..) => { let mut visitor = RawPtrDerivingVisitor { cx: cx }; visit::walk_item(&mut visitor, &*item, ()); } _ => {} } } } declare_lint!(UNUSED_ATTRIBUTE, Warn, "detects attributes that were not used by the compiler") pub struct UnusedAttribute; impl LintPass for UnusedAttribute { fn get_lints(&self) -> LintArray { lint_array!(UNUSED_ATTRIBUTE) } fn check_attribute(&mut self, cx: &Context, attr: &ast::Attribute) { static ATTRIBUTE_WHITELIST: &'static [&'static str] = &'static [ // FIXME: #14408 whitelist docs since rustdoc looks at them "doc", // FIXME: #14406 these are processed in trans, which happens after the // lint pass "cold", "inline", "link", "link_name", "link_section", "no_builtins", "no_mangle", "no_split_stack", "packed", "static_assert", "thread_local", // not used anywhere (!?) but apparently we want to keep them around "comment", "desc", "license", // FIXME: #14407 these are only looked at on-demand so we can't // guarantee they'll have already been checked "deprecated", "experimental", "frozen", "locked", "must_use", "stable", "unstable", ]; static CRATE_ATTRS: &'static [&'static str] = &'static [ "crate_type", "feature", "no_start", "no_main", "no_std", "crate_id", "desc", "comment", "license", "copyright", "no_builtins", ]; for &name in ATTRIBUTE_WHITELIST.iter() { if attr.check_name(name) { break; } } if !attr::is_used(attr) { cx.span_lint(UNUSED_ATTRIBUTE, attr.span, "unused attribute"); if CRATE_ATTRS.contains(&attr.name().get()) { let msg = match attr.node.style { ast::AttrOuter => "crate-level attribute should be an inner \ attribute: add an exclamation mark: #![foo]", ast::AttrInner => "crate-level attribute should be in the \ root module", }; cx.span_lint(UNUSED_ATTRIBUTE, attr.span, msg); } } } } declare_lint!(PATH_STATEMENT, Warn, "path statements with no effect") pub struct PathStatement; impl LintPass for PathStatement { fn get_lints(&self) -> LintArray { lint_array!(PATH_STATEMENT) } fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) { match s.node { ast::StmtSemi(expr, _) => { match expr.node { ast::ExprPath(_) => cx.span_lint(PATH_STATEMENT, s.span, "path statement with no effect"), _ => () } } _ => () } } } declare_lint!(UNUSED_MUST_USE, Warn, "unused result of a type flagged as #[must_use]") declare_lint!(UNUSED_RESULT, Allow, "unused result of an expression in a statement") pub struct UnusedResult; impl LintPass for UnusedResult { fn get_lints(&self) -> LintArray { lint_array!(UNUSED_MUST_USE, UNUSED_RESULT) } fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) { let expr = match s.node { ast::StmtSemi(expr, _) => expr, _ => return }; let t = ty::expr_ty(cx.tcx, &*expr); match ty::get(t).sty { ty::ty_nil | ty::ty_bot | ty::ty_bool => return, _ => {} } match expr.node { ast::ExprRet(..) => return, _ => {} } let t = ty::expr_ty(cx.tcx, &*expr); let mut warned = false; match ty::get(t).sty { ty::ty_struct(did, _) | ty::ty_enum(did, _) => { if ast_util::is_local(did) { match cx.tcx.map.get(did.node) { ast_map::NodeItem(it) => { if attr::contains_name(it.attrs.as_slice(), "must_use") { cx.span_lint(UNUSED_MUST_USE, s.span, "unused result which must be used"); warned = true; } } _ => {} } } else { csearch::get_item_attrs(&cx.sess().cstore, did, |attrs| { if attr::contains_name(attrs.as_slice(), "must_use") { cx.span_lint(UNUSED_MUST_USE, s.span, "unused result which must be used"); warned = true; } }); } } _ => {} } if !warned { cx.span_lint(UNUSED_RESULT, s.span, "unused result"); } } } declare_lint!