diff --git a/qutebrowser/keyinput/basekeyparser.py b/qutebrowser/keyinput/basekeyparser.py
index 56b9cfaac..2b41dac65 100644
--- a/qutebrowser/keyinput/basekeyparser.py
+++ b/qutebrowser/keyinput/basekeyparser.py
@@ -186,9 +186,6 @@ class BaseKeyParser(QObject):
 
         match, binding = self._match_key(cmd_input)
 
-        if not isinstance(match, self.Match):
-            raise TypeError("Value {} is no Match member!".format(match))
-
         if match == self.Match.definitive:
             self._debug_log("Definitive match for '{}'.".format(
                 self._keystring))
@@ -205,6 +202,8 @@ class BaseKeyParser(QObject):
             self._debug_log("Giving up with '{}', no matches".format(
                 self._keystring))
             self._keystring = ''
+        else:
+            raise AssertionError("Invalid match value {!r}".format(match))
         return match
 
     def _match_key(self, cmd_input):
diff --git a/tests/unit/keyinput/test_basekeyparser.py b/tests/unit/keyinput/test_basekeyparser.py
index d5eadbb5e..9abba0e9c 100644
--- a/tests/unit/keyinput/test_basekeyparser.py
+++ b/tests/unit/keyinput/test_basekeyparser.py
@@ -27,9 +27,11 @@ from PyQt5.QtCore import Qt
 import pytest
 
 from qutebrowser.keyinput import basekeyparser
+from qutebrowser.utils import utils
 
 
 CONFIG = {'input': {'timeout': 100}}
+CONFIG_NO_TIMEOUT = {'input': {'timeout': 0}}
 
 
 @pytest.fixture
@@ -131,6 +133,15 @@ class TestSpecialKeys:
         self.kp.handle(fake_keyevent_factory(Qt.Key_A))
         assert not self.kp.execute.called
 
+    def test_no_binding(self, monkeypatch, fake_keyevent_factory):
+        """Test special key with no binding."""
+        def none_return(binding):
+            return None
+
+        monkeypatch.setattr(utils, 'keyevent_to_string', none_return)
+        self.kp.handle(fake_keyevent_factory(Qt.Key_A, Qt.NoModifier))
+        assert not self.kp.execute.called
+
 
 @pytest.mark.usefixtures('mock_timer')
 class TestKeyChain:
@@ -205,6 +216,17 @@ class TestKeyChain:
         assert not timer.isActive()
         assert self.kp._keystring == ''
 
+    def test_ambiguous_keychain_no_timeout(self, fake_keyevent_factory,
+                                           config_stub, monkeypatch):
+        """Test ambiguous keychain with timeout equal to 0."""
+        config_stub.data = CONFIG_NO_TIMEOUT
+        monkeypatch.setattr('qutebrowser.keyinput.basekeyparser.config',
+                            config_stub)
+        self.kp.handle(fake_keyevent_factory(Qt.Key_A, text='a'))
+        assert self.kp.execute.called
+        timer = self.kp._ambiguous_timer
+        assert not timer.isActive()
+
     def test_invalid_keychain(self, fake_keyevent_factory):
         """Test invalid keychain."""
         self.kp.handle(fake_keyevent_factory(Qt.Key_B, text='b'))