X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fnon_expressive_names.rs;h=b1d180c6ceb3793d785cfbf860dc5b82f41af72c;hb=b834dbb2d5924c947c3cbe47c863ea5b7470e567;hp=fbf60db28ee4053a7a19c748a0f771911f3b3126;hpb=1169066a0b501ae508461181b76c37d7e3b8ae6a;p=rust.git diff --git a/clippy_lints/src/non_expressive_names.rs b/clippy_lints/src/non_expressive_names.rs index fbf60db28ee..b1d180c6ceb 100644 --- a/clippy_lints/src/non_expressive_names.rs +++ b/clippy_lints/src/non_expressive_names.rs @@ -1,81 +1,74 @@ 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 syntax::ast::*; use syntax::attr; use syntax::source_map::Span; use syntax::symbol::LocalInternedString; 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, @@ -88,7 +81,33 @@ struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> { names: Vec, cx: &'a EarlyContext<'tcx>, lint: &'a NonExpressiveNames, - single_char_names: Vec, + + /// A stack of scopes containing the single-character bindings in each scope. + single_char_names: Vec>, +} + +impl<'a, 'tcx: 'a> 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::>(); + 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 @@ -109,7 +128,7 @@ struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> { impl<'a, 'tcx: 'a, '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), + PatKind::Ident(_, ident, _) => self.check_ident(ident), PatKind::Struct(_, ref fields, _) => { for field in fields { if !field.node.is_shorthand { @@ -140,27 +159,24 @@ fn whitelisted(interned_name: &str, list: &[&str]) -> bool { } 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() - ), - ); + } else 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; } @@ -168,7 +184,7 @@ fn check_name(&mut self, span: Span, name: Name) { span_lint( self.0.cx, JUST_UNDERSCORES_AND_DIGITS, - span, + ident.span, "consider choosing a more descriptive name", ); return; @@ -176,8 +192,7 @@ fn check_name(&mut self, span: Span, name: Name) { 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; } @@ -241,19 +256,19 @@ fn check_name(&mut self, span: Span, name: Name) { // or too many chars differ (x_foo, y_boo) or (xfoo, yboo) continue; } - split_at = interned_name.chars().next().map(|c| c.len_utf8()); + split_at = interned_name.chars().next().map(char::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: `{}_{}`", @@ -269,7 +284,7 @@ fn check_name(&mut self, span: Span, name: Name) { self.0.names.push(ExistingName { whitelist: get_whitelist(&interned_name).unwrap_or(&[]), interned: interned_name, - span, + span: ident.span, len: count, }); } @@ -297,15 +312,25 @@ fn visit_local(&mut self, local: &'tcx Local) { 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]); 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 @@ -335,14 +360,17 @@ fn do_check(lint: &mut NonExpressiveNames, cx: &EarlyContext<'_>, attrs: &[Attri 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(); } }