(NON_CAMEL_CASE_TYPES, Warn, "types, variants and traits should have camel case names") pub struct NonCamelCaseTypes; impl LintPass for NonCamelCaseTypes { fn get_lints(&self) -> LintArray { lint_array!(NON_CAMEL_CASE_TYPES) } fn check_item(&mut self, cx: &Context, it: &ast::Item) { fn is_camel_case(ident: ast::Ident) -> bool { let ident = token::get_ident(ident); assert!(!ident.get().is_empty()); let ident = ident.get().trim_chars('_'); // start with a non-lowercase letter rather than non-uppercase // ones (some scripts don't have a concept of upper/lowercase) !ident.char_at(0).is_lowercase() && !ident.contains_char('_') } fn to_camel_case(s: &str) -> String { s.split('_').flat_map(|word| word.chars().enumerate().map(|(i, c)| if i == 0 { c.to_uppercase() } else { c } )).collect() } fn check_case(cx: &Context, sort: &str, ident: ast::Ident, span: Span) { let s = token::get_ident(ident); if !is_camel_case(ident) { cx.span_lint(NON_CAMEL_CASE_TYPES, span, format!("{} `{}` should have a camel case name such as `{}`", sort, s, to_camel_case(s.get())).as_slice()); } } match it.node { ast::ItemTy(..) | ast::ItemStruct(..) => { check_case(cx, "type", it.ident, it.span) } ast::ItemTrait(..) => { check_case(cx, "trait", it.ident, it.span) } ast::ItemEnum(ref enum_definition, _) => { check_case(cx, "type", it.ident, it.span); for variant in enum_definition.variants.iter() { check_case(cx, "variant", variant.node.name, variant.span); } } _ => () } } } #[deriving(PartialEq)] enum MethodContext { TraitDefaultImpl, TraitImpl, PlainImpl } fn method_context(cx: &Context, m: &ast::Method) -> MethodContext { let did = ast::DefId { krate: ast::LOCAL_CRATE, node: m.id }; match cx.tcx.methods.borrow().find_copy(&did) { None => cx.sess().span_bug(m.span, "missing method descriptor?!"), Some(md) => { match md.container { ty::TraitContainer(..) => TraitDefaultImpl, ty::ImplContainer(cid) => { match ty::impl_trait_ref(cx.tcx, cid) { Some(..) => TraitImpl, None => PlainImpl } } } } } } declare_lint!(NON_SNAKE_CASE_FUNCTIONS, Warn, "methods and functions should have snake case names") pub struct NonSnakeCaseFunctions; impl NonSnakeCaseFunctions { fn check_snake_case(&self, cx: &Context, sort: &str, ident: ast::Ident, span: Span) { fn is_snake_case(ident: ast::Ident) -> bool { let ident = token::get_ident(ident); assert!(!ident.get().is_empty()); let ident = ident.get().trim_chars('_'); let mut allow_underscore = true; ident.chars().all(|c| { allow_underscore = match c { c if c.is_lowercase() || c.is_digit() => true, '_' if allow_underscore => false, _ => return false, }; true }) } fn to_snake_case(str: &str) -> String { let mut words = vec![]; for s in str.split('_') { let mut buf = String::new(); if s.is_empty() { continue; } for ch in s.chars() { if !buf.is_empty() && ch.is_uppercase() { words.push(buf); buf = String::new(); } buf.push_char(ch.to_lowercase()); } words.push(buf); } words.connect("_") } let s = token::get_ident(ident); if !is_snake_case(ident) { cx.span_lint(NON_SNAKE_CASE_FUNCTIONS, span, format!("{} `{}` should have a snake case name such as `{}`", sort, s, to_snake_case(s.get())).as_slice()); } } } impl LintPass for NonSnakeCaseFunctions { fn get_lints(&self) -> LintArray { lint_array!