clippy_lints/src/unsafe_removed_from_name.rs

   1 use rustc::hir::*;
   2 use rustc::lint::*;
   3 use syntax::ast::Name;
   4 use syntax::codemap::Span;
   5 use syntax::parse::token::InternedString;
   6 use utils::span_lint;
   7
   8 /// **What it does:** Checks for imports that remove "unsafe" from an item's
   9 /// name.
  10 ///
  11 /// **Why is this bad?** Renaming makes it less clear which traits and
  12 /// structures are unsafe.
  13 ///
  14 /// **Known problems:** None.
  15 ///
  16 /// **Example:**
  17 /// ```rust,ignore
  18 /// use std::cell::{UnsafeCell as TotallySafeCell};
  19 ///
  20 /// extern crate crossbeam;
  21 /// use crossbeam::{spawn_unsafe as spawn};
  22 /// ```
  23 declare_lint! {
  24     pub UNSAFE_REMOVED_FROM_NAME,
  25     Warn,
  26     "unsafe removed from name"
  27 }
  28
  29 pub struct UnsafeNameRemoval;
  30
  31 impl LintPass for UnsafeNameRemoval {
  32     fn get_lints(&self) -> LintArray {
  33         lint_array!(UNSAFE_REMOVED_FROM_NAME)
  34     }
  35 }
  36
  37 impl LateLintPass for UnsafeNameRemoval {
  38     fn check_item(&mut self, cx: &LateContext, item: &Item) {
  39         if let ItemUse(ref item_use) = item.node {
  40             match item_use.node {
  41                 ViewPath_::ViewPathSimple(ref name, ref path) => {
  42                     unsafe_to_safe_check(
  43                         path.segments
  44                             .last()
  45                             .expect("use paths cannot be empty")
  46                             .name,
  47                         *name,
  48                         cx, &item.span
  49                         );
  50                 }
  51                 ViewPath_::ViewPathList(_, ref path_list_items) => {
  52                     for path_list_item in path_list_items.iter() {
  53                         let plid = path_list_item.node;
  54                         if let (Some(name), Some(rename)) = (plid.name(), plid.rename()) {
  55                             unsafe_to_safe_check(name, rename, cx, &item.span);
  56                         };
  57                     }
  58                 }
  59                 ViewPath_::ViewPathGlob(_) => {}
  60             }
  61         }
  62     }
  63 }
  64
  65 fn unsafe_to_safe_check(old_name: Name, new_name: Name, cx: &LateContext, span: &Span) {
  66     let old_str = old_name.as_str();
  67     let new_str = new_name.as_str();
  68     if contains_unsafe(&old_str) && !contains_unsafe(&new_str) {
  69         span_lint(cx,
  70                   UNSAFE_REMOVED_FROM_NAME,
  71                   *span,
  72                   &format!(
  73                 "removed \"unsafe\" from the name of `{}` in use as `{}`",
  74                 old_str,
  75                 new_str
  76             ));
  77     }
  78 }
  79
  80 fn contains_unsafe(name: &InternedString) -> bool {
  81     name.contains("Unsafe") || name.contains("unsafe")
  82 }