use crate::utils::{span_lint, span_lint_and_then};
use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
+use rustc::{declare_tool_lint, impl_lint_pass};
+use std::cmp::Ordering;
use syntax::ast::*;
use syntax::attr;
use syntax::source_map::Span;
-use syntax::symbol::LocalInternedString;
+use syntax::symbol::SymbolStr;
use syntax::visit::{walk_block, walk_expr, walk_pat, Visitor};
-/// **What it does:** Checks for names that are very similar and thus confusing.
-///
-/// **Why is this bad?** It's hard to distinguish between names that differ only
-/// by a single character.
-///
-/// **Known problems:** None?
-///
-/// **Example:**
-/// ```rust
-/// let checked_exp = something;
-/// let checked_expr = something_else;
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for names that are very similar and thus confusing.
+ ///
+ /// **Why is this bad?** It's hard to distinguish between names that differ only
+ /// by a single character.
+ ///
+ /// **Known problems:** None?
+ ///
+ /// **Example:**
+ /// ```ignore
+ /// let checked_exp = something;
+ /// let checked_expr = something_else;
+ /// ```
pub SIMILAR_NAMES,
pedantic,
"similarly named items and bindings"
}
-/// **What it does:** Checks for too many variables whose name consists of a
-/// single character.
-///
-/// **Why is this bad?** It's hard to memorize what a variable means without a
-/// descriptive name.
-///
-/// **Known problems:** None?
-///
-/// **Example:**
-/// ```rust
-/// let (a, b, c, d, e, f, g) = (...);
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for too many variables whose name consists of a
+ /// single character.
+ ///
+ /// **Why is this bad?** It's hard to memorize what a variable means without a
+ /// descriptive name.
+ ///
+ /// **Known problems:** None?
+ ///
+ /// **Example:**
+ /// ```ignore
+ /// let (a, b, c, d, e, f, g) = (...);
+ /// ```
pub MANY_SINGLE_CHAR_NAMES,
style,
"too many single character bindings"
}
-/// **What it does:** Checks if you have variables whose name consists of just
-/// underscores and digits.
-///
-/// **Why is this bad?** It's hard to memorize what a variable means without a
-/// descriptive name.
-///
-/// **Known problems:** None?
-///
-/// **Example:**
-/// ```rust
-/// let _1 = 1;
-/// let ___1 = 1;
-/// let __1___2 = 11;
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks if you have variables whose name consists of just
+ /// underscores and digits.
+ ///
+ /// **Why is this bad?** It's hard to memorize what a variable means without a
+ /// descriptive name.
+ ///
+ /// **Known problems:** None?
+ ///
+ /// **Example:**
+ /// ```rust
+ /// let _1 = 1;
+ /// let ___1 = 1;
+ /// let __1___2 = 11;
+ /// ```
pub JUST_UNDERSCORES_AND_DIGITS,
style,
"unclear name"
}
+#[derive(Copy, Clone)]
pub struct NonExpressiveNames {
pub single_char_binding_names_threshold: u64,
}
-impl LintPass for NonExpressiveNames {
- fn get_lints(&self) -> LintArray {
- lint_array!(SIMILAR_NAMES, MANY_SINGLE_CHAR_NAMES, JUST_UNDERSCORES_AND_DIGITS)
- }
-
- fn name(&self) -> &'static str {
- "NoneExpressiveNames"
- }
-}
+impl_lint_pass!(NonExpressiveNames => [SIMILAR_NAMES, MANY_SINGLE_CHAR_NAMES, JUST_UNDERSCORES_AND_DIGITS]);
struct ExistingName {
- interned: LocalInternedString,
+ interned: SymbolStr,
span: Span,
len: usize,
whitelist: &'static [&'static str],
}
-struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> {
+struct SimilarNamesLocalVisitor<'a, 'tcx> {
names: Vec<ExistingName>,
cx: &'a EarlyContext<'tcx>,
lint: &'a NonExpressiveNames,
- single_char_names: Vec<char>,
+
+ /// A stack of scopes containing the single-character bindings in each scope.
