diff --git a/crates/rb-sys-test-helpers/src/ruby_test_executor.rs b/crates/rb-sys-test-helpers/src/ruby_test_executor.rs
index 2c1a1fc5..1fd9fb32 100644
--- a/crates/rb-sys-test-helpers/src/ruby_test_executor.rs
+++ b/crates/rb-sys-test-helpers/src/ruby_test_executor.rs
@@ -121,6 +121,7 @@ impl Drop for RubyTestExecutor {
 }
 
 pub fn global_executor() -> &'static RubyTestExecutor {
+    #[allow(unknown_lints)]
     #[allow(static_mut_refs)]
     unsafe { &GLOBAL_EXECUTOR }.get_or_init(RubyTestExecutor::start)
 }
diff --git a/crates/rb-sys-tests/src/stable_api_test.rs b/crates/rb-sys-tests/src/stable_api_test.rs
index fe6c05d8..73ac2c3b 100644
--- a/crates/rb-sys-tests/src/stable_api_test.rs
+++ b/crates/rb-sys-tests/src/stable_api_test.rs
@@ -1,4 +1,6 @@
-use rb_sys::StableApiDefinition;
+use std::ffi::{c_int, c_long};
+
+use rb_sys::{StableApiDefinition, RUBY_FIXNUM_MAX, RUBY_FIXNUM_MIN};
 use rb_sys_test_helpers::rstring as gen_rstring;
 
 macro_rules! parity_test {
@@ -27,24 +29,25 @@ macro_rules! parity_test {
 }
 
 macro_rules! ruby_eval {
-    ($expr:literal) => {{
-        unsafe {
-            let mut state = 0;
-            let ret =
-                rb_sys::rb_eval_string_protect(concat!($expr, "\0").as_ptr() as _, &mut state as _);
-
-            if state != 0 {
-                let mut err_string = rb_sys::rb_inspect(rb_sys::rb_errinfo());
-                rb_sys::rb_set_errinfo(rb_sys::Qnil as _);
-                let err_string = rb_sys::rb_string_value_cstr(&mut err_string);
-                let err_string = std::ffi::CStr::from_ptr(err_string);
-                let err_string = err_string.to_str().unwrap();
-                panic!("Ruby error: {}", err_string);
-            }
-
-            ret
-        }
-    }};
+  ($expr:literal $(, $arg:expr)*) => {{
+      unsafe {
+          let mut state = 0;
+          let formatted_expr = format!($expr $(, $arg)*);
+          let c_string = std::ffi::CString::new(formatted_expr).unwrap();
+          let ret = rb_sys::rb_eval_string_protect(c_string.as_ptr(), &mut state as _);
+
+          if state != 0 {
+              let mut err_string = rb_sys::rb_inspect(rb_sys::rb_errinfo());
+              rb_sys::rb_set_errinfo(rb_sys::Qnil as _);
+              let err_string = rb_sys::rb_string_value_cstr(&mut err_string);
+              let err_string = std::ffi::CStr::from_ptr(err_string);
+              let err_string = err_string.to_str().unwrap();
+              panic!("Ruby error: {}", err_string);
+          }
+
+          ret
+      }
+  }};
 }
 
 parity_test!(
@@ -231,7 +234,7 @@ parity_test!(
     name: test_builtin_type_for_hash,
     func: builtin_type,
     data_factory: {
-      ruby_eval!("{foo: 'bar'}")
+      ruby_eval!("{{foo: 'bar'}}")
     }
 );
 
