2016-03-01 03:13:54 -06:00
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use rustc::lint::*;
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use syntax::codemap::Span;
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2016-11-23 14:19:03 -06:00
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use syntax::symbol::InternedString;
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2016-03-01 03:13:54 -06:00
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use syntax::ast::*;
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2016-05-02 03:52:55 -05:00
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use syntax::attr;
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2016-05-11 09:44:43 -05:00
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use syntax::visit::{Visitor, walk_block, walk_pat, walk_expr};
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2016-03-01 06:05:39 -06:00
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use utils::{span_lint_and_then, in_macro, span_lint};
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2016-03-01 03:13:54 -06:00
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2016-08-06 02:55:04 -05:00
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/// **What it does:** Checks for names that are very similar and thus confusing.
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2016-03-01 03:13:54 -06:00
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///
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2016-08-06 02:55:04 -05:00
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/// **Why is this bad?** It's hard to distinguish between names that differ only
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/// by a single character.
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2016-03-01 03:13:54 -06:00
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///
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/// **Known problems:** None?
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///
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2016-08-06 02:55:04 -05:00
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/// **Example:**
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/// ```rust
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/// let checked_exp = something;
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/// let checked_expr = something_else;
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/// ```
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2016-03-01 03:13:54 -06:00
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declare_lint! {
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pub SIMILAR_NAMES,
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2016-05-02 03:53:09 -05:00
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Allow,
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2016-03-01 03:13:54 -06:00
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"similarly named items and bindings"
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}
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2016-08-06 02:55:04 -05:00
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/// **What it does:** Checks for too many variables whose name consists of a
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/// single character.
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2016-03-01 06:05:39 -06:00
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///
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2016-08-06 02:55:04 -05:00
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/// **Why is this bad?** It's hard to memorize what a variable means without a
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/// descriptive name.
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2016-03-01 06:05:39 -06:00
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///
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/// **Known problems:** None?
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///
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2016-07-14 10:42:40 -05:00
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/// **Example:**
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/// ```rust
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/// let (a, b, c, d, e, f, g) = (...);
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/// ```
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2016-03-01 06:05:39 -06:00
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declare_lint! {
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pub MANY_SINGLE_CHAR_NAMES,
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Warn,
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"too many single character bindings"
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}
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pub struct NonExpressiveNames {
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2017-05-09 08:23:38 -05:00
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pub single_char_binding_names_threshold: u64,
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2016-03-01 06:05:39 -06:00
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}
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2016-03-01 03:13:54 -06:00
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2016-03-01 06:05:39 -06:00
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impl LintPass for NonExpressiveNames {
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2016-03-01 03:13:54 -06:00
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fn get_lints(&self) -> LintArray {
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2016-03-01 06:05:39 -06:00
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lint_array!(SIMILAR_NAMES, MANY_SINGLE_CHAR_NAMES)
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2016-03-01 03:13:54 -06:00
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}
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}
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2016-03-30 10:05:15 -05:00
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struct ExistingName {
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interned: InternedString,
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span: Span,
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len: usize,
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2016-04-14 13:14:03 -05:00
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whitelist: &'static [&'static str],
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2016-03-30 10:05:15 -05:00
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}
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2016-12-06 04:32:21 -06:00
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struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> {
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2016-03-30 10:05:15 -05:00
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names: Vec<ExistingName>,
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cx: &'a EarlyContext<'tcx>,
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2016-03-01 06:05:39 -06:00
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lint: &'a NonExpressiveNames,
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single_char_names: Vec<char>,
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2016-03-01 03:13:54 -06:00
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}
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2016-03-30 10:05:15 -05:00
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// this list contains lists of names that are allowed to be similar
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// the assumption is that no name is ever contained in multiple lists.
