]> git.lizzy.rs Git - rust.git/blobdiff - clippy_lints/src/non_expressive_names.rs
Merge branch 'master' into fix-3739
[rust.git] / clippy_lints / src / non_expressive_names.rs
index c584e3b1a9e244628ad0f067c98ad4e157214408..7bdeec0a56f0ee0fc53951b92267d12fa9ab9023 100644 (file)
@@ -1,59 +1,84 @@
-use rustc::lint::*;
-use syntax::codemap::Span;
-use syntax::symbol::InternedString;
+use crate::utils::{span_lint, span_lint_and_then};
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
 use syntax::ast::*;
 use syntax::attr;
-use syntax::visit::{Visitor, walk_block, walk_pat, walk_expr};
-use utils::{span_lint_and_then, in_macro, span_lint};
+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_lint! {
+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,
-    Allow,
+    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_lint! {
+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,
-    Warn,
+    style,
     "too many single character bindings"
 }
 
+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"
+}
+
 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)
+        lint_array!(SIMILAR_NAMES, MANY_SINGLE_CHAR_NAMES, JUST_UNDERSCORES_AND_DIGITS)
+    }
+
+    fn name(&self) -> &'static str {
+        "NoneExpressiveNames"
     }
 }
 
 struct ExistingName {
-    interned: InternedString,
+    interned: LocalInternedString,
     span: Span,
     len: usize,
     whitelist: &'static [&'static str],
@@ -68,12 +93,15 @@ struct SimilarNamesLocalVisitor<'a, 'tcx: 'a> {
 
 // this list contains lists of names that are allowed to be similar
 // the assumption is that no name is ever contained in multiple lists.
-#[cfg_attr(rustfmt, rustfmt_skip)]
-const WHITELIST: &'static [&'static [&'static str]] = &[
+#[rustfmt::skip]
+const WHITELIST: &[&[&str]] = &[
     &["parsed", "parser"],
     &["lhs", "rhs"],
     &["tx", "rx"],
     &["set", "get"],
+    &["args", "arms"],
+    &["qpath", "path"],
+    &["lit", "lint"],
 ];
 
 struct SimilarNamesNameVisitor<'a: 'b, 'tcx: 'a, 'b>(&'b mut SimilarNamesLocalVisitor<'a, 'tcx>);
@@ -81,7 +109,7 @@ 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(_, id, _) => self.check_name(id.span, id.node.name),
+            PatKind::Ident(_, ident, _) => self.check_name(ident.span, ident.name),
             PatKind::Struct(_, ref fields, _) => {
                 for field in fields {
                     if !field.node.is_shorthand {
@@ -92,6 +120,9 @@ fn visit_pat(&mut self, pat: &'tcx 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]> {
@@ -104,9 +135,8 @@ fn get_whitelist(interned_name: &str) -> Option<&'static [&'static str]> {
 }
 
 fn whitelisted(interned_name: &str, list: &[&str]) -> bool {
-    list.iter().any(|&name| {
-        interned_name.starts_with(name) || interned_name.ends_with(name)
-    })
+    list.iter()
+        .any(|&name| interned_name.starts_with(name) || interned_name.ends_with(name))
 }
 
 impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
@@ -121,18 +151,28 @@ fn check_short_name(&mut self, c: char, span: Span) {
                 self.0.cx,
                 MANY_SINGLE_CHAR_NAMES,
                 span,
-                &format!("{}th binding whose name is just one char", self.0.single_char_names.len()),
+                &format!(
+                    "{}th binding whose name is just one char",
+                    self.0.single_char_names.len()
+                ),
             );
         }
     }
+    #[allow(clippy::too_many_lines)]
     fn check_name(&mut self, span: Span, name: Name) {
-        if in_macro(span) {
-            return;
-        }
         let interned_name = name.as_str();
         if interned_name.chars().any(char::is_uppercase) {
             return;
         }
+        if interned_name.chars().all(|c| c.is_digit(10) || c == '_') {
+            span_lint(
+                self.0.cx,
+                JUST_UNDERSCORES_AND_DIGITS,
+                span,
+                "consider choosing a more descriptive name",
+            );
+            return;
+        }
         let count = interned_name.chars().count();
         if count < 3 {
             if count == 1 {
@@ -157,38 +197,32 @@ 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;
                         }
                     } 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)
+                        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)
@@ -197,20 +231,17 @@ 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 == '_' ||
-                        !interned_chars.zip(existing_chars).all(eq_or_numeric)
+                    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(
@@ -225,7 +256,7 @@ fn check_name(&mut self, span: Span, name: Name) {
                             span,
                             &format!(
                                 "separate the discriminating character by an \
-                                                                underscore like: `{}_{}`",
+                                 underscore like: `{}_{}`",
                                 &interned_name[..split],
                                 &interned_name[split..]
                             ),
@@ -238,7 +269,7 @@ 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,
+            span,
             len: count,
         });
     }
@@ -279,26 +310,39 @@ fn visit_arm(&mut self, arm: &'tcx Arm) {
     fn visit_item(&mut self, _: &Item) {
         // do not recurse into inner items
     }
+    fn visit_mac(&mut self, _mac: &Mac) {
+        // 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 {
-            if !attr::contains_name(&item.attrs, "test") {
-                let mut visitor = SimilarNamesLocalVisitor {
-                    names: Vec::new(),
-                    cx: cx,
-                    lint: self,
-                    single_char_names: Vec::new(),
-                };
-                // 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);
-            }
+    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);
+        }
+    }
+
+    fn check_impl_item(&mut self, cx: &EarlyContext<'_>, item: &ImplItem) {
+        if let ImplItemKind::Method(ref sig, ref blk) = item.node {
+            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") {
+        let mut visitor = SimilarNamesLocalVisitor {
+            names: Vec::new(),
+            cx,
+            lint,
+            single_char_names: Vec::new(),
+        };
+        // 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);
     }
 }