| // Copyright 2012-2015 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 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Lints in the Rust compiler. |
| //! |
| //! This contains lints which can feasibly be implemented as their own |
| //! AST visitor. Also see `rustc::lint::builtin`, which contains the |
| //! definitions of lints that are emitted directly inside the main |
| //! compiler. |
| //! |
| //! 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` (also, note that such lints will need to be defined in |
| //! `rustc::lint::builtin`, not here). |
| //! |
| //! If you define a new `LintPass`, you will also need to add it to the |
| //! `add_builtin!` or `add_builtin_with_new!` invocation in `lib.rs`. |
| //! Use the former for unit-like structs and the latter for structs with |
| //! a `pub fn new()`. |
| |
| use rustc::hir::def::Def; |
| use rustc::hir::def_id::DefId; |
| use rustc::cfg; |
| use rustc::ty::subst::Substs; |
| use rustc::ty::{self, Ty, TyCtxt}; |
| use rustc::traits::{self, Reveal}; |
| use rustc::hir::map as hir_map; |
| use util::nodemap::NodeSet; |
| use lint::{Level, LateContext, LintContext, LintArray}; |
| use lint::{LintPass, LateLintPass, EarlyLintPass, EarlyContext}; |
| |
| use std::collections::HashSet; |
| |
| use syntax::ast; |
| use syntax::attr; |
| use syntax::feature_gate::{AttributeGate, AttributeType, Stability, deprecated_attributes}; |
| use syntax_pos::Span; |
| |
| use rustc::hir::{self, PatKind}; |
| use rustc::hir::intravisit::FnKind; |
| |
| use bad_style::{MethodLateContext, method_context}; |
| |
| // hardwired lints from librustc |
| pub use lint::builtin::*; |
| |
| declare_lint! { |
| WHILE_TRUE, |
| Warn, |
| "suggest using `loop { }` instead of `while true { }`" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct WhileTrue; |
| |
| impl LintPass for WhileTrue { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(WHILE_TRUE) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for WhileTrue { |
| fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) { |
| if let hir::ExprWhile(ref cond, ..) = e.node { |
| if let hir::ExprLit(ref lit) = cond.node { |
| if let ast::LitKind::Bool(true) = lit.node { |
| cx.span_lint(WHILE_TRUE, |
| e.span, |
| "denote infinite loops with loop { ... }"); |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| BOX_POINTERS, |
| Allow, |
| "use of owned (Box type) heap memory" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct BoxPointers; |
| |
| impl BoxPointers { |
| fn check_heap_type<'a, 'tcx>(&self, cx: &LateContext, span: Span, ty: Ty) { |
| for leaf_ty in ty.walk() { |
| if leaf_ty.is_box() { |
| let m = format!("type uses owned (Box type) pointers: {}", ty); |
| cx.span_lint(BOX_POINTERS, span, &m); |
| } |
| } |
| } |
| } |
| |
| impl LintPass for BoxPointers { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(BOX_POINTERS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxPointers { |
| fn check_item(&mut self, cx: &LateContext, it: &hir::Item) { |
| match it.node { |
| hir::ItemFn(..) | |
| hir::ItemTy(..) | |
| hir::ItemEnum(..) | |
| hir::ItemStruct(..) | |
| hir::ItemUnion(..) => { |
| let def_id = cx.tcx.hir.local_def_id(it.id); |
| self.check_heap_type(cx, it.span, cx.tcx.item_type(def_id)) |
| } |
| _ => () |
| } |
| |
| // If it's a struct, we also have to check the fields' types |
| match it.node { |
| hir::ItemStruct(ref struct_def, _) | |
| hir::ItemUnion(ref struct_def, _) => { |
| for struct_field in struct_def.fields() { |
| let def_id = cx.tcx.hir.local_def_id(struct_field.id); |
| self.check_heap_type(cx, struct_field.span, |
| cx.tcx.item_type(def_id)); |
| } |
| } |
| _ => (), |
| } |
| } |
| |
| fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) { |
| let ty = cx.tables.node_id_to_type(e.id); |
| self.check_heap_type(cx, e.span, ty); |
| } |
| } |
| |
| declare_lint! { |
| NON_SHORTHAND_FIELD_PATTERNS, |
| Warn, |
| "using `Struct { x: x }` instead of `Struct { x }`" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct NonShorthandFieldPatterns; |
| |
