fix: align with upstream PR #44 — restore serialize_i64 encoding

Bad merge resolution had reverted PR #44 changes:
- Restore serialize_i64 instead of to_le_bytes+OpBin2Num for int fields
- Restore Ok(9) field chunk size (was incorrectly Ok(10))
- Remove spurious OpBin2Num injection in validate_output_state
- Update test expectations to match corrected encoding

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Manyfestation

silverscript-lang/src/compiler.rs

@@ -2,6 +2,7 @@ use std::collections::{HashMap, HashSet};
 
 use kaspa_txscript::opcodes::codes::*;
 use kaspa_txscript::script_builder::ScriptBuilder;
+use kaspa_txscript::serialize_i64;
 use serde::{Deserialize, Serialize};
 
 use crate::ast::{
@@ -246,8 +247,9 @@ fn compile_contract_fields<'i>(
             let ExprKind::Int(value) = &resolved.kind else {
                 return Err(CompilerError::Unsupported(format!("contract field '{}' expects compile-time int value", field.name)));
             };
-            builder.add_data(&value.to_le_bytes())?;
-            builder.add_op(OpBin2Num)?;
+            let serialized = serialize_i64(*value, Some(8usize))
+                .map_err(|err| CompilerError::Unsupported(format!("failed to serialize int literal {}: {err}", value)))?;
+            builder.add_data(&serialized)?;
         } else {
             compile_expr(
                 &resolved,
@@ -792,7 +794,8 @@ fn encode_fixed_size_value<'i>(value: &Expr<'i>, type_name: &str) -> Result<Vec<
                 ExprKind::Int(number) | ExprKind::DateLiteral(number) => *number,
                 _ => return Err(CompilerError::Unsupported("array literal element type mismatch".to_string())),
             };
-            Ok(number.to_le_bytes().to_vec())
+            serialize_i64(number, Some(8usize))
+                .map_err(|err| CompilerError::Unsupported(format!("failed to serialize int literal {}: {err}", number)))
         }
         "bool" => {
             let ExprKind::Bool(flag) = &value.kind else {
@@ -1475,7 +1478,9 @@ fn encoded_field_chunk_size<'i>(
     contract_constants: &HashMap<String, Expr<'i>>,
 ) -> Result<usize, CompilerError> {
     if field.type_ref.array_dims.is_empty() && field.type_ref.base == TypeBase::Int {
-        return Ok(10);
+        // Int fields are encoded as PUSHDATA8-prefixed script numbers:
+        // 1-byte push opcode (0x08) + 8-byte payload from serialize_i64(..., Some(8)).
+        return Ok(9);
     }
 
     if field.type_ref.base != TypeBase::Byte {
@@ -1662,10 +1667,6 @@ fn compile_validate_output_state_statement(
             builder.add_op(OpSwap)?;
             builder.add_op(OpCat)?;
             stack_depth -= 1;
-            builder.add_data(&[OpBin2Num])?;
-            stack_depth += 1;
-            builder.add_op(OpCat)?;
-            stack_depth -= 1;
             continue;
         }
 

silverscript-lang/tests/compiler_tests.rs

@@ -1562,8 +1562,6 @@ fn compiles_contract_fields_as_script_prolog() {
     let expected = ScriptBuilder::new()
         .add_data(&5i64.to_le_bytes())
         .unwrap()
-        .add_op(OpBin2Num)
-        .unwrap()
         .add_data(&[0x12, 0x34])
         .unwrap()
         .add_i64(1)
@@ -1622,11 +1620,9 @@ fn compiles_validate_output_state_to_expected_script() {
     let compiled = compile_contract(source, &[5.into(), vec![1u8, 2u8].into()], CompileOptions::default()).expect("compile succeeds");
 
     let expected = ScriptBuilder::new()
-        // <x> as fixed-size int field encoding: <PUSHDATA8><8-byte little-endian><OpBin2Num>
+        // <x> as fixed-size int field encoding: <PUSHDATA8><8-byte little-endian>
         .add_data(&5i64.to_le_bytes())
         .unwrap()
-        .add_op(OpBin2Num)
-        .unwrap()
         // <y>
         .add_data(&[1u8, 2u8])
         .unwrap()
@@ -1645,7 +1641,7 @@ fn compiles_validate_output_state_to_expected_script() {
         .add_op(OpAdd)
         .unwrap()
 
-        // ---- Convert x+1 to fixed-size int field chunk: <0x08><8-byte payload><OpBin2Num> ----
+        // ---- Convert x+1 to fixed-size int field chunk: <0x08><8-byte payload> ----
         // convert numeric value to 8-byte payload
         .add_i64(8)
         .unwrap()
@@ -1658,12 +1654,6 @@ fn compiles_validate_output_state_to_expected_script() {
         .unwrap()
         .add_op(OpCat)
         .unwrap()
-        // append OpBin2Num opcode byte
-        .add_data(&[OpBin2Num])
-        .unwrap()
-        .add_op(OpCat)
-        .unwrap()
-
         // ---- Build new_state.y pushdata chunk ----
         // raw y bytes
         .add_data(&[0x34, 0x12])
@@ -1697,8 +1687,8 @@ fn compiles_validate_output_state_to_expected_script() {
         // sigscript_len - script_size => bytes before current redeem
         .add_op(OpSub)
         .unwrap()
-        // add fixed current-state field prefix length: len(<x><y>) = 13
-        .add_i64(13)
+        // add fixed current-state field prefix length: len(<x><y>) = 12
+        .add_i64(12)
         .unwrap()
         // start offset of REST_OF_SCRIPT inside sigscript
         .add_op(OpAdd)
@@ -1831,9 +1821,6 @@ fn compiles_read_input_state_to_expected_script() {
         // push x payload (8-byte LE)
         .add_data(&5i64.to_le_bytes())
         .unwrap()
-        // decode x to numeric form
-        .add_op(OpBin2Num)
-        .unwrap()
         // push y payload bytes
         .add_data(&[1u8, 2u8])
         .unwrap()
@@ -1917,10 +1904,10 @@ fn compiles_read_input_state_to_expected_script() {
         // base = sig_len - script_size
         .add_op(OpSub)
         .unwrap()
-        // skip x encoded chunk (10 bytes) + y pushdata prefix (1 byte)
-        .add_i64(11)
+        // skip x encoded chunk (9 bytes) + y pushdata prefix (1 byte)
+        .add_i64(10)
         .unwrap()
-        // start_y = base + 11
+        // start_y = base + 10
         .add_op(OpAdd)
         .unwrap()
 
@@ -1937,9 +1924,9 @@ fn compiles_read_input_state_to_expected_script() {
         .add_op(OpSub)
         .unwrap()
         // skip x chunk + y prefix
-        .add_i64(11)
+        .add_i64(10)
         .unwrap()
-        // start_y = base + 11
+        // start_y = base + 10
         .add_op(OpAdd)
         .unwrap()
         // y payload length