// 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. //! A 'lint' check is a kind of miscellaneous constraint that a user _might_ //! want to enforce, but might reasonably want to permit as well, on a //! module-by-module basis. They contrast with static constraints enforced by //! other phases of the compiler, which are generally required to hold in order //! to compile the program at all. //! //! The lint checking is all consolidated into one pass which runs just before //! translation to LLVM bytecode. Throughout compilation, lint warnings can be //! added via the `add_lint` method on the Session structure. This requires a //! span and an id of the node that the lint is being added to. The lint isn't //! actually emitted at that time because it is unknown what the actual lint //! level at that location is. //! //! To actually emit lint warnings/errors, a separate pass is used just before //! translation. A context keeps track of the current state of all lint levels. //! Upon entering a node of the ast which can modify the lint settings, the //! previous lint state is pushed onto a stack and the ast is then recursed //! upon. As the ast is traversed, this keeps track of the current lint level //! for all lint attributes. //! //! To add a new lint warning, all you need to do is to either invoke `add_lint` //! on the session at the appropriate time, or write a few linting functions and //! modify the Context visitor appropriately. If you're adding lints from the //! Context itself, span_lint should be used instead of add_lint. use driver::session; use middle::dead::DEAD_CODE_LINT_STR; use middle::privacy; use middle::trans::adt; // for `adt::is_ffi_safe` use middle::ty; use middle::typeck; use middle::pat_util; use metadata::csearch; use util::ppaux::{ty_to_str}; use std::to_str::ToStr; use middle::typeck::infer; use middle::typeck::astconv::{ast_ty_to_ty, AstConv}; use std::cmp; use std::hashmap::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 extra::smallintmap::SmallIntMap; use syntax::ast_map; use syntax::attr; use syntax::attr::{AttrMetaMethods, AttributeMethods}; use syntax::codemap::Span; use syntax::parse::token; use syntax::{ast, ast_util, visit}; use syntax::ast_util::IdVisitingOperation; use syntax::visit::Visitor; #[deriving(Clone, Eq, Ord, TotalEq, TotalOrd)] pub enum Lint { CTypes, UnusedImports, UnnecessaryQualification, WhileTrue, PathStatement, UnrecognizedLint, NonCamelCaseTypes, NonUppercaseStatics, NonUppercasePatternStatics, UnnecessaryParens, TypeLimits, TypeOverflow, UnusedUnsafe, UnsafeBlock, AttributeUsage, UnknownFeatures, UnknownCrateType, ManagedHeapMemory, OwnedHeapMemory, HeapMemory, UnusedVariable, DeadAssignment, UnusedMut, UnnecessaryAllocation, DeadCode, UnnecessaryTypecast, MissingDoc, UnreachableCode, Deprecated, Experimental, Unstable, UnusedMustUse, UnusedResult, Warnings, } pub fn level_to_str(lv: level) -> &'static str { match lv { allow => "allow", warn => "warn", deny => "deny", forbid => "forbid" } } #[deriving(Clone, Eq, Ord, TotalEq, TotalOrd)] pub enum level { allow, warn, deny, forbid } #[deriving(Clone, Eq, Ord, TotalEq, TotalOrd)] pub struct LintSpec { default: level, lint: Lint, desc: &'static str, } pub type LintDict = HashMap<&'static str, LintSpec>; #[deriving(Eq)] enum LintSource { Node(Span), Default, CommandLine } static lint_table: &'static [(&'static str, LintSpec)] = &[ ("ctypes", LintSpec { lint: CTypes, desc: "proper use of std::libc types in foreign modules", default: warn }), ("unused_imports", LintSpec { lint: UnusedImports, desc: "imports that are never used", default: warn }), ("unnecessary_qualification", LintSpec { lint: UnnecessaryQualification, desc: "detects unnecessarily qualified names", default: allow }), ("while_true", LintSpec { lint: WhileTrue, desc: "suggest using `loop { }` instead of `while true { }`", default: warn }), ("path_statement", LintSpec { lint: PathStatement, desc: "path statements with no effect", default: warn }), ("unrecognized_lint", LintSpec { lint: UnrecognizedLint, desc: "unrecognized lint attribute", default: warn }), ("non_camel_case_types", LintSpec { lint: NonCamelCaseTypes, desc: "types, variants and traits should have camel case names", default: allow }), ("non_uppercase_statics", LintSpec { lint: NonUppercaseStatics, desc: "static constants should have uppercase identifiers", default: allow }), ("non_uppercase_pattern_statics", LintSpec { lint: NonUppercasePatternStatics, desc: "static constants in match patterns should be all caps", default: warn }), ("unnecessary_parens", LintSpec { lint: UnnecessaryParens, desc: "`if`, `match`, `while` and `return` do not need parentheses", default: warn }), ("managed_heap_memory", LintSpec { lint: ManagedHeapMemory, desc: "use of managed (@ type) heap memory", default: allow }), ("owned_heap_memory", LintSpec { lint: OwnedHeapMemory, desc: "use of owned (~ type) heap memory", default: allow }), ("heap_memory", LintSpec { lint: HeapMemory, desc: "use of any (~ type or @ type) heap memory", default: allow }), ("type_limits", LintSpec { lint: TypeLimits, desc: "comparisons made useless by limits of the types involved", default: warn }), ("type_overflow", LintSpec { lint: TypeOverflow, desc: "literal out of range for its type", default: warn }), ("unused_unsafe", LintSpec { lint: UnusedUnsafe, desc: "unnecessary use of an `unsafe` block", default: warn }), ("unsafe_block", LintSpec { lint: UnsafeBlock, desc: "usage of an `unsafe` block", default: allow }), ("attribute_usage", LintSpec { lint: AttributeUsage, desc: "detects bad use of attributes", default: warn }), ("unused_variable", LintSpec { lint: UnusedVariable, desc: "detect variables which are not used in any way", default: warn }), ("dead_assignment", LintSpec { lint: DeadAssignment, desc: "detect assignments that will never be read", default: warn }), ("unnecessary_typecast", LintSpec { lint: UnnecessaryTypecast, desc: "detects unnecessary type casts, that can be removed", default: allow, }), ("unused_mut", LintSpec { lint: UnusedMut, desc: "detect mut variables which don't need to be mutable", default: warn }), ("unnecessary_allocation", LintSpec { lint: UnnecessaryAllocation, desc: "detects unnecessary allocations that can be eliminated", default: warn }), (DEAD_CODE_LINT_STR, LintSpec { lint: DeadCode, desc: "detect piece of code that will never be used", default: warn }), ("missing_doc", LintSpec { lint: MissingDoc, desc: "detects missing documentation for public members", default: allow }), ("unreachable_code", LintSpec { lint: UnreachableCode, desc: "detects unreachable code", default: warn }), ("deprecated", LintSpec { lint: Deprecated, desc: "detects use of #[deprecated] items", default: warn }), ("experimental", LintSpec { lint: Experimental, desc: "detects use of #[experimental] items", default: warn }), ("unstable", LintSpec { lint: Unstable, desc: "detects use of #[unstable] items (incl. items with no stability attribute)", default: allow }), ("warnings", LintSpec { lint: Warnings, desc: "mass-change the level for lints which produce warnings", default: warn }), ("unknown_features", LintSpec { lint: UnknownFeatures, desc: "unknown features found in crate-level #[feature] directives", default: deny, }), ("unknown_crate_type", LintSpec { lint: UnknownCrateType, desc: "unknown crate type found in #[crate_type] directive", default: deny, }), ("unused_must_use", LintSpec { lint: UnusedMustUse, desc: "unused result of an type flagged as #[must_use]", default: warn, }), ("unused_result", LintSpec { lint: UnusedResult, desc: "unused result of an expression in a statement", default: allow, }), ]; /* Pass names should not contain a '-', as the compiler normalizes '-' to '_' in command-line flags */ pub fn get_lint_dict() -> LintDict { let mut map = HashMap::new(); for &(k, v) in lint_table.iter() { map.insert(k, v); } return map; } struct Context<'a> { // All known lint modes (string versions) dict: @LintDict, // Current levels of each lint warning cur: SmallIntMap<(level, LintSource)>, // context we're checking in (used to access fields like sess) tcx: ty::ctxt, // maps from an expression id that corresponds to a method call to the // details of the method to be invoked method_map: typeck::method_map, // Items exported by the crate; used by the missing_doc