| impl LintPass for NonShorthandFieldPatterns { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(NON_SHORTHAND_FIELD_PATTERNS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NonShorthandFieldPatterns { |
| fn check_pat(&mut self, cx: &LateContext, pat: &hir::Pat) { |
| if let PatKind::Struct(_, ref field_pats, _) = pat.node { |
| for fieldpat in field_pats { |
| if fieldpat.node.is_shorthand { |
| continue; |
| } |
| if let PatKind::Binding(_, _, ident, None) = fieldpat.node.pat.node { |
| if ident.node == fieldpat.node.name { |
| cx.span_lint(NON_SHORTHAND_FIELD_PATTERNS, |
| fieldpat.span, |
| &format!("the `{}:` in this pattern is redundant and can \ |
| be removed", |
| ident.node)) |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| UNSAFE_CODE, |
| Allow, |
| "usage of `unsafe` code" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct UnsafeCode; |
| |
| impl LintPass for UnsafeCode { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(UNSAFE_CODE) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnsafeCode { |
| fn check_expr(&mut self, cx: &LateContext, e: &hir::Expr) { |
| if let hir::ExprBlock(ref blk) = e.node { |
| // Don't warn about generated blocks, that'll just pollute the output. |
| if blk.rules == hir::UnsafeBlock(hir::UserProvided) { |
| cx.span_lint(UNSAFE_CODE, blk.span, "usage of an `unsafe` block"); |
| } |
| } |
| } |
| |
| fn check_item(&mut self, cx: &LateContext, it: &hir::Item) { |
| match it.node { |
| hir::ItemTrait(hir::Unsafety::Unsafe, ..) => { |
| cx.span_lint(UNSAFE_CODE, it.span, "declaration of an `unsafe` trait") |
| } |
| |
| hir::ItemImpl(hir::Unsafety::Unsafe, ..) => { |
| cx.span_lint(UNSAFE_CODE, it.span, "implementation of an `unsafe` trait") |
| } |
| |
| _ => return, |
| } |
| } |
| |
| fn check_fn(&mut self, |
| cx: &LateContext, |
| fk: FnKind<'tcx>, |
| _: &hir::FnDecl, |
| _: &hir::Body, |
| span: Span, |
| _: ast::NodeId) { |
| match fk { |
| FnKind::ItemFn(_, _, hir::Unsafety::Unsafe, ..) => { |
| cx.span_lint(UNSAFE_CODE, span, "declaration of an `unsafe` function") |
| } |
| |
| FnKind::Method(_, sig, ..) => { |
| if sig.unsafety == hir::Unsafety::Unsafe { |
| cx.span_lint(UNSAFE_CODE, span, "implementation of an `unsafe` method") |
| } |
| } |
| |
| _ => (), |
| } |
| } |
| |
| fn check_trait_item(&mut self, cx: &LateContext, item: &hir::TraitItem) { |
| if let hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Required(_)) = item.node { |
| if sig.unsafety == hir::Unsafety::Unsafe { |
| cx.span_lint(UNSAFE_CODE, |
| item.span, |
| "declaration of an `unsafe` method") |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| MISSING_DOCS, |
| Allow, |
| "detects missing documentation for public members" |
| } |
| |
| pub struct MissingDoc { |
| /// Stack of IDs of struct definitions. |
| struct_def_stack: Vec<ast::NodeId>, |
| |
| /// True if inside variant definition |
| in_variant: bool, |
| |
| /// Stack of whether #[doc(hidden)] is set |
| /// at each level which has lint attributes. |
| doc_hidden_stack: Vec<bool>, |
| |
| /// Private traits or trait items that leaked through. Don't check their methods. |
| private_traits: HashSet<ast::NodeId>, |
| } |
| |
| impl MissingDoc { |
| pub fn new() -> MissingDoc { |
| MissingDoc { |
| struct_def_stack: vec![], |
| in_variant: false, |
| doc_hidden_stack: vec![false], |
| private_traits: HashSet::new(), |
| } |
| } |
| |
| fn doc_hidden(&self) -> bool { |
| *self.doc_hidden_stack.last().expect("empty doc_hidden_stack") |
| } |
| |
| fn check_missing_docs_attrs(&self, |
| cx: &LateContext, |
| id: Option<ast::NodeId>, |
| 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_docs 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). |
| if let Some(id) = id { |
| if !cx.access_levels.is_exported(id) { |
| return; |
| } |
| } |
| |
| let has_doc = attrs.iter().any(|a| a.is_value_str() && a.name() == "doc"); |
| if !has_doc { |
| cx.span_lint(MISSING_DOCS, |
| sp, |
| &format!("missing documentation for {}", desc)); |
| } |
| } |
| } |
| |
| impl LintPass for MissingDoc { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(MISSING_DOCS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDoc { |
