src/tools/clippy/clippy_lints/src/unsafe_removed_from_name.rs

   1 use clippy_utils::diagnostics::span_lint;
   2 use rustc_ast::ast::{Item, ItemKind, UseTree, UseTreeKind};
   3 use rustc_lint::{EarlyContext, EarlyLintPass};
   4 use rustc_session::{declare_lint_pass, declare_tool_lint};
   5 use rustc_span::source_map::Span;
   6 use rustc_span::symbol::Ident;
   7
   8 declare_clippy_lint! {
   9     /// ### What it does
  10     /// Checks for imports that remove "unsafe" from an item's
  11     /// name.
  12     ///
  13     /// ### Why is this bad?
  14     /// Renaming makes it less clear which traits and
  15     /// structures are unsafe.
  16     ///
  17     /// ### Example
  18     /// ```rust,ignore
  19     /// use std::cell::{UnsafeCell as TotallySafeCell};
  20     ///
  21     /// extern crate crossbeam;
  22     /// use crossbeam::{spawn_unsafe as spawn};
  23     /// ```
  24     #[clippy::version = "pre 1.29.0"]
  25     pub UNSAFE_REMOVED_FROM_NAME,
  26     style,
  27     "`unsafe` removed from API names on import"
  28 }
  29
  30 declare_lint_pass!(UnsafeNameRemoval => [UNSAFE_REMOVED_FROM_NAME]);
  31
  32 impl EarlyLintPass for UnsafeNameRemoval {
  33     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
  34         if let ItemKind::Use(ref use_tree) = item.kind {
  35             check_use_tree(use_tree, cx, item.span);
  36         }
  37     }
  38 }
  39
  40 fn check_use_tree(use_tree: &UseTree, cx: &EarlyContext<'_>, span: Span) {
  41     match use_tree.kind {
  42         UseTreeKind::Simple(Some(new_name), ..) => {
  43             let old_name = use_tree
  44                 .prefix
  45                 .segments
  46                 .last()
  47                 .expect("use paths cannot be empty")
  48                 .ident;
  49             unsafe_to_safe_check(old_name, new_name, cx, span);
  50         },
  51         UseTreeKind::Simple(None, ..) | UseTreeKind::Glob => {},
  52         UseTreeKind::Nested(ref nested_use_tree) => {
  53             for &(ref use_tree, _) in nested_use_tree {
  54                 check_use_tree(use_tree, cx, span);
  55             }
  56         },
  57     }
  58 }
  59
  60 fn unsafe_to_safe_check(old_name: Ident, new_name: Ident, cx: &EarlyContext<'_>, span: Span) {
  61     let old_str = old_name.name.as_str();
  62     let new_str = new_name.name.as_str();
  63     if contains_unsafe(old_str) && !contains_unsafe(new_str) {
  64         span_lint(
  65             cx,
  66             UNSAFE_REMOVED_FROM_NAME,
  67             span,
  68             &format!("removed `unsafe` from the name of `{old_str}` in use as `{new_str}`"),
  69         );
  70     }
  71 }
  72
  73 #[must_use]
  74 fn contains_unsafe(name: &str) -> bool {
  75     name.contains("Unsafe") || name.contains("unsafe")
  76 }