Rename TransactionCompiler to Script and use it to replace the type alias

runtime/src/bank_client.rs

@@ -1,8 +1,9 @@
 use crate::bank::Bank;
 use solana_sdk::pubkey::Pubkey;
+use solana_sdk::script::Script;
 use solana_sdk::signature::{Keypair, KeypairUtil};
 use solana_sdk::system_instruction::SystemInstruction;
-use solana_sdk::transaction::{Script, Transaction, TransactionError};
+use solana_sdk::transaction::{Instruction, Transaction, TransactionError};
 
 pub struct BankClient<'a> {
     bank: &'a Bank,
@@ -25,12 +26,25 @@ impl<'a> BankClient<'a> {
 
     /// Create and process a transaction.
     pub fn process_script(&self, script: Script) -> Result<(), TransactionError> {
-        self.process_transaction(Transaction::new(script))
+        self.process_transaction(script.compile())
+    }
+
+    /// Create and process a transaction from a list of instructions.
+    pub fn process_instructions(
+        &self,
+        instructions: Vec<Instruction>,
+    ) -> Result<(), TransactionError> {
+        self.process_script(Script::new(instructions))
+    }
+
+    /// Create and process a transaction from a single instruction.
+    pub fn process_instruction(&self, instruction: Instruction) -> Result<(), TransactionError> {
+        self.process_instructions(vec![instruction])
     }
 
     /// Transfer lamports to pubkey
     pub fn transfer(&self, lamports: u64, pubkey: &Pubkey) -> Result<(), TransactionError> {
         let move_instruction = SystemInstruction::new_move(&self.pubkey(), pubkey, lamports);
-        self.process_script(vec![move_instruction])
+        self.process_instruction(move_instruction)
     }
 }

runtime/src/system_program.rs

@@ -109,6 +109,7 @@ mod tests {
     use solana_sdk::account::Account;
     use solana_sdk::genesis_block::GenesisBlock;
     use solana_sdk::native_program::ProgramError;
+    use solana_sdk::script::Script;
     use solana_sdk::signature::{Keypair, KeypairUtil};
     use solana_sdk::system_instruction::SystemInstruction;
     use solana_sdk::system_program;
@@ -291,11 +292,11 @@ mod tests {
 
         // Erroneously sign transaction with recipient account key
         // No signature case is tested by bank `test_zero_signatures()`
-        let malicious_script = vec![Instruction::new(
+        let malicious_script = Script::new(vec![Instruction::new(
             system_program::id(),
             &SystemInstruction::Move { lamports: 10 },
             vec![(alice_pubkey, false), (mallory_pubkey, true)],
-        )];
+        )]);
         assert_eq!(
             mallory_client.process_script(malicious_script),
             Err(TransactionError::InstructionError(