(NON_SNAKE_CASE_FUNCTIONS) } fn check_fn(&mut self, cx: &Context, fk: &visit::FnKind, _: &ast::FnDecl, _: &ast::Block, span: Span, _: ast::NodeId) { match *fk { visit::FkMethod(ident, _, m) => match method_context(cx, m) { PlainImpl => self.check_snake_case(cx, "method", ident, span), TraitDefaultImpl => self.check_snake_case(cx, "trait method", ident, span), _ => (), }, visit::FkItemFn(ident, _, _, _) => self.check_snake_case(cx, "function", ident, span), _ => (), } } fn check_ty_method(&mut self, cx: &Context, t: &ast::TypeMethod) { self.check_snake_case(cx, "trait method", t.ident, t.span); } } declare_lint!(NON_UPPERCASE_STATICS, Allow, "static constants should have uppercase identifiers") pub struct NonUppercaseStatics; impl LintPass for NonUppercaseStatics { fn get_lints(&self) -> LintArray { lint_array!(NON_UPPERCASE_STATICS) } fn check_item(&mut self, cx: &Context, it: &ast::Item) { match it.node { // only check static constants ast::ItemStatic(_, ast::MutImmutable, _) => { let s = token::get_ident(it.ident); // check for lowercase letters rather than non-uppercase // ones (some scripts don't have a concept of // upper/lowercase) if s.get().chars().any(|c| c.is_lowercase()) { cx.span_lint(NON_UPPERCASE_STATICS, it.span, format!("static constant `{}` should have an uppercase name \ such as `{}`", s.get(), s.get().chars().map(|c| c.to_uppercase()) .collect::().as_slice()).as_slice()); } } _ => {} } } } declare_lint!(NON_UPPERCASE_PATTERN_STATICS, Warn, "static constants in match patterns should be all caps") pub struct NonUppercasePatternStatics; impl LintPass for NonUppercasePatternStatics { fn get_lints(&self) -> LintArray { lint_array!(NON_UPPERCASE_PATTERN_STATICS) } fn check_pat(&mut self, cx: &Context, p: &ast::Pat) { // Lint for constants that look like binding identifiers (#7526) match (&p.node, cx.tcx.def_map.borrow().find(&p.id)) { (&ast::PatIdent(_, ref path1, _), Some(&def::DefStatic(_, false))) => { let s = token::get_ident(path1.node); if s.get().chars().any(|c| c.is_lowercase()) { cx.span_lint(NON_UPPERCASE_PATTERN_STATICS, path1.span, format!("static constant in pattern `{}` should have an uppercase \ name such as `{}`", s.get(), s.get().chars().map(|c| c.to_uppercase()) .collect::().as_slice()).as_slice()); } } _ => {} } } } declare_lint!(UPPERCASE_VARIABLES, Warn, "variable and structure field names should start with a lowercase character") pub struct UppercaseVariables; impl LintPass for UppercaseVariables { fn get_lints(&self) -> LintArray { lint_array!(UPPERCASE_VARIABLES) } fn check_pat(&mut self, cx: &Context, p: &ast::Pat) { match &p.node { &ast::PatIdent(_, ref path1, _) => { match cx.tcx.def_map.borrow().find(&p.id) { Some(&def::DefLocal(_, _)) | Some(&def::DefBinding(_, _)) | Some(&def::DefArg(_, _)) => { let s = token::get_ident(path1.node); if s.get().len() > 0 && s.get().char_at(0).is_uppercase() { cx.span_lint(UPPERCASE_VARIABLES, path1.span, "variable names should start with \ a lowercase character"); } } _ => {} } } _ => {} } } fn check_struct_def(&mut self, cx: &Context, s: &ast::StructDef, _: ast::Ident, _: &ast::Generics, _: ast::NodeId) { for sf in s.fields.iter() { match sf.node { ast::StructField_ { kind: ast::NamedField(ident, _), .. } => { let s = token::get_ident(ident); if s.get().char_at(0).is_uppercase() { cx.span_lint(UPPERCASE_VARIABLES, sf.span, "structure field names should start with \ a lowercase character"); } } _ => {} } } } } declare_lint!