| //! 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 `EarlyLintPass`, you will also need to add it to the |
| //! `add_early_builtin!` or `add_early_builtin_with_new!` invocation in |
| //! `lib.rs`. Use the former for unit-like structs and the latter for structs |
| //! with a `pub fn new()`. |
| //! |
| //! If you define a new `LateLintPass`, you will also need to add it to the |
| //! `late_lint_methods!` invocation in `lib.rs`. |
| |
| use std::fmt::Write; |
| |
| use rustc::hir::def::{Res, DefKind}; |
| use rustc::hir::def_id::DefId; |
| use rustc::ty::{self, Ty, TyCtxt, layout::VariantIdx}; |
| use rustc::{lint, util}; |
| use rustc::lint::FutureIncompatibleInfo; |
| use hir::Node; |
| use util::nodemap::HirIdSet; |
| use lint::{LateContext, LintContext, LintArray}; |
| use lint::{LintPass, LateLintPass, EarlyLintPass, EarlyContext}; |
| |
| use rustc::util::nodemap::FxHashSet; |
| use rustc_feature::{AttributeGate, AttributeTemplate, AttributeType, deprecated_attributes}; |
| use rustc_feature::Stability; |
| |
| use syntax::tokenstream::{TokenTree, TokenStream}; |
| use syntax::ast::{self, Expr}; |
| use syntax::ptr::P; |
| use syntax::attr::{self, HasAttrs}; |
| use syntax::source_map::Spanned; |
| use syntax::edition::Edition; |
| use syntax_pos::{BytePos, Span}; |
| use syntax::symbol::{Symbol, kw, sym}; |
| use syntax::errors::{Applicability, DiagnosticBuilder}; |
| use syntax::print::pprust::{self, expr_to_string}; |
| use syntax::visit::FnKind; |
| |
| use rustc::hir::{self, GenericParamKind, PatKind}; |
| |
| use crate::nonstandard_style::{MethodLateContext, method_context}; |
| |
| use log::debug; |
| |
| // hardwired lints from librustc |
| pub use lint::builtin::*; |
| |
| declare_lint! { |
| WHILE_TRUE, |
| Warn, |
| "suggest using `loop { }` instead of `while true { }`" |
| } |
| |
| declare_lint_pass!(WhileTrue => [WHILE_TRUE]); |
| |
| /// Traverse through any amount of parenthesis and return the first non-parens expression. |
| fn pierce_parens(mut expr: &ast::Expr) -> &ast::Expr { |
| while let ast::ExprKind::Paren(sub) = &expr.kind { |
| expr = sub; |
| } |
| expr |
| } |
| |
| impl EarlyLintPass for WhileTrue { |
| fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) { |
| if let ast::ExprKind::While(cond, ..) = &e.kind { |
| if let ast::ExprKind::Lit(ref lit) = pierce_parens(cond).kind { |
| if let ast::LitKind::Bool(true) = lit.kind { |
| if !lit.span.from_expansion() { |
| let msg = "denote infinite loops with `loop { ... }`"; |
| let condition_span = cx.sess.source_map().def_span(e.span); |
| cx.struct_span_lint(WHILE_TRUE, condition_span, msg) |
| .span_suggestion_short( |
| condition_span, |
| "use `loop`", |
| "loop".to_owned(), |
| Applicability::MachineApplicable |
| ) |
| .emit(); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| BOX_POINTERS, |
| Allow, |
| "use of owned (Box type) heap memory" |
| } |
| |
| declare_lint_pass!(BoxPointers => [BOX_POINTERS]); |
| |
| impl BoxPointers { |
| fn check_heap_type(&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<'a, 'tcx> LateLintPass<'a, 'tcx> for BoxPointers { |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) { |
| match it.kind { |
| hir::ItemKind::Fn(..) | |
| hir::ItemKind::TyAlias(..) | |
| hir::ItemKind::Enum(..) | |
| hir::ItemKind::Struct(..) | |
| hir::ItemKind::Union(..) => { |
| let def_id = cx.tcx.hir().local_def_id(it.hir_id); |
| self.check_heap_type(cx, it.span, cx.tcx.type_of(def_id)) |
| } |
| _ => () |
| } |
| |
| // If it's a struct, we also have to check the fields' types |
| match it.kind { |
| hir::ItemKind::Struct(ref struct_def, _) | |
| hir::ItemKind::Union(ref struct_def, _) => { |
| for struct_field in struct_def.fields() { |
| let def_id = cx.tcx.hir().local_def_id(struct_field.hir_id); |
| self.check_heap_type(cx, struct_field.span, |
| cx.tcx.type_of(def_id)); |
| } |
| } |
| _ => (), |
| } |
| } |
| |
| fn check_expr(&mut self, cx: &LateContext<'_, '_>, e: &hir::Expr) { |
| let ty = cx.tables.node_type(e.hir_id); |
| self.check_heap_type(cx, e.span, ty); |
| } |
| } |
| |
| declare_lint! { |
| NON_SHORTHAND_FIELD_PATTERNS, |
| Warn, |
| "using `Struct { x: x }` instead of `Struct { x }` in a pattern" |
| } |
| |
| declare_lint_pass!(NonShorthandFieldPatterns => [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 qpath, ref field_pats, _) = pat.kind { |
| let variant = cx.tables.pat_ty(pat).ty_adt_def() |
| .expect("struct pattern type is not an ADT") |
| .variant_of_res(cx.tables.qpath_res(qpath, pat.hir_id)); |
| for fieldpat in field_pats { |
| if fieldpat.is_shorthand { |
| continue; |
| } |
| if fieldpat.span.from_expansion() { |
| // Don't lint if this is a macro expansion: macro authors |
| // shouldn't have to worry about this kind of style issue |
| // (Issue #49588) |
| continue; |
| } |
| if let PatKind::Binding(_, _, ident, None) = fieldpat.pat.kind { |
| if cx.tcx.find_field_index(ident, &variant) == |
| Some(cx.tcx.field_index(fieldpat.hir_id, cx.tables)) { |
| let mut err = cx.struct_span_lint(NON_SHORTHAND_FIELD_PATTERNS, |
| fieldpat.span, |
| &format!("the `{}:` in this pattern is redundant", ident)); |
| let subspan = cx.tcx.sess.source_map().span_through_char(fieldpat.span, |
| ':'); |
| err.span_suggestion_short( |
| subspan, |
| "remove this", |
| ident.to_string(), |
| Applicability::MachineApplicable |
| ); |
| err.emit(); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| UNSAFE_CODE, |
| Allow, |
| "usage of `unsafe` code" |
| } |
| |
| declare_lint_pass!(UnsafeCode => [UNSAFE_CODE]); |
| |
| impl UnsafeCode { |
| fn report_unsafe(&self, cx: &EarlyContext<'_>, span: Span, desc: &'static str) { |
| // This comes from a macro that has `#[allow_internal_unsafe]`. |
| if span.allows_unsafe() { |
| return; |
| } |
| |
| cx.span_lint(UNSAFE_CODE, span, desc); |
| } |
| } |
| |
| impl EarlyLintPass for UnsafeCode { |
| fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) { |
| if attr.check_name(sym::allow_internal_unsafe) { |
| self.report_unsafe(cx, attr.span, "`allow_internal_unsafe` allows defining \ |
| macros using unsafe without triggering \ |
| the `unsafe_code` lint at their call site"); |
| } |
| } |
| |
| fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) { |
| if let ast::ExprKind::Block(ref blk, _) = e.kind { |
| // Don't warn about generated blocks; that'll just pollute the output. |
| if blk.rules == ast::BlockCheckMode::Unsafe(ast::UserProvided) { |
| self.report_unsafe(cx, blk.span, "usage of an `unsafe` block"); |
| } |
| } |
| } |
| |
| fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) { |
| match it.kind { |
| ast::ItemKind::Trait(_, ast::Unsafety::Unsafe, ..) => { |
| self.report_unsafe(cx, it.span, "declaration of an `unsafe` trait") |
| } |
| |
| ast::ItemKind::Impl(ast::Unsafety::Unsafe, ..) => { |
| self.report_unsafe(cx, it.span, "implementation of an `unsafe` trait") |
| } |
| |
| _ => return, |
| } |
| } |
| |
| fn check_fn(&mut self, |
| cx: &EarlyContext<'_>, |
| fk: FnKind<'_>, |
| _: &ast::FnDecl, |
| span: Span, |
| _: ast::NodeId) { |
| match fk { |
