X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fnon_expressive_names.rs;h=b1d180c6ceb3793d785cfbf860dc5b82f41af72c;hb=a0e9f9bd0dca39ccff47baedffa94aca74911a86;hp=ad4f52a528f48ef055a8c23609b50aae1d2ef1da;hpb=e9c025ea70f9297836d62e0f0c959b9359a8035a;p=rust.git diff --git a/clippy_lints/src/non_expressive_names.rs b/clippy_lints/src/non_expressive_names.rs index ad4f52a528f..5f14fe97afe 100644 --- a/clippy_lints/src/non_expressive_names.rs +++ b/clippy_lints/src/non_expressive_names.rs @@ -1,100 +1,117 @@ -// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution. -// -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - - -use crate::rustc::lint::{LintArray, LintPass, EarlyContext, EarlyLintPass}; -use crate::rustc::{declare_tool_lint, lint_array}; -use crate::syntax::source_map::Span; -use crate::syntax::symbol::LocalInternedString; -use crate::syntax::ast::*; -use crate::syntax::attr; -use crate::syntax::visit::{walk_block, walk_expr, walk_pat, Visitor}; use crate::utils::{span_lint, span_lint_and_then}; +use rustc_ast::ast::{ + Arm, AssocItem, AssocItemKind, Attribute, Block, FnDecl, Item, ItemKind, Local, MacCall, Pat, PatKind, +}; +use rustc_ast::attr; +use rustc_ast::visit::{walk_block, walk_expr, walk_pat, Visitor}; +use rustc_lint::{EarlyContext, EarlyLintPass}; +use rustc_middle::lint::in_external_macro; +use rustc_session::{declare_tool_lint, impl_lint_pass}; +use rustc_span::source_map::Span; +use rustc_span::symbol::{Ident, SymbolStr}; +use std::cmp::Ordering; -/// **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, + interned: SymbolStr, span: Span, len: usize, whitelist: &'static [&'static str], } -struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> { +struct SimilarNamesLocalVisitor<'a, 'tcx> { 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> 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 @@ -110,25 +127,35 @@ struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> { &["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), - PatKind::Struct(_, ref fields, _) => for field in fields { - if !field.node.is_shorthand { - self.visit_pat(&field.node.pat); + match pat.kind { + PatKind::Ident(_, ident, _) => { + if !pat.span.from_expansion() { + self.check_ident(ident); + } + }, + PatKind::Struct(_, ref fields, _) => { + for field in fields { + 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), } } - fn visit_mac(&mut self, _mac: &Mac) { + fn visit_mac(&mut self, _mac: &MacCall) { // do not check macs } } +#[must_use] fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> { for &allow in WHITELIST { if whitelisted(interned_name, allow) { @@ -138,29 +165,33 @@ fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> { 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); } } - 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; } @@ -168,7 +199,7 @@ 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 +207,7 @@ 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; } @@ -186,83 +216,78 @@ fn check_name(&mut self, span: Span, name: Name) { 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(); - - 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; + 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; + } + } 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); + split_at = interned_name.chars().next().map(char::len_utf8); } - } 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(|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: `{}_{}`", @@ -278,7 +303,7 @@ 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, }); } @@ -306,56 +331,76 @@ 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]); + 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 } - fn visit_mac(&mut self, _mac: &Mac) { + fn visit_mac(&mut self, _mac: &MacCall) { // do not check macs } } 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 in_external_macro(cx.sess, item.span) { + return; + } + + if let ItemKind::Fn(_, ref sig, _, Some(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 { + fn check_impl_item(&mut self, cx: &EarlyContext<'_>, item: &AssocItem) { + if in_external_macro(cx.sess, item.span) { + return; + } + + if let AssocItemKind::Fn(_, ref sig, _, Some(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();