Added supposed check for windows paths.

Author: Mason Ray Hanna III

clippy_lints/src/methods/path_join_correction.rs

@@ -14,14 +14,14 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>, join_a
         if_chain!(
          if let ExprKind::Lit(spanned) = &join_arg.kind;
          if let LitKind::Str(symbol, _) = spanned.node;
-         if symbol.as_str().starts_with('/');
+         if symbol.as_str().starts_with('/') || symbol.as_str().starts_with('\\');
           then {
            span_lint_and_sugg(
            cx,
            PATH_JOIN_CORRECTION,
            span.with_hi(expr.span.hi()),
            r#"argument in join called on path contains a starting '/'"#,
-           "try removing first '/'",
+           "try removing first '/' or '\\'",
            "join(\"your/path/here\")".to_owned(),
            applicability
          );

tests/ui/path_join_correction.fixed

@@ -10,6 +10,11 @@ fn main() {
     path.join("/sh");
     println!("{}", path.display());
 
+    //should be linted
+    let path = Path::new("C:\\Users");
+    path.join("\\user");
+    println!("{}", path.display());
+
     // should not be linted
     let path: &[&str] = &["/bin"];
     path.join("/sh");

tests/ui/path_join_correction.rs

@@ -10,6 +10,11 @@ fn main() {
     path.join("/sh");
     println!("{}", path.display());
 
+    //should be linted
+    let path = Path::new("C:\\Users");
+    path.join("\\user");
+    println!("{}", path.display());
+
     // should not be linted
     let path: &[&str] = &["/bin"];
     path.join("/sh");