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2016-04-14 13:14:03 -05:00
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#[cfg_attr(rustfmt, rustfmt_skip)]
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const WHITELIST: &'static [&'static [&'static str]] = &[
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&["parsed", "parser"],
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&["lhs", "rhs"],
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2016-03-31 08:38:43 -05:00
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&["tx", "rx"],
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&["set", "get"],
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2016-03-01 03:13:54 -06:00
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];
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2016-12-06 04:32:21 -06:00
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struct SimilarNamesNameVisitor<'a: 'b, 'tcx: 'a, 'b>(&'b mut SimilarNamesLocalVisitor<'a, 'tcx>);
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2016-03-01 03:13:54 -06:00
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2016-12-06 04:32:21 -06:00
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impl<'a, 'tcx: 'a, 'b> Visitor<'tcx> for SimilarNamesNameVisitor<'a, 'tcx, 'b> {
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fn visit_pat(&mut self, pat: &'tcx Pat) {
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2016-05-11 09:44:43 -05:00
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match pat.node {
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PatKind::Ident(_, id, _) => self.check_name(id.span, id.node.name),
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2016-06-05 18:42:39 -05:00
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PatKind::Struct(_, ref fields, _) => {
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for field in fields {
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if !field.node.is_shorthand {
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self.visit_pat(&field.node.pat);
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}
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2016-05-11 09:44:43 -05:00
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}
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2016-12-20 11:21:30 -06:00
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},
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2016-05-11 09:44:43 -05:00
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_ => walk_pat(self, pat),
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2016-03-01 03:13:54 -06:00
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}
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}
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}
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2016-04-14 13:14:03 -05:00
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fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> {
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2016-03-14 08:34:47 -05:00
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for &allow in WHITELIST {
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2016-03-30 10:05:15 -05:00
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if whitelisted(interned_name, allow) {
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return Some(allow);
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2016-03-14 08:34:47 -05:00
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}
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2016-03-30 10:05:15 -05:00
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}
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None
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}
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fn whitelisted(interned_name: &str, list: &[&str]) -> bool {
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2017-08-09 02:59:38 -05:00
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list.iter().any(|&name| interned_name.starts_with(name) || interned_name.ends_with(name))
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2016-03-14 08:34:47 -05:00
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}
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2016-12-06 04:32:21 -06:00
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impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
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2016-03-14 08:34:47 -05:00
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fn check_short_name(&mut self, c: char, span: Span) {
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// make sure we ignore shadowing
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if self.0.single_char_names.contains(&c) {
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return;
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}
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self.0.single_char_names.push(c);
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2017-05-09 08:23:38 -05:00
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if self.0.single_char_names.len() as u64 >= self.0.lint.single_char_binding_names_threshold {
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2017-08-09 02:30:56 -05:00
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span_lint(
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self.0.cx,
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MANY_SINGLE_CHAR_NAMES,
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span,
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&format!("{}th binding whose name is just one char", self.0.single_char_names.len()),
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);
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2016-03-14 08:34:47 -05:00
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}
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}
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2016-03-01 03:13:54 -06:00
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fn check_name(&mut self, span: Span, name: Name) {
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2017-03-31 17:14:04 -05:00
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if in_macro(span) {
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2016-03-01 03:13:54 -06:00
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return;
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}
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let interned_name = name.as_str();
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if interned_name.chars().any(char::is_uppercase) {
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return;
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}
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2016-03-01 06:05:39 -06:00
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let count = interned_name.chars().count();
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if count < 3 {
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2016-03-30 10:05:15 -05:00
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if count == 1 {
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let c = interned_name.chars().next().expect("already checked");
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self.check_short_name(c, span);
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2016-03-08 07:36:21 -06:00
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}
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2016-03-01 03:13:54 -06:00
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return;
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}
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2016-03-30 10:05:15 -05:00
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for existing_name in &self.0.names {
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if whitelisted(&interned_name, existing_name.whitelist) {
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continue;
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}
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2016-03-01 03:34:45 -06:00
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let mut split_at = None;
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2016-03-30 10:05:15 -05:00
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if existing_name.len > count {
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if existing_name.len - count != 1 || levenstein_not_1(&interned_name, &existing_name.interned) {
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2016-03-14 08:34:47 -05:00
