1 //! lint on enum variants that are prefixed or suffixed by the same characters
3 use crate::utils::{camel_case, in_macro};
4 use crate::utils::{span_help_and_lint, span_lint};
5 use rustc::lint::{EarlyContext, EarlyLintPass, Lint, LintArray, LintPass};
6 use rustc::{declare_tool_lint, lint_array};
8 use syntax::source_map::Span;
9 use syntax::symbol::{InternedString, LocalInternedString};
11 declare_clippy_lint! {
12 /// **What it does:** Detects enumeration variants that are prefixed or suffixed
13 /// by the same characters.
15 /// **Why is this bad?** Enumeration variant names should specify their variant,
16 /// not repeat the enumeration name.
18 /// **Known problems:** None.
28 pub ENUM_VARIANT_NAMES,
30 "enums where all variants share a prefix/postfix"
33 declare_clippy_lint! {
34 /// **What it does:** Detects enumeration variants that are prefixed or suffixed
35 /// by the same characters.
37 /// **Why is this bad?** Enumeration variant names should specify their variant,
38 /// not repeat the enumeration name.
40 /// **Known problems:** None.
50 pub PUB_ENUM_VARIANT_NAMES,
52 "enums where all variants share a prefix/postfix"
55 declare_clippy_lint! {
56 /// **What it does:** Detects type names that are prefixed or suffixed by the
57 /// containing module's name.
59 /// **Why is this bad?** It requires the user to type the module name twice.
61 /// **Known problems:** None.
66 /// struct BlackForestCake;
69 pub MODULE_NAME_REPETITIONS,
71 "type names prefixed/postfixed with their containing module's name"
74 declare_clippy_lint! {
75 /// **What it does:** Checks for modules that have the same name as their
78 /// **Why is this bad?** A typical beginner mistake is to have `mod foo;` and
79 /// again `mod foo { ..
81 /// The expectation is that items inside the inner `mod foo { .. }` are then
83 /// through `foo::x`, but they are only available through
85 /// If this is done on purpose, it would be better to choose a more
86 /// representative module name.
88 /// **Known problems:** None.
101 "modules that have the same name as their parent module"
104 pub struct EnumVariantNames {
105 modules: Vec<(InternedString, String)>,
109 impl EnumVariantNames {
110 pub fn new(threshold: u64) -> Self {
118 impl LintPass for EnumVariantNames {
119 fn get_lints(&self) -> LintArray {
122 PUB_ENUM_VARIANT_NAMES,
123 MODULE_NAME_REPETITIONS,
128 fn name(&self) -> &'static str {
133 fn var2str(var: &Variant) -> LocalInternedString {
134 var.node.ident.as_str()
137 /// Returns the number of chars that match from the start
138 fn partial_match(pre: &str, name: &str) -> usize {
139 let mut name_iter = name.chars();
140 let _ = name_iter.next_back(); // make sure the name is never fully matched
141 pre.chars().zip(name_iter).take_while(|&(l, r)| l == r).count()
144 /// Returns the number of chars that match from the end
145 fn partial_rmatch(post: &str, name: &str) -> usize {
146 let mut name_iter = name.chars();
147 let _ = name_iter.next(); // make sure the name is never fully matched
150 .zip(name_iter.rev())
151 .take_while(|&(l, r)| l == r)
156 cx: &EarlyContext<'_>,
160 item_name_chars: usize,
164 if (def.variants.len() as u64) < threshold {
167 for var in &def.variants {
168 let name = var2str(var);
169 if partial_match(item_name, &name) == item_name_chars
170 && name.chars().nth(item_name_chars).map_or(false, |c| !c.is_lowercase())
172 span_lint(cx, lint, var.span, "Variant name starts with the enum's name");
174 if partial_rmatch(item_name, &name) == item_name_chars {
175 span_lint(cx, lint, var.span, "Variant name ends with the enum's name");
178 let first = var2str(&def.variants[0]);
179 let mut pre = &first[..camel_case::until(&*first)];
180 let mut post = &first[camel_case::from(&*first)..];
181 for var in &def.variants {
182 let name = var2str(var);
184 let pre_match = partial_match(pre, &name);
185 pre = &pre[..pre_match];
186 let pre_camel = camel_case::until(pre);
187 pre = &pre[..pre_camel];
188 while let Some((next, last)) = name[pre.len()..].chars().zip(pre.chars().rev()).next() {
189 if next.is_lowercase() {
190 let last = pre.len() - last.len_utf8();
191 let last_camel = camel_case::until(&pre[..last]);
192 pre = &pre[..last_camel];
198 let post_match = partial_rmatch(post, &name);
199 let post_end = post.len() - post_match;
200 post = &post[post_end..];
201 let post_camel = camel_case::from(post);
202 post = &post[post_camel..];
204 let (what, value) = match (pre.is_empty(), post.is_empty()) {
205 (true, true) => return,
206 (false, _) => ("pre", pre),
207 (true, false) => ("post", post),
213 &format!("All variants have the same {}fix: `{}`", what, value),
215 "remove the {}fixes and use full paths to \
216 the variants instead of glob imports",
222 fn to_camel_case(item_name: &str) -> String {
223 let mut s = String::new();
225 for c in item_name.chars() {
226 if c.is_uppercase() {
227 // we only turn snake case text into CamelCase
228 return item_name.to_string();
236 s.extend(c.to_uppercase());
244 impl EarlyLintPass for EnumVariantNames {
245 fn check_item_post(&mut self, _cx: &EarlyContext<'_>, _item: &Item) {
246 let last = self.modules.pop();
247 assert!(last.is_some());
250 #[allow(clippy::similar_names)]
251 fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
252 let item_name = item.ident.as_str();
253 let item_name_chars = item_name.chars().count();
254 let item_camel = to_camel_case(&item_name);
255 if !in_macro(item.span) {
256 if let Some(&(ref mod_name, ref mod_camel)) = self.modules.last() {
257 // constants don't have surrounding modules
258 if !mod_camel.is_empty() {
259 if *mod_name == item_name {
260 if let ItemKind::Mod(..) = item.node {
265 "module has the same name as its containing module",
269 if item.vis.node.is_pub() {
270 let matching = partial_match(mod_camel, &item_camel);
271 let rmatching = partial_rmatch(mod_camel, &item_camel);
272 let nchars = mod_camel.chars().count();
274 let is_word_beginning = |c: char| c == '_' || c.is_uppercase() || c.is_numeric();
276 if matching == nchars {
277 match item_camel.chars().nth(nchars) {
278 Some(c) if is_word_beginning(c) => span_lint(
280 MODULE_NAME_REPETITIONS,
282 "item name starts with its containing module's name",
287 if rmatching == nchars {
290 MODULE_NAME_REPETITIONS,
292 "item name ends with its containing module's name",
299 if let ItemKind::Enum(ref def, _) = item.node {
300 let lint = match item.vis.node {
301 VisibilityKind::Public => PUB_ENUM_VARIANT_NAMES,
302 _ => ENUM_VARIANT_NAMES,
304 check_variant(cx, self.threshold, def, &item_name, item_name_chars, item.span, lint);
306 self.modules.push((item_name.as_interned_str(), item_camel));