| //! This module handles checking if the span given is from a proc-macro or not. |
| //! |
| //! Proc-macros are capable of setting the span of every token they output to a few possible spans. |
| //! This includes spans we can detect easily as coming from a proc-macro (e.g. the call site |
| //! or the def site), and spans we can't easily detect as such (e.g. the span of any token |
| //! passed into the proc macro). This capability means proc-macros are capable of generating code |
| //! with a span that looks like it was written by the user, but which should not be linted by clippy |
| //! as it was generated by an external macro. |
| //! |
| //! That brings us to this module. The current approach is to determine a small bit of text which |
| //! must exist at both the start and the end of an item (e.g. an expression or a path) assuming the |
| //! code was written, and check if the span contains that text. Note this will only work correctly |
| //! if the span is not from a `macro_rules` based macro. |
| |
| use rustc_ast::ast::{AttrKind, Attribute, IntTy, LitIntType, LitKind, StrStyle, TraitObjectSyntax, UintTy}; |
| use rustc_ast::token::CommentKind; |
| use rustc_ast::AttrStyle; |
| use rustc_hir::intravisit::FnKind; |
| use rustc_hir::{ |
| Block, BlockCheckMode, Body, Closure, Destination, Expr, ExprKind, FieldDef, FnHeader, FnRetTy, HirId, Impl, |
| ImplItem, ImplItemKind, IsAuto, Item, ItemKind, LoopSource, MatchSource, MutTy, Node, QPath, TraitItem, |
| TraitItemKind, Ty, TyKind, UnOp, UnsafeSource, Unsafety, Variant, VariantData, YieldSource, |
| }; |
| use rustc_lint::{LateContext, LintContext}; |
| use rustc_middle::ty::TyCtxt; |
| use rustc_session::Session; |
| use rustc_span::symbol::Ident; |
| use rustc_span::{Span, Symbol}; |
| use rustc_target::spec::abi::Abi; |
| |
| /// The search pattern to look for. Used by `span_matches_pat` |
| #[derive(Clone)] |
| pub enum Pat { |
| /// A single string. |
| Str(&'static str), |
| /// Any of the given strings. |
| MultiStr(&'static [&'static str]), |
| /// Any of the given strings. |
| OwnedMultiStr(Vec<String>), |
| /// The string representation of the symbol. |
| Sym(Symbol), |
| /// Any decimal or hexadecimal digit depending on the location. |
| Num, |
| } |
| |
| /// Checks if the start and the end of the span's text matches the patterns. This will return false |
| /// if the span crosses multiple files or if source is not available. |
| fn span_matches_pat(sess: &Session, span: Span, start_pat: Pat, end_pat: Pat) -> bool { |
| let pos = sess.source_map().lookup_byte_offset(span.lo()); |
| let Some(ref src) = pos.sf.src else { |
| return false; |
| }; |
| let end = span.hi() - pos.sf.start_pos; |
| src.get(pos.pos.0 as usize..end.0 as usize).map_or(false, |s| { |
| // Spans can be wrapped in a mixture or parenthesis, whitespace, and trailing commas. |
| let start_str = s.trim_start_matches(|c: char| c.is_whitespace() || c == '('); |
| let end_str = s.trim_end_matches(|c: char| c.is_whitespace() || c == ')' || c == ','); |
| (match start_pat { |
| Pat::Str(text) => start_str.starts_with(text), |
