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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs b/src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs new file mode 100644 index 000000000..454ec2338 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/crate_in_macro_def.rs @@ -0,0 +1,125 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use rustc_ast::ast::{AttrKind, Attribute, Item, ItemKind}; +use rustc_ast::token::{Token, TokenKind}; +use rustc_ast::tokenstream::{TokenStream, TokenTree}; +use rustc_errors::Applicability; +use rustc_lint::{EarlyContext, EarlyLintPass}; +use rustc_session::{declare_lint_pass, declare_tool_lint}; +use rustc_span::{symbol::sym, Span}; + +declare_clippy_lint! { + /// ### What it does + /// Checks for use of `crate` as opposed to `$crate` in a macro definition. + /// + /// ### Why is this bad? + /// `crate` refers to the macro call's crate, whereas `$crate` refers to the macro definition's + /// crate. Rarely is the former intended. See: + /// https://doc.rust-lang.org/reference/macros-by-example.html#hygiene + /// + /// ### Example + /// ```rust + /// #[macro_export] + /// macro_rules! print_message { + /// () => { + /// println!("{}", crate::MESSAGE); + /// }; + /// } + /// pub const MESSAGE: &str = "Hello!"; + /// ``` + /// Use instead: + /// ```rust + /// #[macro_export] + /// macro_rules! print_message { + /// () => { + /// println!("{}", $crate::MESSAGE); + /// }; + /// } + /// pub const MESSAGE: &str = "Hello!"; + /// ``` + /// + /// Note that if the use of `crate` is intentional, an `allow` attribute can be applied to the + /// macro definition, e.g.: + /// ```rust,ignore + /// #[allow(clippy::crate_in_macro_def)] + /// macro_rules! ok { ... crate::foo ... } + /// ``` + #[clippy::version = "1.62.0"] + pub CRATE_IN_MACRO_DEF, + suspicious, + "using `crate` in a macro definition" +} +declare_lint_pass!(CrateInMacroDef => [CRATE_IN_MACRO_DEF]); + +impl EarlyLintPass for CrateInMacroDef { + fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) { + if_chain! { + if item.attrs.iter().any(is_macro_export); + if let ItemKind::MacroDef(macro_def) = &item.kind; + let tts = macro_def.body.inner_tokens(); + if let Some(span) = contains_unhygienic_crate_reference(&tts); + then { + span_lint_and_sugg( + cx, + CRATE_IN_MACRO_DEF, + span, + "`crate` references the macro call's crate", + "to reference the macro definition's crate, use", + String::from("$crate"), + Applicability::MachineApplicable, + ); + } + } + } +} + +fn is_macro_export(attr: &Attribute) -> bool { + if_chain! { + if let AttrKind::Normal(attr_item, _) = &attr.kind; + if let [segment] = attr_item.path.segments.as_slice(); + then { + segment.ident.name == sym::macro_export + } else { + false + } + } +} + +fn contains_unhygienic_crate_reference(tts: &TokenStream) -> Option<Span> { + let mut prev_is_dollar = false; + let mut cursor = tts.trees(); + while let Some(curr) = cursor.next() { + if_chain! { + if !prev_is_dollar; + if let Some(span) = is_crate_keyword(curr); + if let Some(next) = cursor.look_ahead(0); + if is_token(next, &TokenKind::ModSep); + then { + return Some(span); + } + } + if let TokenTree::Delimited(_, _, tts) = &curr { + let span = contains_unhygienic_crate_reference(tts); + if span.is_some() { + return span; + } + } + prev_is_dollar = is_token(curr, &TokenKind::Dollar); + } + None +} + +fn is_crate_keyword(tt: &TokenTree) -> Option<Span> { + if_chain! { + if let TokenTree::Token(Token { kind: TokenKind::Ident(symbol, _), span }, _) = tt; + if symbol.as_str() == "crate"; + then { Some(*span) } else { None } + } +} + +fn is_token(tt: &TokenTree, kind: &TokenKind) -> bool { + if let TokenTree::Token(Token { kind: other, .. }, _) = tt { + kind == other + } else { + false + } +} |