(UNNECESSARY_PARENS, Warn, "`if`, `match`, `while` and `return` do not need parentheses") pub struct UnnecessaryParens; impl UnnecessaryParens { fn check_unnecessary_parens_core(&self, cx: &Context, value: &ast::Expr, msg: &str, struct_lit_needs_parens: bool) { match value.node { ast::ExprParen(ref inner) => { let necessary = struct_lit_needs_parens && contains_exterior_struct_lit(&**inner); if !necessary { cx.span_lint(UNNECESSARY_PARENS, value.span, format!("unnecessary parentheses around {}", msg).as_slice()) } } _ => {} } /// Expressions that syntatically contain an "exterior" struct /// literal i.e. not surrounded by any parens or other /// delimiters, e.g. `X { y: 1 }`, `X { y: 1 }.method()`, `foo /// == X { y: 1 }` and `X { y: 1 } == foo` all do, but `(X { /// y: 1 }) == foo` does not. fn contains_exterior_struct_lit(value: &ast::Expr) -> bool { match value.node { ast::ExprStruct(..) => true, ast::ExprAssign(ref lhs, ref rhs) | ast::ExprAssignOp(_, ref lhs, ref rhs) | ast::ExprBinary(_, ref lhs, ref rhs) => { // X { y: 1 } + X { y: 2 } contains_exterior_struct_lit(&**lhs) || contains_exterior_struct_lit(&**rhs) } ast::ExprUnary(_, ref x) | ast::ExprCast(ref x, _) | ast::ExprField(ref x, _, _) | ast::ExprIndex(ref x, _) => { // &X { y: 1 }, X { y: 1 }.y contains_exterior_struct_lit(&**x) } ast::ExprMethodCall(_, _, ref exprs) => { // X { y: 1 }.bar(...) contains_exterior_struct_lit(&**exprs.get(0)) } _ => false } } } } impl LintPass for UnnecessaryParens { fn get_lints(&self) -> LintArray { lint_array!(UNNECESSARY_PARENS) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { let (value, msg, struct_lit_needs_parens) = match e.node { ast::ExprIf(cond, _, _) => (cond, "`if` condition", true), ast::ExprWhile(cond, _) => (cond, "`while` condition", true), ast::ExprMatch(head, _) => (head, "`match` head expression", true), ast::ExprRet(Some(value)) => (value, "`return` value", false), ast::ExprAssign(_, value) => (value, "assigned value", false), ast::ExprAssignOp(_, _, value) => (value, "assigned value", false), _ => return }; self.check_unnecessary_parens_core(cx, &*value, msg, struct_lit_needs_parens); } fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) { let (value, msg) = match s.node { ast::StmtDecl(decl, _) => match decl.node { ast::DeclLocal(local) => match local.init { Some(value) => (value, "assigned value"), None => return }, _ => return }, _ => return }; self.check_unnecessary_parens_core(cx, &*value, msg, false); } } declare_lint!(UNUSED_UNSAFE, Warn, "unnecessary use of an `unsafe` block") pub struct UnusedUnsafe; impl LintPass for UnusedUnsafe { fn get_lints(&self) -> LintArray { lint_array!(UNUSED_UNSAFE) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { // Don't warn about generated blocks, that'll just pollute the output. ast::ExprBlock(ref blk) => { if blk.rules == ast::UnsafeBlock(ast::UserProvided) && !cx.tcx.used_unsafe.borrow().contains(&blk.id) { cx.span_lint(UNUSED_UNSAFE, blk.span, "unnecessary `unsafe` block"); } } _ => () } } } declare_lint!(UNSAFE_BLOCK, Allow, "usage of an `unsafe` block") pub struct UnsafeBlock; impl LintPass for UnsafeBlock { fn get_lints(&self) -> LintArray { lint_array!(UNSAFE_BLOCK) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { // Don't warn about generated blocks, that'll just pollute the output. ast::ExprBlock(ref blk) if blk.rules == ast::UnsafeBlock(ast::UserProvided) => { cx.span_lint(UNSAFE_BLOCK, blk.span, "usage of an `unsafe` block"); } _ => () } } } declare_lint!