@@ -474,7 +477,7 @@ parity_test! (
     name: test_rb_type_for_hash,
     func: rb_type,
     data_factory: {
-      ruby_eval!("{foo: 'bar'}")
+      ruby_eval!("{{foo: 'bar'}}")
     },
     expected: rb_sys::ruby_value_type::RUBY_T_HASH
 );
@@ -533,3 +536,171 @@ parity_test!(
     },
     expected: false
 );
+
+parity_test!(
+  name: test_int2fix_positive,
+  func: int2fix,
+  data_factory: { 42 },
+  expected: ruby_eval!("42")
+);
+
+parity_test!(
+  name: test_int2fix_negative,
+  func: int2fix,
+  data_factory: { -42 },
+  expected: ruby_eval!("-42")
+);
+
+parity_test!(
+  name: test_int2fix_zero,
+  func: int2fix,
+  data_factory: { 0 },
+  expected: ruby_eval!("0")
+);
+
+parity_test!(
+  name: test_int2num_fixnum,
+  func: int2num,
+  data_factory: { 42 },
+  expected: ruby_eval!("42")
+);
+
+parity_test!(
+  name: test_int2num_bignum_positive,
+  func: int2num,
+  data_factory: { i32::MAX },
+  expected: ruby_eval!("2147483647")
+);
+
+parity_test!(
+  name: test_int2num_bignum_negative,
+  func: int2num,
+  data_factory: { i32::MIN },
+  expected: ruby_eval!("-2147483648")
+);
+
+parity_test!(
+  name: test_fix2long_positive,
+  func: fix2long,
+  data_factory: { ruby_eval!("42") },
+  expected: 42
+);
+
+parity_test!(
+  name: test_fix2long_negative,
+  func: fix2long,
+  data_factory: { ruby_eval!("-42") },
+  expected: -42
+);
+
+parity_test!(
+  name: test_fix2long_zero,
+  func: fix2long,
+  data_factory: { ruby_eval!("0") },
+  expected: 0
+);
+
+parity_test!(
+  name: test_num2long_fixnum,
+  func: num2long,
+  data_factory: { ruby_eval!("42") },
+  expected: 42
+);
+
+parity_test!(
+  name: test_num2long_bignum,
+  func: num2long,
+  data_factory: { ruby_eval!("9223372036854775807") },  // i64::MAX
+  expected: 9223372036854775807
+);
+
+parity_test!(
+  name: test_num2long_negative_bignum,
+  func: num2long,
+  data_factory: { ruby_eval!("-9223372036854775808") },  // i64::MIN
+  expected: -9223372036854775808
+);
+
+parity_test!(
+    name: test_int2fix_max,
+    func: int2fix,
+    data_factory: { RUBY_FIXNUM_MAX as c_int },
+    expected: ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MAX as c_int)
+);
+
+parity_test!(
+    name: test_int2fix_min,
+    func: int2fix,
+    data_factory: { RUBY_FIXNUM_MIN as c_int },
+    expected: ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MIN as c_int)
+);
+
+parity_test!(
+    name: test_int2num_max_fixnum,
+    func: int2num,
+    data_factory: { RUBY_FIXNUM_MAX as c_int },
+    expected: ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MAX as c_int)
+);
+
+parity_test!(
+    name: test_int2num_min_fixnum,
+    func: int2num,
+    data_factory: { RUBY_FIXNUM_MIN as c_int },
+    expected: ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MIN as c_int)
+);
+
+parity_test!(
+    name: test_int2num_max_int,
+    func: int2num,
+    data_factory: { c_int::MAX },
+    expected: ruby_eval!("2147483647")  // Assuming 32-bit int
+);
+
+parity_test!(
+    name: test_int2num_min_int,
+    func: int2num,
+    data_factory: { c_int::MIN },
+    expected: ruby_eval!("-2147483648")  // Assuming 32-bit int
+);
+
+parity_test!(
+    name: test_fix2long_max,
+    func: fix2long,
+    data_factory: { ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MAX) },
+    expected: RUBY_FIXNUM_MAX as c_long
+);
+
+parity_test!(
+    name: test_fix2long_min,
+    func: fix2long,
+    data_factory: { ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MIN) },
+    expected: RUBY_FIXNUM_MIN as c_long
+);
+
+parity_test!(
+    name: test_num2long_max_fixnum,
+    func: num2long,
+    data_factory: { ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MAX) },
+    expected: RUBY_FIXNUM_MAX as c_long
+);
+
+parity_test!(
+    name: test_num2long_min_fixnum,
+    func: num2long,
+    data_factory: { ruby_eval!("{}", rb_sys::RUBY_FIXNUM_MIN) },
+    expected: RUBY_FIXNUM_MIN as c_long
+);
+
+parity_test!(
+    name: test_num2long_max_long,
+    func: num2long,
+    data_factory: { ruby_eval!("9223372036854775807") },  // Assuming 64-bit long
+    expected: c_long::MAX
+);
+
+parity_test!(
+    name: test_num2long_min_long,
+    func: num2long,
+    data_factory: { ruby_eval!("-9223372036854775808") },  // Assuming 64-bit long
+    expected: c_long::MIN
+);
diff --git a/crates/rb-sys/src/bindings.rs b/crates/rb-sys/src/bindings.rs
index 8e527801..afd77aad 100644
--- a/crates/rb-sys/src/bindings.rs
+++ b/crates/rb-sys/src/bindings.rs
@@ -16,5 +16,11 @@
 
 include!(env!("RB_SYS_BINDINGS_PATH"));
 
