ensure bytecode::Instruction never grows more than 8bytes

Cargo.lock

@@ -1616,6 +1616,7 @@ dependencies = [
  "num-bigint",
  "num-complex",
  "serde",
+ "static_assertions",
 ]
 
 [[package]]

bytecode/Cargo.toml

@@ -17,3 +17,4 @@ num-complex = { version = "0.4.0", features = ["serde"] }
 serde = { version = "1.0.136", features = ["derive"] }
 itertools = "0.10.3"
 bstr = "0.2.17"
+static_assertions = "1.1.0"

bytecode/src/lib.rs

@@ -401,6 +401,7 @@ pub enum Instruction {
         i: u32,
     },
 }
+static_assertions::assert_eq_size!(Instruction, u64);
 
 use self::Instruction::*;