Add #[must_use] to core and std constructors

1 files changed, 2 insertions, 0 deletions

diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index c305519dd44..e4ad6cba880 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -119,6 +119,7 @@ impl OsString {
     /// let os_string = OsString::new();
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
     #[inline]
     pub fn new() -> OsString {
         OsString { inner: Buf::from_string(String::new()) }
@@ -199,6 +200,7 @@ impl OsString {
     /// assert_eq!(capacity, os_string.capacity());
     /// ```
     #[stable(feature = "osstring_simple_functions", since = "1.9.0")]
+    #[must_use]
     #[inline]
     pub fn with_capacity(capacity: usize) -> OsString {
         OsString { inner: Buf::with_capacity(capacity) }