+pub const RUBY_LONG_MIN: isize = std::ffi::c_long::MIN as isize;
+pub const RUBY_LONG_MAX: isize = std::ffi::c_long::MAX as isize;
+
+pub const RUBY_FIXNUM_MIN: isize = RUBY_LONG_MIN / 2;
+pub const RUBY_FIXNUM_MAX: isize = RUBY_LONG_MAX / 2;
+
 pub use uncategorized::*;
 pub use unstable::*;
diff --git a/crates/rb-sys/src/macros.rs b/crates/rb-sys/src/macros.rs
index f135244f..78bb79e7 100644
--- a/crates/rb-sys/src/macros.rs
+++ b/crates/rb-sys/src/macros.rs
@@ -17,6 +17,7 @@ use crate::ruby_value_type;
 use crate::stable_api::get_default as api;
 use crate::StableApiDefinition;
 use crate::VALUE;
+use std::ffi::c_int;
 use std::os::raw::{c_char, c_long};
 
 /// Emulates Ruby's "if" statement.
@@ -283,3 +284,45 @@ pub unsafe fn RB_TYPE_P(obj: VALUE, ty: ruby_value_type) -> bool {
 pub unsafe fn RB_FLOAT_TYPE_P(obj: VALUE) -> bool {
     api().float_type_p(obj)
 }
+
+/// Converts a C int to a Ruby Fixnum.
+///
+/// @param[in]  i  A C int to convert.
+/// @return     A Ruby Fixnum.
+#[inline]
+pub fn INT2FIX(i: c_int) -> VALUE {
+    api().int2fix(i)
+}
+
+/// Converts a C int to a Ruby Integer (Fixnum or Bignum).
+///
+/// @param[in]  i  A C int to convert.
+/// @return     A Ruby Integer.
+#[inline]
+pub fn INT2NUM(i: c_int) -> VALUE {
+    api().int2num(i)
+}
+
+/// Converts a Ruby Fixnum to a C long.
+///
+/// @param[in]  val  A Ruby Fixnum.
+/// @return     A C long.
+///
+/// # Safety
+/// This function is unsafe because it assumes the input is a valid Fixnum.
+#[inline]
+pub fn FIX2LONG(val: VALUE) -> c_long {
+    api().fix2long(val)
+}
+
+/// Converts a Ruby Integer (Fixnum or Bignum) to a C long.
+///
+/// @param[in]  val  A Ruby Integer.
+/// @return     A C long.
+///
+/// # Safety
+/// This function is unsafe because it may involve C-level operations.
+#[inline]
+pub unsafe fn NUM2LONG(val: VALUE) -> c_long {
+    api().num2long(val)
+}
diff --git a/crates/rb-sys/src/stable_api.rs b/crates/rb-sys/src/stable_api.rs
index 72bb0386..fb36b0ae 100644
--- a/crates/rb-sys/src/stable_api.rs
+++ b/crates/rb-sys/src/stable_api.rs
@@ -11,8 +11,11 @@
 //!    to ensure Rust extensions don't prevent the Ruby core team from testing
 //!    changes in production.
 
-use crate::VALUE;
-use std::os::raw::{c_char, c_long};
+use crate::{rb_int2big, rb_num2long, ruby_special_consts, VALUE};
+use std::{
+    ffi::{c_int, c_ulong},
+    os::raw::{c_char, c_long},
+};
 
