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-rw-r--r--src/tools/clippy/clippy_utils/src/check_proc_macro.rs329
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diff --git a/src/tools/clippy/clippy_utils/src/check_proc_macro.rs b/src/tools/clippy/clippy_utils/src/check_proc_macro.rs
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index 000000000..7a8d4e806
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+++ b/src/tools/clippy/clippy_utils/src/check_proc_macro.rs
@@ -0,0 +1,329 @@
+//! 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::{IntTy, LitIntType, LitKind, StrStyle, UintTy};
+use rustc_hir::{
+ intravisit::FnKind, Block, BlockCheckMode, Body, Closure, Destination, Expr, ExprKind, FieldDef, FnHeader, HirId,
+ Impl, ImplItem, ImplItemKind, IsAuto, Item, ItemKind, LoopSource, MatchSource, Node, QPath, TraitItem,
+ TraitItemKind, UnOp, UnsafeSource, Unsafety, Variant, VariantData, YieldSource,
+};
+use rustc_lint::{LateContext, LintContext};
+use rustc_middle::ty::TyCtxt;
+use rustc_session::Session;
+use rustc_span::{Span, Symbol};
+use rustc_target::spec::abi::Abi;
+
+/// The search pattern to look for. Used by `span_matches_pat`
+#[derive(Clone, Copy)]
+pub enum Pat {
+ /// A single string.
+ Str(&'static str),
+ /// Any of the given strings.
+ MultiStr(&'static [&'static str]),
+ /// 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::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::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(_) => (Pat::Str("b\""), 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::Box(e) => (Pat::Str("box"), expr_search_pat(tcx, e).1),
+ ExprKind::ConstBlock(_) => (Pat::Str("const"), Pat::Str("}")),
+ 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(ref 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::TyAlias(..) => (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)
+}
+
+pub trait WithSearchPat {
+ 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 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<'cx> WithSearchPat 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
+ }
+}
+
+/// 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<T: WithSearchPat>(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("}"))
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-18 16:55:47 +0000