(UNUSED_MUT, Warn, "detect mut variables which don't need to be mutable") pub struct UnusedMut; impl UnusedMut { fn check_unused_mut_pat(&self, cx: &Context, pats: &[Gc]) { // collect all mutable pattern and group their NodeIDs by their Identifier to // avoid false warnings in match arms with multiple patterns let mut mutables = HashMap::new(); for &p in pats.iter() { pat_util::pat_bindings(&cx.tcx.def_map, &*p, |mode, id, _, path1| { let ident = path1.node; match mode { ast::BindByValue(ast::MutMutable) => { if !token::get_ident(ident).get().starts_with("_") { mutables.insert_or_update_with(ident.name as uint, vec!(id), |_, old| { old.push(id); }); } } _ => { } } }); } let used_mutables = cx.tcx.used_mut_nodes.borrow(); for (_, v) in mutables.iter() { if !v.iter().any(|e| used_mutables.contains(e)) { cx.span_lint(UNUSED_MUT, cx.tcx.map.span(*v.get(0)), "variable does not need to be mutable"); } } } } impl LintPass for UnusedMut { fn get_lints(&self) -> LintArray { lint_array!(UNUSED_MUT) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { match e.node { ast::ExprMatch(_, ref arms) => { for a in arms.iter() { self.check_unused_mut_pat(cx, a.pats.as_slice()) } } _ => {} } } fn check_stmt(&mut self, cx: &Context, s: &ast::Stmt) { match s.node { ast::StmtDecl(d, _) => { match d.node { ast::DeclLocal(l) => { self.check_unused_mut_pat(cx, &[l.pat]); }, _ => {} } }, _ => {} } } fn check_fn(&mut self, cx: &Context, _: &visit::FnKind, decl: &ast::FnDecl, _: &ast::Block, _: Span, _: ast::NodeId) { for a in decl.inputs.iter() { self.check_unused_mut_pat(cx, &[a.pat]); } } } enum Allocation { VectorAllocation, BoxAllocation } declare_lint!(UNNECESSARY_ALLOCATION, Warn, "detects unnecessary allocations that can be eliminated") pub struct UnnecessaryAllocation; impl LintPass for UnnecessaryAllocation { fn get_lints(&self) -> LintArray { lint_array!(UNNECESSARY_ALLOCATION) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { // Warn if string and vector literals with sigils, or boxing expressions, // are immediately borrowed. let allocation = match e.node { ast::ExprVstore(e2, ast::ExprVstoreUniq) => { match e2.node { ast::ExprLit(lit) if ast_util::lit_is_str(lit) => { VectorAllocation } ast::ExprVec(..) => VectorAllocation, _ => return } } ast::ExprUnary(ast::UnUniq, _) | ast::ExprUnary(ast::UnBox, _) => BoxAllocation, _ => return }; match cx.tcx.adjustments.borrow().find(&e.id) { Some(adjustment) => { match *adjustment { ty::AutoDerefRef(ty::AutoDerefRef { autoref, .. }) => { match (allocation, autoref) { (VectorAllocation, Some(ty::AutoBorrowVec(..))) => { cx.span_lint(UNNECESSARY_ALLOCATION, e.span, "unnecessary allocation, the sigil can be removed"); } (BoxAllocation, Some(ty::AutoPtr(_, ast::MutImmutable))) => { cx.span_lint(UNNECESSARY_ALLOCATION, e.span, "unnecessary allocation, use & instead"); } (BoxAllocation, Some(ty::AutoPtr(_, ast::MutMutable))) => { cx.span_lint(UNNECESSARY_ALLOCATION, e.span, "unnecessary allocation, use &mut instead"); } _ => () } } _ => {} } } _ => () } } } declare_lint!(MISSING_DOC, Allow, "detects missing documentation for public members") pub struct MissingDoc { /// Stack of IDs of struct definitions. struct_def_stack: Vec, /// Stack of whether #[doc(hidden)] is set /// at each level which has lint attributes. doc_hidden_stack: Vec, } impl MissingDoc { pub fn new() -> MissingDoc { MissingDoc { struct_def_stack: vec!(), doc_hidden_stack: vec!