Fix trac 34292

src/sage/algebras/group_algebra.py

@@ -172,6 +172,14 @@ def _coerce_map_from_(self, S):
               From: Algebra of Cyclic group of order 3 as a permutation group over Integer Ring
               To:   Algebra of Dihedral group of order 6 as a permutation group over Rational Field
 
+            sage: H = PermutationGroup([ [(1,2), (3,4)], [(5,6,7),(12,14,18)] ])
+            sage: kH = H.algebra(GF(2))
+            sage: [a, b] = kH.gens()
+            sage: x = kH(a) + kH(b) + kH.one(); print(x)
+            () + (5,6,7)(12,14,18) + (1,2)(3,4)
+            sage: x*x  #checks :trac:34292
+            (5,7,6)(12,18,14)
+
         As expected, there is no coercion when restricting the
         field::
 
@@ -184,6 +192,8 @@ def _coerce_map_from_(self, S):
             sage: ZG = G.algebra(ZZ, category=AdditiveMagmas())
             sage: ZG.has_coerce_map_from(G)
             False
+
+
         """
         G = self.basis().keys()
         K = self.base_ring()

src/sage/structure/coerce.pyx

@@ -1326,9 +1326,10 @@ cdef class CoercionModel:
                 return x_elt,y_elt
             elif x_elt._parent == y_elt._parent:
                 # TODO: Non-uniqueness of parents strikes again!
-                y_elt = parent(x_elt)(y_elt)
+                x_elt = parent(y_elt)(x_elt)
                 if x_elt._parent is y_elt._parent:
                     return x_elt,y_elt
+
             self._coercion_error(x, x_map, x_elt, y, y_map, y_elt)
 
         cdef bint x_numeric = isinstance(x, (int, long, float, complex))