| Pat::MultiStr(texts) => texts.iter().any(|s| start_str.starts_with(s)), |
| Pat::OwnedMultiStr(texts) => texts.iter().any(|s| start_str.starts_with(s)), |
| Pat::Sym(sym) => start_str.starts_with(sym.as_str()), |
| Pat::Num => start_str.as_bytes().first().map_or(false, u8::is_ascii_digit), |
| } && match end_pat { |
| Pat::Str(text) => end_str.ends_with(text), |
| Pat::MultiStr(texts) => texts.iter().any(|s| start_str.ends_with(s)), |
| Pat::OwnedMultiStr(texts) => texts.iter().any(|s| start_str.starts_with(s)), |
| Pat::Sym(sym) => end_str.ends_with(sym.as_str()), |
| Pat::Num => end_str.as_bytes().last().map_or(false, u8::is_ascii_hexdigit), |
| }) |
| }) |
| } |
| |
| /// Get the search patterns to use for the given literal |
| fn lit_search_pat(lit: &LitKind) -> (Pat, Pat) { |
| match lit { |
| LitKind::Str(_, StrStyle::Cooked) => (Pat::Str("\""), Pat::Str("\"")), |
| LitKind::Str(_, StrStyle::Raw(0)) => (Pat::Str("r"), Pat::Str("\"")), |
| LitKind::Str(_, StrStyle::Raw(_)) => (Pat::Str("r#"), Pat::Str("#")), |
| LitKind::ByteStr(_, StrStyle::Cooked) => (Pat::Str("b\""), Pat::Str("\"")), |
| LitKind::ByteStr(_, StrStyle::Raw(0)) => (Pat::Str("br\""), Pat::Str("\"")), |
| LitKind::ByteStr(_, StrStyle::Raw(_)) => (Pat::Str("br#\""), Pat::Str("#")), |
| LitKind::Byte(_) => (Pat::Str("b'"), Pat::Str("'")), |
| LitKind::Char(_) => (Pat::Str("'"), Pat::Str("'")), |
| LitKind::Int(_, LitIntType::Signed(IntTy::Isize)) => (Pat::Num, Pat::Str("isize")), |
| LitKind::Int(_, LitIntType::Unsigned(UintTy::Usize)) => (Pat::Num, Pat::Str("usize")), |
| LitKind::Int(..) => (Pat::Num, Pat::Num), |
| LitKind::Float(..) => (Pat::Num, Pat::Str("")), |
| LitKind::Bool(true) => (Pat::Str("true"), Pat::Str("true")), |
| LitKind::Bool(false) => (Pat::Str("false"), Pat::Str("false")), |
| _ => (Pat::Str(""), Pat::Str("")), |
| } |
| } |
| |
| /// Get the search patterns to use for the given path |
| fn qpath_search_pat(path: &QPath<'_>) -> (Pat, Pat) { |
| match path { |
| QPath::Resolved(ty, path) => { |
| let start = if ty.is_some() { |
| Pat::Str("<") |
| } else { |
| path.segments |
| .first() |
| .map_or(Pat::Str(""), |seg| Pat::Sym(seg.ident.name)) |
| }; |
| let end = path.segments.last().map_or(Pat::Str(""), |seg| { |
| if seg.args.is_some() { |
| Pat::Str(">") |
| } else { |
| Pat::Sym(seg.ident.name) |
| } |
| }); |
| (start, end) |
| }, |
| QPath::TypeRelative(_, name) => (Pat::Str(""), Pat::Sym(name.ident.name)), |
| QPath::LangItem(..) => (Pat::Str(""), Pat::Str("")), |
| } |
| } |
| |
| /// Get the search patterns to use for the given expression |
| fn expr_search_pat(tcx: TyCtxt<'_>, e: &Expr<'_>) -> (Pat, Pat) { |
| match e.kind { |
| ExprKind::ConstBlock(_) => (Pat::Str("const"), Pat::Str("}")), |
| // Parenthesis are trimmed from the text before the search patterns are matched. |
| // See: `span_matches_pat` |
| ExprKind::Tup([]) => (Pat::Str(")"), Pat::Str("(")), |
| ExprKind::Unary(UnOp::Deref, e) => (Pat::Str("*"), expr_search_pat(tcx, e).1), |
| ExprKind::Unary(UnOp::Not, e) => (Pat::Str("!"), expr_search_pat(tcx, e).1), |