(false), } } fn doc_hidden(&self) -> bool { *self.doc_hidden_stack.last().expect("empty doc_hidden_stack") } fn check_missing_doc_attrs(&self, cx: &Context, id: Option, attrs: &[ast::Attribute], sp: Span, desc: &'static str) { // If we're building a test harness, then warning about // documentation is probably not really relevant right now. if cx.sess().opts.test { return } // `#[doc(hidden)]` disables missing_doc check. if self.doc_hidden() { return } // Only check publicly-visible items, using the result from the privacy pass. // It's an option so the crate root can also use this function (it doesn't // have a NodeId). match id { Some(ref id) if !cx.exported_items.contains(id) => return, _ => () } let has_doc = attrs.iter().any(|a| { match a.node.value.node { ast::MetaNameValue(ref name, _) if name.equiv(&("doc")) => true, _ => false } }); if !has_doc { cx.span_lint(MISSING_DOC, sp, format!("missing documentation for {}", desc).as_slice()); } } } impl LintPass for MissingDoc { fn get_lints(&self) -> LintArray { lint_array!(MISSING_DOC) } fn enter_lint_attrs(&mut self, _: &Context, attrs: &[ast::Attribute]) { let doc_hidden = self.doc_hidden() || attrs.iter().any(|attr| { attr.check_name("doc") && match attr.meta_item_list() { None => false, Some(l) => attr::contains_name(l.as_slice(), "hidden"), } }); self.doc_hidden_stack.push(doc_hidden); } fn exit_lint_attrs(&mut self, _: &Context, _: &[ast::Attribute]) { self.doc_hidden_stack.pop().expect("empty doc_hidden_stack"); } fn check_struct_def(&mut self, _: &Context, _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) { self.struct_def_stack.push(id); } fn check_struct_def_post(&mut self, _: &Context, _: &ast::StructDef, _: ast::Ident, _: &ast::Generics, id: ast::NodeId) { let popped = self.struct_def_stack.pop().expect("empty struct_def_stack"); assert!(popped == id); } fn check_crate(&mut self, cx: &Context, krate: &ast::Crate) { self.check_missing_doc_attrs(cx, None, krate.attrs.as_slice(), krate.span, "crate"); } fn check_item(&mut self, cx: &Context, it: &ast::Item) { let desc = match it.node { ast::ItemFn(..) => "a function", ast::ItemMod(..) => "a module", ast::ItemEnum(..) => "an enum", ast::ItemStruct(..) => "a struct", ast::ItemTrait(..) => "a trait", _ => return }; self.check_missing_doc_attrs(cx, Some(it.id), it.attrs.as_slice(), it.span, desc); } fn check_fn(&mut self, cx: &Context, fk: &visit::FnKind, _: &ast::FnDecl, _: &ast::Block, _: Span, _: ast::NodeId) { match *fk { visit::FkMethod(_, _, m) => { // If the method is an impl for a trait, don't doc. if method_context(cx, m) == TraitImpl { return; } // Otherwise, doc according to privacy. This will also check // doc for default methods defined on traits. self.check_missing_doc_attrs(cx, Some(m.id), m.attrs.as_slice(), m.span, "a method"); } _ => {} } } fn check_ty_method(&mut self, cx: &Context, tm: &ast::TypeMethod) { self.check_missing_doc_attrs(cx, Some(tm.id), tm.attrs.as_slice(), tm.span, "a type method"); } fn check_struct_field(&mut self, cx: &Context, sf: &ast::StructField) { match sf.node.kind { ast::NamedField(_, vis) if vis == ast::Public => { let cur_struct_def = *self.struct_def_stack.last() .expect("empty struct_def_stack"); self.check_missing_doc_attrs(cx, Some(cur_struct_def), sf.node.attrs.as_slice(), sf.span, "a struct field") } _ => {} } } fn check_variant(&mut self, cx: &Context, v: &ast::Variant, _: &ast::Generics) { self.check_missing_doc_attrs(cx, Some(v.node.id), v.node.attrs.as_slice(), v.span, "a variant"); } } declare_lint!(DEPRECATED, Warn, "detects use of #[deprecated] items") // FIXME #6875: Change to Warn after std library stabilization is complete declare_lint!