Fix remaining clippy warnings

src/decoded_inst.rs

@@ -148,6 +148,10 @@ impl<'a, 'd> OperandValues<'a, 'd> {
         Self { inst }
     }
 
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     pub fn len(&self) -> usize {
         unsafe { xed_decoded_inst_noperands(self.inst.as_raw()) as usize }
     }
@@ -309,6 +313,10 @@ impl<'d> DecodedInst<'d> {
 pub struct MemoryOperands<'a, 'd>(OperandValues<'a, 'd>);
 
 impl<'a, 'd> MemoryOperands<'a, 'd> {
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
     pub fn len(&self) -> usize {
         unsafe { xed_decoded_inst_number_of_memory_operands(self.0.inst.as_raw()) as usize }
     }

src/macros/wrapper_enum.rs

@@ -187,6 +187,11 @@ pub(crate) const fn is_contiguous(variants: &[c_uint], assert: bool) -> Option<(
         if !contains(variants, variant) {
             if assert {
                 let slice: [(); 0] = [];
+
+                // This statement isn't supposed to have an effect. It's just meant to create an
+                // assertion message that specifies the value of the variant that is contained
+                // within.
+                #[allow(clippy::no_effect)]
                 slice[variant as usize];
             }