| ExprKind::Unary(UnOp::Neg, e) => (Pat::Str("-"), expr_search_pat(tcx, e).1), |
| ExprKind::Lit(lit) => lit_search_pat(&lit.node), |
| ExprKind::Array(_) | ExprKind::Repeat(..) => (Pat::Str("["), Pat::Str("]")), |
| ExprKind::Call(e, []) | ExprKind::MethodCall(_, e, [], _) => (expr_search_pat(tcx, e).0, Pat::Str("(")), |
| ExprKind::Call(first, [.., last]) |
| | ExprKind::MethodCall(_, first, [.., last], _) |
| | ExprKind::Binary(_, first, last) |
| | ExprKind::Tup([first, .., last]) |
| | ExprKind::Assign(first, last, _) |
| | ExprKind::AssignOp(_, first, last) => (expr_search_pat(tcx, first).0, expr_search_pat(tcx, last).1), |
| ExprKind::Tup([e]) | ExprKind::DropTemps(e) => expr_search_pat(tcx, e), |
| ExprKind::Cast(e, _) | ExprKind::Type(e, _) => (expr_search_pat(tcx, e).0, Pat::Str("")), |
| ExprKind::Let(let_expr) => (Pat::Str("let"), expr_search_pat(tcx, let_expr.init).1), |
| ExprKind::If(..) => (Pat::Str("if"), Pat::Str("}")), |
| ExprKind::Loop(_, Some(_), _, _) | ExprKind::Block(_, Some(_)) => (Pat::Str("'"), Pat::Str("}")), |
| ExprKind::Loop(_, None, LoopSource::Loop, _) => (Pat::Str("loop"), Pat::Str("}")), |
| ExprKind::Loop(_, None, LoopSource::While, _) => (Pat::Str("while"), Pat::Str("}")), |
| ExprKind::Loop(_, None, LoopSource::ForLoop, _) | ExprKind::Match(_, _, MatchSource::ForLoopDesugar) => { |
| (Pat::Str("for"), Pat::Str("}")) |
| }, |
| ExprKind::Match(_, _, MatchSource::Normal) => (Pat::Str("match"), Pat::Str("}")), |
| ExprKind::Match(e, _, MatchSource::TryDesugar(_)) => (expr_search_pat(tcx, e).0, Pat::Str("?")), |
| ExprKind::Match(e, _, MatchSource::AwaitDesugar) | ExprKind::Yield(e, YieldSource::Await { .. }) => { |
| (expr_search_pat(tcx, e).0, Pat::Str("await")) |
| }, |
| ExprKind::Closure(&Closure { body, .. }) => (Pat::Str(""), expr_search_pat(tcx, tcx.hir().body(body).value).1), |
| ExprKind::Block( |
| Block { |
| rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided), |
| .. |
| }, |
| None, |
| ) => (Pat::Str("unsafe"), Pat::Str("}")), |
| ExprKind::Block(_, None) => (Pat::Str("{"), Pat::Str("}")), |
| ExprKind::Field(e, name) => (expr_search_pat(tcx, e).0, Pat::Sym(name.name)), |
| ExprKind::Index(e, _, _) => (expr_search_pat(tcx, e).0, Pat::Str("]")), |
| ExprKind::Path(ref path) => qpath_search_pat(path), |
| ExprKind::AddrOf(_, _, e) => (Pat::Str("&"), expr_search_pat(tcx, e).1), |
| ExprKind::Break(Destination { label: None, .. }, None) => (Pat::Str("break"), Pat::Str("break")), |
| ExprKind::Break(Destination { label: Some(name), .. }, None) => (Pat::Str("break"), Pat::Sym(name.ident.name)), |
| ExprKind::Break(_, Some(e)) => (Pat::Str("break"), expr_search_pat(tcx, e).1), |
| ExprKind::Continue(Destination { label: None, .. }) => (Pat::Str("continue"), Pat::Str("continue")), |
| ExprKind::Continue(Destination { label: Some(name), .. }) => (Pat::Str("continue"), Pat::Sym(name.ident.name)), |
| ExprKind::Ret(None) => (Pat::Str("return"), Pat::Str("return")), |
| ExprKind::Ret(Some(e)) => (Pat::Str("return"), expr_search_pat(tcx, e).1), |
| ExprKind::Struct(path, _, _) => (qpath_search_pat(path).0, Pat::Str("}")), |