| FnKind::ItemFn(_, ast::FnHeader { unsafety: ast::Unsafety::Unsafe, .. }, ..) => { |
| self.report_unsafe(cx, span, "declaration of an `unsafe` function") |
| } |
| |
| FnKind::Method(_, sig, ..) => { |
| if sig.header.unsafety == ast::Unsafety::Unsafe { |
| self.report_unsafe(cx, span, "implementation of an `unsafe` method") |
| } |
| } |
| |
| _ => (), |
| } |
| } |
| |
| fn check_trait_item(&mut self, cx: &EarlyContext<'_>, item: &ast::TraitItem) { |
| if let ast::TraitItemKind::Method(ref sig, None) = item.kind { |
| if sig.header.unsafety == ast::Unsafety::Unsafe { |
| self.report_unsafe(cx, item.span, "declaration of an `unsafe` method") |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub MISSING_DOCS, |
| Allow, |
| "detects missing documentation for public members", |
| report_in_external_macro |
| } |
| |
| pub struct MissingDoc { |
| /// 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: FxHashSet<hir::HirId>, |
| } |
| |
| impl_lint_pass!(MissingDoc => [MISSING_DOCS]); |
| |
| fn has_doc(attr: &ast::Attribute) -> bool { |
| if !attr.check_name(sym::doc) { |
| return false; |
| } |
| |
| if attr.is_value_str() { |
| return true; |
| } |
| |
| if let Some(list) = attr.meta_item_list() { |
| for meta in list { |
| if meta.check_name(sym::include) || meta.check_name(sym::hidden) { |
| return true; |
| } |
| } |
| } |
| |
| false |
| } |
| |
| impl MissingDoc { |
| pub fn new() -> MissingDoc { |
| MissingDoc { |
| doc_hidden_stack: vec![false], |
| private_traits: FxHashSet::default(), |
| } |
| } |
| |
| 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<hir::HirId>, |
| 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| has_doc(a)); |
| if !has_doc { |
| cx.span_lint(MISSING_DOCS, |
| cx.tcx.sess.source_map().def_span(sp), |
| &format!("missing documentation for {}", desc)); |
| } |
| } |
| } |
| |
| 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(sym::doc) && |
| match attr.meta_item_list() { |
| None => false, |
| Some(l) => attr::list_contains_name(&l, sym::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_crate(&mut self, cx: &LateContext<'_, '_>, krate: &hir::Crate) { |
| self.check_missing_docs_attrs(cx, None, &krate.attrs, krate.span, "crate"); |
| |
| for macro_def in &krate.exported_macros { |
| let has_doc = macro_def.attrs.iter().any(|a| has_doc(a)); |
| if !has_doc { |
| cx.span_lint(MISSING_DOCS, |
| cx.tcx.sess.source_map().def_span(macro_def.span), |
| "missing documentation for macro"); |
| } |
| } |
| } |
| |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) { |
| let desc = match it.kind { |
| hir::ItemKind::Fn(..) => "a function", |
| hir::ItemKind::Mod(..) => "a module", |
| hir::ItemKind::Enum(..) => "an enum", |
| hir::ItemKind::Struct(..) => "a struct", |
| hir::ItemKind::Union(..) => "a union", |
| hir::ItemKind::Trait(.., ref trait_item_refs) => { |
| // Issue #11592: traits are always considered exported, even when private. |
| if let hir::VisibilityKind::Inherited = it.vis.node { |
| self.private_traits.insert(it.hir_id); |
| for trait_item_ref in trait_item_refs { |
| self.private_traits.insert(trait_item_ref.id.hir_id); |
| } |
| return; |
| } |
| "a trait" |
| } |
| hir::ItemKind::TyAlias(..) => "a type alias", |
| hir::ItemKind::Impl(.., 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.res.def_id(); |
| if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(real_trait) { |
| match cx.tcx.hir().find(hir_id) { |
| Some(Node::Item(item)) => { |
| if let hir::VisibilityKind::Inherited = item.vis.node { |
| for impl_item_ref in impl_item_refs { |
| self.private_traits.insert(impl_item_ref.id.hir_id); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| return; |
| } |
| hir::ItemKind::Const(..) => "a constant", |
| hir::ItemKind::Static(..) => "a static", |
| _ => return, |
| }; |
| |
| self.check_missing_docs_attrs(cx, Some(it.hir_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.hir_id) { |
| return; |
| } |
| |
| let desc = match trait_item.kind { |
| 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.hir_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.hir_id) == MethodLateContext::TraitImpl { |
| return; |
| } |
| |
| let desc = match impl_item.kind { |
| hir::ImplItemKind::Const(..) => "an associated constant", |
| hir::ImplItemKind::Method(..) => "a method", |
| hir::ImplItemKind::TyAlias(_) => "an associated type", |
| hir::ImplItemKind::OpaqueTy(_) => "an associated `impl Trait` type", |
| }; |
| self.check_missing_docs_attrs(cx, |
| Some(impl_item.hir_id), |
| &impl_item.attrs, |
| impl_item.span, |
| desc); |
| } |
| |
| fn check_struct_field(&mut self, cx: &LateContext<'_, '_>, sf: &hir::StructField) { |
| if !sf.is_positional() { |
| self.check_missing_docs_attrs(cx, |
| Some(sf.hir_id), |
| &sf.attrs, |
| sf.span, |
| "a struct field") |
| } |
| } |
| |
| fn check_variant(&mut self, cx: &LateContext<'_, '_>, v: &hir::Variant) { |
| self.check_missing_docs_attrs(cx, |
| Some(v.id), |
| &v.attrs, |
| v.span, |
| "a variant"); |
| } |
| } |
| |
| declare_lint! { |
| pub MISSING_COPY_IMPLEMENTATIONS, |
| Allow, |
| "detects potentially-forgotten implementations of `Copy`" |
| } |
| |
| declare_lint_pass!(MissingCopyImplementations => [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.hir_id) { |
| return; |
| } |
| let (def, ty) = match item.kind { |
| hir::ItemKind::Struct(_, ref ast_generics) => { |
| if !ast_generics.params.is_empty() { |
| return; |
| } |
| let def = cx.tcx.adt_def(cx.tcx.hir().local_def_id(item.hir_id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| hir::ItemKind::Union(_, ref ast_generics) => { |
| if !ast_generics.params.is_empty() { |
| return; |
| } |
| let def = cx.tcx.adt_def(cx.tcx.hir().local_def_id(item.hir_id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| hir::ItemKind::Enum(_, ref ast_generics) => { |
| if !ast_generics.params.is_empty() { |
| return; |
| } |
| let def = cx.tcx.adt_def(cx.tcx.hir().local_def_id(item.hir_id)); |
| (def, cx.tcx.mk_adt(def, cx.tcx.intern_substs(&[]))) |
| } |
| _ => return, |
| }; |
| if def.has_dtor(cx.tcx) { |
| return; |
| } |
| let param_env = ty::ParamEnv::empty(); |
| if ty.is_copy_modulo_regions(cx.tcx, param_env, item.span) { |
| return; |
| } |
| if param_env.can_type_implement_copy(cx.tcx, ty).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" |
| } |
| |
| #[derive(Default)] |
| pub struct MissingDebugImplementations { |
| impling_types: Option<HirIdSet>, |
| } |
| |
| impl_lint_pass!(MissingDebugImplementations => [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.hir_id) { |
| return; |
| } |
| |
| match item.kind { |
| hir::ItemKind::Struct(..) | |
| hir::ItemKind::Union(..) | |
| hir::ItemKind::Enum(..) => {} |
| _ => return, |
| } |
| |
| let debug = match cx.tcx.get_diagnostic_item(sym::debug_trait) { |
| Some(debug) => debug, |
| None => return, |
| }; |
| |
| if self.impling_types.is_none() { |
| let mut impls = HirIdSet::default(); |
| cx.tcx.for_each_impl(debug, |d| { |
| if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() { |