lint. exported_items: &'a privacy::ExportedItems, // The id of the current `ast::StructDef` being walked. cur_struct_def_id: ast::NodeId, // Whether some ancestor of the current node was marked // #[doc(hidden)]. is_doc_hidden: bool, // When recursing into an attributed node of the ast which modifies lint // levels, this stack keeps track of the previous lint levels of whatever // was modified. lint_stack: ~[(Lint, level, LintSource)], // id of the last visited negated expression negated_expr_id: ast::NodeId } impl<'a> Context<'a> { fn get_level(&self, lint: Lint) -> level { match self.cur.find(&(lint as uint)) { Some(&(lvl, _)) => lvl, None => allow } } fn get_source(&self, lint: Lint) -> LintSource { match self.cur.find(&(lint as uint)) { Some(&(_, src)) => src, None => Default } } fn set_level(&mut self, lint: Lint, level: level, src: LintSource) { if level == allow { self.cur.remove(&(lint as uint)); } else { self.cur.insert(lint as uint, (level, src)); } } fn lint_to_str(&self, lint: Lint) -> &'static str { for (k, v) in self.dict.iter() { if v.lint == lint { return *k; } } fail!("unregistered lint {:?}", lint); } fn span_lint(&self, lint: Lint, span: Span, msg: &str) { let (level, src) = match self.cur.find(&(lint as uint)) { None => { return } Some(&(warn, src)) => (self.get_level(Warnings), src), Some(&pair) => pair, }; if level == allow { return } let mut note = None; let msg = match src { Default => { format!("{}, \\#[{}({})] on by default", msg, level_to_str(level), self.lint_to_str(lint)) }, CommandLine => { format!("{} [-{} {}]", msg, match level { warn => 'W', deny => 'D', forbid => 'F', allow => fail!() }, self.lint_to_str(lint).replace("_", "-")) }, Node(src) => { note = Some(src); msg.to_str() } }; match level { warn => { self.tcx.sess.span_warn(span, msg); } deny | forbid => { self.tcx.sess.span_err(span, msg); } allow => fail!(), } for &span in note.iter() { self.tcx.sess.span_note(span, "lint level defined here"); } } /** * Merge the lints specified by any lint attributes into the * current lint context, call the provided function, then reset the * lints in effect to their previous state. */ fn with_lint_attrs(&mut self, attrs: &[ast::Attribute], f: |&mut Context|) { // Parse all of the lint attributes, and then add them all to the // current dictionary of lint information. Along the way, keep a history // of what we changed so we can roll everything back after invoking the // specified closure let mut pushed = 0u; each_lint(self.tcx.sess, attrs, |meta, level, lintname| { match self.dict.find_equiv(&lintname) { None => { self.span_lint( UnrecognizedLint, meta.span, format!("unknown `{}` attribute: `{}`", level_to_str(level), lintname)); } Some(lint) => { let lint = lint.lint; let now = self.get_level(lint); if now == forbid && level != forbid { self.tcx.sess.span_err(meta.span, format!("{}({}) overruled by outer forbid({})", level_to_str(level), lintname, lintname)); } else if now != level { let src = self.get_source(lint); self.lint_stack.push((lint, now, src)); pushed += 1; self.set_level(lint, level, Node(meta.span)); } } } true }); let old_is_doc_hidden = self.is_doc_hidden; self.is_doc_hidden = self.is_doc_hidden || attrs.iter().any(|attr| ("doc" == attr.name() && match attr.meta_item_list() { None => false, Some(l) => attr::contains_name(l, "hidden") })); f(self); // rollback self.is_doc_hidden = old_is_doc_hidden; pushed.times(|| { let (lint, lvl, src) = self.lint_stack.pop().unwrap(); self.set_level(lint, lvl, src); }) } fn visit_ids(&self, f: |&mut ast_util::IdVisitor|) { let mut v = ast_util::IdVisitor { operation: self, pass_through_items: false, visited_outermost: false, }; f(&mut v); } } // Check that every lint from the list of attributes satisfies `f`. // Return true if that's the case. Otherwise return false. pub fn each_lint(sess: session::Session, attrs: &[ast::Attribute], f: |@ast::MetaItem, level, @str| -> bool) -> bool { let xs = [allow, warn, deny, forbid]; for &level in xs.iter() { let level_name = level_to_str(level); for attr in attrs.iter().filter(|m| level_name == m.name()) { let meta = attr.node.value; let metas = match meta.node { ast::MetaList(_, ref