diff --git a/tests/unit/test_model.py b/tests/unit/test_model.py
index 2fc7090b79..1ab698b5f3 100644
--- a/tests/unit/test_model.py
+++ b/tests/unit/test_model.py
@@ -31,6 +31,7 @@ import zuul.lib.connections
 from tests.base import BaseTestCase, FIXTURE_DIR
 from zuul.lib.ansible import AnsibleManager
 from zuul.zk.zkobject import LocalZKContext
+from zuul import change_matcher
 
 
 class Dummy(object):
@@ -746,3 +747,22 @@ class TestRef(BaseTestCase):
 
         self.assertFalse(branch1.equals(change1))
         self.assertFalse(branch1.equals(tag1))
+
+
+class TestSourceContext(BaseTestCase):
+    def setUp(self):
+        super().setUp()
+        self.connection = Dummy(connection_name='dummy_connection')
+        self.source = Dummy(canonical_hostname='git.example.com',
+                            connection=self.connection)
+        self.project = model.Project('project', self.source)
+        self.context = model.SourceContext(
+            self.project.canonical_name, self.project.name,
+            self.project.connection_name, 'master', 'test', True)
+        self.context.implied_branches = [
+            change_matcher.BranchMatcher('foo'),
+            change_matcher.ImpliedBranchMatcher('foo'),
+        ]
+
+    def test_serialize(self):
+        self.context.deserialize(self.context.serialize())
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index 5e21cd57f4..b8db861887 100644
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -890,6 +890,39 @@ class TestBranchMismatch(ZuulTestCase):
             dict(name='project-test1', result='SUCCESS', changes='1,1'),
         ], ordered=False)
 
+    def test_implied_branch_matcher_pragma_syntax_error(self):
+        # Test that syntax errors are reported if the implied branch
+        # matcher pragma is set.  This catches potential errors when
+        # serializing configuration errors since the pragma causes
+        # extra information to be added to the error source context.
+        self.create_branch('org/project1', 'feature/test')
+        self.fake_gerrit.addEvent(
+            self.fake_gerrit.getFakeBranchCreatedEvent(
+                'org/project1', 'feature/test'))
+
+        in_repo_conf = textwrap.dedent(
+            """
+            - job:
+                name: project-test1
+                nodeset: bar
+            - pragma:
+                implied-branches:
+                  - master
+                  - feature/r1
+            """)
+        file_dict = {'zuul.yaml': in_repo_conf}
+        A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A',
+                                           files=file_dict)
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertHistory([])
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1,
+                         "A should report failure")
+        self.assertIn('nodeset "bar" was not found', A.messages[0],
+                      "A should have a syntax error reported")
+
 
 class TestBranchRef(ZuulTestCase):
     tenant_config_file = 'config/branch-ref/main.yaml'
@@ -1717,6 +1750,25 @@ class TestInRepoConfig(ZuulTestCase):
         self.assertIn('while constructing a mapping', A.messages[0],
                       "A should have a syntax error reported")
 
+    def test_yaml_dict_error3(self):
+        in_repo_conf = textwrap.dedent(
+            """
+            - job:
+            """)
+
+        file_dict = {'.zuul.yaml': in_repo_conf}
+        A = self.fake_gerrit.addFakeChange('org/project', 'master', 'A',
+                                           files=file_dict)
+        A.addApproval('Code-Review', 2)
+        self.fake_gerrit.addEvent(A.addApproval('Approved', 1))
+        self.waitUntilSettled()
+
+        self.assertEqual(A.data['status'], 'NEW')
+        self.assertEqual(A.reported, 1,
+                         "A should report failure")
+        self.assertIn('is not a dictionary', A.messages[0],
+                      "A should have a syntax error reported")
+
     def test_yaml_duplicate_key_error(self):
         in_repo_conf = textwrap.dedent(
             """
diff --git a/zuul/change_matcher.py b/zuul/change_matcher.py
index 139c7b6a9c..0a347bc72b 100644
--- a/zuul/change_matcher.py
+++ b/zuul/change_matcher.py
@@ -82,6 +82,17 @@ class BranchMatcher(AbstractChangeMatcher):
                         return True
         return False
 
+    def serialize(self):
+        return {
+            "implied": self.exactmatch,
+            "regex": self._regex,
+        }
+
+    @classmethod
+    def deserialize(cls, data):
+        o = cls.__new__(cls, data['regex'])
+        return o
+
 
 class ImpliedBranchMatcher(BranchMatcher):
     exactmatch = True
diff --git a/zuul/model.py b/zuul/model.py
index 9500647076..cb75f58706 100644
--- a/zuul/model.py
+++ b/zuul/model.py
@@ -1695,6 +1695,9 @@ class SourceContext(ConfigObject):
                 self.trusted == other.trusted)
 
     def serialize(self):
+        ibs = None
+        if self.implied_branches:
+            ibs = [ibm.serialize() for ibm in self.implied_branches]
         return {
             "project_canonical_name": self.project_canonical_name,
             "project_name": self.project_name,
@@ -1703,12 +1706,22 @@ class SourceContext(ConfigObject):
             "path": self.path,
             "trusted": self.trusted,
             "implied_branch_matchers": self.implied_branch_matchers,
-            "implied_branches": self.implied_branches,
+            "implied_branches": ibs,
         }
 
     @classmethod
     def deserialize(cls, data):
         o = cls.__new__(cls)
+        ibs = data.get('implied_branches')
+        if ibs:
+            data['implied_branches'] = []
+            for matcher_data in ibs:
+                if matcher_data['implied']:
+                    cls = change_matcher.ImpliedBranchMatcher
+                else:
+                    cls = change_matcher.BranchMatcher
+                data['implied_branches'].append(
+                    cls.deserialize(matcher_data))
         o.__dict__.update(data)
         return o
 
@@ -6738,6 +6751,8 @@ class UnparsedConfig(object):
             if len(item.keys()) > 1:
                 raise ConfigItemMultipleKeysError(item)
             key, value = list(item.items())[0]
+            if not isinstance(value, dict):
+                raise ConfigItemNotDictError(item)
             if key == 'project':
                 self.projects.append(value)
             elif key == 'job':