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continue;
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}
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2016-03-30 10:05:15 -05:00
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} else if existing_name.len < count {
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if count - existing_name.len != 1 || levenstein_not_1(&existing_name.interned, &interned_name) {
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2016-03-14 08:34:47 -05:00
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continue;
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}
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} else {
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let mut interned_chars = interned_name.chars();
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2016-03-30 10:05:15 -05:00
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let mut existing_chars = existing_name.interned.chars();
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2017-08-09 02:30:56 -05:00
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let first_i = interned_chars.next().expect(
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"we know we have at least one char",
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);
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let first_e = existing_chars.next().expect(
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"we know we have at least one char",
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);
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2017-08-09 02:59:38 -05:00
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let eq_or_numeric = |(a, b): (char, char)| a == b || a.is_numeric() && b.is_numeric();
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2016-03-14 08:34:47 -05:00
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2017-08-09 02:59:38 -05:00
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if eq_or_numeric((first_i, first_e)) {
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2017-08-09 02:30:56 -05:00
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let last_i = interned_chars.next_back().expect(
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"we know we have at least two chars",
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);
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let last_e = existing_chars.next_back().expect(
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"we know we have at least two chars",
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);
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2017-08-09 02:59:38 -05:00
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if eq_or_numeric((last_i, last_e)) {
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2017-08-09 02:30:56 -05:00
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if interned_chars
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.zip(existing_chars)
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2017-08-09 02:59:38 -05:00
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.filter(|&ie| !eq_or_numeric(ie))
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2017-08-09 02:30:56 -05:00
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.count() != 1
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{
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2016-03-14 08:34:47 -05:00
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continue;
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}
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} else {
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2017-08-09 02:30:56 -05:00
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let second_last_i = interned_chars.next_back().expect(
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"we know we have at least three chars",
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);
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let second_last_e = existing_chars.next_back().expect(
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"we know we have at least three chars",
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);
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2017-08-09 02:59:38 -05:00
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if !eq_or_numeric((second_last_i, second_last_e)) || second_last_i == '_' ||
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!interned_chars.zip(existing_chars).all(eq_or_numeric)
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2017-08-09 02:30:56 -05:00
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{
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2016-03-30 09:40:21 -05:00
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// allowed similarity foo_x, foo_y
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// or too many chars differ (foo_x, boo_y) or (foox, booy)
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2016-03-14 08:34:47 -05:00
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continue;
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}
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2016-03-30 09:40:21 -05:00
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split_at = interned_name.char_indices().rev().next().map(|(i, _)| i);
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}
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} else {
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2017-08-09 02:30:56 -05:00
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let second_i = interned_chars.next().expect(
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"we know we have at least two chars",
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);
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let second_e = existing_chars.next().expect(
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"we know we have at least two chars",
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);
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2017-08-09 02:59:38 -05:00
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if !eq_or_numeric((second_i, second_e)) || second_i == '_' ||
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!interned_chars.zip(existing_chars).all(eq_or_numeric)
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2017-08-09 02:30:56 -05:00
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{
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2016-03-30 09:40:21 -05:00
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// allowed similarity x_foo, y_foo
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// or too many chars differ (x_foo, y_boo) or (xfoo, yboo)
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2016-03-01 03:34:45 -06:00
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continue;
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}
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2016-03-30 09:40:21 -05:00
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split_at = interned_name.chars().next().map(|c| c.len_utf8());
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2016-03-01 03:13:54 -06:00
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}
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}
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2017-08-09 02:30:56 -05:00
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span_lint_and_then(
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self.0.cx,
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SIMILAR_NAMES,
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span,
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"binding's name is too similar to existing binding",
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|diag| {
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diag.span_note(existing_name.span, "existing binding defined here");
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if let Some(split) = split_at {
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diag.span_help(
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span,
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&format!(
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"separate the discriminating character by an \
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2016-04-14 13:14:03 -05:00
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underscore like: `{}_{}`",
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2017-08-09 02:30:56 -05:00
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&interned_name[..split],
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&interned_name[split..]
