1 files changed, 37 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs b/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs
new file mode 100644
index 000000000..0cc28c0dc
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/path_buf_push_overwrite.rs
@@ -0,0 +1,37 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
+use if_chain::if_chain;
+use rustc_ast::ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::symbol::sym;
+use std::path::{Component, Path};
+
+use super::PATH_BUF_PUSH_OVERWRITE;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'tcx Expr<'_>) {
+    if_chain! {
+        if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
+        if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
+        if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::PathBuf);
+        if let ExprKind::Lit(ref lit) = arg.kind;
+        if let LitKind::Str(ref path_lit, _) = lit.node;
+        if let pushed_path = Path::new(path_lit.as_str());
+        if let Some(pushed_path_lit) = pushed_path.to_str();
+        if pushed_path.has_root();
+        if let Some(root) = pushed_path.components().next();
+        if root == Component::RootDir;
+        then {
+            span_lint_and_sugg(
+                cx,
+                PATH_BUF_PUSH_OVERWRITE,
+                lit.span,
+                "calling `push` with '/' or '\\' (file system root) will overwrite the previous path definition",
+                "try",
+                format!("\"{}\"", pushed_path_lit.trim_start_matches(|c| c == '/' || c == '\\')),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}