| if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(ty_def.did) { |
| impls.insert(hir_id); |
| } |
| } |
| }); |
| |
| self.impling_types = Some(impls); |
| debug!("{:?}", self.impling_types); |
| } |
| |
| if !self.impling_types.as_ref().unwrap().contains(&item.hir_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! { |
| pub ANONYMOUS_PARAMETERS, |
| Allow, |
| "detects anonymous parameters", |
| @future_incompatible = FutureIncompatibleInfo { |
| reference: "issue #41686 <https://github.com/rust-lang/rust/issues/41686>", |
| edition: Some(Edition::Edition2018), |
| }; |
| } |
| |
| declare_lint_pass!( |
| /// Checks for use of anonymous parameters (RFC 1685). |
| AnonymousParameters => [ANONYMOUS_PARAMETERS] |
| ); |
| |
| impl EarlyLintPass for AnonymousParameters { |
| fn check_trait_item(&mut self, cx: &EarlyContext<'_>, it: &ast::TraitItem) { |
| match it.kind { |
| ast::TraitItemKind::Method(ref sig, _) => { |
| for arg in sig.decl.inputs.iter() { |
| match arg.pat.kind { |
| ast::PatKind::Ident(_, ident, None) => { |
| if ident.name == kw::Invalid { |
| let ty_snip = cx |
| .sess |
| .source_map() |
| .span_to_snippet(arg.ty.span); |
| |
| let (ty_snip, appl) = if let Ok(snip) = ty_snip { |
| (snip, Applicability::MachineApplicable) |
| } else { |
| ("<type>".to_owned(), Applicability::HasPlaceholders) |
| }; |
| |
| cx.struct_span_lint( |
| ANONYMOUS_PARAMETERS, |
| arg.pat.span, |
| "anonymous parameters are deprecated and will be \ |
| removed in the next edition." |
| ).span_suggestion( |
| arg.pat.span, |
| "Try naming the parameter or explicitly \ |
| ignoring it", |
| format!("_: {}", ty_snip), |
| appl |
| ).emit(); |
| } |
| } |
| _ => (), |
| } |
| } |
| }, |
| _ => (), |
| } |
| } |
| } |
| |
| /// Check 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 (Symbol, AttributeType, AttributeTemplate, AttributeGate)>, |
| } |
| |
| impl_lint_pass!(DeprecatedAttr => []); |
| |
| impl DeprecatedAttr { |
| pub fn new() -> DeprecatedAttr { |
| DeprecatedAttr { |
| depr_attrs: deprecated_attributes(), |
| } |
| } |
| } |
| |
| fn lint_deprecated_attr( |
| cx: &EarlyContext<'_>, |
| attr: &ast::Attribute, |
| msg: &str, |
| suggestion: Option<&str>, |
| ) { |
| cx.struct_span_lint(DEPRECATED, attr.span, &msg) |
| .span_suggestion_short( |
| attr.span, |
| suggestion.unwrap_or("remove this attribute"), |
| String::new(), |
| Applicability::MachineApplicable |
| ) |
| .emit(); |
| } |
| |
| impl EarlyLintPass for DeprecatedAttr { |
| fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &ast::Attribute) { |
| for &&(n, _, _, ref g) in &self.depr_attrs { |
| if attr.ident().map(|ident| ident.name) == Some(n) { |
| if let &AttributeGate::Gated(Stability::Deprecated(link, suggestion), |
| ref name, |
| ref reason, |
| _) = g { |
| let msg = format!("use of deprecated attribute `{}`: {}. See {}", |
| name, reason, link); |
| lint_deprecated_attr(cx, attr, &msg, suggestion); |
| } |
| return; |
| } |
| } |
| if attr.check_name(sym::no_start) || attr.check_name(sym::crate_id) { |
| let path_str = pprust::path_to_string(&attr.get_normal_item().path); |
| let msg = format!("use of deprecated attribute `{}`: no longer used.", path_str); |
| lint_deprecated_attr(cx, attr, &msg, None); |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub UNUSED_DOC_COMMENTS, |
| Warn, |
| "detects doc comments that aren't used by rustdoc" |
| } |
| |
| declare_lint_pass!(UnusedDocComment => [UNUSED_DOC_COMMENTS]); |
| |
| impl UnusedDocComment { |
| fn warn_if_doc( |
| &self, |
| cx: &EarlyContext<'_>, |
| node_span: Span, |
| node_kind: &str, |
| is_macro_expansion: bool, |
| attrs: &[ast::Attribute] |
| ) { |
| let mut attrs = attrs.into_iter().peekable(); |
| |
| // Accumulate a single span for sugared doc comments. |
| let mut sugared_span: Option<Span> = None; |
| |
| while let Some(attr) = attrs.next() { |
| if attr.is_doc_comment() { |
| sugared_span = Some( |
| sugared_span.map_or_else( |
| || attr.span, |
| |span| span.with_hi(attr.span.hi()), |
| ), |
| ); |
| } |
| |
| if attrs.peek().map(|next_attr| next_attr.is_doc_comment()).unwrap_or_default() { |
| continue; |
| } |
| |
| let span = sugared_span.take().unwrap_or_else(|| attr.span); |
| |
| if attr.check_name(sym::doc) { |
| let mut err = cx.struct_span_lint(UNUSED_DOC_COMMENTS, span, "unused doc comment"); |
| |
| err.span_label( |
| node_span, |
| format!("rustdoc does not generate documentation for {}", node_kind) |
| ); |
| |
| if is_macro_expansion { |
| err.help("to document an item produced by a macro, \ |
| the macro must produce the documentation as part of its expansion"); |
| } |
| |
| err.emit(); |
| } |
| } |
| } |
| } |
| |
| impl EarlyLintPass for UnusedDocComment { |
| fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) { |
| if let ast::ItemKind::Mac(..) = item.kind { |
| self.warn_if_doc(cx, item.span, "macro expansions", true, &item.attrs); |
| } |
| } |
| |
| fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &ast::Stmt) { |
| let (kind, is_macro_expansion) = match stmt.kind { |
| ast::StmtKind::Local(..) => ("statements", false), |
| ast::StmtKind::Item(..) => ("inner items", false), |
| ast::StmtKind::Mac(..) => ("macro expansions", true), |
| // expressions will be reported by `check_expr`. |
| ast::StmtKind::Semi(..) | |
| ast::StmtKind::Expr(..) => return, |
| }; |
| |
| self.warn_if_doc(cx, stmt.span, kind, is_macro_expansion, stmt.kind.attrs()); |
| } |
| |
| fn check_arm(&mut self, cx: &EarlyContext<'_>, arm: &ast::Arm) { |
| let arm_span = arm.pat.span.with_hi(arm.body.span.hi()); |
| self.warn_if_doc(cx, arm_span, "match arms", false, &arm.attrs); |
| } |
| |
| fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) { |
| self.warn_if_doc(cx, expr.span, "expressions", false, &expr.attrs); |
| } |
| } |
| |
| 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" |
| } |
| |
| declare_lint_pass!(InvalidNoMangleItems => [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.kind { |
| hir::ItemKind::Fn(.., ref generics, _) => { |
| if let Some(no_mangle_attr) = attr::find_by_name(&it.attrs, sym::no_mangle) { |
| for param in &generics.params { |
| match param.kind { |
| GenericParamKind::Lifetime { .. } => {} |
| GenericParamKind::Type { .. } | |
| GenericParamKind::Const { .. } => { |
| let mut err = cx.struct_span_lint( |
| NO_MANGLE_GENERIC_ITEMS, |
| it.span, |
| "functions generic over types or consts must be mangled", |
| ); |
| err.span_suggestion_short( |
| no_mangle_attr.span, |
| "remove this attribute", |
| String::new(), |
| // Use of `#[no_mangle]` suggests FFI intent; correct |
| // fix may be to monomorphize source by hand |
| Applicability::MaybeIncorrect |
| ); |
| err.emit(); |
| break; |
| } |
| } |
| } |
| } |
| } |
| hir::ItemKind::Const(..) => { |
| if attr::contains_name(&it.attrs, sym::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]`"; |
| let mut err = cx.struct_span_lint(NO_MANGLE_CONST_ITEMS, it.span, msg); |
| |
| // account for "pub const" (#45562) |
| let start = cx.tcx.sess.source_map().span_to_snippet(it.span) |