+ single_char_names: Vec<Vec<Ident>>,
+}
+
+impl<'a, 'tcx> SimilarNamesLocalVisitor<'a, 'tcx> {
+ fn check_single_char_names(&self) {
+ let num_single_char_names = self.single_char_names.iter().flatten().count();
+ let threshold = self.lint.single_char_binding_names_threshold;
+ if num_single_char_names as u64 >= threshold {
+ let span = self
+ .single_char_names
+ .iter()
+ .flatten()
+ .map(|ident| ident.span)
+ .collect::<Vec<_>>();
+ span_lint(
+ self.cx,
+ MANY_SINGLE_CHAR_NAMES,
+ span,
+ &format!(
+ "{} bindings with single-character names in scope",
+ num_single_char_names
+ ),
+ );
+ }
+ }
}
// this list contains lists of names that are allowed to be similar
&["lit", "lint"],
];
-struct SimilarNamesNameVisitor<'a: 'b, 'tcx: 'a, 'b>(&'b mut SimilarNamesLocalVisitor<'a, 'tcx>);
+struct SimilarNamesNameVisitor<'a, 'tcx, 'b>(&'b mut SimilarNamesLocalVisitor<'a, 'tcx>);
-impl<'a, 'tcx: 'a, 'b> Visitor<'tcx> for SimilarNamesNameVisitor<'a, 'tcx, 'b> {
+impl<'a, 'tcx, 'b> Visitor<'tcx> for SimilarNamesNameVisitor<'a, 'tcx, 'b> {
fn visit_pat(&mut self, pat: &'tcx Pat) {
- match pat.node {
- PatKind::Ident(_, ident, _) => self.check_name(ident.span, ident.name),
+ match pat.kind {
+ PatKind::Ident(_, ident, _) => self.check_ident(ident),
PatKind::Struct(_, ref fields, _) => {
for field in fields {
- if !field.node.is_shorthand {
- self.visit_pat(&field.node.pat);
+ if !field.is_shorthand {
+ self.visit_pat(&field.pat);
}
}
},
+ // just go through the first pattern, as either all patterns
+ // bind the same bindings or rustc would have errored much earlier
+ PatKind::Or(ref pats) => self.visit_pat(&pats[0]),
_ => walk_pat(self, pat),
}
}
}
}
+#[must_use]
fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> {
for &allow in WHITELIST {
if whitelisted(interned_name, allow) {
None
}
+#[must_use]
fn whitelisted(interned_name: &str, list: &[&str]) -> bool {
list.iter()
.any(|&name| interned_name.starts_with(name) || interned_name.ends_with(name))
}
impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
- fn check_short_name(&mut self, c: char, span: Span) {
- // make sure we ignore shadowing
- if self.0.single_char_names.contains(&c) {
+ fn check_short_ident(&mut self, ident: Ident) {
+ // Ignore shadowing
+ if self
+ .0
+ .single_char_names
+ .iter()
+ .flatten()
+ .any(|id| id.name == ident.name)
+ {
return;
}
- self.0.single_char_names.push(c);
- if self.0.single_char_names.len() as u64 >= self.0.lint.single_char_binding_names_threshold {
- span_lint(
- self.0.cx,
- MANY_SINGLE_CHAR_NAMES,
- span,
- &format!(
- "{}th binding whose name is just one char",
- self.0.single_char_names.len()
- ),
- );
+
+ if let Some(scope) = &mut self.0.single_char_names.last_mut() {
+ scope.push(ident);
}
}
+
#[allow(clippy::too_many_lines)]
- fn check_name(&mut self, span: Span, name: Name) {
- let interned_name = name.as_str();
+ fn check_ident(&mut self, ident: Ident) {
+ let interned_name = ident.name.as_str();
if interned_name.chars().any(char::is_uppercase) {
return;
}
span_lint(
self.0.cx,
JUST_UNDERSCORES_AND_DIGITS,
- span,
+ ident.span,
"consider choosing a more descriptive name",
);
return;
let count = interned_name.chars().count();
if count < 3 {
if count == 1 {
- let c = interned_name.chars().next().expect("already checked");
- self.check_short_name(c, span);
+ self.check_short_ident(ident);
}
return;
}
continue;