metas) => metas, _ => { sess.span_err(meta.span, "malformed lint attribute"); continue; } }; for meta in metas.iter() { match meta.node { ast::MetaWord(lintname) => { if !f(*meta, level, lintname) { return false; } } _ => { sess.span_err(meta.span, "malformed lint attribute"); } } } } } true } // Check from a list of attributes if it contains the appropriate // `#[level(lintname)]` attribute (e.g. `#[allow(dead_code)]). pub fn contains_lint(attrs: &[ast::Attribute], level: level, lintname: &'static str) -> bool { let level_name = level_to_str(level); for attr in attrs.iter().filter(|m| level_name == m.name()) { if attr.meta_item_list().is_none() { continue } let list = attr.meta_item_list().unwrap(); for meta_item in list.iter() { if lintname == meta_item.name() { return true; } } } false } fn check_while_true_expr(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(WhileTrue, e.span, "denote infinite loops with loop \ { ... }"); } _ => {} } } _ => () } } _ => () } } impl<'a> AstConv for Context<'a>{ fn tcx(&self) -> ty::ctxt { self.tcx } fn get_item_ty(&self, id: ast::DefId) -> ty::ty_param_bounds_and_ty { ty::lookup_item_type(self.tcx, id) } fn get_trait_def(&self, id: ast::DefId) -> @ty::TraitDef { ty::lookup_trait_def(self.tcx, id) } fn ty_infer(&self, _span: Span) -> ty::t { let infcx: @infer::InferCtxt = infer::new_infer_ctxt(self.tcx); infcx.next_ty_var() } } fn check_unused_casts(cx: &Context, e: &ast::Expr) { return match e.node { ast::ExprCast(expr, ty) => { let infcx: @infer::InferCtxt = infer::new_infer_ctxt(cx.tcx); let t_t = ast_ty_to_ty(cx, &infcx, ty); if ty::get(ty::expr_ty(cx.tcx, expr)).sty == ty::get(t_t).sty { cx.span_lint(UnnecessaryTypecast, ty.span, "unnecessary type cast"); } } _ => () }; } fn check_type_limits(cx: &Context, e: &ast::Expr) { return match e.node { ast::ExprBinary(_, binop, l, r) => { if is_comparison(binop) && !check_limits(cx.tcx, binop, l, r) { cx.span_lint(TypeLimits, 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.tcx.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 cx.negated_expr_id == e.id { lit_val *= -1; } if lit_val < min || lit_val > max { cx.span_lint(TypeOverflow, e.span, "literal out of range for its type"); } }, ty::ty_uint(t) => { let uint_type = if t == ast::TyU { cx.tcx.sess.targ_cfg.uint_type } else { t }; let (min, max) = uint_ty_range(uint_type); let lit_val: u64 = match lit.node { 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(TypeOverflow, 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 <= max, ast::BiLe => v < max, ast::BiGt => v >= min, ast::BiGe => v > min, 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 } } } fn check_item_ctypes(cx: &Context, it: &ast::Item) { fn check_ty(cx: &Context, ty: &ast::Ty) { match ty.node { ast::TyPath(_, _, id) => { let def_map = cx.tcx.def_map.borrow(); match def_map.get().get_copy(&id) { ast::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"); } ast::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"); } ast::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.abis.is_intrinsic() => { 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 */ } } } fn check_heap_type(cx: &Context, span: Span, ty: ty::t) { let xs = [ManagedHeapMemory, OwnedHeapMemory, HeapMemory]; for &lint in xs.iter() { if cx.get_level(lint) == allow { continue } let mut n_box = 0; let mut n_uniq = 0; ty::fold_ty(cx.tcx, ty, |t| { match ty::get(t).sty { ty::ty_box(_) | ty::ty_str(ty::vstore_box) | ty::ty_vec(_, ty::vstore_box) | ty::ty_trait(_, _, ty::BoxTraitStore, _, _) => { n_box += 1; } ty::ty_uniq(_) | ty::ty_str(ty::vstore_uniq) | ty::ty_vec(_, ty::vstore_uniq) | ty::ty_trait(_, _, ty::UniqTraitStore, _, _) => { n_uniq += 1; } ty::ty_closure(ref c) if c.sigil == ast::OwnedSigil => { n_uniq += 1; } _ => () }; t }); if n_uniq > 0 && lint != ManagedHeapMemory { let s = ty_to_str(cx.tcx, ty); let m = format!("type uses owned (~ type) pointers: {}", s); cx.span_lint(lint, span, m); } if n_box > 0 && lint != OwnedHeapMemory { let s = ty_to_str(cx.tcx, ty); let m = format!