Bug: Fix scope issues

[PeterGriffinSr]

Description:
Currently, variable shadowing within functions does not work correctly. A local variable that has the same name as an outer variable incorrectly overrides the outer variable across all scopes, rather than being limited to the inner block.

Example:

let x = 10 in

let add() {
    let x = 20 in
    x
}

print(add() + x)

Expected Behavior:
This should print 30 because:

• add() returns the inner x (20).
• The outer x remains 10.
• Therefore, 20 + 10 = 30.

Actual Behavior:
Instead, it prints 40. The inner x (20) shadows the outer x everywhere, causing the calculation to become 20 + 20.

Impact:
This behavior breaks proper lexical scoping rules, making it impossible to reliably shadow variables without affecting the outer scopes.

Steps to Reproduce:

1. Declare a variable in an outer scope.
2. Create a function that contains a variable with the same name.
3. Attempt to access both the inner and outer variables.
4. Observe that the shadowed variable incorrectly affects the outer scope.