| fn enter_lint_attrs(&mut self, _: &LateContext, 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::list_contains_name(&l[..], "hidden"), |
| } |
| }); |
| self.doc_hidden_stack.push(doc_hidden); |
| } |
| |
| fn exit_lint_attrs(&mut self, _: &LateContext, _attrs: &[ast::Attribute]) { |
| self.doc_hidden_stack.pop().expect("empty doc_hidden_stack"); |
| } |
| |
| fn check_struct_def(&mut self, |
| _: &LateContext, |
| _: &hir::VariantData, |
| _: ast::Name, |
| _: &hir::Generics, |
| item_id: ast::NodeId) { |
| self.struct_def_stack.push(item_id); |
| } |
| |
| fn check_struct_def_post(&mut self, |
| _: &LateContext, |
| _: &hir::VariantData, |
| _: ast::Name, |
| _: &hir::Generics, |
| item_id: ast::NodeId) { |
| let popped = self.struct_def_stack.pop().expect("empty struct_def_stack"); |
| assert!(popped == item_id); |
| } |
| |
| fn check_crate(&mut self, cx: &LateContext, krate: &hir::Crate) { |
| self.check_missing_docs_attrs(cx, None, &krate.attrs, krate.span, "crate"); |
| } |
| |
| fn check_item(&mut self, cx: &LateContext, it: &hir::Item) { |
| let desc = match it.node { |
| hir::ItemFn(..) => "a function", |
| hir::ItemMod(..) => "a module", |
| hir::ItemEnum(..) => "an enum", |
| hir::ItemStruct(..) => "a struct", |
| hir::ItemUnion(..) => "a union", |
| hir::ItemTrait(.., ref trait_item_refs) => { |
| // Issue #11592, traits are always considered exported, even when private. |
| if it.vis == hir::Visibility::Inherited { |
| self.private_traits.insert(it.id); |
| for trait_item_ref in trait_item_refs { |
| self.private_traits.insert(trait_item_ref.id.node_id); |
| } |
| return; |
| } |
| "a trait" |
| } |
| hir::ItemTy(..) => "a type alias", |
| hir::ItemImpl(.., Some(ref trait_ref), _, ref impl_item_refs) => { |
| // If the trait is private, add the impl items to private_traits so they don't get |
| // reported for missing docs. |
| let real_trait = trait_ref.path.def.def_id(); |
| if let Some(node_id) = cx.tcx.hir.as_local_node_id(real_trait) { |
| match cx.tcx.hir.find(node_id) { |
| Some(hir_map::NodeItem(item)) => { |
| if item.vis == hir::Visibility::Inherited { |
| for impl_item_ref in impl_item_refs { |
| self.private_traits.insert(impl_item_ref.id.node_id); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| return; |
| } |
| hir::ItemConst(..) => "a constant", |
| hir::ItemStatic(..) => "a static", |
| _ => return, |
| }; |
| |
| self.check_missing_docs_attrs(cx, Some(it.id), &it.attrs, it.span, desc); |
| } |
| |
| fn check_trait_item(&mut self, cx: &LateContext, trait_item: &hir::TraitItem) { |
| if self.private_traits.contains(&trait_item.id) { |
| return; |
| } |
| |
| let desc = match trait_item.node { |
| hir::TraitItemKind::Const(..) => "an associated constant", |
| hir::TraitItemKind::Method(..) => "a trait method", |
| hir::TraitItemKind::Type(..) => "an associated type", |
| }; |
| |
| self.check_missing_docs_attrs(cx, |
| Some(trait_item.id), |
| &trait_item.attrs, |
| trait_item.span, |
| desc); |
| } |
| |
| fn check_impl_item(&mut self, cx: &LateContext, impl_item: &hir::ImplItem) { |
| // If the method is an impl for a trait, don't doc. |
| if method_context(cx, impl_item.id, impl_item.span) == MethodLateContext::TraitImpl { |
| return; |
| } |
| |
| let desc = match impl_item.node { |
| hir::ImplItemKind::Const(..) => "an associated constant", |
| hir::ImplItemKind::Method(..) => "a method", |
| hir::ImplItemKind::Type(_) => "an associated type", |
| }; |
| self.check_missing_docs_attrs(cx, |
| Some(impl_item.id), |
| &impl_item.attrs, |
| impl_item.span, |
| desc); |
| } |
| |
| fn check_struct_field(&mut self, cx: &LateContext, sf: &hir::StructField) { |
| if !sf.is_positional() { |
| if sf.vis == hir::Public || self.in_variant { |
| let cur_struct_def = *self.struct_def_stack |
| .last() |
| .expect("empty struct_def_stack"); |
| self.check_missing_docs_attrs(cx, |
| Some(cur_struct_def), |
| &sf.attrs, |
| sf.span, |
| "a struct field") |
| } |
| } |
| } |
| |
| fn check_variant(&mut self, cx: &LateContext, v: &hir::Variant, _: &hir::Generics) { |
| self.check_missing_docs_attrs(cx, |
| Some(v.node.data.id()), |