| ExprKind::Yield(e, YieldSource::Yield) => (Pat::Str("yield"), expr_search_pat(tcx, e).1), |
| _ => (Pat::Str(""), Pat::Str("")), |
| } |
| } |
| |
| fn fn_header_search_pat(header: FnHeader) -> Pat { |
| if header.is_async() { |
| Pat::Str("async") |
| } else if header.is_const() { |
| Pat::Str("const") |
| } else if header.is_unsafe() { |
| Pat::Str("unsafe") |
| } else if header.abi != Abi::Rust { |
| Pat::Str("extern") |
| } else { |
| Pat::MultiStr(&["fn", "extern"]) |
| } |
| } |
| |
| fn item_search_pat(item: &Item<'_>) -> (Pat, Pat) { |
| let (start_pat, end_pat) = match &item.kind { |
| ItemKind::ExternCrate(_) => (Pat::Str("extern"), Pat::Str(";")), |
| ItemKind::Static(..) => (Pat::Str("static"), Pat::Str(";")), |
| ItemKind::Const(..) => (Pat::Str("const"), Pat::Str(";")), |
| ItemKind::Fn(sig, ..) => (fn_header_search_pat(sig.header), Pat::Str("")), |
| ItemKind::ForeignMod { .. } => (Pat::Str("extern"), Pat::Str("}")), |
| ItemKind::TyAlias(..) | ItemKind::OpaqueTy(_) => (Pat::Str("type"), Pat::Str(";")), |
| ItemKind::Enum(..) => (Pat::Str("enum"), Pat::Str("}")), |
| ItemKind::Struct(VariantData::Struct(..), _) => (Pat::Str("struct"), Pat::Str("}")), |
| ItemKind::Struct(..) => (Pat::Str("struct"), Pat::Str(";")), |
| ItemKind::Union(..) => (Pat::Str("union"), Pat::Str("}")), |
| ItemKind::Trait(_, Unsafety::Unsafe, ..) |
| | ItemKind::Impl(Impl { |
| unsafety: Unsafety::Unsafe, |
| .. |
| }) => (Pat::Str("unsafe"), Pat::Str("}")), |
| ItemKind::Trait(IsAuto::Yes, ..) => (Pat::Str("auto"), Pat::Str("}")), |
| ItemKind::Trait(..) => (Pat::Str("trait"), Pat::Str("}")), |
| ItemKind::Impl(_) => (Pat::Str("impl"), Pat::Str("}")), |
| _ => return (Pat::Str(""), Pat::Str("")), |
| }; |
| if item.vis_span.is_empty() { |
| (start_pat, end_pat) |
| } else { |
| (Pat::Str("pub"), end_pat) |
| } |
| } |
| |
| fn trait_item_search_pat(item: &TraitItem<'_>) -> (Pat, Pat) { |
| match &item.kind { |
| TraitItemKind::Const(..) => (Pat::Str("const"), Pat::Str(";")), |
| TraitItemKind::Type(..) => (Pat::Str("type"), Pat::Str(";")), |
| TraitItemKind::Fn(sig, ..) => (fn_header_search_pat(sig.header), Pat::Str("")), |
| } |
| } |
| |
| fn impl_item_search_pat(item: &ImplItem<'_>) -> (Pat, Pat) { |
| let (start_pat, end_pat) = match &item.kind { |
| ImplItemKind::Const(..) => (Pat::Str("const"), Pat::Str(";")), |
| ImplItemKind::Type(..) => (Pat::Str("type"), Pat::Str(";")), |
| ImplItemKind::Fn(sig, ..) => (fn_header_search_pat(sig.header), Pat::Str("")), |
| }; |
| if item.vis_span.is_empty() { |
| (start_pat, end_pat) |
| } else { |
| (Pat::Str("pub"), end_pat) |
| } |
| } |
| |
| fn field_def_search_pat(def: &FieldDef<'_>) -> (Pat, Pat) { |
| if def.vis_span.is_empty() { |
| if def.is_positional() { |
| (Pat::Str(""), Pat::Str("")) |
| } else { |
| (Pat::Sym(def.ident.name), Pat::Str("")) |
| } |
| } else { |
| (Pat::Str("pub"), Pat::Str("")) |
| } |
| } |
| |
| fn variant_search_pat(v: &Variant<'_>) -> (Pat, Pat) { |
| match v.data { |
| VariantData::Struct(..) => (Pat::Sym(v.ident.name), Pat::Str("}")), |
| VariantData::Tuple(..) => (Pat::Sym(v.ident.name), Pat::Str("")), |
