Fix a call signature issue.

jedi/api/classes.py

@@ -347,7 +347,10 @@ class BaseDefinition(object):
                 # Just take the first one here, not optimal, but currently
                 # there's no better solution.
                 inferred = names[0].infer()
-                return get_param_names(next(iter(inferred)))
+                param_names = get_param_names(next(iter(inferred)))
+                if isinstance(context, er.ClassContext):
+                    param_names = param_names[1:]
+                return param_names
             elif isinstance(context, compiled.CompiledObject):
                 return context.get_param_names()
             return param_names

test/test_api/test_call_signatures.py

@@ -386,3 +386,37 @@ def test_lambda_params():
     assert sig.index == 0
     assert sig.name == '<lambda>'
     assert [p.name for p in sig.params] == ['x']
+
+
+def test_class_creation():
+    code = dedent('''\
+    class X():
+        def __init__(self, foo, bar):
+            self.foo = foo
+    ''')
+    sig, = Script(code + 'X(').call_signatures()
+    assert sig.index == 0
+    assert sig.name == 'X'
+    assert [p.name for p in sig.params] == ['foo', 'bar']
+
+    sig, = Script(code + 'X.__init__(').call_signatures()
+    assert [p.name for p in sig.params] == ['self', 'foo', 'bar']
+    sig, = Script(code + 'X().__init__(').call_signatures()
+    assert [p.name for p in sig.params] == ['foo', 'bar']
+
+
+def test_call_magic_method():
+    code = dedent('''\
+    class X():
+        def __call__(self, baz):
+            pass
+    ''')
+    sig, = Script(code + 'X()(').call_signatures()
+    assert sig.index == 0
+    assert sig.name == 'X'
+    assert [p.name for p in sig.params] == ['baz']
+
+    sig, = Script(code + 'X.__call__(').call_signatures()
+    assert [p.name for p in sig.params] == ['self', 'baz']
+    sig, = Script(code + 'X().__call__(').call_signatures()
+    assert [p.name for p in sig.params] == ['baz']