("type uses managed (@ type) pointers: {}", s); cx.span_lint(lint, span, m); } } } fn check_heap_item(cx: &Context, it: &ast::Item) { match it.node { ast::ItemFn(..) | ast::ItemTy(..) | ast::ItemEnum(..) | ast::ItemStruct(..) => 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() { check_heap_type(cx, struct_field.span, ty::node_id_to_type(cx.tcx, struct_field.node.id)); } } _ => () } } static crate_attrs: &'static [&'static str] = &[ "crate_type", "feature", "no_uv", "no_main", "no_std", "crate_id", "desc", "comment", "license", "copyright", // not used in rustc now ]; static obsolete_attrs: &'static [(&'static str, &'static str)] = &[ ("abi", "Use `extern \"abi\" fn` instead"), ("auto_encode", "Use `#[deriving(Encodable)]` instead"), ("auto_decode", "Use `#[deriving(Decodable)]` instead"), ("fast_ffi", "Remove it"), ("fixed_stack_segment", "Remove it"), ("rust_stack", "Remove it"), ]; static other_attrs: &'static [&'static str] = &[ // item-level "address_insignificant", // can be crate-level too "thread_local", // for statics "allow", "deny", "forbid", "warn", // lint options "deprecated", "experimental", "unstable", "stable", "locked", "frozen", //item stability "crate_map", "cfg", "doc", "export_name", "link_section", "no_freeze", "no_mangle", "no_send", "static_assert", "unsafe_no_drop_flag", "packed", "simd", "repr", "deriving", "unsafe_destructor", "link", "phase", "macro_export", "must_use", //mod-level "path", "link_name", "link_args", "nolink", "macro_escape", "no_implicit_prelude", // fn-level "test", "bench", "should_fail", "ignore", "inline", "lang", "main", "start", "no_split_stack", "cold", "macro_registrar", // internal attribute: bypass privacy inside items "!resolve_unexported", ]; fn check_crate_attrs_usage(cx: &Context, attrs: &[ast::Attribute]) { for attr in attrs.iter() { let name = attr.node.value.name(); let mut iter = crate_attrs.iter().chain(other_attrs.iter()); if !iter.any(|other_attr| { name.equiv(other_attr) }) { cx.span_lint(AttributeUsage, attr.span, "unknown crate attribute"); } if name.equiv(& &"link") { cx.tcx.sess.span_err(attr.span, "obsolete crate `link` attribute"); cx.tcx.sess.note("the link attribute has been superceded by the crate_id \ attribute, which has the format `#[crate_id = \"name#version\"]`"); } } } fn check_attrs_usage(cx: &Context, attrs: &[ast::Attribute]) { // check if element has crate-level, obsolete, or any unknown attributes. for attr in attrs.iter() { let name = attr.node.value.name(); for crate_attr in crate_attrs.iter() { if name.equiv(crate_attr) { let msg = match attr.node.style { ast::AttrOuter => "crate-level attribute should be an inner attribute: \ add semicolon at end", ast::AttrInner => "crate-level attribute should be in the root module", }; cx.span_lint(AttributeUsage, attr.span, msg); return; } } for &(obs_attr, obs_alter) in obsolete_attrs.iter() { if name.equiv(&obs_attr) { cx.span_lint(AttributeUsage, attr.span, format!("obsolete attribute: {:s}", obs_alter)); return; } } if !other_attrs.iter().any(|other_attr| { name.equiv(other_attr) }) { cx.span_lint(AttributeUsage, attr.span, "unknown attribute"); } } } fn check_heap_expr(cx: &Context, e: &ast::Expr) { let ty = ty::expr_ty(cx.tcx, e); check_heap_type(cx, e.span, ty); } fn check_path_statement(cx: &Context, s: &ast::Stmt) { match s.node { ast::StmtSemi(expr, _) => { match expr.node { ast::ExprPath(_) => { cx.span_lint(PathStatement, s.span, "path statement with no effect"); } _ => {} } } _ => () } } fn check_unused_result(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.items.get(did.node) { ast_map::NodeItem(it, _) => { if attr::contains_name(it.attrs, "must_use") { cx.span_lint(UnusedMustUse, s.span, "unused result which must be used"); warned = true; } } _ => {} } } else { csearch::get_item_attrs(cx.tcx.sess.cstore, did, |attrs| { if attr::contains_name(attrs, "must_use") { cx.span_lint(UnusedMustUse, s.span, "unused result which must be used"); warned = true; } }); } } _ => {} } if !warned { cx.span_lint(UnusedResult, s.span, "unused result"); } } fn check_item_non_camel_case_types(cx: &Context, it: &ast::Item) { fn is_camel_case(cx: ty::ctxt, ident: ast::Ident) -> bool { let ident = cx.sess.str_of(ident); assert!(!ident.is_empty()); let ident = ident.