remove unnecessary empty check

Author: mbhall88

std/src/path.rs

@@ -2217,9 +2217,7 @@ impl Path {
     ///
     #[unstable(feature = "path_file_prefix", issue = "86319")]
     pub fn file_prefix(&self) -> Option<&OsStr> {
-        self.file_name()
-            .map(split_file_at_dot)
-            .and_then(|(before, after)| if before.is_empty() { after } else { Some(before) })
+        self.file_name().map(split_file_at_dot).and_then(|(before, _after)| Some(before))
     }
 
     /// Extracts the extension of [`self.file_name`], if possible.

std/src/path/tests.rs

@@ -1127,6 +1127,8 @@ pub fn test_stem_ext() {
 
     t!(".x.y.z", file_stem: Some(".x.y"), extension: Some("z"));
 
+    t!("..x.y.z", file_stem: Some("..x.y"), extension: Some("z"));
+
     t!("", file_stem: None, extension: None);
 }
 
@@ -1168,6 +1170,8 @@ pub fn test_prefix_ext() {
 
     t!(".x.y.z", file_prefix: Some(".x"), extension: Some("z"));
 
+    t!("..x.y.z", file_prefix: Some("."), extension: Some("z"));
+
     t!("", file_prefix: None, extension: None);
 }