Repository: reflex-dev/reflex

Issue:
`ImmutableVar.guess_type()` hides the original var type on fields derived from integral types
**Describe the bug**
In the example below you can see my problem, currently the bottom assertion fails.

**To Reproduce**
```python
class Email(str):
    ... # validation and stuff ...
    
class State(rx.State):
  email: Email = Email("someone@reflex.dev")

assert State.email._original_var._var_type == Email  # passes
assert State.email._var_type == Email  # fails
```

**Expected behavior**
I would expect the type information to be preserved.

**Specifics (please complete the following information):**
 - Python Version: 3.12.5
 - Reflex Version: main
 - OS: archlinux
 - Browser (Optional): Firefox
 
**Additional context**
Maybe something like this could help (Would also be needed for the other integral types)
```python
class ToStringOperation(...):

   def create(...):
        var_type = (
            original_var._var_type if issubclass(original_var._var_type, str) else str
        )

        return cls(
            _var_name="",
            _var_type=var_type,
            _var_data=ImmutableVarData.merge(_var_data),
            _original_var=original_var,
        )
```



Discussion:
Or maybe 
```python
        var_type = (
            original_var._var_type 
            if original_var is not None 
            and isclass(original_var._var_type) 
            and issubclass(original_var._var_type, str) 
            else str
        )
Failing test:
```python
def test_to_string_operation():
    class Email(str): ...

    class TestState(BaseState):
        optional_email: Optional[Email] = None
        email: Email = "test@reflex.dev"

    assert (
        str(TestState.optional_email) == f"{TestState.get_full_name()}.optional_email"
    )
    my_state = TestState()
    assert my_state.optional_email is None
    assert str(my_state.email) == "test@reflex.dev"

    assert cast(ImmutableVar, TestState.email)._var_type == Email
    assert cast(ImmutableVar, TestState.optional_email)._var_type == Optional[Email]



Patch:
diff --git a/reflex/ivars/base.py b/reflex/ivars/base.py
index 27c4828afb8..8bb7957c494 100644
--- a/reflex/ivars/base.py
+++ b/reflex/ivars/base.py
@@ -416,7 +416,7 @@ def to(
             return ToArrayOperation.create(self, var_type or list)
 
         if issubclass(output, StringVar):
-            return ToStringOperation.create(self)
+            return ToStringOperation.create(self, var_type or str)
 
         if issubclass(output, (ObjectVar, Base)):
             return ToObjectOperation.create(self, var_type or dict)
@@ -496,7 +496,7 @@ def guess_type(self) -> ImmutableVar:
         if issubclass(fixed_type, (list, tuple, set)):
             return self.to(ArrayVar, self._var_type)
         if issubclass(fixed_type, str):
-            return self.to(StringVar)
+            return self.to(StringVar, self._var_type)
         if issubclass(fixed_type, Base):
             return self.to(ObjectVar, self._var_type)
         return self


Test patch:
diff --git a/tests/test_var.py b/tests/test_var.py
index 5902590f5bf..460cee39ece 100644
--- a/tests/test_var.py
+++ b/tests/test_var.py
@@ -1,7 +1,7 @@
 import json
 import math
 import typing
-from typing import Dict, List, Set, Tuple, Union
+from typing import Dict, List, Optional, Set, Tuple, Union, cast
 
 import pytest
 from pandas import DataFrame
@@ -1756,3 +1756,21 @@ def test_invalid_computed_var_deps(deps: List):
         )
         def test_var(state) -> int:
             return 1
+
+
+def test_to_string_operation():
+    class Email(str): ...
+
+    class TestState(BaseState):
+        optional_email: Optional[Email] = None
+        email: Email = Email("test@reflex.dev")
+
+    assert (
+        str(TestState.optional_email) == f"{TestState.get_full_name()}.optional_email"
+    )
+    my_state = TestState()
+    assert my_state.optional_email is None
+    assert my_state.email == "test@reflex.dev"
+
+    assert cast(ImmutableVar, TestState.email)._var_type == Email
+    assert cast(ImmutableVar, TestState.optional_email)._var_type == Optional[Email]