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 check_case(cx: &Context, sort: &str, ident: ast::Ident, span: Span) { if !is_camel_case(cx.tcx, ident) { cx.span_lint( NonCamelCaseTypes, span, format!("{} `{}` should have a camel case identifier", sort, cx.tcx.sess.str_of(ident))); } } 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); } } _ => () } } fn check_item_non_uppercase_statics(cx: &Context, it: &ast::Item) { match it.node { // only check static constants ast::ItemStatic(_, ast::MutImmutable, _) => { let s = cx.tcx.sess.str_of(it.ident); // check for lowercase letters rather than non-uppercase // ones (some scripts don't have a concept of // upper/lowercase) if s.chars().any(|c| c.is_lowercase()) { cx.span_lint(NonUppercaseStatics, it.span, "static constant should have an uppercase identifier"); } } _ => {} } } fn check_pat_non_uppercase_statics(cx: &Context, p: &ast::Pat) { // Lint for constants that look like binding identifiers (#7526) let def_map = cx.tcx.def_map.borrow(); match (&p.node, def_map.get().find(&p.id)) { (&ast::PatIdent(_, ref path, _), Some(&ast::DefStatic(_, false))) => { // last identifier alone is right choice for this lint. let ident = path.segments.last().unwrap().identifier; let s = cx.tcx.sess.str_of(ident); if s.chars().any(|c| c.is_lowercase()) { cx.span_lint(NonUppercasePatternStatics, path.span, "static constant in pattern should be all caps"); } } _ => {} } } fn check_unnecessary_parens(cx: &Context, e: &ast::Expr) { let (value, msg) = match e.node { ast::ExprIf(cond, _, _) => (cond, "`if` condition"), ast::ExprWhile(cond, _) => (cond, "`while` condition"), ast::ExprMatch(head, _) => (head, "`match` head expression"), ast::ExprRet(Some(value)) => (value, "`return` value"), _ => return }; match value.node { ast::ExprParen(_) => { cx.span_lint(UnnecessaryParens, value.span, format!("unnecessary parentheses around {}", msg)) } _ => {} } } fn check_unused_unsafe(cx: &Context, e: &ast::Expr) { match e.node { // Don't warn about generated blocks, that'll just pollute the output. ast::ExprBlock(ref blk) => { let used_unsafe = cx.tcx.used_unsafe.borrow(); if blk.rules == ast::UnsafeBlock(ast::UserProvided) && !used_unsafe.get().contains(&blk.id) { cx.span_lint(UnusedUnsafe, blk.span, "unnecessary `unsafe` block"); } } _ => () } } fn check_unsafe_block(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(UnsafeBlock, blk.span, "usage of an `unsafe` block"); } _ => () } } fn check_unused_mut_pat(cx: &Context, p: &ast::Pat) { match p.node { ast::PatIdent(ast::BindByValue(ast::MutMutable), ref path, _) if pat_util::pat_is_binding(cx.tcx.def_map, p)=> { // `let mut _a = 1;` doesn't need a warning. let initial_underscore = match path.segments { [ast::PathSegment { identifier: id, .. }] => { cx.tcx.sess.str_of(id).starts_with("_") } _ => { cx.tcx.sess.span_bug(p.span, "mutable binding that doesn't \ consist of exactly one segment"); } }; let used_mut_nodes = cx.tcx.used_mut_nodes.borrow(); if !initial_underscore && !used_mut_nodes.get().contains(&p.id) { cx.span_lint(UnusedMut, p.span, "variable does not need to be mutable"); } } _ => () } } enum Allocation { VectorAllocation, BoxAllocation } fn check_unnecessary_allocation(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) | ast::ExprVstore(e2, ast::ExprVstoreBox) => { 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 }; let report = |msg| { cx.span_lint(UnnecessaryAllocation, e.span, msg); }; let adjustment = { let adjustments = cx.tcx.adjustments.borrow(); adjustments.get().find_copy(&e.id) }; match adjustment { Some(adjustment) => { match *adjustment { ty::AutoDerefRef(ty::AutoDerefRef { autoref, .. }) => { match (allocation, autoref) { (VectorAllocation, Some(ty::AutoBorrowVec(..))) => { report("unnecessary allocation, the sigil can be \ removed"); } (BoxAllocation, Some(ty::AutoPtr(_, ast::MutImmutable))) => { report("unnecessary allocation, use & instead"); } (BoxAllocation, Some(ty::AutoPtr(_, ast::MutMutable))) => { report("unnecessary allocation, use &mut \ instead"); } _ => () } } _ => {} } } _ => () } } fn check_missing_doc_attrs(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.tcx.sess.opts.test { return } // `#[doc(hidden)]` disables missing_doc check. if cx.is_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 "doc" == *name => true, _ => false } }); if !has_doc { cx.span_lint(MissingDoc, sp, format!