src/tools/clippy/clippy_lints/src/exit.rs

   1 use crate::utils::{is_entrypoint_fn, match_def_path, paths, span_lint};
   2 use if_chain::if_chain;
   3 use rustc_hir::{Expr, ExprKind, Item, ItemKind, Node};
   4 use rustc_lint::{LateContext, LateLintPass};
   5 use rustc_session::{declare_lint_pass, declare_tool_lint};
   6
   7 declare_clippy_lint! {
   8     /// **What it does:** `exit()`  terminates the program and doesn't provide a
   9     /// stack trace.
  10     ///
  11     /// **Why is this bad?** Ideally a program is terminated by finishing
  12     /// the main function.
  13     ///
  14     /// **Known problems:** None.
  15     ///
  16     /// **Example:**
  17     /// ```ignore
  18     /// std::process::exit(0)
  19     /// ```
  20     pub EXIT,
  21     restriction,
  22     "`std::process::exit` is called, terminating the program"
  23 }
  24
  25 declare_lint_pass!(Exit => [EXIT]);
  26
  27 impl<'tcx> LateLintPass<'tcx> for Exit {
  28     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
  29         if_chain! {
  30             if let ExprKind::Call(ref path_expr, ref _args) = e.kind;
  31             if let ExprKind::Path(ref path) = path_expr.kind;
  32             if let Some(def_id) = cx.qpath_res(path, path_expr.hir_id).opt_def_id();
  33             if match_def_path(cx, def_id, &paths::EXIT);
  34             then {
  35                 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
  36                 if let Some(Node::Item(Item{kind: ItemKind::Fn(..), ..})) = cx.tcx.hir().find(parent) {
  37                     // If the next item up is a function we check if it is an entry point
  38                     // and only then emit a linter warning
  39                     let def_id = cx.tcx.hir().local_def_id(parent);
  40                     if !is_entrypoint_fn(cx, def_id.to_def_id()) {
  41                         span_lint(cx, EXIT, e.span, "usage of `process::exit`");
  42                     }
  43                 }
  44             }
  45         }
  46     }
  47 }