| .map(|snippet| snippet.find("const").unwrap_or(0)) |
| .unwrap_or(0) as u32; |
| // `const` is 5 chars |
| let const_span = it.span.with_hi(BytePos(it.span.lo().0 + start + 5)); |
| err.span_suggestion( |
| const_span, |
| "try a static value", |
| "pub static".to_owned(), |
| Applicability::MachineApplicable |
| ); |
| err.emit(); |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| declare_lint! { |
| MUTABLE_TRANSMUTES, |
| Deny, |
| "mutating transmuted &mut T from &T may cause undefined behavior" |
| } |
| |
| declare_lint_pass!(MutableTransmutes => [MUTABLE_TRANSMUTES]); |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutableTransmutes { |
| fn check_expr(&mut self, cx: &LateContext<'_, '_>, expr: &hir::Expr) { |
| use rustc_target::spec::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).map(|(ty1, ty2)| (&ty1.kind, &ty2.kind)) { |
| Some((&ty::Ref(_, _, from_mt), &ty::Ref(_, _, to_mt))) => { |
| if to_mt == hir::Mutability::Mutable && |
| from_mt == hir::Mutability::Immutable { |
| cx.span_lint(MUTABLE_TRANSMUTES, expr.span, msg); |
| } |
| } |
| _ => (), |
| } |
| |
| fn get_transmute_from_to<'a, 'tcx> |
| (cx: &LateContext<'a, 'tcx>, |
| expr: &hir::Expr) |
| -> Option<(Ty<'tcx>, Ty<'tcx>)> { |
| let def = if let hir::ExprKind::Path(ref qpath) = expr.kind { |
| cx.tables.qpath_res(qpath, expr.hir_id) |
| } else { |
| return None; |
| }; |
| if let Res::Def(DefKind::Fn, did) = def { |
| if !def_id_is_transmute(cx, did) { |
| return None; |
| } |
| let sig = cx.tables.node_type(expr.hir_id).fn_sig(cx.tcx); |
| let from = sig.inputs().skip_binder()[0]; |
| let to = *sig.output().skip_binder(); |
| return Some((from, to)); |
| } |
| None |
| } |
| |
| fn def_id_is_transmute(cx: &LateContext<'_, '_>, def_id: DefId) -> bool { |
| cx.tcx.fn_sig(def_id).abi() == RustIntrinsic && |
| cx.tcx.item_name(def_id) == sym::transmute |
| } |
| } |
| } |
| |
| declare_lint! { |
| UNSTABLE_FEATURES, |
| Allow, |
| "enabling unstable features (deprecated. do not use)" |
| } |
| |
| declare_lint_pass!( |
| /// Forbids using the `#[feature(...)]` attribute |
| UnstableFeatures => [UNSTABLE_FEATURES] |
| ); |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnstableFeatures { |
| fn check_attribute(&mut self, ctx: &LateContext<'_, '_>, attr: &ast::Attribute) { |
| if attr.check_name(sym::feature) { |
| if let Some(items) = attr.meta_item_list() { |
| for item in items { |
| ctx.span_lint(UNSTABLE_FEATURES, item.span(), "unstable feature"); |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub UNREACHABLE_PUB, |
| Allow, |
| "`pub` items not reachable from crate root" |
| } |
| |
| declare_lint_pass!( |
| /// Lint for items marked `pub` that aren't reachable from other crates. |
| UnreachablePub => [UNREACHABLE_PUB] |
| ); |
| |
| impl UnreachablePub { |
| fn perform_lint(&self, cx: &LateContext<'_, '_>, what: &str, id: hir::HirId, |
| vis: &hir::Visibility, span: Span, exportable: bool) { |
| let mut applicability = Applicability::MachineApplicable; |
| match vis.node { |
| hir::VisibilityKind::Public if !cx.access_levels.is_reachable(id) => { |
| if span.from_expansion() { |
| applicability = Applicability::MaybeIncorrect; |
| } |
| let def_span = cx.tcx.sess.source_map().def_span(span); |
| let mut err = cx.struct_span_lint(UNREACHABLE_PUB, def_span, |
| &format!("unreachable `pub` {}", what)); |
| let replacement = if cx.tcx.features().crate_visibility_modifier { |
| "crate" |
| } else { |
| "pub(crate)" |
| }.to_owned(); |
| |
| err.span_suggestion( |
| vis.span, |
| "consider restricting its visibility", |
| replacement, |
| applicability, |
| ); |
| if exportable { |
| err.help("or consider exporting it for use by other crates"); |
| } |
| err.emit(); |
| }, |
| _ => {} |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnreachablePub { |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) { |
| self.perform_lint(cx, "item", item.hir_id, &item.vis, item.span, true); |
| } |
| |
| fn check_foreign_item(&mut self, cx: &LateContext<'_, '_>, foreign_item: &hir::ForeignItem) { |
| self.perform_lint(cx, "item", foreign_item.hir_id, &foreign_item.vis, |
| foreign_item.span, true); |
| } |
| |
| fn check_struct_field(&mut self, cx: &LateContext<'_, '_>, field: &hir::StructField) { |
| self.perform_lint(cx, "field", field.hir_id, &field.vis, field.span, false); |
| } |
| |
| fn check_impl_item(&mut self, cx: &LateContext<'_, '_>, impl_item: &hir::ImplItem) { |
| self.perform_lint(cx, "item", impl_item.hir_id, &impl_item.vis, impl_item.span, false); |
| } |
| } |
| |
| declare_lint! { |
| TYPE_ALIAS_BOUNDS, |
| Warn, |
| "bounds in type aliases are not enforced" |
| } |
| |
| declare_lint_pass!( |
| /// Lint for trait and lifetime bounds in type aliases being mostly ignored. |
| /// They are relevant when using associated types, but otherwise neither checked |
| /// at definition site nor enforced at use site. |
| TypeAliasBounds => [TYPE_ALIAS_BOUNDS] |
| ); |
| |
| impl TypeAliasBounds { |
| fn is_type_variable_assoc(qpath: &hir::QPath) -> bool { |
| match *qpath { |
| hir::QPath::TypeRelative(ref ty, _) => { |
| // If this is a type variable, we found a `T::Assoc`. |
| match ty.kind { |
| hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => { |
| match path.res { |
| Res::Def(DefKind::TyParam, _) => true, |
| _ => false |
| } |
| } |
| _ => false |
| } |
| } |
| hir::QPath::Resolved(..) => false, |
| } |
| } |
| |
| fn suggest_changing_assoc_types(ty: &hir::Ty, err: &mut DiagnosticBuilder<'_>) { |
| // Access to associates types should use `<T as Bound>::Assoc`, which does not need a |
| // bound. Let's see if this type does that. |
| |
| // We use a HIR visitor to walk the type. |
| use rustc::hir::intravisit::{self, Visitor}; |
| struct WalkAssocTypes<'a, 'db> { |
| err: &'a mut DiagnosticBuilder<'db> |
| } |
| impl<'a, 'db, 'v> Visitor<'v> for WalkAssocTypes<'a, 'db> { |
| fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'v> |
| { |
| intravisit::NestedVisitorMap::None |
| } |
| |
| fn visit_qpath(&mut self, qpath: &'v hir::QPath, id: hir::HirId, span: Span) { |
| if TypeAliasBounds::is_type_variable_assoc(qpath) { |
| self.err.span_help(span, |
| "use fully disambiguated paths (i.e., `<T as Trait>::Assoc`) to refer to \ |
| associated types in type aliases"); |
| } |
| intravisit::walk_qpath(self, qpath, id, span) |
| } |
| } |
| |
| // Let's go for a walk! |
| let mut visitor = WalkAssocTypes { err }; |
| visitor.visit_ty(ty); |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TypeAliasBounds { |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &hir::Item) { |
| let (ty, type_alias_generics) = match item.kind { |
| hir::ItemKind::TyAlias(ref ty, ref generics) => (&*ty, generics), |
| _ => return, |
| }; |
| let mut suggested_changing_assoc_types = false; |
| // There must not be a where clause |
| if !type_alias_generics.where_clause.predicates.is_empty() { |
| let spans : Vec<_> = type_alias_generics.where_clause.predicates.iter() |
| .map(|pred| pred.span()).collect(); |
| let mut err = cx.struct_span_lint(TYPE_ALIAS_BOUNDS, spans, |