| VariantData::Unit(..) => (Pat::Sym(v.ident.name), Pat::Sym(v.ident.name)), |
| } |
| } |
| |
| fn fn_kind_pat(tcx: TyCtxt<'_>, kind: &FnKind<'_>, body: &Body<'_>, hir_id: HirId) -> (Pat, Pat) { |
| let (start_pat, end_pat) = match kind { |
| FnKind::ItemFn(.., header) => (fn_header_search_pat(*header), Pat::Str("")), |
| FnKind::Method(.., sig) => (fn_header_search_pat(sig.header), Pat::Str("")), |
| FnKind::Closure => return (Pat::Str(""), expr_search_pat(tcx, body.value).1), |
| }; |
| let start_pat = match tcx.hir().get(hir_id) { |
| Node::Item(Item { vis_span, .. }) | Node::ImplItem(ImplItem { vis_span, .. }) => { |
| if vis_span.is_empty() { |
| start_pat |
| } else { |
| Pat::Str("pub") |
| } |
| }, |
| Node::TraitItem(_) => start_pat, |
| _ => Pat::Str(""), |
| }; |
| (start_pat, end_pat) |
| } |
| |
| fn attr_search_pat(attr: &Attribute) -> (Pat, Pat) { |
| match attr.kind { |
| AttrKind::Normal(..) => { |
| if let Some(ident) = attr.ident() { |
| // TODO: I feel like it's likely we can use `Cow` instead but this will require quite a bit of |
| // refactoring |
| // NOTE: This will likely have false positives, like `allow = 1` |
| ( |
| Pat::OwnedMultiStr(vec![ident.to_string(), "#".to_owned()]), |
| Pat::Str(""), |
| ) |
| } else { |
| (Pat::Str("#"), Pat::Str("]")) |
| } |
| }, |
| AttrKind::DocComment(_kind @ CommentKind::Line, ..) => { |
| if matches!(attr.style, AttrStyle::Outer) { |
| (Pat::Str("///"), Pat::Str("")) |
| } else { |
| (Pat::Str("//!"), Pat::Str("")) |
| } |
| }, |
| AttrKind::DocComment(_kind @ CommentKind::Block, ..) => { |
| if matches!(attr.style, AttrStyle::Outer) { |
| (Pat::Str("/**"), Pat::Str("*/")) |
| } else { |
| (Pat::Str("/*!"), Pat::Str("*/")) |
| } |
| }, |
| } |
| } |
| |
| fn ty_search_pat(ty: &Ty<'_>) -> (Pat, Pat) { |
| match ty.kind { |
| TyKind::Slice(..) | TyKind::Array(..) => (Pat::Str("["), Pat::Str("]")), |
| TyKind::Ptr(MutTy { ty, .. }) => (Pat::Str("*"), ty_search_pat(ty).1), |
| TyKind::Ref(_, MutTy { ty, .. }) => (Pat::Str("&"), ty_search_pat(ty).1), |
| TyKind::BareFn(bare_fn) => ( |
| if bare_fn.unsafety == Unsafety::Unsafe { |
| Pat::Str("unsafe") |
| } else if bare_fn.abi != Abi::Rust { |
| Pat::Str("extern") |
| } else { |
| Pat::MultiStr(&["fn", "extern"]) |
| }, |
| match bare_fn.decl.output { |
| FnRetTy::DefaultReturn(_) => { |
| if let [.., ty] = bare_fn.decl.inputs { |
| ty_search_pat(ty).1 |
| } else { |
| Pat::Str("(") |
| } |
| }, |
| FnRetTy::Return(ty) => ty_search_pat(ty).1, |
| }, |
| ), |
| TyKind::Never => (Pat::Str("!"), Pat::Str("!")), |
| // Parenthesis are trimmed from the text before the search patterns are matched. |
| // See: `span_matches_pat` |
| TyKind::Tup([]) => (Pat::Str(")"), Pat::Str("(")), |
| TyKind::Tup([ty]) => ty_search_pat(ty), |
| TyKind::Tup([head, .., tail]) => (ty_search_pat(head).0, ty_search_pat(tail).1), |
| TyKind::OpaqueDef(..) => (Pat::Str("impl"), Pat::Str("")), |
| TyKind::Path(qpath) => qpath_search_pat(&qpath), |
| TyKind::Infer => (Pat::Str("_"), Pat::Str("_")), |
