This is not the sympy repository. This issue is about the sympy/sympy repository. Based on the problem statement, I need to create a patch for the Mod function's eval logic. Let me understand the issue: The problem is in the `Mod` function's eval method where it incorrectly returns 0 for `Mod(x**2, x)` when `x` is not an integer. The current code: ```python if (p == q or p == -q or p.is_Pow and p.exp.is_Integer and p.base == q or p.is_integer and q == 1): return S.Zero ``` The fix should: 1. Check `p.is_Pow` first (to avoid AttributeError on `p.base`) 2. Check that `q.is_integer` (the base must be an integer) 3. Check that `p.exp.is_positive` (the exponent must be positive) Based on the hints, the correct fix is: ```python if (p == q or p == -q or p.is_Pow and p.base == q and q.is_integer and p.exp.is_Integer and p.exp.is_positive or p.is_integer and q == 1): return S.Zero ``` The file would be in `sympy/core/mod.py`. Let me produce the patch: --- a/sympy/core/mod.py +++ b/sympy/core/mod.py @@ -123,7 +123,8 @@ def doit(p, q): return p if (p == q or p == -q or - p.is_Pow and p.exp.is_Integer and p.base == q or + p.is_Pow and p.base == q and q.is_integer and + p.exp.is_Integer and p.exp.is_positive or p.is_integer and q == 1): return S.Zero