| "where clauses are not enforced in type aliases"); |
| err.span_suggestion( |
| type_alias_generics.where_clause.span_for_predicates_or_empty_place(), |
| "the clause will not be checked when the type alias is used, and should be removed", |
| String::new(), |
| Applicability::MachineApplicable, |
| ); |
| if !suggested_changing_assoc_types { |
| TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err); |
| suggested_changing_assoc_types = true; |
| } |
| err.emit(); |
| } |
| // The parameters must not have bounds |
| for param in type_alias_generics.params.iter() { |
| let spans: Vec<_> = param.bounds.iter().map(|b| b.span()).collect(); |
| let suggestion = spans.iter().map(|sp| { |
| let start = param.span.between(*sp); // Include the `:` in `T: Bound`. |
| (start.to(*sp), String::new()) |
| }).collect(); |
| if !spans.is_empty() { |
| let mut err = cx.struct_span_lint( |
| TYPE_ALIAS_BOUNDS, |
| spans, |
| "bounds on generic parameters are not enforced in type aliases", |
| ); |
| let msg = "the bound will not be checked when the type alias is used, \ |
| and should be removed"; |
| err.multipart_suggestion(&msg, suggestion, Applicability::MachineApplicable); |
| if !suggested_changing_assoc_types { |
| TypeAliasBounds::suggest_changing_assoc_types(ty, &mut err); |
| suggested_changing_assoc_types = true; |
| } |
| err.emit(); |
| } |
| } |
| } |
| } |
| |
| declare_lint_pass!( |
| /// Lint constants that are erroneous. |
| /// Without this lint, we might not get any diagnostic if the constant is |
| /// unused within this crate, even though downstream crates can't use it |
| /// without producing an error. |
| UnusedBrokenConst => [] |
| ); |
| |
| fn check_const(cx: &LateContext<'_, '_>, body_id: hir::BodyId) { |
| let def_id = cx.tcx.hir().body_owner_def_id(body_id); |
| let param_env = if cx.tcx.is_static(def_id) { |
| // Use the same param_env as `codegen_static_initializer`, to reuse the cache. |
| ty::ParamEnv::reveal_all() |
| } else { |
| cx.tcx.param_env(def_id) |
| }; |
| let cid = ::rustc::mir::interpret::GlobalId { |
| instance: ty::Instance::mono(cx.tcx, def_id), |
| promoted: None |
| }; |
| // trigger the query once for all constants since that will already report the errors |
| // FIXME: Use ensure here |
| let _ = cx.tcx.const_eval(param_env.and(cid)); |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedBrokenConst { |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) { |
| match it.kind { |
| hir::ItemKind::Const(_, body_id) => { |
| check_const(cx, body_id); |
| }, |
| hir::ItemKind::Static(_, _, body_id) => { |
| check_const(cx, body_id); |
| }, |
| _ => {}, |
| } |
| } |
| } |
| |
| declare_lint! { |
| TRIVIAL_BOUNDS, |
| Warn, |
| "these bounds don't depend on an type parameters" |
| } |
| |
| declare_lint_pass!( |
| /// Lint for trait and lifetime bounds that don't depend on type parameters |
| /// which either do nothing, or stop the item from being used. |
| TrivialConstraints => [TRIVIAL_BOUNDS] |
| ); |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for TrivialConstraints { |
| fn check_item( |
| &mut self, |
| cx: &LateContext<'a, 'tcx>, |
| item: &'tcx hir::Item, |
| ) { |
| use rustc::ty::fold::TypeFoldable; |
| use rustc::ty::Predicate::*; |
| |
| if cx.tcx.features().trivial_bounds { |
| let def_id = cx.tcx.hir().local_def_id(item.hir_id); |
| let predicates = cx.tcx.predicates_of(def_id); |
| for &(predicate, span) in predicates.predicates { |
| let predicate_kind_name = match predicate { |
| Trait(..) => "Trait", |
| TypeOutlives(..) | |
| RegionOutlives(..) => "Lifetime", |
| |
| // Ignore projections, as they can only be global |
| // if the trait bound is global |
| Projection(..) | |
| // Ignore bounds that a user can't type |
| WellFormed(..) | |
| ObjectSafe(..) | |
| ClosureKind(..) | |
| Subtype(..) | |
| ConstEvaluatable(..) => continue, |
| }; |
| if predicate.is_global() { |
| cx.span_lint( |
| TRIVIAL_BOUNDS, |
| span, |
| &format!("{} bound {} does not depend on any type \ |
| or lifetime parameters", predicate_kind_name, predicate), |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| declare_lint_pass!( |
| /// Does nothing as a lint pass, but registers some `Lint`s |
| /// which are used by other parts of the compiler. |
| SoftLints => [ |
| WHILE_TRUE, |
| BOX_POINTERS, |
| NON_SHORTHAND_FIELD_PATTERNS, |
| UNSAFE_CODE, |
| MISSING_DOCS, |
| MISSING_COPY_IMPLEMENTATIONS, |
| MISSING_DEBUG_IMPLEMENTATIONS, |
| ANONYMOUS_PARAMETERS, |
| UNUSED_DOC_COMMENTS, |
| NO_MANGLE_CONST_ITEMS, |
| NO_MANGLE_GENERIC_ITEMS, |
| MUTABLE_TRANSMUTES, |
| UNSTABLE_FEATURES, |
| UNREACHABLE_PUB, |
| TYPE_ALIAS_BOUNDS, |
| TRIVIAL_BOUNDS |
| ] |
| ); |
| |
| declare_lint! { |
| pub ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, |
| Warn, |
| "`...` range patterns are deprecated" |
| } |
| |
| #[derive(Default)] |
| pub struct EllipsisInclusiveRangePatterns { |
| /// If `Some(_)`, suppress all subsequent pattern |
| /// warnings for better diagnostics. |
| node_id: Option<ast::NodeId>, |
| } |
| |
| impl_lint_pass!(EllipsisInclusiveRangePatterns => [ELLIPSIS_INCLUSIVE_RANGE_PATTERNS]); |
| |
| impl EarlyLintPass for EllipsisInclusiveRangePatterns { |
| fn check_pat(&mut self, cx: &EarlyContext<'_>, pat: &ast::Pat) { |
| if self.node_id.is_some() { |
| // Don't recursively warn about patterns inside range endpoints. |
| return |
| } |
| |
| use self::ast::{PatKind, RangeEnd, RangeSyntax::DotDotDot}; |
| |
| /// If `pat` is a `...` pattern, return the start and end of the range, as well as the span |
| /// corresponding to the ellipsis. |
| fn matches_ellipsis_pat(pat: &ast::Pat) -> Option<(&P<Expr>, &P<Expr>, Span)> { |
| match &pat.kind { |
| PatKind::Range(a, b, Spanned { span, node: RangeEnd::Included(DotDotDot), .. }) => { |
| Some((a, b, *span)) |
| } |
| _ => None, |
| } |
| } |
| |
| let (parenthesise, endpoints) = match &pat.kind { |
| PatKind::Ref(subpat, _) => (true, matches_ellipsis_pat(&subpat)), |
| _ => (false, matches_ellipsis_pat(pat)), |
| }; |
| |
| if let Some((start, end, join)) = endpoints { |
| let msg = "`...` range patterns are deprecated"; |
| let suggestion = "use `..=` for an inclusive range"; |
| if parenthesise { |
| self.node_id = Some(pat.id); |
| let mut err = cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, pat.span, msg); |
| err.span_suggestion( |
| pat.span, |
| suggestion, |
| format!("&({}..={})", expr_to_string(&start), expr_to_string(&end)), |
| Applicability::MachineApplicable, |
| ); |
| err.emit(); |
| } else { |
| let mut err = cx.struct_span_lint(ELLIPSIS_INCLUSIVE_RANGE_PATTERNS, join, msg); |
| err.span_suggestion_short( |
| join, |
| suggestion, |
| "..=".to_owned(), |
| Applicability::MachineApplicable, |
| ); |
| err.emit(); |
| }; |
| } |
| } |
| |
| fn check_pat_post(&mut self, _cx: &EarlyContext<'_>, pat: &ast::Pat) { |
| if let Some(node_id) = self.node_id { |
| if pat.id == node_id { |
| self.node_id = None |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| UNNAMEABLE_TEST_ITEMS, |
| Warn, |
| "detects an item that cannot be named being marked as `#[test_case]`", |
