polys: correct conversion of expressions to field elements

Closes sympy/sympy#14433

diofant/polys/fields.py

@@ -140,6 +140,8 @@ def from_expr(self, expr):
         def _rebuild(expr):
             if (generator := mapping.get(expr)) is not None:
                 return generator
+            elif 1/expr in mapping:
+                return 1/mapping[1/expr]
             elif expr.is_Add:
                 return functools.reduce(operator.add, list(map(_rebuild, expr.args)))
             elif expr.is_Mul:

diofant/tests/domains/test_domains.py

@@ -458,6 +458,10 @@ def test_Domain__contains__():
 
     assert F(1) in ZZ
 
+    # issue sympy/sympy#14433
+    F = QQ.inject(1/x).field
+    assert all(_ in F for _ in [x, 1/x])
+
 
 def test_Domain_ring():
     assert ZZ.has_assoc_Ring is True

docs/release/notes-0.14.rst

@@ -42,3 +42,4 @@ These Sympy issues also were addressed:
 * :sympyissue:`22878`: RecursionError in trigsimp
 * :sympyissue:`22982`: limit((log(E + 1/x) - 1)**(1 - sqrt(E + 1/x)), x, oo) returns 0 instead of oo
 * :sympyissue:`22986`: limit(acosh(1 + 1/x)*sqrt(x), x, oo) is evaluated incorrectly.
+* :sympyissue:`14433`: x not in QQ.frac_field(1/x)