4 use rustc::middle::const_val::ConstVal;
5 use rustc_const_eval::EvalHint::ExprTypeChecked;
6 use rustc_const_eval::eval_const_expr_partial;
7 use std::collections::HashSet;
9 use syntax::ast::{LitKind, NodeId};
10 use syntax::codemap::{Span, BytePos};
11 use syntax::parse::token::InternedString;
12 use utils::{is_expn_of, match_def_path, match_type, paths, span_lint, span_help_and_lint};
14 /// **What it does:** This lint checks [regex] creation (with `Regex::new`, `RegexBuilder::new` or
15 /// `RegexSet::new`) for correct regex syntax.
17 /// **Why is this bad?** This will lead to a runtime panic.
19 /// **Known problems:** None.
21 /// **Example:** `Regex::new("|")`
25 "finds invalid regular expressions"
28 /// **What it does:** This lint checks for trivial [regex] creation (with `Regex::new`,
29 /// `RegexBuilder::new` or `RegexSet::new`).
31 /// **Why is this bad?** This can likely be replaced by `==` or `str::starts_with`,
32 /// `str::ends_with` or `std::contains` or other `str` methods.
34 /// **Known problems:** None.
36 /// **Example:** `Regex::new("^foobar")`
38 /// [regex]: https://crates.io/crates/regex
42 "finds trivial regular expressions"
45 /// **What it does:** This lint checks for usage of `regex!(_)` which as of now is usually slower than `Regex::new(_)` unless called in a loop (which is a bad idea anyway).
47 /// **Why is this bad?** Performance, at least for now. The macro version is likely to catch up long-term, but for now the dynamic version is faster.
49 /// **Known problems:** None
51 /// **Example:** `regex!("foo|bar")`
55 "finds use of `regex!(_)`, suggests `Regex::new(_)` instead"
58 #[derive(Clone, Default)]
59 pub struct RegexPass {
64 impl LintPass for RegexPass {
65 fn get_lints(&self) -> LintArray {
66 lint_array!(INVALID_REGEX, REGEX_MACRO, TRIVIAL_REGEX)
70 impl LateLintPass for RegexPass {
71 fn check_crate(&mut self, _: &LateContext, _: &Crate) {
75 fn check_block(&mut self, cx: &LateContext, block: &Block) {
78 let Some(ref expr) = block.expr,
79 match_type(cx, cx.tcx.expr_ty(expr), &paths::REGEX),
80 let Some(span) = is_expn_of(cx, expr.span, "regex"),
82 if !self.spans.contains(&span) {
87 Please use `Regex::new(_)`, which is faster for now.");
88 self.spans.insert(span);
90 self.last = Some(block.id);
94 fn check_block_post(&mut self, _: &LateContext, block: &Block) {
95 if self.last.map_or(false, |id| block.id == id) {
100 fn check_expr(&mut self, cx: &LateContext, expr: &Expr) {
102 let ExprCall(ref fun, ref args) = expr.node,
104 let Some(def) = cx.tcx.def_map.borrow().get(&fun.id),
106 let def_id = def.def_id();
107 if match_def_path(cx, def_id, &paths::REGEX_NEW) {
108 check_regex(cx, &args[0], true);
109 } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_NEW) {
110 check_regex(cx, &args[0], false);
111 } else if match_def_path(cx, def_id, &paths::REGEX_BUILDER_NEW) {
112 check_regex(cx, &args[0], true);
113 } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_BUILDER_NEW) {
114 check_regex(cx, &args[0], false);
115 } else if match_def_path(cx, def_id, &paths::REGEX_SET_NEW) {
116 check_set(cx, &args[0], true);
117 } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_SET_NEW) {
118 check_set(cx, &args[0], false);
124 #[allow(cast_possible_truncation)]
125 fn str_span(base: Span, s: &str, c: usize) -> Span {
126 let mut si = s.char_indices().skip(c);
128 match (si.next(), si.next()) {
129 (Some((l, _)), Some((h, _))) => {
131 lo: base.lo + BytePos(l as u32),
132 hi: base.lo + BytePos(h as u32),
140 fn const_str(cx: &LateContext, e: &Expr) -> Option<InternedString> {
141 match eval_const_expr_partial(cx.tcx, e, ExprTypeChecked, None) {
142 Ok(ConstVal::Str(r)) => Some(r),
147 fn is_trivial_regex(s: ®ex_syntax::Expr) -> Option<&'static str> {
148 use regex_syntax::Expr;
151 Expr::Empty | Expr::StartText | Expr::EndText => Some("the regex is unlikely to be useful as it is"),
152 Expr::Literal { .. } => Some("consider using `str::contains`"),
153 Expr::Concat(ref exprs) => {
156 match (&exprs[0], &exprs[1]) {
157 (&Expr::StartText, &Expr::EndText) => Some("consider using `str::is_empty`"),
158 (&Expr::StartText, &Expr::Literal { .. }) => Some("consider using `str::starts_with`"),
159 (&Expr::Literal { .. }, &Expr::EndText) => Some("consider using `str::ends_with`"),
164 if let (&Expr::StartText, &Expr::Literal {..}, &Expr::EndText) = (&exprs[0], &exprs[1], &exprs[2]) {
165 Some("consider using `==` on `str`s")
177 fn check_set(cx: &LateContext, expr: &Expr, utf8: bool) {
179 let ExprAddrOf(_, ref expr) = expr.node,
180 let ExprVec(ref exprs) = expr.node,
183 check_regex(cx, expr, utf8);
188 fn check_regex(cx: &LateContext, expr: &Expr, utf8: bool) {
189 let builder = regex_syntax::ExprBuilder::new().unicode(utf8);
191 if let ExprLit(ref lit) = expr.node {
192 if let LitKind::Str(ref r, _) = lit.node {
193 match builder.parse(r) {
195 if let Some(repl) = is_trivial_regex(&r) {
196 span_help_and_lint(cx, TRIVIAL_REGEX, expr.span,
198 &format!("consider using {}", repl));
204 str_span(expr.span, r, e.position()),
205 &format!("regex syntax error: {}",
210 } else if let Some(r) = const_str(cx, expr) {
211 match builder.parse(&r) {
213 if let Some(repl) = is_trivial_regex(&r) {
214 span_help_and_lint(cx, TRIVIAL_REGEX, expr.span,
216 &format!("consider using {}", repl));
223 &format!("regex syntax error on position {}: {}",