| report_in_external_macro |
| } |
| |
| pub struct UnnameableTestItems { |
| boundary: hir::HirId, // HirId of the item under which things are not nameable |
| items_nameable: bool, |
| } |
| |
| impl_lint_pass!(UnnameableTestItems => [UNNAMEABLE_TEST_ITEMS]); |
| |
| impl UnnameableTestItems { |
| pub fn new() -> Self { |
| Self { |
| boundary: hir::DUMMY_HIR_ID, |
| items_nameable: true |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnnameableTestItems { |
| fn check_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::Item) { |
| if self.items_nameable { |
| if let hir::ItemKind::Mod(..) = it.kind {} |
| else { |
| self.items_nameable = false; |
| self.boundary = it.hir_id; |
| } |
| return; |
| } |
| |
| if let Some(attr) = attr::find_by_name(&it.attrs, sym::rustc_test_marker) { |
| cx.struct_span_lint( |
| UNNAMEABLE_TEST_ITEMS, |
| attr.span, |
| "cannot test inner items", |
| ).emit(); |
| } |
| } |
| |
| fn check_item_post(&mut self, _cx: &LateContext<'_, '_>, it: &hir::Item) { |
| if !self.items_nameable && self.boundary == it.hir_id { |
| self.items_nameable = true; |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub KEYWORD_IDENTS, |
| Allow, |
| "detects edition keywords being used as an identifier", |
| @future_incompatible = FutureIncompatibleInfo { |
| reference: "issue #49716 <https://github.com/rust-lang/rust/issues/49716>", |
| edition: Some(Edition::Edition2018), |
| }; |
| } |
| |
| declare_lint_pass!( |
| /// Check for uses of edition keywords used as an identifier. |
| KeywordIdents => [KEYWORD_IDENTS] |
| ); |
| |
| struct UnderMacro(bool); |
| |
| impl KeywordIdents { |
| fn check_tokens(&mut self, cx: &EarlyContext<'_>, tokens: TokenStream) { |
| for tt in tokens.into_trees() { |
| match tt { |
| // Only report non-raw idents. |
| TokenTree::Token(token) => if let Some((ident, false)) = token.ident() { |
| self.check_ident_token(cx, UnderMacro(true), ident); |
| } |
| TokenTree::Delimited(_, _, tts) => { |
| self.check_tokens(cx, tts) |
| }, |
| } |
| } |
| } |
| |
| fn check_ident_token(&mut self, |
| cx: &EarlyContext<'_>, |
| UnderMacro(under_macro): UnderMacro, |
| ident: ast::Ident) |
| { |
| let next_edition = match cx.sess.edition() { |
| Edition::Edition2015 => { |
| match ident.name { |
| kw::Async | kw::Await | kw::Try => Edition::Edition2018, |
| |
| // rust-lang/rust#56327: Conservatively do not |
| // attempt to report occurrences of `dyn` within |
| // macro definitions or invocations, because `dyn` |
| // can legitimately occur as a contextual keyword |
| // in 2015 code denoting its 2018 meaning, and we |
| // do not want rustfix to inject bugs into working |
| // code by rewriting such occurrences. |
| // |
| // But if we see `dyn` outside of a macro, we know |
| // its precise role in the parsed AST and thus are |
| // assured this is truly an attempt to use it as |
| // an identifier. |
| kw::Dyn if !under_macro => Edition::Edition2018, |
| |
| _ => return, |
| } |
| } |
| |
| // There are no new keywords yet for the 2018 edition and beyond. |
| _ => return, |
| }; |
| |
| // Don't lint `r#foo`. |
| if cx.sess.parse_sess.raw_identifier_spans.borrow().contains(&ident.span) { |
| return; |
| } |
| |
| let mut lint = cx.struct_span_lint( |
| KEYWORD_IDENTS, |
| ident.span, |
| &format!("`{}` is a keyword in the {} edition", ident, next_edition), |
| ); |
| lint.span_suggestion( |
| ident.span, |
| "you can use a raw identifier to stay compatible", |
| format!("r#{}", ident), |
| Applicability::MachineApplicable, |
| ); |
| lint.emit() |
| } |
| } |
| |
| impl EarlyLintPass for KeywordIdents { |
| fn check_mac_def(&mut self, cx: &EarlyContext<'_>, mac_def: &ast::MacroDef, _id: ast::NodeId) { |
| self.check_tokens(cx, mac_def.body.inner_tokens()); |
| } |
| fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &ast::Mac) { |
| self.check_tokens(cx, mac.args.inner_tokens()); |
| } |
| fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: ast::Ident) { |
| self.check_ident_token(cx, UnderMacro(false), ident); |
| } |
| } |
| |
| declare_lint_pass!(ExplicitOutlivesRequirements => [EXPLICIT_OUTLIVES_REQUIREMENTS]); |
| |
| impl ExplicitOutlivesRequirements { |
| fn lifetimes_outliving_lifetime<'tcx>( |
| inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
| index: u32, |
| ) -> Vec<ty::Region<'tcx>> { |
| inferred_outlives.iter().filter_map(|(pred, _)| { |
| match pred { |
| ty::Predicate::RegionOutlives(outlives) => { |
| let outlives = outlives.skip_binder(); |
| match outlives.0 { |
| ty::ReEarlyBound(ebr) if ebr.index == index => { |
| Some(outlives.1) |
| } |
| _ => None, |
| } |
| } |
| _ => None |
| } |
| }).collect() |
| } |
| |
| fn lifetimes_outliving_type<'tcx>( |
| inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
| index: u32, |
| ) -> Vec<ty::Region<'tcx>> { |
| inferred_outlives.iter().filter_map(|(pred, _)| { |
| match pred { |
| ty::Predicate::TypeOutlives(outlives) => { |
| let outlives = outlives.skip_binder(); |
| outlives.0.is_param(index).then_some(outlives.1) |
| } |
| _ => None |
| } |
| }).collect() |
| } |
| |
| fn collect_outlived_lifetimes<'tcx>( |
| &self, |
| param: &'tcx hir::GenericParam, |
| tcx: TyCtxt<'tcx>, |
| inferred_outlives: &'tcx [(ty::Predicate<'tcx>, Span)], |
| ty_generics: &'tcx ty::Generics, |
| ) -> Vec<ty::Region<'tcx>> { |
| let index = ty_generics.param_def_id_to_index[ |
| &tcx.hir().local_def_id(param.hir_id)]; |
| |
| match param.kind { |
| hir::GenericParamKind::Lifetime { .. } => { |
| Self::lifetimes_outliving_lifetime(inferred_outlives, index) |
| } |
| hir::GenericParamKind::Type { .. } => { |
| Self::lifetimes_outliving_type(inferred_outlives, index) |
| } |
| hir::GenericParamKind::Const { .. } => Vec::new(), |
| } |
| } |
| |
| |
| fn collect_outlives_bound_spans<'tcx>( |
| &self, |
| tcx: TyCtxt<'tcx>, |
| bounds: &hir::GenericBounds, |
| inferred_outlives: &[ty::Region<'tcx>], |
| infer_static: bool, |
| ) -> Vec<(usize, Span)> { |
| use rustc::middle::resolve_lifetime::Region; |
| |
| bounds |
| .iter() |
| .enumerate() |
| .filter_map(|(i, bound)| { |
| if let hir::GenericBound::Outlives(lifetime) = bound { |
| let is_inferred = match tcx.named_region(lifetime.hir_id) { |
| Some(Region::Static) if infer_static => { |
| inferred_outlives.iter() |
| .any(|r| if let ty::ReStatic = r { true } else { false }) |
| } |
| Some(Region::EarlyBound(index, ..)) => inferred_outlives |
| .iter() |
| .any(|r| { |
| if let ty::ReEarlyBound(ebr) = r { |
| ebr.index == index |
| } else { |
| false |
| } |
| }), |
| _ => false, |
| }; |
| is_inferred.then_some((i, bound.span())) |
| } else { |
| None |
| } |
| }) |
| .collect() |
| } |
| |
| fn consolidate_outlives_bound_spans( |
| &self, |
| lo: Span, |
| bounds: &hir::GenericBounds, |
| bound_spans: Vec<(usize, Span)> |
| ) -> Vec<Span> { |
| if bounds.is_empty() { |
| return Vec::new(); |
| } |
| if bound_spans.len() == bounds.len() { |
| let (_, last_bound_span) = bound_spans[bound_spans.len()-1]; |
| // If all bounds are inferable, we want to delete the colon, so |