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),
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);
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}
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},
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);
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2016-03-01 03:13:54 -06:00
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return;
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}
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2016-03-30 10:05:15 -05:00
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self.0.names.push(ExistingName {
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whitelist: get_whitelist(&interned_name).unwrap_or(&[]),
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interned: interned_name,
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span: span,
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len: count,
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});
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2016-03-01 03:13:54 -06:00
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}
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}
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2016-03-01 06:05:39 -06:00
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impl<'a, 'b> SimilarNamesLocalVisitor<'a, 'b> {
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2016-03-08 07:36:21 -06:00
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/// ensure scoping rules work
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fn apply<F: for<'c> Fn(&'c mut Self)>(&mut self, f: F) {
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let n = self.names.len();
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let single_char_count = self.single_char_names.len();
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f(self);
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self.names.truncate(n);
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self.single_char_names.truncate(single_char_count);
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2016-03-01 06:05:39 -06:00
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}
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}
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2016-12-06 04:32:21 -06:00
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impl<'a, 'tcx> Visitor<'tcx> for SimilarNamesLocalVisitor<'a, 'tcx> {
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fn visit_local(&mut self, local: &'tcx Local) {
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2016-03-08 07:36:21 -06:00
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if let Some(ref init) = local.init {
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2016-05-11 09:44:43 -05:00
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self.apply(|this| walk_expr(this, &**init));
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2016-03-08 07:36:21 -06:00
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}
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2017-08-09 02:30:56 -05:00
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// add the pattern after the expression because the bindings aren't available
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// yet in the init
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2016-12-21 03:25:14 -06:00
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// expression
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2016-03-08 07:36:21 -06:00
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SimilarNamesNameVisitor(self).visit_pat(&*local.pat);
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2016-03-01 03:13:54 -06:00
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}
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2016-12-06 04:32:21 -06:00
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fn visit_block(&mut self, blk: &'tcx Block) {
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2016-05-11 09:44:43 -05:00
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self.apply(|this| walk_block(this, blk));
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2016-03-01 03:13:54 -06:00
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}
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2016-12-06 04:32:21 -06:00
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fn visit_arm(&mut self, arm: &'tcx Arm) {
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2016-03-08 07:36:21 -06:00
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self.apply(|this| {
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2016-12-21 03:25:14 -06:00
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// just go through the first pattern, as either all patterns
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// bind the same bindings or rustc would have errored much earlier
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2016-03-08 07:36:21 -06:00
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SimilarNamesNameVisitor(this).visit_pat(&arm.pats[0]);
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2016-05-11 09:44:43 -05:00
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this.apply(|this| walk_expr(this, &arm.body));
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2016-03-08 07:36:21 -06:00
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});
|
2016-03-01 03:13:54 -06:00
|
|
|
}
|
2016-06-28 08:54:23 -05:00
|
|
|
fn visit_item(&mut self, _: &Item) {
|
2016-05-02 03:52:55 -05:00
|
|
|
// do not recurse into inner items
|
2016-03-01 03:13:54 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2016-03-01 06:05:39 -06:00
|
|
|
impl EarlyLintPass for NonExpressiveNames {
|
2016-05-02 03:52:55 -05:00
|
|
|
fn check_item(&mut self, cx: &EarlyContext, item: &Item) {
|
|
|
|
if let ItemKind::Fn(ref decl, _, _, _, _, ref blk) = item.node {
|
|
|
|
if !attr::contains_name(&item.attrs, "test") {
|
|
|
|
let mut visitor = SimilarNamesLocalVisitor {
|
|
|
|
names: Vec::new(),
|
|
|
|
cx: cx,
|
2016-04-26 10:05:39 -05:00
|
|
|
lint: self,
|
2016-05-02 03:52:55 -05:00
|
|
|
single_char_names: Vec::new(),
|
|
|
|
};
|
|
|
|
// initialize with function arguments
|
|
|
|
for arg in &decl.inputs {
|
2016-05-11 09:45:06 -05:00
|
|
|
SimilarNamesNameVisitor(&mut visitor).visit_pat(&arg.pat);
|
2016-05-02 03:52:55 -05:00
|
|
|
}
|
|
|
|
// walk all other bindings
|
2016-05-11 09:44:43 -05:00
|
|
|
walk_block(&mut visitor, blk);
|
2016-05-02 03:52:55 -05:00
|
|
|
}
|
2016-03-01 03:13:54 -06:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2016-03-14 08:34:47 -05:00
|
|
|
|
2016-03-19 11:48:29 -05:00
|
|
|
/// Precondition: `a_name.chars().count() < b_name.chars().count()`.
|
2016-03-14 08:34:47 -05:00
|
|
|
fn levenstein_not_1(a_name: &str, b_name: &str) -> bool {
|
|
|
|
debug_assert!(a_name.chars().count() < b_name.chars().count());
|
|
|
|
let mut a_chars = a_name.chars();
|
|
|
|
let mut b_chars = b_name.chars();
|
|
|
|
while let (Some(a), Some(b)) = (a_chars.next(), b_chars.next()) {
|
|
|
|
if a == b {
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
if let Some(b2) = b_chars.next() {
|
|
|
|
// check if there's just one character inserted
|
2016-03-23 08:50:47 -05:00
|
|
|
return a != b2 || a_chars.ne(b_chars);
|
2016-03-14 08:34:47 -05:00
|
|
|
} else {
|
|
|
|
// tuple
|
|
|
|
// ntuple
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// for item in items
|
|
|
|
true
|
|
|
|
}
|