| &v.node.attrs, |
| v.span, |
| "a variant"); |
| assert!(!self.in_variant); |
| self.in_variant = true; |
| } |
| |
| fn check_variant_post(&mut self, _: &LateContext, _: &hir::Variant, _: &hir::Generics) { |
| assert!(self.in_variant); |
| self.in_variant = false; |
| } |
| } |
| |
| declare_lint! { |
| pub MISSING_COPY_IMPLEMENTATIONS, |
| Allow, |
| "detects potentially-forgotten implementations of `Copy`" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct MissingCopyImplementations; |
| |
| impl LintPass for MissingCopyImplementations { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(MISSING_COPY_IMPLEMENTATIONS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingCopyImplementations { |
| fn check_item(&mut self, cx: &LateContext, item: &hir::Item) { |
| if !cx.access_levels.is_reachable(item.id) { |
| return; |
| } |
| let (def, ty) = match item.node { |
| hir::ItemStruct(_, ref ast_generics) => { |
| if ast_generics.is_parameterized() { |
| return; |
| } |
| let def = cx.tcx.lookup_adt_def(cx.tcx.hir.local_def_id(item.id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| hir::ItemUnion(_, ref ast_generics) => { |
| if ast_generics.is_parameterized() { |
| return; |
| } |
| let def = cx.tcx.lookup_adt_def(cx.tcx.hir.local_def_id(item.id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| hir::ItemEnum(_, ref ast_generics) => { |
| if ast_generics.is_parameterized() { |
| return; |
| } |
| let def = cx.tcx.lookup_adt_def(cx.tcx.hir.local_def_id(item.id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| _ => return, |
| }; |
| if def.has_dtor() { |
| return; |
| } |
| let parameter_environment = cx.tcx.empty_parameter_environment(); |
| // FIXME (@jroesch) should probably inver this so that the parameter env still impls this |
| // method |
| if !ty.moves_by_default(cx.tcx, ¶meter_environment, item.span) { |
| return; |
| } |
| if parameter_environment.can_type_implement_copy(cx.tcx, ty, item.span).is_ok() { |
| cx.span_lint(MISSING_COPY_IMPLEMENTATIONS, |
| item.span, |
| "type could implement `Copy`; consider adding `impl \ |
| Copy`") |
| } |
| } |
| } |
| |
| declare_lint! { |
| MISSING_DEBUG_IMPLEMENTATIONS, |
| Allow, |
| "detects missing implementations of fmt::Debug" |
| } |
| |
| pub struct MissingDebugImplementations { |
| impling_types: Option<NodeSet>, |
| } |
| |
| impl MissingDebugImplementations { |
| pub fn new() -> MissingDebugImplementations { |
| MissingDebugImplementations { impling_types: None } |
| } |
| } |
| |
| impl LintPass for MissingDebugImplementations { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(MISSING_DEBUG_IMPLEMENTATIONS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MissingDebugImplementations { |
| fn check_item(&mut self, cx: &LateContext, item: &hir::Item) { |
| if !cx.access_levels.is_reachable(item.id) { |
| return; |
| } |
| |
| match item.node { |
| hir::ItemStruct(..) | |
| hir::ItemUnion(..) | |
| hir::ItemEnum(..) => {} |
| _ => return, |
| } |
| |
| let debug = match cx.tcx.lang_items.debug_trait() { |
| Some(debug) => debug, |
| None => return, |
| }; |
| |
| if self.impling_types.is_none() { |
| let debug_def = cx.tcx.lookup_trait_def(debug); |
| let mut impls = NodeSet(); |
| debug_def.for_each_impl(cx.tcx, |d| { |
| if let Some(ty_def) = cx.tcx.item_type(d).ty_to_def_id() { |
| if let Some(node_id) = cx.tcx.hir.as_local_node_id(ty_def) { |
| impls.insert(node_id); |
| } |
| } |
| }); |
| |
| self.impling_types = Some(impls); |
| debug!("{:?}", self.impling_types); |
| } |
| |
| if !self.impling_types.as_ref().unwrap().contains(&item.id) { |
| cx.span_lint(MISSING_DEBUG_IMPLEMENTATIONS, |
| item.span, |
| "type does not implement `fmt::Debug`; consider adding #[derive(Debug)] \ |
| or a manual implementation") |
| } |
| } |
| } |
| |
| declare_lint! { |
| DEPRECATED_ATTR, |
| Warn, |
| "detects use of deprecated attributes" |
| } |
| |
| /// Checks for use of attributes which have been deprecated. |
| #[derive(Clone)] |
| pub struct DeprecatedAttr { |
| // This is not free to compute, so we want to keep it around, rather than |
| // compute it for every attribute. |
