src/tools/clippy/clippy_lints/src/disallowed_method.rs

   1 use crate::utils::span_lint;
   2
   3 use rustc_data_structures::fx::FxHashSet;
   4 use rustc_hir::{Expr, ExprKind};
   5 use rustc_lint::{LateContext, LateLintPass};
   6 use rustc_session::{declare_tool_lint, impl_lint_pass};
   7 use rustc_span::Symbol;
   8
   9 declare_clippy_lint! {
  10     /// **What it does:** Lints for specific trait methods defined in clippy.toml
  11     ///
  12     /// **Why is this bad?** Some methods are undesirable in certain contexts,
  13     /// and it would be beneficial to lint for them as needed.
  14     ///
  15     /// **Known problems:** None.
  16     ///
  17     /// **Example:**
  18     ///
  19     /// ```rust,ignore
  20     /// // example code where clippy issues a warning
  21     /// foo.bad_method(); // Foo::bad_method is disallowed in the configuration
  22     /// ```
  23     /// Use instead:
  24     /// ```rust,ignore
  25     /// // example code which does not raise clippy warning
  26     /// goodStruct.bad_method(); // GoodStruct::bad_method is not disallowed
  27     /// ```
  28     pub DISALLOWED_METHOD,
  29     nursery,
  30     "use of a disallowed method call"
  31 }
  32
  33 #[derive(Clone, Debug)]
  34 pub struct DisallowedMethod {
  35     disallowed: FxHashSet<Vec<Symbol>>,
  36 }
  37
  38 impl DisallowedMethod {
  39     pub fn new(disallowed: &FxHashSet<String>) -> Self {
  40         Self {
  41             disallowed: disallowed
  42                 .iter()
  43                 .map(|s| s.split("::").map(|seg| Symbol::intern(seg)).collect::<Vec<_>>())
  44                 .collect(),
  45         }
  46     }
  47 }
  48
  49 impl_lint_pass!(DisallowedMethod => [DISALLOWED_METHOD]);
  50
  51 impl<'tcx> LateLintPass<'tcx> for DisallowedMethod {
  52     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
  53         if let ExprKind::MethodCall(_path, _, _args, _) = &expr.kind {
  54             let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
  55
  56             let method_call = cx.get_def_path(def_id);
  57             if self.disallowed.contains(&method_call) {
  58                 let method = method_call
  59                     .iter()
  60                     .map(|s| s.to_ident_string())
  61                     .collect::<Vec<_>>()
  62                     .join("::");
  63
  64                 span_lint(
  65                     cx,
  66                     DISALLOWED_METHOD,
  67                     expr.span,
  68                     &format!("use of a disallowed method `{}`", method),
  69                 );
  70             }
  71         }
  72     }
  73 }