X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fnon_expressive_names.rs;h=b1d180c6ceb3793d785cfbf860dc5b82f41af72c;hb=b834dbb2d5924c947c3cbe47c863ea5b7470e567;hp=acfa341ed1fae969ce31beaaf8b70070f4c95a4e;hpb=89012722ba71eeffc0303ecb99b3da9694798a79;p=rust.git diff --git a/clippy_lints/src/non_expressive_names.rs b/clippy_lints/src/non_expressive_names.rs index acfa341ed1f..b1d180c6ceb 100644 --- a/clippy_lints/src/non_expressive_names.rs +++ b/clippy_lints/src/non_expressive_names.rs @@ -1,77 +1,74 @@ -use rustc::lint::*; -use rustc::{declare_lint, lint_array}; -use syntax::source_map::Span; -use syntax::symbol::LocalInternedString; +use crate::utils::{span_lint, span_lint_and_then}; +use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass}; +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}; -use crate::utils::{span_lint, span_lint_and_then}; -/// **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) - } -} +impl_lint_pass!(NonExpressiveNames => [SIMILAR_NAMES, MANY_SINGLE_CHAR_NAMES, JUST_UNDERSCORES_AND_DIGITS]); struct ExistingName { interned: LocalInternedString, @@ -84,7 +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 @@ -105,15 +128,20 @@ 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::Struct(_, ref fields, _) => for field in fields { - if !field.node.is_shorthand { - self.visit_pat(&field.node.pat); + 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); + } } }, _ => walk_pat(self, pat), } } + fn visit_mac(&mut self, _mac: &Mac) { + // do not check macs + } } fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> { @@ -131,23 +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); } } - fn check_name(&mut self, span: Span, name: Name) { - let interned_name = name.as_str(); + + #[allow(clippy::too_many_lines)] + fn check_ident(&mut self, ident: Ident) { + let interned_name = ident.name.as_str(); if interned_name.chars().any(char::is_uppercase) { return; } @@ -155,7 +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; @@ -163,8 +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; } @@ -184,26 +212,19 @@ fn check_name(&mut self, span: Span, name: Name) { } 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 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"); + 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 + .count() + != 1 { continue; } @@ -214,7 +235,8 @@ fn check_name(&mut self, span: Span, name: Name) { 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 == '_' + 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 @@ -224,32 +246,29 @@ fn check_name(&mut self, span: Span, name: Name) { 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 == '_' + 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(|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: `{}_{}`", @@ -265,7 +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, }); } @@ -293,15 +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 @@ -331,14 +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(); } }