| depr_attrs: Vec<&'static (&'static str, AttributeType, AttributeGate)>, |
| } |
| |
| impl DeprecatedAttr { |
| pub fn new() -> DeprecatedAttr { |
| DeprecatedAttr { |
| depr_attrs: deprecated_attributes(), |
| } |
| } |
| } |
| |
| impl LintPass for DeprecatedAttr { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(DEPRECATED_ATTR) |
| } |
| } |
| |
| impl EarlyLintPass for DeprecatedAttr { |
| fn check_attribute(&mut self, cx: &EarlyContext, attr: &ast::Attribute) { |
| let name = attr.name(); |
| for &&(n, _, ref g) in &self.depr_attrs { |
| if name == n { |
| if let &AttributeGate::Gated(Stability::Deprecated(link), |
| ref name, |
| ref reason, |
| _) = g { |
| cx.span_lint(DEPRECATED, |
| attr.span, |
| &format!("use of deprecated attribute `{}`: {}. See {}", |
| name, reason, link)); |
| } |
| return; |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub UNCONDITIONAL_RECURSION, |
| Warn, |
| "functions that cannot return without calling themselves" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct UnconditionalRecursion; |
| |
| |
| impl LintPass for UnconditionalRecursion { |
| fn get_lints(&self) -> LintArray { |
| lint_array![UNCONDITIONAL_RECURSION] |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnconditionalRecursion { |
| fn check_fn(&mut self, |
| cx: &LateContext, |
| fn_kind: FnKind, |
| _: &hir::FnDecl, |
| body: &hir::Body, |
| sp: Span, |
| id: ast::NodeId) { |
| let method = match fn_kind { |
| FnKind::ItemFn(..) => None, |
| FnKind::Method(..) => { |
| Some(cx.tcx.associated_item(cx.tcx.hir.local_def_id(id))) |
| } |
| // closures can't recur, so they don't matter. |
| FnKind::Closure(_) => return, |
| }; |
| |
| // Walk through this function (say `f`) looking to see if |
| // every possible path references itself, i.e. the function is |
| // called recursively unconditionally. This is done by trying |
| // to find a path from the entry node to the exit node that |
| // *doesn't* call `f` by traversing from the entry while |
| // pretending that calls of `f` are sinks (i.e. ignoring any |
| // exit edges from them). |
| // |
| // NB. this has an edge case with non-returning statements, |
| // like `loop {}` or `panic!()`: control flow never reaches |
| // the exit node through these, so one can have a function |
| // that never actually calls itselfs but is still picked up by |
| // this lint: |
| // |
| // fn f(cond: bool) { |
| // if !cond { panic!() } // could come from `assert!(cond)` |
| // f(false) |
| // } |
| // |
| // In general, functions of that form may be able to call |
| // itself a finite number of times and then diverge. The lint |
| // considers this to be an error for two reasons, (a) it is |
| // easier to implement, and (b) it seems rare to actually want |
| // to have behaviour like the above, rather than |
| // e.g. accidentally recurring after an assert. |
| |
| let cfg = cfg::CFG::new(cx.tcx, &body.value); |
| |
| let mut work_queue = vec![cfg.entry]; |
| let mut reached_exit_without_self_call = false; |
| let mut self_call_spans = vec![]; |
| let mut visited = HashSet::new(); |
| |
| while let Some(idx) = work_queue.pop() { |
| if idx == cfg.exit { |
| // found a path! |
| reached_exit_without_self_call = true; |
| break; |
| } |
| |
| let cfg_id = idx.node_id(); |
| if visited.contains(&cfg_id) { |
| // already done |
| continue; |
| } |
| visited.insert(cfg_id); |
| |
| let node_id = cfg.graph.node_data(idx).id(); |
| |
| // is this a recursive call? |
| let self_recursive = if node_id != ast::DUMMY_NODE_ID { |
| match method { |
| Some(ref method) => expr_refers_to_this_method(cx, method, node_id), |
| None => expr_refers_to_this_fn(cx, id, node_id), |
| } |
| } else { |
| false |
| }; |
| if self_recursive { |
| self_call_spans.push(cx.tcx.hir.span(node_id)); |
| // this is a self call, so we shouldn't explore past |
| // this node in the CFG. |
| continue; |
| } |
| // add the successors of this node to explore the graph further. |
| for (_, edge) in cfg.graph.outgoing_edges(idx) { |
| let target_idx = edge.target(); |
| let target_cfg_id = target_idx.node_id(); |
| if !visited.contains(&target_cfg_id) { |
