6 use clippy_utils::diagnostics::span_lint_and_help;
7 use clippy_utils::source::snippet_opt;
8 use if_chain::if_chain;
10 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
11 use rustc_hir::def_id::DefId;
12 use rustc_lint::{EarlyContext, EarlyLintPass};
13 use rustc_session::{declare_tool_lint, impl_lint_pass};
14 use rustc_span::hygiene::{ExpnKind, MacroKind};
15 use rustc_span::{Span, Symbol};
16 use serde::{de, Deserialize};
18 declare_clippy_lint! {
20 /// Checks that common macros are used with consistent bracing.
22 /// ### Why is this bad?
23 /// This is mostly a consistency lint although using () or []
24 /// doesn't give you a semicolon in item position, which can be unexpected.
34 #[clippy::version = "1.55.0"]
35 pub NONSTANDARD_MACRO_BRACES,
37 "check consistent use of braces in macro"
40 const BRACES: &[(&str, &str)] = &[("(", ")"), ("{", "}"), ("[", "]")];
42 /// The (name, (open brace, close brace), source snippet)
43 type MacroInfo<'a> = (Symbol, &'a (String, String), String);
45 #[derive(Clone, Debug, Default)]
46 pub struct MacroBraces {
47 macro_braces: FxHashMap<String, (String, String)>,
48 done: FxHashSet<Span>,
52 pub fn new(conf: &FxHashSet<MacroMatcher>) -> Self {
53 let macro_braces = macro_braces(conf.clone());
56 done: FxHashSet::default(),
61 impl_lint_pass!(MacroBraces => [NONSTANDARD_MACRO_BRACES]);
63 impl EarlyLintPass for MacroBraces {
64 fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
65 if let Some((name, braces, snip)) = is_offending_macro(cx, item.span, self) {
66 let span = item.span.ctxt().outer_expn_data().call_site;
67 emit_help(cx, snip, braces, name, span);
68 self.done.insert(span);
72 fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &ast::Stmt) {
73 if let Some((name, braces, snip)) = is_offending_macro(cx, stmt.span, self) {
74 let span = stmt.span.ctxt().outer_expn_data().call_site;
75 emit_help(cx, snip, braces, name, span);
76 self.done.insert(span);
80 fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
81 if let Some((name, braces, snip)) = is_offending_macro(cx, expr.span, self) {
82 let span = expr.span.ctxt().outer_expn_data().call_site;
83 emit_help(cx, snip, braces, name, span);
84 self.done.insert(span);
88 fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {
89 if let Some((name, braces, snip)) = is_offending_macro(cx, ty.span, self) {
90 let span = ty.span.ctxt().outer_expn_data().call_site;
91 emit_help(cx, snip, braces, name, span);
92 self.done.insert(span);
97 fn is_offending_macro<'a>(cx: &EarlyContext<'_>, span: Span, mac_braces: &'a MacroBraces) -> Option<MacroInfo<'a>> {
98 let unnested_or_local = || {
99 !span.ctxt().outer_expn_data().call_site.from_expansion()
103 .map_or(false, |e| e.macro_def_id.map_or(false, DefId::is_local))
106 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = span.ctxt().outer_expn_data().kind;
107 let name = &*mac_name.as_str();
108 if let Some(braces) = mac_braces.macro_braces.get(name);
109 if let Some(snip) = snippet_opt(cx, span.ctxt().outer_expn_data().call_site);
110 // we must check only invocation sites
111 // https://github.com/rust-lang/rust-clippy/issues/7422
112 if snip.starts_with(&format!("{}!", name));
113 if unnested_or_local();
114 // make formatting consistent
115 let c = snip.replace(' ', "");
116 if !c.starts_with(&format!("{}!{}", name, braces.0));
117 if !mac_braces.done.contains(&span.ctxt().outer_expn_data().call_site);
119 Some((mac_name, braces, snip))
126 fn emit_help(cx: &EarlyContext<'_>, snip: String, braces: &(String, String), name: Symbol, span: Span) {
127 let with_space = &format!("! {}", braces.0);
128 let without_space = &format!("!{}", braces.0);
130 for b in BRACES.iter().filter(|b| b.0 != braces.0) {
131 help = help.replace(b.0, &braces.0).replace(b.1, &braces.1);
132 // Only `{` traditionally has space before the brace
133 if braces.0 != "{" && help.contains(with_space) {
134 help = help.replace(with_space, without_space);
135 } else if braces.0 == "{" && help.contains(without_space) {
136 help = help.replace(without_space, with_space);
141 NONSTANDARD_MACRO_BRACES,
143 &format!("use of irregular braces for `{}!` macro", name),
145 &format!("consider writing `{}`", help),
149 fn macro_braces(conf: FxHashSet<MacroMatcher>) -> FxHashMap<String, (String, String)> {
150 let mut braces = vec![
189 .collect::<FxHashMap<_, _>>();
190 // We want users items to override any existing items
192 braces.insert(it.name, it.braces);
197 macro_rules! macro_matcher {
198 (name: $name:expr, braces: ($open:expr, $close:expr) $(,)?) => {
199 ($name.to_owned(), ($open.to_owned(), $close.to_owned()))
202 pub(crate) use macro_matcher;
204 #[derive(Clone, Debug)]
205 pub struct MacroMatcher {
207 braces: (String, String),
210 impl Hash for MacroMatcher {
211 fn hash<H: Hasher>(&self, state: &mut H) {
212 self.name.hash(state);
216 impl PartialEq for MacroMatcher {
217 fn eq(&self, other: &Self) -> bool {
218 self.name == other.name
221 impl Eq for MacroMatcher {}
223 impl<'de> Deserialize<'de> for MacroMatcher {
224 fn deserialize<D>(deser: D) -> Result<Self, D::Error>
226 D: de::Deserializer<'de>,
228 #[derive(Deserialize)]
229 #[serde(field_identifier, rename_all = "lowercase")]
235 impl<'de> de::Visitor<'de> for MacVisitor {
236 type Value = MacroMatcher;
238 fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
239 formatter.write_str("struct MacroMatcher")
242 fn visit_map<V>(self, mut map: V) -> Result<Self::Value, V::Error>
244 V: de::MapAccess<'de>,
247 let mut brace: Option<&str> = None;
248 while let Some(key) = map.next_key()? {
252 return Err(de::Error::duplicate_field("name"));
254 name = Some(map.next_value()?);
258 return Err(de::Error::duplicate_field("brace"));
260 brace = Some(map.next_value()?);
264 let name = name.ok_or_else(|| de::Error::missing_field("name"))?;
265 let brace = brace.ok_or_else(|| de::Error::missing_field("brace"))?;
270 .find(|b| b.0 == brace)
271 .map(|(o, c)| ((*o).to_owned(), (*c).to_owned()))
273 de::Error::custom(&format!("expected one of `(`, `{{`, `[` found `{}`", brace))
279 const FIELDS: &[&str] = &["name", "brace"];
280 deser.deserialize_struct("MacroMatcher", FIELDS, MacVisitor)