("missing documentation for {}", desc)); } } fn check_missing_doc_item(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 }; check_missing_doc_attrs(cx, Some(it.id), it.attrs, it.span, desc); } fn check_missing_doc_method(cx: &Context, m: &ast::Method) { let did = ast::DefId { crate: ast::LOCAL_CRATE, node: m.id }; let method_opt; { let methods = cx.tcx.methods.borrow(); method_opt = methods.get().find(&did).map(|method| *method); } match method_opt { None => cx.tcx.sess.span_bug(m.span, "missing method descriptor?!"), Some(md) => { match md.container { // Always check default methods defined on traits. ty::TraitContainer(..) => {} // For methods defined on impls, it depends on whether // it is an implementation for a trait or is a plain // impl. ty::ImplContainer(cid) => { match ty::impl_trait_ref(cx.tcx, cid) { Some(..) => return, // impl for trait: don't doc None => {} // plain impl: doc according to privacy } } } } } check_missing_doc_attrs(cx, Some(m.id), m.attrs, m.span, "a method"); } fn check_missing_doc_ty_method(cx: &Context, tm: &ast::TypeMethod) { check_missing_doc_attrs(cx, Some(tm.id), tm.attrs, tm.span, "a type method"); } fn check_missing_doc_struct_field(cx: &Context, sf: &ast::StructField) { match sf.node.kind { ast::NamedField(_, vis) if vis != ast::Private => check_missing_doc_attrs(cx, Some(cx.cur_struct_def_id), sf.node.attrs, sf.span, "a struct field"), _ => {} } } fn check_missing_doc_variant(cx: &Context, v: &ast::Variant) { check_missing_doc_attrs(cx, Some(v.node.id), v.node.attrs, v.span, "a variant"); } /// Checks for use of items with #[deprecated], #[experimental] and /// #[unstable] (or none of them) attributes. fn check_stability(cx: &Context, e: &ast::Expr) { let id = match e.node { ast::ExprPath(..) | ast::ExprStruct(..) => { let def_map = cx.tcx.def_map.borrow(); match def_map.get().find(&e.id) { Some(&def) => ast_util::def_id_of_def(def), None => return } } ast::ExprMethodCall(..) => { let method_map = cx.method_map.borrow(); match method_map.get().find(&e.id) { Some(&typeck::method_map_entry { origin, .. }) => { match origin { typeck::method_static(def_id) => { // If this implements a trait method, get def_id // of the method inside trait definition. // Otherwise, use the current def_id (which refers // to the method inside impl). ty::trait_method_of_method( cx.tcx, def_id).unwrap_or(def_id) } typeck::method_param(typeck::method_param { trait_id: trait_id, method_num: index, .. }) | typeck::method_object(typeck::method_object { trait_id: trait_id, method_num: index, .. }) => ty::trait_method(cx.tcx, trait_id, index).def_id } } None => return } } _ => return }; let stability = if ast_util::is_local(id) { // this crate match cx.tcx.items.find(id.node) { Some(ast_node) => { let s = ast_node.with_attrs(|attrs| { attrs.map(|a| { attr::find_stability(a.iter().map(|a| a.meta())) }) }); match s { Some(s) => s, // no possibility of having attributes // (e.g. it's a local variable), so just // ignore it. None => return } } _ => cx.tcx.sess.span_bug(e.span, format!("handle_def: {:?} not found", id)) } } else { // cross-crate let mut s = None; // run through all the attributes and take the first // stability one. csearch::get_item_attrs(cx.tcx.cstore, id, |meta_items| { if s.is_none() { s = attr::find_stability(meta_items.move_iter()) } }); s }; 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); } impl<'a> Visitor<()> for Context<'a> { fn visit_item(&mut self, it: &ast::Item, _: ()) { self.with_lint_attrs(it.attrs, |cx| { check_item_ctypes(cx, it); check_item_non_camel_case_types(cx, it); check_item_non_uppercase_statics(cx, it); check_heap_item(cx, it); check_missing_doc_item(cx, it); check_attrs_usage(cx, it.attrs); cx.visit_ids(|v| v.visit_item(it, ())); visit::walk_item(cx, it, ()); }) } fn visit_foreign_item(&mut self, it: &ast::ForeignItem, _: ()) { self.with_lint_attrs(it.attrs, |cx| { check_attrs_usage(cx, it.attrs); visit::walk_foreign_item(cx, it, ()); }) } fn