diff --git a/packages/melos/lib/src/commands/exec.dart b/packages/melos/lib/src/commands/exec.dart
index 3a19e84a..74af9761 100644
--- a/packages/melos/lib/src/commands/exec.dart
+++ b/packages/melos/lib/src/commands/exec.dart
@@ -129,7 +129,7 @@ mixin _ExecMixin on _Melos {
           final dependenciesResults = await Future.wait(
             package.allDependenciesInWorkspace.values
                 .map((package) => packageResults[package.name]?.future)
-                .whereNotNull(),
+                .nonNulls,
           );
 
           final dependencyFailed = dependenciesResults.any(
diff --git a/packages/melos/lib/src/workspace_configs.dart b/packages/melos/lib/src/workspace_configs.dart
index 11738067..9bf71a8a 100644
--- a/packages/melos/lib/src/workspace_configs.dart
+++ b/packages/melos/lib/src/workspace_configs.dart
@@ -297,7 +297,7 @@ class MelosWorkspaceConfig {
       ),
       assertValue: (key, value) => assertListIsA<String>(
         key: key!,
-        map: yaml['categories'] as Map<Object?, Object?>,
+        map: (yaml['categories'] ?? {}) as Map<Object?, Object?>,
         isRequired: false,
         assertItemIsA: (index, value) => assertIsA<String>(
           value: value,