(EXPERIMENTAL, Allow, "detects use of #[experimental] items") declare_lint!(UNSTABLE, Allow, "detects use of #[unstable] items (incl. items with no stability attribute)") /// Checks for use of items with `#[deprecated]`, `#[experimental]` and /// `#[unstable]` attributes, or no stability attribute. pub struct Stability; impl LintPass for Stability { fn get_lints(&self) -> LintArray { lint_array!(DEPRECATED, EXPERIMENTAL, UNSTABLE) } fn check_expr(&mut self, cx: &Context, e: &ast::Expr) { let id = match e.node { ast::ExprPath(..) | ast::ExprStruct(..) => { match cx.tcx.def_map.borrow().find(&e.id) { Some(&def) => def.def_id(), None => return } } ast::ExprMethodCall(..) => { let method_call = typeck::MethodCall::expr(e.id); match cx.tcx.method_map.borrow().find(&method_call) { Some(method) => { match method.origin { typeck::MethodStatic(def_id) => { def_id } typeck::MethodParam(typeck::MethodParam { trait_id: trait_id, method_num: index, .. }) | typeck::MethodObject(typeck::MethodObject { trait_id: trait_id, method_num: index, .. }) => ty::trait_method(cx.tcx, trait_id, index).def_id } } None => return } } _ => return }; // stability attributes are promises made across crates; do not // check anything for crate-local usage. if ast_util::is_local(id) { return } let stability = stability::lookup(cx.tcx, id); let (lint, label) = match stability { // no stability attributes == Unstable None => (UNSTABLE, "unmarked"), Some(attr::Stability { level: attr::Unstable, .. }) => (UNSTABLE, "unstable"), Some(attr::Stability { level: attr::Experimental, .. }) => (EXPERIMENTAL, "experimental"), Some(attr::Stability { level: attr::Deprecated, .. }) => (DEPRECATED, "deprecated"), _ => return }; let msg = match stability { Some(attr::Stability { text: Some(ref s), .. }) => { format!("use of {} item: {}", label, *s) } _ => format!("use of {} item", label) }; cx.span_lint(lint, e.span, msg.as_slice()); } } declare_lint!(pub UNUSED_IMPORTS, Warn, "imports that are never used") declare_lint!(pub UNNECESSARY_QUALIFICATION, Allow, "detects unnecessarily qualified names") declare_lint!(pub UNRECOGNIZED_LINT, Warn, "unrecognized lint attribute") declare_lint!(pub UNUSED_VARIABLE, Warn, "detect variables which are not used in any way") declare_lint!(pub DEAD_ASSIGNMENT, Warn, "detect assignments that will never be read") declare_lint!(pub DEAD_CODE, Warn, "detect piece of code that will never be used") declare_lint!(pub VISIBLE_PRIVATE_TYPES, Warn, "detect use of private types in exported type signatures") declare_lint!(pub UNREACHABLE_CODE, Warn, "detects unreachable code") declare_lint!(pub WARNINGS, Warn, "mass-change the level for lints which produce warnings") declare_lint!(pub UNKNOWN_FEATURES, Deny, "unknown features found in crate-level #[feature] directives") declare_lint!(pub UNKNOWN_CRATE_TYPE, Deny, "unknown crate type found in #[crate_type] directive") declare_lint!(pub VARIANT_SIZE_DIFFERENCE, Allow, "detects enums with widely varying variant sizes") /// Does nothing as a lint pass, but registers some `Lint`s /// which are used by other parts of the compiler. pub struct HardwiredLints; impl LintPass for HardwiredLints { fn get_lints(&self) -> LintArray { lint_array!( UNUSED_IMPORTS, UNNECESSARY_QUALIFICATION, UNRECOGNIZED_LINT, UNUSED_VARIABLE, DEAD_ASSIGNMENT, DEAD_CODE, VISIBLE_PRIVATE_TYPES, UNREACHABLE_CODE, WARNINGS, UNKNOWN_FEATURES, UNKNOWN_CRATE_TYPE, VARIANT_SIZE_DIFFERENCE ) } }