let extend_to_fraction_field be more tolerant

sagemath · Jul 5, 2020 · 070792b · 070792b
1 parent 3cf021a
commit 070792b
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Showing 3 changed files with 3 additions and 3 deletions.
diff --git a/src/sage/categories/rings.py b/src/sage/categories/rings.py
@@ -238,7 +238,7 @@ def extend_to_fraction_field(self):
             try:
                 if not self.is_injective():
                     raise ValueError("the morphism is not injective")
-            except NotImplementedError:   # we trust the user
+            except (NotImplementedError, TypeError):   # we trust the user
                 pass
             domain = self.domain().fraction_field()
             codomain = self.codomain().fraction_field()

diff --git a/src/sage/rings/polynomial/ore_function_field.py b/src/sage/rings/polynomial/ore_function_field.py
@@ -509,7 +509,7 @@ def is_sparse(self):
 
             sage: R.<t> = RR[]
             sage: sigma = R.hom([t+1])
-            sage: S.<x> = R['x',sigma]
+            sage: S.<x> = R['x', sigma]
             sage: K = S.fraction_field()
             sage: K.is_sparse()
             False

diff --git a/src/sage/rings/polynomial/ore_polynomial_ring.py b/src/sage/rings/polynomial/ore_polynomial_ring.py
@@ -1129,7 +1129,7 @@ def fraction_field(self):
             :module:`sage.rings.polynomial.ore_function_field`
         """
         if self._fraction_field is None:
-            if self.base_ring() in Fields():
+            if self.base_ring() in _Fields:
                 self._fraction_field = self._fraction_field_class(self)
             else:
                 base = self.base_ring().fraction_field()