clippy_lints/src/unsafe_removed_from_name.rs

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