src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::ty::is_type_diagnostic_item;
   3 use if_chain::if_chain;
   4 use rustc_ast::ast::LitKind;
   5 use rustc_errors::Applicability;
   6 use rustc_hir::{Expr, ExprKind};
   7 use rustc_lint::LateContext;
   8 use rustc_span::symbol::sym;
   9 use std::path::{Component, Path};
  10
  11 use super::PATH_BUF_PUSH_OVERWRITE;
  12
  13 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
  14     if_chain! {
  15         if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
  16         if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
  17         if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::PathBuf);
  18         if let ExprKind::Lit(ref lit) = arg.kind;
  19         if let LitKind::Str(ref path_lit, _) = lit.node;
  20         if let pushed_path = Path::new(path_lit.as_str());
  21         if let Some(pushed_path_lit) = pushed_path.to_str();
  22         if pushed_path.has_root();
  23         if let Some(root) = pushed_path.components().next();
  24         if root == Component::RootDir;
  25         then {
  26             span_lint_and_sugg(
  27                 cx,
  28                 PATH_BUF_PUSH_OVERWRITE,
  29                 lit.span,
  30                 "calling `push` with '/' or '\\' (file system root) will overwrite the previous path definition",
  31                 "try",
  32                 format!("\"{}\"", pushed_path_lit.trim_start_matches(|c| c == '/' || c == '\\')),
  33                 Applicability::MachineApplicable,
  34             );
  35         }
  36     }
  37 }