Fix fd.rs

Author: newpavlov

src/shims/unix/fd.rs

@@ -445,7 +445,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         let mut bytes = vec![0; usize::try_from(count).unwrap()];
         let result = match offset {
             None => fd.borrow_mut().read(communicate, &mut bytes, this),
-            Some(Ok(offset)) => {
+            Some(offset) => {
                 let Ok(offset) = u64::try_from(offset) else {
                     let einval = this.eval_libc("EINVAL");
                     this.set_last_error(einval)?;