visit_view_item(&mut self, i: &ast::ViewItem, _: ()) { self.with_lint_attrs(i.attrs, |cx| { check_attrs_usage(cx, i.attrs); visit::walk_view_item(cx, i, ()); }) } fn visit_pat(&mut self, p: &ast::Pat, _: ()) { check_pat_non_uppercase_statics(self, p); check_unused_mut_pat(self, p); visit::walk_pat(self, p, ()); } fn visit_expr(&mut self, e: &ast::Expr, _: ()) { match e.node { ast::ExprUnary(_, ast::UnNeg, expr) => { // 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 }, _ => () }; check_while_true_expr(self, e); check_stability(self, e); check_unnecessary_parens(self, e); check_unused_unsafe(self, e); check_unsafe_block(self, e); check_unnecessary_allocation(self, e); check_heap_expr(self, e); check_type_limits(self, e); check_unused_casts(self, e); visit::walk_expr(self, e, ()); } fn visit_stmt(&mut self, s: &ast::Stmt, _: ()) { check_path_statement(self, s); check_unused_result(self, s); visit::walk_stmt(self, s, ()); } fn visit_fn(&mut self, fk: &visit::FnKind, decl: &ast::FnDecl, body: &ast::Block, span: Span, id: ast::NodeId, _: ()) { let recurse = |this: &mut Context| { visit::walk_fn(this, fk, decl, body, span, id, ()); }; match *fk { visit::FkMethod(_, _, m) => { self.with_lint_attrs(m.attrs, |cx| { check_missing_doc_method(cx, m); check_attrs_usage(cx, m.attrs); cx.visit_ids(|v| { v.visit_fn(fk, decl, body, span, id, ()); }); recurse(cx); }) } _ => recurse(self), } } fn visit_ty_method(&mut self, t: &ast::TypeMethod, _: ()) { self.with_lint_attrs(t.attrs, |cx| { check_missing_doc_ty_method(cx, t); check_attrs_usage(cx, t.attrs); visit::walk_ty_method(cx, t, ()); }) } fn visit_struct_def(&mut self, s: &ast::StructDef, i: ast::Ident, g: &ast::Generics, id: ast::NodeId, _: ()) { let old_id = self.cur_struct_def_id; self.cur_struct_def_id = id; visit::walk_struct_def(self, s, i, g, id, ()); self.cur_struct_def_id = old_id; } fn visit_struct_field(&mut self, s: &ast::StructField, _: ()) { self.with_lint_attrs(s.node.attrs, |cx| { check_missing_doc_struct_field(cx, s); check_attrs_usage(cx, s.node.attrs); visit::walk_struct_field(cx, s, ()); }) } fn visit_variant(&mut self, v: &ast::Variant, g: &ast::Generics, _: ()) { self.with_lint_attrs(v.node.attrs, |cx| { check_missing_doc_variant(cx, v); check_attrs_usage(cx, v.node.attrs); visit::walk_variant(cx, v, g, ()); }) } // FIXME(#10894) should continue recursing fn visit_ty(&mut self, _t: &ast::Ty, _: ()) {} } impl<'a> IdVisitingOperation for Context<'a> { fn visit_id(&self, id: ast::NodeId) { let mut lints = self.tcx.sess.lints.borrow_mut(); match lints.get().pop(&id) { None => {} Some(l) => { for (lint, span, msg) in l.move_iter() { self.span_lint(lint, span, msg) } } } } } pub fn check_crate(tcx: ty::ctxt, method_map: typeck::method_map, exported_items: &privacy::ExportedItems, crate: &ast::Crate) { let mut cx = Context { dict: @get_lint_dict(), cur: SmallIntMap::new(), tcx: tcx, method_map: method_map, exported_items: exported_items, cur_struct_def_id: -1, is_doc_hidden: false, lint_stack: ~[], negated_expr_id: -1 }; // Install default lint levels, followed by the command line levels, and // then actually visit the whole crate. for (_, spec) in cx.dict.iter() { cx.set_level(spec.lint, spec.default, Default); } for &(lint, level) in tcx.sess.opts.lint_opts.iter() { cx.set_level(lint, level, CommandLine); } cx.with_lint_attrs(crate.attrs, |cx| { cx.visit_id(ast::CRATE_NODE_ID); cx.visit_ids(|v| { v.visited_outermost = true; visit::walk_crate(v, crate, ()); }); check_crate_attrs_usage(cx, crate.attrs); // since the root module isn't visited as an item (because it isn't an item), warn for it // here. check_missing_doc_attrs(cx, None, crate.attrs, crate.span, "crate"); visit::walk_crate(cx, crate, ()); }); // If we missed any lints added to the session, then there's a bug somewhere // in the iteration code. let lints = tcx.sess.lints.borrow(); for (id, v) in lints.get().iter() { for &(lint, span, ref msg) in v.iter() { tcx.sess.span_bug(span, format!("unprocessed lint {:?} at {}: {}", lint, ast_map::node_id_to_str(tcx.items, *id, token::get_ident_interner()), *msg)) } } tcx.sess.abort_if_errors(); }