 pub trait StableApiDefinition {
     /// Get the length of a Ruby string (akin to `RSTRING_LEN`).
@@ -125,6 +128,49 @@ pub trait StableApiDefinition {
     /// This function is unsafe because it could dereference a raw pointer when
     /// attemping to access the underlying [`RBasic`] struct.
     unsafe fn rb_type(&self, obj: VALUE) -> crate::ruby_value_type;
+
+    /// Converts a `c_int` to a Ruby Fixnum.
+    fn int2fix(&self, i: c_int) -> VALUE {
+        let j = i as c_ulong;
+        let k = (j << 1) + ruby_special_consts::RUBY_FIXNUM_FLAG as c_ulong;
+        let l = k as c_long;
+        let m = l as isize;
+        m as VALUE
+    }
+
+    /// Converts a `c_int` to a Ruby number, either a Fixnum or a Bignum.
+    fn int2num(&self, i: c_int) -> VALUE {
+        let value = i as c_long;
+
+        let fixable_pos = value < (crate::FIXNUM_MAX as c_long) + 1;
+        let fixable_neg = value >= (crate::FIXNUM_MIN as c_long);
+
+        if fixable_pos && fixable_neg {
+            self.int2fix(i)
+        } else {
+            unsafe { rb_int2big(i as _) }
+        }
+    }
+
+    /// Converts a Fixnum to a `c_long`.
+    fn fix2long(&self, val: VALUE) -> c_long {
+        let y: isize = val as _;
+        let z = y >> 1;
+        z as c_long
+    }
+
+    /// Converts a Ruby number to a `c_long`. If the number is a Fixnum, it is
+    /// converted directly.
+    ///
+    /// # Safety
+    /// This function assumes a valid Ruby num value.
+    unsafe fn num2long(&self, val: VALUE) -> c_long {
+        if self.fixnum_p(val) {
+            self.fix2long(val)
+        } else {
+            rb_num2long(val)
+        }
+    }
 }
 
 #[cfg(stable_api_enable_compiled_mod)]
diff --git a/crates/rb-sys/src/stable_api/compiled.c b/crates/rb-sys/src/stable_api/compiled.c
index 915331c9..fcc279bc 100644
--- a/crates/rb-sys/src/stable_api/compiled.c
+++ b/crates/rb-sys/src/stable_api/compiled.c
@@ -87,3 +87,23 @@ int
 impl_integer_type_p(VALUE obj) {
   return RB_INTEGER_TYPE_P(obj);
 }
+
+VALUE
+impl_int2fix(int i) {
+  return INT2FIX(i);
+}
+
+VALUE
+impl_int2num(int i) {
+  return INT2NUM(i);
+}
+
+long
+impl_fix2long(VALUE val) {
+  return FIX2LONG(val);
+}
+
+long
+impl_num2long(VALUE val) {
+  return NUM2LONG(val);
+}
diff --git a/crates/rb-sys/src/stable_api/compiled.rs b/crates/rb-sys/src/stable_api/compiled.rs
index 18aabf2f..25ecb86e 100644
--- a/crates/rb-sys/src/stable_api/compiled.rs
+++ b/crates/rb-sys/src/stable_api/compiled.rs
@@ -1,6 +1,9 @@
 use super::StableApiDefinition;
 use crate::{ruby_value_type, VALUE};
-use std::os::raw::{c_char, c_long};
+use std::{
+    ffi::c_int,
+    os::raw::{c_char, c_long},
+};
 
 #[allow(dead_code)]
 extern "C" {
@@ -57,6 +60,18 @@ extern "C" {
 
     #[link_name = "impl_integer_type_p"]
     fn impl_integer_type_p(obj: VALUE) -> bool;
+
+    #[link_name = "impl_int2fix"]
+    fn impl_int2fix(i: c_int) -> VALUE;
+
+    #[link_name = "impl_int2num"]
+    fn impl_int2num(i: c_int) -> VALUE;
+
+    #[link_name = "impl_fix2long"]
+    fn impl_fix2long(val: VALUE) -> c_long;
+
+    #[link_name = "impl_num2long"]
+    fn impl_num2long(val: VALUE) -> c_long;
 }
 
 pub struct Definition;
@@ -151,4 +166,28 @@ impl StableApiDefinition for Definition {
     unsafe fn integer_type_p(&self, obj: VALUE) -> bool {
         impl_integer_type_p(obj)
     }
+
+    #[cfg(feature = "stable-api-compiled-testing")]
+    #[inline]
+    fn int2fix(&self, i: c_int) -> VALUE {
+        unsafe { impl_int2fix(i) }
+    }
+
+    #[cfg(feature = "stable-api-compiled-testing")]
+    #[inline]
+    fn int2num(&self, i: c_int) -> VALUE {
+        unsafe { impl_int2num(i) }
+    }
+
+    #[cfg(feature = "stable-api-compiled-testing")]
+    #[inline]
+    fn fix2long(&self, val: VALUE) -> c_long {
+        unsafe { impl_fix2long(val) }
+    }
+
+    #[cfg(feature = "stable-api-compiled-testing")]
+    #[inline]
+    unsafe fn num2long(&self, val: VALUE) -> c_long {
+        impl_num2long(val)
+    }
 }