| work_queue.push(target_idx) |
| } |
| } |
| } |
| |
| // Check the number of self calls because a function that |
| // doesn't return (e.g. calls a `-> !` function or `loop { /* |
| // no break */ }`) shouldn't be linted unless it actually |
| // recurs. |
| if !reached_exit_without_self_call && !self_call_spans.is_empty() { |
| let mut db = cx.struct_span_lint(UNCONDITIONAL_RECURSION, |
| sp, |
| "function cannot return without recurring"); |
| |
| // FIXME #19668: these could be span_lint_note's instead of this manual guard. |
| if cx.current_level(UNCONDITIONAL_RECURSION) != Level::Allow { |
| // offer some help to the programmer. |
| for call in &self_call_spans { |
| db.span_note(*call, "recursive call site"); |
| } |
| db.help("a `loop` may express intention \ |
| better if this is on purpose"); |
| } |
| db.emit(); |
| } |
| |
| // all done |
| return; |
| |
| // Functions for identifying if the given Expr NodeId `id` |
| // represents a call to the function `fn_id`/method `method`. |
| |
| fn expr_refers_to_this_fn(cx: &LateContext, fn_id: ast::NodeId, id: ast::NodeId) -> bool { |
| match cx.tcx.hir.get(id) { |
| hir_map::NodeExpr(&hir::Expr { node: hir::ExprCall(ref callee, _), .. }) => { |
| let def = if let hir::ExprPath(ref qpath) = callee.node { |
| cx.tables.qpath_def(qpath, callee.id) |
| } else { |
| return false; |
| }; |
| def.def_id() == cx.tcx.hir.local_def_id(fn_id) |
| } |
| _ => false, |
| } |
| } |
| |
| // Check if the expression `id` performs a call to `method`. |
| fn expr_refers_to_this_method(cx: &LateContext, |
| method: &ty::AssociatedItem, |
| id: ast::NodeId) |
| -> bool { |
| use rustc::ty::adjustment::*; |
| |
| // Check for method calls and overloaded operators. |
| let opt_m = cx.tables.method_map.get(&ty::MethodCall::expr(id)).cloned(); |
| if let Some(m) = opt_m { |
| if method_call_refers_to_method(cx.tcx, method, m.def_id, m.substs, id) { |
| return true; |
| } |
| } |
| |
| // Check for overloaded autoderef method calls. |
| let opt_adj = cx.tables.adjustments.get(&id).cloned(); |
| if let Some(Adjustment { kind: Adjust::DerefRef { autoderefs, .. }, .. }) = opt_adj { |
| for i in 0..autoderefs { |
| let method_call = ty::MethodCall::autoderef(id, i as u32); |
| if let Some(m) = cx.tables.method_map.get(&method_call).cloned() { |
| if method_call_refers_to_method(cx.tcx, method, m.def_id, m.substs, id) { |
| return true; |
| } |
| } |
| } |
| } |
| |
| // Check for calls to methods via explicit paths (e.g. `T::method()`). |
| match cx.tcx.hir.get(id) { |
| hir_map::NodeExpr(&hir::Expr { node: hir::ExprCall(ref callee, _), .. }) => { |
| let def = if let hir::ExprPath(ref qpath) = callee.node { |
| cx.tables.qpath_def(qpath, callee.id) |
| } else { |
| return false; |
| }; |
| match def { |
| Def::Method(def_id) => { |
| let substs = cx.tables.node_id_item_substs(callee.id) |
| .unwrap_or_else(|| cx.tcx.intern_substs(&[])); |
| method_call_refers_to_method( |
| cx.tcx, method, def_id, substs, id) |
| } |
| _ => false, |
| } |
| } |
| _ => false, |
| } |
| } |
| |
| // Check if the method call to the method with the ID `callee_id` |
| // and instantiated with `callee_substs` refers to method `method`. |
| fn method_call_refers_to_method<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| method: &ty::AssociatedItem, |
| callee_id: DefId, |
| callee_substs: &Substs<'tcx>, |
| expr_id: ast::NodeId) |
| -> bool { |
| let callee_item = tcx.associated_item(callee_id); |
| |
| match callee_item.container { |
| // This is an inherent method, so the `def_id` refers |
| // directly to the method definition. |
| ty::ImplContainer(_) => callee_id == method.def_id, |
| |
| // A trait method, from any number of possible sources. |
| // Attempt to select a concrete impl before checking. |
| ty::TraitContainer(trait_def_id) => { |
| let trait_ref = ty::TraitRef::from_method(tcx, trait_def_id, callee_substs); |
| let trait_ref = ty::Binder(trait_ref); |
| let span = tcx.hir.span(expr_id); |
| let obligation = |
| traits::Obligation::new(traits::ObligationCause::misc(span, expr_id), |
| trait_ref.to_poly_trait_predicate()); |