| TyKind::TraitObject(_, _, TraitObjectSyntax::Dyn) => (Pat::Str("dyn"), Pat::Str("")), |
| // NOTE: `TraitObject` is incomplete. It will always return true then. |
| _ => (Pat::Str(""), Pat::Str("")), |
| } |
| } |
| |
| pub trait WithSearchPat<'cx> { |
| type Context: LintContext; |
| fn search_pat(&self, cx: &Self::Context) -> (Pat, Pat); |
| fn span(&self) -> Span; |
| } |
| macro_rules! impl_with_search_pat { |
| ($cx:ident: $ty:ident with $fn:ident $(($tcx:ident))?) => { |
| impl<'cx> WithSearchPat<'cx> for $ty<'cx> { |
| type Context = $cx<'cx>; |
| #[allow(unused_variables)] |
| fn search_pat(&self, cx: &Self::Context) -> (Pat, Pat) { |
| $(let $tcx = cx.tcx;)? |
| $fn($($tcx,)? self) |
| } |
| fn span(&self) -> Span { |
| self.span |
| } |
| } |
| }; |
| } |
| impl_with_search_pat!(LateContext: Expr with expr_search_pat(tcx)); |
| impl_with_search_pat!(LateContext: Item with item_search_pat); |
| impl_with_search_pat!(LateContext: TraitItem with trait_item_search_pat); |
| impl_with_search_pat!(LateContext: ImplItem with impl_item_search_pat); |
| impl_with_search_pat!(LateContext: FieldDef with field_def_search_pat); |
| impl_with_search_pat!(LateContext: Variant with variant_search_pat); |
| impl_with_search_pat!(LateContext: Ty with ty_search_pat); |
| |
| impl<'cx> WithSearchPat<'cx> for (&FnKind<'cx>, &Body<'cx>, HirId, Span) { |
| type Context = LateContext<'cx>; |
| |
| fn search_pat(&self, cx: &Self::Context) -> (Pat, Pat) { |
| fn_kind_pat(cx.tcx, self.0, self.1, self.2) |
| } |
| |
| fn span(&self) -> Span { |
| self.3 |
| } |
| } |
| |
| // `Attribute` does not have the `hir` associated lifetime, so we cannot use the macro |
| impl<'cx> WithSearchPat<'cx> for &'cx Attribute { |
| type Context = LateContext<'cx>; |
| |
| fn search_pat(&self, _cx: &Self::Context) -> (Pat, Pat) { |
| attr_search_pat(self) |
| } |
| |
| fn span(&self) -> Span { |
| self.span |
| } |
| } |
| |
| // `Ident` does not have the `hir` associated lifetime, so we cannot use the macro |
| impl<'cx> WithSearchPat<'cx> for Ident { |
| type Context = LateContext<'cx>; |
| |
| fn search_pat(&self, _cx: &Self::Context) -> (Pat, Pat) { |
| (Pat::Sym(self.name), Pat::Sym(self.name)) |
| } |
| |
| fn span(&self) -> Span { |
| self.span |
| } |
| } |
| |
| /// Checks if the item likely came from a proc-macro. |
| /// |
| /// This should be called after `in_external_macro` and the initial pattern matching of the ast as |
| /// it is significantly slower than both of those. |
| pub fn is_from_proc_macro<'cx, T: WithSearchPat<'cx>>(cx: &T::Context, item: &T) -> bool { |
| let (start_pat, end_pat) = item.search_pat(cx); |
| !span_matches_pat(cx.sess(), item.span(), start_pat, end_pat) |
| } |
| |
| /// Checks if the span actually refers to a match expression |
| pub fn is_span_match(cx: &impl LintContext, span: Span) -> bool { |
| span_matches_pat(cx.sess(), span, Pat::Str("match"), Pat::Str("}")) |
| } |
| |
| /// Checks if the span actually refers to an if expression |
| pub fn is_span_if(cx: &impl LintContext, span: Span) -> bool { |
| span_matches_pat(cx.sess(), span, Pat::Str("if"), Pat::Str("}")) |
| } |