| // start from just after the parameter (span passed as argument) |
| vec![lo.to(last_bound_span)] |
| } else { |
| let mut merged = Vec::new(); |
| let mut last_merged_i = None; |
| |
| let mut from_start = true; |
| for (i, bound_span) in bound_spans { |
| match last_merged_i { |
| // If the first bound is inferable, our span should also eat the leading `+`. |
| None if i == 0 => { |
| merged.push(bound_span.to(bounds[1].span().shrink_to_lo())); |
| last_merged_i = Some(0); |
| }, |
| // If consecutive bounds are inferable, merge their spans |
| Some(h) if i == h+1 => { |
| if let Some(tail) = merged.last_mut() { |
| // Also eat the trailing `+` if the first |
| // more-than-one bound is inferable |
| let to_span = if from_start && i < bounds.len() { |
| bounds[i+1].span().shrink_to_lo() |
| } else { |
| bound_span |
| }; |
| *tail = tail.to(to_span); |
| last_merged_i = Some(i); |
| } else { |
| bug!("another bound-span visited earlier"); |
| } |
| }, |
| _ => { |
| // When we find a non-inferable bound, subsequent inferable bounds |
| // won't be consecutive from the start (and we'll eat the leading |
| // `+` rather than the trailing one) |
| from_start = false; |
| merged.push(bounds[i-1].span().shrink_to_hi().to(bound_span)); |
| last_merged_i = Some(i); |
| } |
| } |
| } |
| merged |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ExplicitOutlivesRequirements { |
| fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) { |
| use rustc::middle::resolve_lifetime::Region; |
| |
| let infer_static = cx.tcx.features().infer_static_outlives_requirements; |
| let def_id = cx.tcx.hir().local_def_id(item.hir_id); |
| if let hir::ItemKind::Struct(_, ref hir_generics) |
| | hir::ItemKind::Enum(_, ref hir_generics) |
| | hir::ItemKind::Union(_, ref hir_generics) = item.kind |
| { |
| let inferred_outlives = cx.tcx.inferred_outlives_of(def_id); |
| if inferred_outlives.is_empty() { |
| return; |
| } |
| |
| let ty_generics = cx.tcx.generics_of(def_id); |
| |
| let mut bound_count = 0; |
| let mut lint_spans = Vec::new(); |
| |
| for param in &hir_generics.params { |
| let has_lifetime_bounds = param.bounds.iter().any(|bound| { |
| if let hir::GenericBound::Outlives(_) = bound { |
| true |
| } else { |
| false |
| } |
| }); |
| if !has_lifetime_bounds { |
| continue; |
| } |
| |
| let relevant_lifetimes = self.collect_outlived_lifetimes( |
| param, |
| cx.tcx, |
| inferred_outlives, |
| ty_generics, |
| ); |
| if relevant_lifetimes.is_empty() { |
| continue; |
| } |
| |
| let bound_spans = self.collect_outlives_bound_spans( |
| cx.tcx, ¶m.bounds, &relevant_lifetimes, infer_static, |
| ); |
| bound_count += bound_spans.len(); |
| lint_spans.extend( |
| self.consolidate_outlives_bound_spans( |
| param.span.shrink_to_hi(), ¶m.bounds, bound_spans |
| ) |
| ); |
| } |
| |
| let mut where_lint_spans = Vec::new(); |
| let mut dropped_predicate_count = 0; |
| let num_predicates = hir_generics.where_clause.predicates.len(); |
| for (i, where_predicate) in hir_generics.where_clause.predicates.iter().enumerate() { |
| let (relevant_lifetimes, bounds, span) = match where_predicate { |
| hir::WherePredicate::RegionPredicate(predicate) => { |
| if let Some(Region::EarlyBound(index, ..)) |
| = cx.tcx.named_region(predicate.lifetime.hir_id) |
| { |
| ( |
| Self::lifetimes_outliving_lifetime(inferred_outlives, index), |
| &predicate.bounds, |
| predicate.span, |
| ) |
| } else { |
| continue; |
| } |
| } |
| hir::WherePredicate::BoundPredicate(predicate) => { |
| // FIXME we can also infer bounds on associated types, |
| // and should check for them here. |
| match predicate.bounded_ty.kind { |
| hir::TyKind::Path(hir::QPath::Resolved( |
| None, |
| ref path, |
| )) => { |
| if let Res::Def(DefKind::TyParam, def_id) = path.res { |
| let index = ty_generics.param_def_id_to_index[&def_id]; |
| ( |
| Self::lifetimes_outliving_type(inferred_outlives, index), |
| &predicate.bounds, |
| predicate.span, |
| ) |
| } else { |
| continue; |
| } |
| }, |
| _ => { continue; } |
| } |
| } |
| _ => continue, |
| }; |
| if relevant_lifetimes.is_empty() { |
| continue; |
| } |
| |
| let bound_spans = self.collect_outlives_bound_spans( |
| cx.tcx, bounds, &relevant_lifetimes, infer_static, |
| ); |
| bound_count += bound_spans.len(); |
| |
| let drop_predicate = bound_spans.len() == bounds.len(); |
| if drop_predicate { |
| dropped_predicate_count += 1; |
| } |
| |
| // If all the bounds on a predicate were inferable and there are |
| // further predicates, we want to eat the trailing comma. |
| if drop_predicate && i + 1 < num_predicates { |
| let next_predicate_span = hir_generics.where_clause.predicates[i + 1].span(); |
| where_lint_spans.push( |
| span.to(next_predicate_span.shrink_to_lo()) |
| ); |
| } else { |
| where_lint_spans.extend( |
| self.consolidate_outlives_bound_spans( |
| span.shrink_to_lo(), |
| bounds, |
| bound_spans |
| ) |
| ); |
| } |
| } |
| |
| // If all predicates are inferable, drop the entire clause |
| // (including the `where`) |
| if num_predicates > 0 && dropped_predicate_count == num_predicates { |
| let where_span = hir_generics.where_clause.span() |
| .expect("span of (nonempty) where clause should exist"); |
| // Extend the where clause back to the closing `>` of the |
| // generics, except for tuple struct, which have the `where` |
| // after the fields of the struct. |
| let full_where_span = if let hir::ItemKind::Struct(hir::VariantData::Tuple(..), _) |
| = item.kind |
| { |
| where_span |
| } else { |
| hir_generics.span.shrink_to_hi().to(where_span) |
| }; |
| lint_spans.push( |
| full_where_span |
| ); |
| } else { |
| lint_spans.extend(where_lint_spans); |
| } |
| |
| if !lint_spans.is_empty() { |
| let mut err = cx.struct_span_lint( |
| EXPLICIT_OUTLIVES_REQUIREMENTS, |
| lint_spans.clone(), |
| "outlives requirements can be inferred" |
| ); |
| err.multipart_suggestion( |
| if bound_count == 1 { |
| "remove this bound" |
| } else { |
| "remove these bounds" |
| }, |
| lint_spans.into_iter().map(|span| (span, "".to_owned())).collect::<Vec<_>>(), |
| Applicability::MachineApplicable |
| ); |
| err.emit(); |
| } |
| } |
| } |
| } |
| |
| declare_lint! { |
| pub INCOMPLETE_FEATURES, |
| Warn, |
| "incomplete features that may function improperly in some or all cases" |
| } |
| |
| declare_lint_pass!( |
| /// Check for used feature gates in `INCOMPLETE_FEATURES` in `feature_gate.rs`. |
| IncompleteFeatures => [INCOMPLETE_FEATURES] |
| ); |
| |
| impl EarlyLintPass for IncompleteFeatures { |
| fn check_crate(&mut self, cx: &EarlyContext<'_>, _: &ast::Crate) { |
| let features = cx.sess.features_untracked(); |
| features.declared_lang_features |
| .iter().map(|(name, span, _)| (name, span)) |
| .chain(features.declared_lib_features.iter().map(|(name, span)| (name, span))) |
| .filter(|(name, _)| rustc_feature::INCOMPLETE_FEATURES.iter().any(|f| name == &f)) |
| .for_each(|(name, &span)| { |
| cx.struct_span_lint( |
| INCOMPLETE_FEATURES, |
| span, |
| &format!( |
| "the feature `{}` is incomplete and may cause the compiler to crash", |