| |
| // unwrap() is ok here b/c `method` is the method |
| // defined in this crate whose body we are |
| // checking, so it's always local |
| let node_id = tcx.hir.as_local_node_id(method.def_id).unwrap(); |
| |
| let param_env = ty::ParameterEnvironment::for_item(tcx, node_id); |
| tcx.infer_ctxt(param_env, Reveal::NotSpecializable).enter(|infcx| { |
| let mut selcx = traits::SelectionContext::new(&infcx); |
| match selcx.select(&obligation) { |
| // The method comes from a `T: Trait` bound. |
| // If `T` is `Self`, then this call is inside |
| // a default method definition. |
| Ok(Some(traits::VtableParam(_))) => { |
| let on_self = trait_ref.self_ty().is_self(); |
| // We can only be recurring in a default |
| // method if we're being called literally |
| // on the `Self` type. |
| on_self && callee_id == method.def_id |
| } |
| |
| // The `impl` is known, so we check that with a |
| // special case: |
| Ok(Some(traits::VtableImpl(vtable_impl))) => { |
| let container = ty::ImplContainer(vtable_impl.impl_def_id); |
| // It matches if it comes from the same impl, |
| // and has the same method name. |
| container == method.container && callee_item.name == method.name |
| } |
| |
| // There's no way to know if this call is |
| // recursive, so we assume it's not. |
| _ => false, |
| } |
| }) |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| PLUGIN_AS_LIBRARY, |
| Warn, |
| "compiler plugin used as ordinary library in non-plugin crate" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct PluginAsLibrary; |
| |
| impl LintPass for PluginAsLibrary { |
| fn get_lints(&self) -> LintArray { |
| lint_array![PLUGIN_AS_LIBRARY] |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for PluginAsLibrary { |
| fn check_item(&mut self, cx: &LateContext, it: &hir::Item) { |
| if cx.sess().plugin_registrar_fn.get().is_some() { |
| // We're compiling a plugin; it's fine to link other plugins. |
| return; |
| } |
| |
| match it.node { |
| hir::ItemExternCrate(..) => (), |
| _ => return, |
| }; |
| |
| let prfn = match cx.sess().cstore.extern_mod_stmt_cnum(it.id) { |
| Some(cnum) => cx.sess().cstore.plugin_registrar_fn(cnum), |
| None => { |
| // Probably means we aren't linking the crate for some reason. |
| // |
| // Not sure if / when this could happen. |
| return; |
| } |
| }; |
| |
| if prfn.is_some() { |
| cx.span_lint(PLUGIN_AS_LIBRARY, |
| it.span, |
| "compiler plugin used as an ordinary library"); |
| } |
| } |
| } |
| |
| declare_lint! { |
| PRIVATE_NO_MANGLE_FNS, |
| Warn, |
| "functions marked #[no_mangle] should be exported" |
| } |
| |
| declare_lint! { |
| PRIVATE_NO_MANGLE_STATICS, |
| Warn, |
| "statics marked #[no_mangle] should be exported" |
| } |
| |
| declare_lint! { |
| NO_MANGLE_CONST_ITEMS, |
| Deny, |
| "const items will not have their symbols exported" |
| } |
| |
| declare_lint! { |
| NO_MANGLE_GENERIC_ITEMS, |
| Warn, |
| "generic items must be mangled" |
| } |
| |
| #[derive(Copy, Clone)] |
| pub struct InvalidNoMangleItems; |
| |
| impl LintPass for InvalidNoMangleItems { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(PRIVATE_NO_MANGLE_FNS, |
| PRIVATE_NO_MANGLE_STATICS, |
| NO_MANGLE_CONST_ITEMS, |
| NO_MANGLE_GENERIC_ITEMS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidNoMangleItems { |
| fn check_item(&mut self, cx: &LateContext, it: &hir::Item) { |
| match it.node { |
| hir::ItemFn(.., ref generics, _) => { |
| if attr::contains_name(&it.attrs, "no_mangle") { |
| if !cx.access_levels.is_reachable(it.id) { |
| let msg = format!("function {} is marked #[no_mangle], but not exported", |
| it.name); |
| cx.span_lint(PRIVATE_NO_MANGLE_FNS, it.span, &msg); |
| } |
| if generics.is_parameterized() { |
| cx.span_lint(NO_MANGLE_GENERIC_ITEMS, |
| it.span, |
| "generic functions must be mangled"); |
| } |
| } |
| } |
| hir::ItemStatic(..) => { |
| if attr::contains_name(&it.attrs, "no_mangle") && |
| !cx.access_levels.is_reachable(it.id) { |
| let msg = format!("static {} is marked #[no_mangle], but not exported", |
| it.name); |
| cx.span_lint(PRIVATE_NO_MANGLE_STATICS, it.span, &msg); |
| } |
| } |
