Make the Dirichlet series input only convert Dirichlet series.

src/sage/rings/lazy_series.py

@@ -88,7 +88,7 @@
 
 
 from sage.rings.infinity import infinity
-from sage.structure.element import Element
+from sage.structure.element import Element, parent
 from sage.rings.integer_ring import ZZ
 from sage.structure.richcmp import op_EQ, op_NE
 from sage.arith.power import generic_power
@@ -1782,6 +1782,8 @@ def __call__(self, g):
             z^-6 + 4*z^-5 + 12*z^-4 + 33*z^-3 + 82*z^-2 + 196*z^-1 + 457 + O(z)
             sage: g^2 + 1 + g
             z^-6 + 4*z^-5 + 12*z^-4 + 33*z^-3 + 82*z^-2 + 196*z^-1 + 457 + O(z)
+            sage: f(int(2))
+            7
 
             sage: f = z^-2 + z + 4*z^3
             sage: f(f)
@@ -2027,7 +2029,7 @@ def __call__(self, g):
         # f = self and compute f(g)
         from sage.structure.element import get_coercion_model
         cm = get_coercion_model()
-        P = cm.common_parent(self.base_ring(), g.parent())
+        P = cm.common_parent(self.base_ring(), parent(g))
 
         # f = 0
         if isinstance(self._coeff_stream, Stream_zero):

src/sage/rings/lazy_series_ring.py

@@ -280,7 +280,7 @@ def _element_constructor_(self, x=None, valuation=None, degree=None, constant=No
                 raise ValueError("the valuation must be specified")
             return self.element_class(self, Stream_uninitialized(self._sparse, valuation))
 
-        if coefficients is not None and (not isinstance(x, int) or x):
+        if coefficients is not None and (x is not None and (not isinstance(x, int) or x)):
             raise ValueError("coefficients must be None if x is provided")
 
         BR = self.base_ring()
@@ -1112,8 +1112,8 @@ def _element_constructor_(self, x=None, valuation=None, degree=None, constant=No
 
             sage: L.<z> = LazyLaurentSeriesRing(QQ)
             sage: D = LazyDirichletSeriesRing(QQ, 't')
-            sage: D(z+z^2)
-            1 + 1/(2^t)
+            sage: D(L.one())
+            1 + 1/(2^t) + 1/(3^t) + 1/(4^t) + 1/(5^t) + 1/(6^t) + 1/(7^t) + O(1/(8^t))
 
             sage: R.<z> = LaurentPolynomialRing(QQ)
             sage: D = LazyDirichletSeriesRing(QQ, 't')
@@ -1132,18 +1132,24 @@ def _element_constructor_(self, x=None, valuation=None, degree=None, constant=No
                     x = p
                 else:
                     x = p.shift(1)
-        elif not isinstance(x, LazyModuleElement) and valuation is None:
-            valuation = 1
+        else:
+            if valuation is None:
+                valuation = 1
 
-        if valuation is not None and (valuation not in ZZ or valuation <= 0):
-            raise ValueError("the valuation must be a positive integer")
+            if coefficients is not None:
+                return super()._element_constructor_(x, valuation, degree, constant, coefficients)
 
-        if coefficients is not None:
-            return super()._element_constructor_(x, valuation, degree, constant, coefficients)
+            BR = self.base_ring()
+            if x in BR:
+                x = BR(x)
+            if (isinstance(x, LazyModuleElement) and not isinstance(x, LazyDirichletSeries)) or callable(x):
+                if coefficients is not None:
+                    raise ValueError("coefficients must be None if x is provided")
+                coefficients = x
+                x = None
 
-        BR = self.base_ring()
-        if x in BR:
-            x = BR(x)
+        if valuation is not None and (valuation not in ZZ or valuation <= 0):
+            raise ValueError("the valuation must be a positive integer")
 
         return super()._element_constructor_(x, valuation, degree, constant, coefficients)