diff --git a/jedi/api/classes.py b/jedi/api/classes.py
index 77fb7ee9..c8740373 100644
--- a/jedi/api/classes.py
+++ b/jedi/api/classes.py
@@ -13,6 +13,7 @@ from jedi.cache import memoize_method
 from jedi.evaluate import imports
 from jedi.evaluate import compiled
 from jedi.evaluate.imports import ImportName
+from jedi.evaluate.filters import ParamName
 from jedi.evaluate.context import FunctionExecutionContext
 from jedi.evaluate.gradual.typeshed import StubOnlyModuleContext
 from jedi.api.keywords import KeywordName
@@ -323,7 +324,9 @@ class BaseDefinition(object):
     def infer(self):
         tree_name = self._name.tree_name
         parent_context = self._name.parent_context
-        if tree_name is None or parent_context is None:
+        # Param names are special because they are not handled by
+        # the evaluator method.
+        if tree_name is None or parent_context is None or isinstance(self._name, ParamName):
             context_set = self._name.infer()
         else:
             context_set = self._evaluator.goto_definitions(parent_context, tree_name)
diff --git a/test/test_api/test_call_signatures.py b/test/test_api/test_call_signatures.py
index 47d17da7..28cb619d 100644
--- a/test/test_api/test_call_signatures.py
+++ b/test/test_api/test_call_signatures.py
@@ -7,7 +7,6 @@ import pytest
 from ..helpers import TestCase
 from jedi import cache
 from jedi.parser_utils import get_call_signature
-from jedi._compatibility import is_py3
 
 
 def assert_signature(Script, source, expected_name, expected_index=0, line=None, column=None):
@@ -308,18 +307,16 @@ def test_signature_is_definition(Script):
 
     # Now compare all the attributes that a CallSignature must also have.
     for attr_name in dir(definition):
-        dont_scan = ['defined_names', 'parent', 'goto_assignments', 'params']
+        dont_scan = ['defined_names', 'parent', 'goto_assignments', 'infer', 'params']
         if attr_name.startswith('_') or attr_name in dont_scan:
             continue
 
-        # Might trigger some deprecation warnings.
-        with warnings.catch_warnings(record=True):
-            attribute = getattr(definition, attr_name)
-            signature_attribute = getattr(signature, attr_name)
-            if inspect.ismethod(attribute):
-                assert attribute() == signature_attribute()
-            else:
-                assert attribute == signature_attribute
+        attribute = getattr(definition, attr_name)
+        signature_attribute = getattr(signature, attr_name)
+        if inspect.ismethod(attribute):
+            assert attribute() == signature_attribute()
+        else:
+            assert attribute == signature_attribute
 
 
 def test_no_signature(Script):
diff --git a/test/test_api/test_environment.py b/test/test_api/test_environment.py
index 40f48d36..2d774a8e 100644
--- a/test/test_api/test_environment.py
+++ b/test/test_api/test_environment.py
@@ -79,7 +79,7 @@ def test_killed_subprocess(evaluator, Script, environment):
     if isinstance(environment, InterpreterEnvironment):
         pytest.skip("We cannot kill our own process")
     # Just kill the subprocess.
-    evaluator.compiled_subprocess._compiled_subprocess._process.kill()
+    evaluator.compiled_subprocess._compiled_subprocess._get_process().kill()
     # Since the process was terminated (and nobody knows about it) the first
     # Jedi call fails.
     with pytest.raises(jedi.InternalError):