}
let mut split_at = None;
- if existing_name.len > count {
- if existing_name.len - count != 1 || levenstein_not_1(&interned_name, &existing_name.interned) {
- continue;
- }
- } else if existing_name.len < count {
- if count - existing_name.len != 1 || levenstein_not_1(&existing_name.interned, &interned_name) {
- continue;
- }
- } else {
- let mut interned_chars = interned_name.chars();
- let mut existing_chars = existing_name.interned.chars();
- let first_i = interned_chars.next().expect("we know we have at least one char");
- let first_e = existing_chars.next().expect("we know we have at least one char");
- let eq_or_numeric = |(a, b): (char, char)| a == b || a.is_numeric() && b.is_numeric();
+ match existing_name.len.cmp(&count) {
+ Ordering::Greater => {
+ if existing_name.len - count != 1 || levenstein_not_1(&interned_name, &existing_name.interned) {
+ continue;
+ }
+ },
+ Ordering::Less => {
+ if count - existing_name.len != 1 || levenstein_not_1(&existing_name.interned, &interned_name) {
+ continue;
+ }
+ },
+ Ordering::Equal => {
+ let mut interned_chars = interned_name.chars();
+ let mut existing_chars = existing_name.interned.chars();
+ let first_i = interned_chars.next().expect("we know we have at least one char");
+ let first_e = existing_chars.next().expect("we know we have at least one char");
+ let eq_or_numeric = |(a, b): (char, char)| a == b || a.is_numeric() && b.is_numeric();
- if eq_or_numeric((first_i, first_e)) {
- let last_i = interned_chars.next_back().expect("we know we have at least two chars");
- let last_e = existing_chars.next_back().expect("we know we have at least two chars");
- if eq_or_numeric((last_i, last_e)) {
- if interned_chars
- .zip(existing_chars)
- .filter(|&ie| !eq_or_numeric(ie))
- .count()
- != 1
- {
- continue;
+ if eq_or_numeric((first_i, first_e)) {
+ let last_i = interned_chars.next_back().expect("we know we have at least two chars");
+ let last_e = existing_chars.next_back().expect("we know we have at least two chars");
+ if eq_or_numeric((last_i, last_e)) {
+ if interned_chars
+ .zip(existing_chars)
+ .filter(|&ie| !eq_or_numeric(ie))
+ .count()
+ != 1
+ {
+ continue;
+ }
+ } else {
+ let second_last_i = interned_chars
+ .next_back()
+ .expect("we know we have at least three chars");
+ let second_last_e = existing_chars
+ .next_back()
+ .expect("we know we have at least three chars");
+ if !eq_or_numeric((second_last_i, second_last_e))
+ || second_last_i == '_'
+ || !interned_chars.zip(existing_chars).all(eq_or_numeric)
+ {
+ // allowed similarity foo_x, foo_y
+ // or too many chars differ (foo_x, boo_y) or (foox, booy)
+ continue;
+ }
+ split_at = interned_name.char_indices().rev().next().map(|(i, _)| i);
}
} else {
- let second_last_i = interned_chars
- .next_back()
- .expect("we know we have at least three chars");
- let second_last_e = existing_chars
- .next_back()
- .expect("we know we have at least three chars");
- if !eq_or_numeric((second_last_i, second_last_e))
- || second_last_i == '_'
+ let second_i = interned_chars.next().expect("we know we have at least two chars");
+ let second_e = existing_chars.next().expect("we know we have at least two chars");
+ if !eq_or_numeric((second_i, second_e))
+ || second_i == '_'
|| !interned_chars.zip(existing_chars).all(eq_or_numeric)
{
- // allowed similarity foo_x, foo_y
- // or too many chars differ (foo_x, boo_y) or (foox, booy)