| name, |
| ) |
| ) |
| .emit(); |
| }); |
| } |
| } |
| |
| declare_lint! { |
| pub INVALID_VALUE, |
| Warn, |
| "an invalid value is being created (such as a NULL reference)" |
| } |
| |
| declare_lint_pass!(InvalidValue => [INVALID_VALUE]); |
| |
| impl<'a, 'tcx> LateLintPass<'a, 'tcx> for InvalidValue { |
| fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &hir::Expr) { |
| |
| #[derive(Debug, Copy, Clone, PartialEq)] |
| enum InitKind { Zeroed, Uninit }; |
| |
| /// Information about why a type cannot be initialized this way. |
| /// Contains an error message and optionally a span to point at. |
| type InitError = (String, Option<Span>); |
| |
| /// Test if this constant is all-0. |
| fn is_zero(expr: &hir::Expr) -> bool { |
| use hir::ExprKind::*; |
| use syntax::ast::LitKind::*; |
| match &expr.kind { |
| Lit(lit) => |
| if let Int(i, _) = lit.node { |
| i == 0 |
| } else { |
| false |
| }, |
| Tup(tup) => |
| tup.iter().all(is_zero), |
| _ => |
| false |
| } |
| } |
| |
| /// Determine if this expression is a "dangerous initialization". |
| fn is_dangerous_init(cx: &LateContext<'_, '_>, expr: &hir::Expr) -> Option<InitKind> { |
| // `transmute` is inside an anonymous module (the `extern` block?); |
| // `Invalid` represents the empty string and matches that. |
| // FIXME(#66075): use diagnostic items. Somehow, that does not seem to work |
| // on intrinsics right now. |
| const TRANSMUTE_PATH: &[Symbol] = |
| &[sym::core, sym::intrinsics, kw::Invalid, sym::transmute]; |
| |
| if let hir::ExprKind::Call(ref path_expr, ref args) = expr.kind { |
| // Find calls to `mem::{uninitialized,zeroed}` methods. |
| if let hir::ExprKind::Path(ref qpath) = path_expr.kind { |
| let def_id = cx.tables.qpath_res(qpath, path_expr.hir_id).opt_def_id()?; |
| |
| if cx.tcx.is_diagnostic_item(sym::mem_zeroed, def_id) { |
| return Some(InitKind::Zeroed); |
| } else if cx.tcx.is_diagnostic_item(sym::mem_uninitialized, def_id) { |
| return Some(InitKind::Uninit); |
| } else if cx.match_def_path(def_id, TRANSMUTE_PATH) { |
| if is_zero(&args[0]) { |
| return Some(InitKind::Zeroed); |
| } |
| } |
| } |
| } else if let hir::ExprKind::MethodCall(_, _, ref args) = expr.kind { |
| // Find problematic calls to `MaybeUninit::assume_init`. |
| let def_id = cx.tables.type_dependent_def_id(expr.hir_id)?; |
| if cx.tcx.is_diagnostic_item(sym::assume_init, def_id) { |
| // This is a call to *some* method named `assume_init`. |
| // See if the `self` parameter is one of the dangerous constructors. |
| if let hir::ExprKind::Call(ref path_expr, _) = args[0].kind { |
| if let hir::ExprKind::Path(ref qpath) = path_expr.kind { |
| let def_id = cx.tables.qpath_res(qpath, path_expr.hir_id).opt_def_id()?; |
| |
| if cx.tcx.is_diagnostic_item(sym::maybe_uninit_zeroed, def_id) { |
| return Some(InitKind::Zeroed); |
| } else if cx.tcx.is_diagnostic_item(sym::maybe_uninit_uninit, def_id) { |
| return Some(InitKind::Uninit); |
| } |
| } |
| } |
| } |
| } |
| |
| None |
| } |
| |
| /// Return `Some` only if we are sure this type does *not* |
| /// allow zero initialization. |
| fn ty_find_init_error<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| ty: Ty<'tcx>, |
| init: InitKind, |
| ) -> Option<InitError> { |
| use rustc::ty::TyKind::*; |
| match ty.kind { |
| // Primitive types that don't like 0 as a value. |
| Ref(..) => Some((format!("References must be non-null"), None)), |
| Adt(..) if ty.is_box() => Some((format!("`Box` must be non-null"), None)), |
| FnPtr(..) => Some((format!("Function pointers must be non-null"), None)), |
| Never => Some((format!("The never type (`!`) has no valid value"), None)), |
| RawPtr(tm) if matches!(tm.ty.kind, Dynamic(..)) => // raw ptr to dyn Trait |
| Some((format!("The vtable of a wide raw pointer must be non-null"), None)), |
| // Primitive types with other constraints. |
| Bool if init == InitKind::Uninit => |
| Some((format!("Booleans must be `true` or `false`"), None)), |
| Char if init == InitKind::Uninit => |
| Some((format!("Characters must be a valid unicode codepoint"), None)), |
| // Recurse and checks for some compound types. |
| Adt(adt_def, substs) if !adt_def.is_union() => { |
| // First check f this ADT has a layout attribute (like `NonNull` and friends). |
| use std::ops::Bound; |
| match tcx.layout_scalar_valid_range(adt_def.did) { |
| // We exploit here that `layout_scalar_valid_range` will never |
| // return `Bound::Excluded`. (And we have tests checking that we |
| // handle the attribute correctly.) |
| (Bound::Included(lo), _) if lo > 0 => |
| return Some((format!("{} must be non-null", ty), None)), |
| (Bound::Included(_), _) | (_, Bound::Included(_)) |
| if init == InitKind::Uninit => |
| return Some(( |
| format!("{} must be initialized inside its custom valid range", ty), |
| None, |
| )), |
| _ => {} |
| } |
| // Now, recurse. |
| match adt_def.variants.len() { |
| 0 => Some((format!("0-variant enums have no valid value"), None)), |
| 1 => { |
| // Struct, or enum with exactly one variant. |
| // Proceed recursively, check all fields. |
| let variant = &adt_def.variants[VariantIdx::from_u32(0)]; |
| variant.fields.iter().find_map(|field| { |
| ty_find_init_error( |
| tcx, |
| field.ty(tcx, substs), |
| init, |
| ).map(|(mut msg, span)| if span.is_none() { |
| // Point to this field, should be helpful for figuring |
| // out where the source of the error is. |
| let span = tcx.def_span(field.did); |
| write!(&mut msg, " (in this {} field)", adt_def.descr()) |
| .unwrap(); |
| (msg, Some(span)) |
| } else { |
| // Just forward. |
| (msg, span) |
| }) |
| }) |
| } |
| // Multi-variant enums are tricky: if all but one variant are |
| // uninhabited, we might actually do layout like for a single-variant |
| // enum, and then even leaving them uninitialized could be okay. |
| _ => None, // Conservative fallback for multi-variant enum. |
| } |
| } |
| Tuple(..) => { |
| // Proceed recursively, check all fields. |
| ty.tuple_fields().find_map(|field| ty_find_init_error(tcx, field, init)) |
| } |
| // Conservative fallback. |
| _ => None, |
| } |
| } |
| |
| if let Some(init) = is_dangerous_init(cx, expr) { |
| // This conjures an instance of a type out of nothing, |
| // using zeroed or uninitialized memory. |
| // We are extremely conservative with what we warn about. |
| let conjured_ty = cx.tables.expr_ty(expr); |
| if let Some((msg, span)) = ty_find_init_error(cx.tcx, conjured_ty, init) { |
| let mut err = cx.struct_span_lint( |
| INVALID_VALUE, |
| expr.span, |
| &format!( |
| "the type `{}` does not permit {}", |
| conjured_ty, |
| match init { |
| InitKind::Zeroed => "zero-initialization", |
| InitKind::Uninit => "being left uninitialized", |
| }, |
| ), |
| ); |
| err.span_label(expr.span, |
| "this code causes undefined behavior when executed"); |
| err.span_label(expr.span, "help: use `MaybeUninit<T>` instead, \ |
| and only call `assume_init` after initialization is done"); |
| if let Some(span) = span { |
| err.span_note(span, &msg); |
| } else { |
| err.note(&msg); |
| } |
| err.emit(); |
| } |
| } |
| } |
| } |