| hir::ItemConst(..) => { |
| if attr::contains_name(&it.attrs, "no_mangle") { |
| // Const items do not refer to a particular location in memory, and therefore |
| // don't have anything to attach a symbol to |
| let msg = "const items should never be #[no_mangle], consider instead using \ |
| `pub static`"; |
| cx.span_lint(NO_MANGLE_CONST_ITEMS, it.span, msg); |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| #[derive(Clone, Copy)] |
| pub struct MutableTransmutes; |
| |
| declare_lint! { |
| MUTABLE_TRANSMUTES, |
| Deny, |
| "mutating transmuted &mut T from &T may cause undefined behavior" |
| } |
| |
| impl LintPass for MutableTransmutes { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(MUTABLE_TRANSMUTES) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes { |
| fn check_expr(&mut self, cx: &LateContext, expr: &hir::Expr) { |
| use syntax::abi::Abi::RustIntrinsic; |
| |
| let msg = "mutating transmuted &mut T from &T may cause undefined behavior, \ |
| consider instead using an UnsafeCell"; |
| match get_transmute_from_to(cx, expr) { |
| Some((&ty::TyRef(_, from_mt), &ty::TyRef(_, to_mt))) => { |
| if to_mt.mutbl == hir::Mutability::MutMutable && |
| from_mt.mutbl == hir::Mutability::MutImmutable { |
| cx.span_lint(MUTABLE_TRANSMUTES, expr.span, msg); |
| } |
| } |
| _ => (), |
| } |
| |
| fn get_transmute_from_to<'a, 'tcx> |
| (cx: &LateContext<'a, 'tcx>, |
| expr: &hir::Expr) |
| -> Option<(&'tcx ty::TypeVariants<'tcx>, &'tcx ty::TypeVariants<'tcx>)> { |
| let def = if let hir::ExprPath(ref qpath) = expr.node { |
| cx.tables.qpath_def(qpath, expr.id) |
| } else { |
| return None; |
| }; |
| if let Def::Fn(did) = def { |
| if !def_id_is_transmute(cx, did) { |
| return None; |
| } |
| let typ = cx.tables.node_id_to_type(expr.id); |
| match typ.sty { |
| ty::TyFnDef(.., ref bare_fn) if bare_fn.abi == RustIntrinsic => { |
| let from = bare_fn.sig.skip_binder().inputs()[0]; |
| let to = bare_fn.sig.skip_binder().output(); |
| return Some((&from.sty, &to.sty)); |
| } |
| _ => (), |
| } |
| } |
| None |
| } |
| |
| fn def_id_is_transmute(cx: &LateContext, def_id: DefId) -> bool { |
| match cx.tcx.item_type(def_id).sty { |
| ty::TyFnDef(.., ref bfty) if bfty.abi == RustIntrinsic => (), |
| _ => return false, |
| } |
| cx.tcx.item_name(def_id) == "transmute" |
| } |
| } |
| } |
| |
| /// Forbids using the `#[feature(...)]` attribute |
| #[derive(Copy, Clone)] |
| pub struct UnstableFeatures; |
| |
| declare_lint! { |
| UNSTABLE_FEATURES, |
| Allow, |
| "enabling unstable features (deprecated. do not use)" |
| } |
| |
| impl LintPass for UnstableFeatures { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(UNSTABLE_FEATURES) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnstableFeatures { |
| fn check_attribute(&mut self, ctx: &LateContext, attr: &ast::Attribute) { |
| if attr.meta().check_name("feature") { |
| if let Some(items) = attr.meta().meta_item_list() { |
| for item in items { |
| ctx.span_lint(UNSTABLE_FEATURES, item.span(), "unstable feature"); |
| } |
| } |
| } |
| } |
| } |
| |
| /// Lint for unions that contain fields with possibly non-trivial destructors. |
| pub struct UnionsWithDropFields; |
| |
| declare_lint! { |
| UNIONS_WITH_DROP_FIELDS, |
| Warn, |
| "use of unions that contain fields with possibly non-trivial drop code" |
| } |
| |
| impl LintPass for UnionsWithDropFields { |
| fn get_lints(&self) -> LintArray { |
| lint_array!(UNIONS_WITH_DROP_FIELDS) |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnionsWithDropFields { |
| fn check_item(&mut self, ctx: &LateContext, item: &hir::Item) { |
| if let hir::ItemUnion(ref vdata, _) = item.node { |
| let param_env = &ty::ParameterEnvironment::for_item(ctx.tcx, item.id); |
| for field in vdata.fields() { |
| let field_ty = ctx.tcx.item_type(ctx.tcx.hir.local_def_id(field.id)); |
| if ctx.tcx.type_needs_drop_given_env(field_ty, param_env) { |
| ctx.span_lint(UNIONS_WITH_DROP_FIELDS, |
| field.span, |
| "union contains a field with possibly non-trivial drop code, \ |
| drop code of union fields is ignored when dropping the union"); |
| return; |
| } |
| } |
| } |
| } |
| } |
