1 //! lint on enum variants that are prefixed or suffixed by the same characters
3 use crate::utils::{camel_case, is_present_in_source};
4 use crate::utils::{span_help_and_lint, span_lint};
5 use rustc::impl_lint_pass;
6 use rustc::lint::{EarlyContext, EarlyLintPass, Lint, LintArray, LintPass};
7 use rustc_session::declare_tool_lint;
9 use syntax::source_map::Span;
10 use syntax::symbol::Symbol;
12 declare_clippy_lint! {
13 /// **What it does:** Detects enumeration variants that are prefixed or suffixed
14 /// by the same characters.
16 /// **Why is this bad?** Enumeration variant names should specify their variant,
17 /// not repeat the enumeration name.
19 /// **Known problems:** None.
29 pub ENUM_VARIANT_NAMES,
31 "enums where all variants share a prefix/postfix"
34 declare_clippy_lint! {
35 /// **What it does:** Detects enumeration variants that are prefixed or suffixed
36 /// by the same characters.
38 /// **Why is this bad?** Enumeration variant names should specify their variant,
39 /// not repeat the enumeration name.
41 /// **Known problems:** None.
51 pub PUB_ENUM_VARIANT_NAMES,
53 "enums where all variants share a prefix/postfix"
56 declare_clippy_lint! {
57 /// **What it does:** Detects type names that are prefixed or suffixed by the
58 /// containing module's name.
60 /// **Why is this bad?** It requires the user to type the module name twice.
62 /// **Known problems:** None.
67 /// struct BlackForestCake;
70 pub MODULE_NAME_REPETITIONS,
72 "type names prefixed/postfixed with their containing module's name"
75 declare_clippy_lint! {
76 /// **What it does:** Checks for modules that have the same name as their
79 /// **Why is this bad?** A typical beginner mistake is to have `mod foo;` and
80 /// again `mod foo { ..
82 /// The expectation is that items inside the inner `mod foo { .. }` are then
84 /// through `foo::x`, but they are only available through
86 /// If this is done on purpose, it would be better to choose a more
87 /// representative module name.
89 /// **Known problems:** None.
100 pub MODULE_INCEPTION,
102 "modules that have the same name as their parent module"
105 pub struct EnumVariantNames {
106 modules: Vec<(Symbol, String)>,
110 impl EnumVariantNames {
112 pub fn new(threshold: u64) -> Self {
120 impl_lint_pass!(EnumVariantNames => [
122 PUB_ENUM_VARIANT_NAMES,
123 MODULE_NAME_REPETITIONS,
127 /// Returns the number of chars that match from the start
129 fn partial_match(pre: &str, name: &str) -> usize {
130 let mut name_iter = name.chars();
131 let _ = name_iter.next_back(); // make sure the name is never fully matched
132 pre.chars().zip(name_iter).take_while(|&(l, r)| l == r).count()
135 /// Returns the number of chars that match from the end
137 fn partial_rmatch(post: &str, name: &str) -> usize {
138 let mut name_iter = name.chars();
139 let _ = name_iter.next(); // make sure the name is never fully matched
142 .zip(name_iter.rev())
143 .take_while(|&(l, r)| l == r)
148 cx: &EarlyContext<'_>,
152 item_name_chars: usize,
156 if (def.variants.len() as u64) < threshold {
159 for var in &def.variants {
160 let name = var.ident.name.as_str();
161 if partial_match(item_name, &name) == item_name_chars
162 && name.chars().nth(item_name_chars).map_or(false, |c| !c.is_lowercase())
163 && name.chars().nth(item_name_chars + 1).map_or(false, |c| !c.is_numeric())
165 span_lint(cx, lint, var.span, "Variant name starts with the enum's name");
167 if partial_rmatch(item_name, &name) == item_name_chars {
168 span_lint(cx, lint, var.span, "Variant name ends with the enum's name");
171 let first = &def.variants[0].ident.name.as_str();
172 let mut pre = &first[..camel_case::until(&*first)];
173 let mut post = &first[camel_case::from(&*first)..];
174 for var in &def.variants {
175 let name = var.ident.name.as_str();
177 let pre_match = partial_match(pre, &name);
178 pre = &pre[..pre_match];
179 let pre_camel = camel_case::until(pre);
180 pre = &pre[..pre_camel];
181 while let Some((next, last)) = name[pre.len()..].chars().zip(pre.chars().rev()).next() {
182 if next.is_numeric() {
185 if next.is_lowercase() {
186 let last = pre.len() - last.len_utf8();
187 let last_camel = camel_case::until(&pre[..last]);
188 pre = &pre[..last_camel];
194 let post_match = partial_rmatch(post, &name);
195 let post_end = post.len() - post_match;
196 post = &post[post_end..];
197 let post_camel = camel_case::from(post);
198 post = &post[post_camel..];
200 let (what, value) = match (pre.is_empty(), post.is_empty()) {
201 (true, true) => return,
202 (false, _) => ("pre", pre),
203 (true, false) => ("post", post),
209 &format!("All variants have the same {}fix: `{}`", what, value),
211 "remove the {}fixes and use full paths to \
212 the variants instead of glob imports",
219 fn to_camel_case(item_name: &str) -> String {
220 let mut s = String::new();
222 for c in item_name.chars() {
223 if c.is_uppercase() {
224 // we only turn snake case text into CamelCase
225 return item_name.to_string();
233 s.extend(c.to_uppercase());
241 impl EarlyLintPass for EnumVariantNames {
242 fn check_item_post(&mut self, _cx: &EarlyContext<'_>, _item: &Item) {
243 let last = self.modules.pop();
244 assert!(last.is_some());
247 #[allow(clippy::similar_names)]
248 fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
249 let item_name = item.ident.name.as_str();
250 let item_name_chars = item_name.chars().count();
251 let item_camel = to_camel_case(&item_name);
252 if !item.span.from_expansion() && is_present_in_source(cx, item.span) {
253 if let Some(&(ref mod_name, ref mod_camel)) = self.modules.last() {
254 // constants don't have surrounding modules
255 if !mod_camel.is_empty() {
256 if mod_name == &item.ident.name {
257 if let ItemKind::Mod(..) = item.kind {
262 "module has the same name as its containing module",
266 if item.vis.node.is_pub() {
267 let matching = partial_match(mod_camel, &item_camel);
268 let rmatching = partial_rmatch(mod_camel, &item_camel);
269 let nchars = mod_camel.chars().count();
271 let is_word_beginning = |c: char| c == '_' || c.is_uppercase() || c.is_numeric();
273 if matching == nchars {
274 match item_camel.chars().nth(nchars) {
275 Some(c) if is_word_beginning(c) => span_lint(
277 MODULE_NAME_REPETITIONS,
279 "item name starts with its containing module's name",
284 if rmatching == nchars {
287 MODULE_NAME_REPETITIONS,
289 "item name ends with its containing module's name",
296 if let ItemKind::Enum(ref def, _) = item.kind {
297 let lint = match item.vis.node {
298 VisibilityKind::Public => PUB_ENUM_VARIANT_NAMES,
299 _ => ENUM_VARIANT_NAMES,
301 check_variant(cx, self.threshold, def, &item_name, item_name_chars, item.span, lint);
303 self.modules.push((item.ident.name, item_camel));