remove unneeded casts and conversions in rand48

src/header/stdlib/rand48.rs

@@ -15,13 +15,9 @@ pub struct U48(u64);
 
 impl From<&[c_ushort; 3]> for U48 {
     fn from(value: &[c_ushort; 3]) -> Self {
-        /* Cast via u16 to ensure we get only the lower 16 bits of each
+        /* c_ushort is u16 so we get only the lower 16 bits of each
          * element, as specified by POSIX. */
-        Self(
-            u64::from(value[0] as u16)
-                | (u64::from(value[1] as u16) << 16)
-                | (u64::from(value[2] as u16) << 32),
-        )
+        Self(u64::from(value[0]) | (u64::from(value[1]) << 16) | (u64::from(value[2]) << 32))
     }
 }
 
@@ -52,10 +48,9 @@ impl From<U48> for u64 {
 impl From<U48> for [c_ushort; 3] {
     fn from(value: U48) -> Self {
         [
-            // "as u16" in case c_ushort is larger than u16
-            (value.0 as u16).into(),
-            ((value.0 >> 16) as u16).into(),
-            ((value.0 >> 32) as u16).into(),
+            (value.0 as u16),
+            ((value.0 >> 16) as u16),
+            ((value.0 >> 32) as u16),
         ]
     }
 }
@@ -105,7 +100,7 @@ impl Params {
     /// For use in lcong48().
     pub fn set(&mut self, a: &[c_ushort; 3], c: c_ushort) {
         self.a = a.into();
-        self.c = c as u16; // Per POSIX, discard higher bits in case unsigned short is larger than u16
+        self.c = c;
     }
 
     pub fn step(&self, xsubi: U48) -> U48 {