diff --git a/library/std/src/sys/wasi/fs.rs b/library/std/src/sys/wasi/fs.rs
index 6782d845bb0..8408756f1b3 100644
--- a/library/std/src/sys/wasi/fs.rs
+++ b/library/std/src/sys/wasi/fs.rs
@@ -46,6 +46,7 @@ pub struct DirEntry {
 pub struct OpenOptions {
     read: bool,
     write: bool,
+    append: bool,
     dirflags: wasi::Lookupflags,
     fdflags: wasi::Fdflags,
     oflags: wasi::Oflags,
@@ -270,8 +271,9 @@ fn oflag(&mut self, bit: wasi::Oflags, set: bool) {
         }
     }
 
-    pub fn append(&mut self, set: bool) {
-        self.fdflag(wasi::FDFLAGS_APPEND, set);
+    pub fn append(&mut self, append: bool) {
+        self.append = append;
+        self.fdflag(wasi::FDFLAGS_APPEND, append);
     }
 
     pub fn dsync(&mut self, set: bool) {
@@ -321,7 +323,7 @@ fn rights_base(&self) -> wasi::Rights {
             base |= wasi::RIGHTS_FD_READ;
             base |= wasi::RIGHTS_FD_READDIR;
         }
-        if self.write {
+        if self.write || self.append {
             base |= wasi::RIGHTS_FD_WRITE;
             base |= wasi::RIGHTS_FD_DATASYNC;
             base |= wasi::RIGHTS_FD_ALLOCATE;