Fix: Prevent float coercion on BigInt overflow in fast-path.

Author: dylan-sutton-chavez

compiler/src/modules/vm/mod.rs

@@ -155,19 +155,18 @@ impl<'a> VM<'a> {
         let a = self.stack[len - 2];
         let b = self.stack[len - 1];
         let result = match fast {
+            FastOp::AddFloat if a.is_float() && b.is_float() => Val::float(a.as_float() + b.as_float()),
             FastOp::AddInt if a.is_int() && b.is_int() => {
                 let r = a.as_int() as i128 + b.as_int() as i128;
-                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { Val::float(r as f64) }
+                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { return Ok(false); }
             }
-            FastOp::AddFloat if a.is_float() && b.is_float() => Val::float(a.as_float() + b.as_float()),
             FastOp::SubInt if a.is_int() && b.is_int() => {
                 let r = a.as_int() as i128 - b.as_int() as i128;
-                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { Val::float(r as f64) }
+                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { return Ok(false); }
             }
-            FastOp::SubFloat if a.is_float() && b.is_float() => Val::float(a.as_float() - b.as_float()),
             FastOp::MulInt if a.is_int() && b.is_int() => {
                 let r = a.as_int() as i128 * b.as_int() as i128;
-                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { Val::float(r as f64) }
+                if r >= Val::INT_MIN as i128 && r <= Val::INT_MAX as i128 { Val::int(r as i64) } else { return Ok(false); }
             }
             FastOp::MulFloat if a.is_float() && b.is_float() => Val::float(a.as_float() * b.as_float()),
             FastOp::LtInt if a.is_int() && b.is_int() => Val::bool(a.as_int() < b.as_int()),

compiler/tests/cases/vm_cases.json

@@ -210,5 +210,6 @@
   {"src": "x = 2**63\nprint(-x)", "output": ["-9223372036854775808"], "result": "None"},
   {"src": "print(abs(-2**100))", "output": ["1267650600228229401496703205376"], "result": "None"},
   {"src": "print(int(2**100))", "output": ["1267650600228229401496703205376"], "result": "None"},
-  {"src": "x = 99999999999999999999\nprint(x)", "output": ["99999999999999999999"], "result": "None"}
+  {"src": "x = 99999999999999999999\nprint(x)", "output": ["99999999999999999999"], "result": "None"},
+  {"src": "scale = 1\nfor _ in range(110):\n    scale = scale * 10\nterm_a = scale // 5\nprint(term_a)", "output": ["20000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"], "result": "None"}
 ]