+ // allowed similarity x_foo, y_foo
+ // or too many chars differ (x_foo, y_boo) or (xfoo, yboo)
continue;
}
- split_at = interned_name.char_indices().rev().next().map(|(i, _)| i);
- }
- } else {
- let second_i = interned_chars.next().expect("we know we have at least two chars");
- let second_e = existing_chars.next().expect("we know we have at least two chars");
- if !eq_or_numeric((second_i, second_e))
- || second_i == '_'
- || !interned_chars.zip(existing_chars).all(eq_or_numeric)
- {
- // allowed similarity x_foo, y_foo
- // or too many chars differ (x_foo, y_boo) or (xfoo, yboo)
- continue;
+ split_at = interned_name.chars().next().map(char::len_utf8);
}
- split_at = interned_name.chars().next().map(|c| c.len_utf8());
- }
+ },
}
span_lint_and_then(
self.0.cx,
SIMILAR_NAMES,
- span,
+ ident.span,
"binding's name is too similar to existing binding",
|diag| {
diag.span_note(existing_name.span, "existing binding defined here");
if let Some(split) = split_at {
diag.span_help(
- span,
+ ident.span,
&format!(
"separate the discriminating character by an \
underscore like: `{}_{}`",
self.0.names.push(ExistingName {
whitelist: get_whitelist(&interned_name).unwrap_or(&[]),
interned: interned_name,
- span,
+ span: ident.span,
len: count,
});
}
SimilarNamesNameVisitor(self).visit_pat(&*local.pat);
}
fn visit_block(&mut self, blk: &'tcx Block) {
+ self.single_char_names.push(vec![]);
+
self.apply(|this| walk_block(this, blk));
+
+ self.check_single_char_names();
+ self.single_char_names.pop();
}
fn visit_arm(&mut self, arm: &'tcx Arm) {
+ self.single_char_names.push(vec![]);
+
self.apply(|this| {
- // just go through the first pattern, as either all patterns
- // bind the same bindings or rustc would have errored much earlier
- SimilarNamesNameVisitor(this).visit_pat(&arm.pats[0]);
+ SimilarNamesNameVisitor(this).visit_pat(&arm.pat);
this.apply(|this| walk_expr(this, &arm.body));
});
+
+ self.check_single_char_names();
+ self.single_char_names.pop();
}
fn visit_item(&mut self, _: &Item) {
// do not recurse into inner items
impl EarlyLintPass for NonExpressiveNames {
fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
- if let ItemKind::Fn(ref decl, _, _, ref blk) = item.node {
- do_check(self, cx, &item.attrs, decl, blk);
+ if let ItemKind::Fn(ref sig, _, ref blk) = item.kind {
+ do_check(self, cx, &item.attrs, &sig.decl, blk);
}
}
fn check_impl_item(&mut self, cx: &EarlyContext<'_>, item: &ImplItem) {
- if let ImplItemKind::Method(ref sig, ref blk) = item.node {
+ if let ImplItemKind::Method(ref sig, ref blk) = item.kind {
do_check(self, cx, &item.attrs, &sig.decl, blk);
}
}
}
fn do_check(lint: &mut NonExpressiveNames, cx: &EarlyContext<'_>, attrs: &[Attribute], decl: &FnDecl, blk: &Block) {
- if !attr::contains_name(attrs, "test") {
+ if !attr::contains_name(attrs, sym!(test)) {
let mut visitor = SimilarNamesLocalVisitor {
names: Vec::new(),
cx,
lint,
- single_char_names: Vec::new(),
+ single_char_names: vec![vec![]],
};
+
// initialize with function arguments
for arg in &decl.inputs {
SimilarNamesNameVisitor(&mut visitor).visit_pat(&arg.pat);
}
// walk all other bindings
walk_block(&mut visitor, blk);
+
+ visitor.check_single_char_names();
}
}
/// Precondition: `a_name.chars().count() < b_name.chars().count()`.
+#[must_use]
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();