6 use clippy_utils::{diagnostics::span_lint_and_help, in_macro, is_direct_expn_of, source::snippet_opt};
7 use if_chain::if_chain;
9 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
10 use rustc_lint::{EarlyContext, EarlyLintPass};
11 use rustc_session::{declare_tool_lint, impl_lint_pass};
13 use serde::{de, Deserialize};
15 declare_clippy_lint! {
16 /// **What it does:** Checks that common macros are used with consistent bracing.
18 /// **Why is this bad?** This is mostly a consistency lint although using () or []
19 /// doesn't give you a semicolon in item position, which can be unexpected.
21 /// **Known problems:**
33 pub NONSTANDARD_MACRO_BRACES,
35 "check consistent use of braces in macro"
38 const BRACES: &[(&str, &str)] = &[("(", ")"), ("{", "}"), ("[", "]")];
40 /// The (name, (open brace, close brace), source snippet)
41 type MacroInfo<'a> = (&'a str, &'a (String, String), String);
43 #[derive(Clone, Debug, Default)]
44 pub struct MacroBraces {
45 macro_braces: FxHashMap<String, (String, String)>,
46 done: FxHashSet<Span>,
50 pub fn new(conf: &FxHashSet<MacroMatcher>) -> Self {
51 let macro_braces = macro_braces(conf.clone());
54 done: FxHashSet::default(),
59 impl_lint_pass!(MacroBraces => [NONSTANDARD_MACRO_BRACES]);
61 impl EarlyLintPass for MacroBraces {
62 fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
63 if let Some((name, braces, snip)) = is_offending_macro(cx, item.span, self) {
64 let span = item.span.ctxt().outer_expn_data().call_site;
65 emit_help(cx, snip, braces, name, span);
66 self.done.insert(span);
70 fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &ast::Stmt) {
71 if let Some((name, braces, snip)) = is_offending_macro(cx, stmt.span, self) {
72 let span = stmt.span.ctxt().outer_expn_data().call_site;
73 emit_help(cx, snip, braces, name, span);
74 self.done.insert(span);
78 fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
79 if let Some((name, braces, snip)) = is_offending_macro(cx, expr.span, self) {
80 let span = expr.span.ctxt().outer_expn_data().call_site;
81 emit_help(cx, snip, braces, name, span);
82 self.done.insert(span);
86 fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {
87 if let Some((name, braces, snip)) = is_offending_macro(cx, ty.span, self) {
88 let span = ty.span.ctxt().outer_expn_data().call_site;
89 emit_help(cx, snip, braces, name, span);
90 self.done.insert(span);
95 fn is_offending_macro<'a>(cx: &EarlyContext<'_>, span: Span, mac_braces: &'a MacroBraces) -> Option<MacroInfo<'a>> {
96 let unnested_or_local = || {
97 let nested = in_macro(span.ctxt().outer_expn_data().call_site);
98 let in_local_macro = nested
99 && matches!(span.macro_backtrace().last().and_then(|e| e.macro_def_id), Some(defid) if defid.is_local());
100 !nested || in_local_macro
103 // Make sure we are only one level deep otherwise there are to many FP's
105 if let Some((name, braces)) = find_matching_macro(span, &mac_braces.macro_braces);
106 if let Some(snip) = snippet_opt(cx, span.ctxt().outer_expn_data().call_site);
107 // we must check only invocation sites
108 // https://github.com/rust-lang/rust-clippy/issues/7422
109 if snip.starts_with(&format!("{}!", name));
110 if unnested_or_local();
111 // make formatting consistent
112 let c = snip.replace(" ", "");
113 if !c.starts_with(&format!("{}!{}", name, braces.0));
114 if !mac_braces.done.contains(&span.ctxt().outer_expn_data().call_site);
116 Some((name, braces, snip))
123 fn emit_help(cx: &EarlyContext<'_>, snip: String, braces: &(String, String), name: &str, span: Span) {
124 let with_space = &format!("! {}", braces.0);
125 let without_space = &format!("!{}", braces.0);
127 for b in BRACES.iter().filter(|b| b.0 != braces.0) {
128 help = help.replace(b.0, &braces.0).replace(b.1, &braces.1);
129 // Only `{` traditionally has space before the brace
130 if braces.0 != "{" && help.contains(with_space) {
131 help = help.replace(with_space, without_space);
132 } else if braces.0 == "{" && help.contains(without_space) {
133 help = help.replace(without_space, with_space);
138 NONSTANDARD_MACRO_BRACES,
140 &format!("use of irregular braces for `{}!` macro", name),
142 &format!("consider writing `{}`", help),
146 fn find_matching_macro(
148 braces: &FxHashMap<String, (String, String)>,
149 ) -> Option<(&String, &(String, String))> {
152 .find(|(macro_name, _)| is_direct_expn_of(span, macro_name).is_some())
155 fn macro_braces(conf: FxHashSet<MacroMatcher>) -> FxHashMap<String, (String, String)> {
156 let mut braces = vec![
195 .collect::<FxHashMap<_, _>>();
196 // We want users items to override any existing items
198 braces.insert(it.name, it.braces);
203 macro_rules! macro_matcher {
204 (name: $name:expr, braces: ($open:expr, $close:expr) $(,)?) => {
205 ($name.to_owned(), ($open.to_owned(), $close.to_owned()))
208 pub(crate) use macro_matcher;
210 #[derive(Clone, Debug)]
211 pub struct MacroMatcher {
213 braces: (String, String),
216 impl Hash for MacroMatcher {
217 fn hash<H: Hasher>(&self, state: &mut H) {
218 self.name.hash(state);
222 impl PartialEq for MacroMatcher {
223 fn eq(&self, other: &Self) -> bool {
224 self.name == other.name
227 impl Eq for MacroMatcher {}
229 impl<'de> Deserialize<'de> for MacroMatcher {
230 fn deserialize<D>(deser: D) -> Result<Self, D::Error>
232 D: de::Deserializer<'de>,
234 #[derive(Deserialize)]
235 #[serde(field_identifier, rename_all = "lowercase")]
241 impl<'de> de::Visitor<'de> for MacVisitor {
242 type Value = MacroMatcher;
244 fn expecting(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
245 formatter.write_str("struct MacroMatcher")
248 fn visit_map<V>(self, mut map: V) -> Result<Self::Value, V::Error>
250 V: de::MapAccess<'de>,
253 let mut brace: Option<&str> = None;
254 while let Some(key) = map.next_key()? {
258 return Err(de::Error::duplicate_field("name"));
260 name = Some(map.next_value()?);
264 return Err(de::Error::duplicate_field("brace"));
266 brace = Some(map.next_value()?);
270 let name = name.ok_or_else(|| de::Error::missing_field("name"))?;
271 let brace = brace.ok_or_else(|| de::Error::missing_field("brace"))?;
276 .find(|b| b.0 == brace)
277 .map(|(o, c)| ((*o).to_owned(), (*c).to_owned()))
279 de::Error::custom(&format!("expected one of `(`, `{{`, `[` found `{}`", brace))
285 const FIELDS: &[&str] = &["name", "brace"];
286 deser.deserialize_struct("MacroMatcher", FIELDS, MacVisitor)