diff --git a/lib/src/authentication/client.dart b/lib/src/authentication/client.dart
index ffa7889cd..412e3f436 100644
--- a/lib/src/authentication/client.dart
+++ b/lib/src/authentication/client.dart
@@ -40,13 +40,13 @@ class _AuthenticatedClient extends http.BaseClient {
     // request.
     //
     // This check ensures that this client will only authenticate requests sent
-    // to given serverBaseUrl. Otherwise credential leaks might ocurr when
+    // to given serverBaseUrl. Otherwise credential leaks might occur when
     // archive_url hosted on 3rd party server that should not receive
     // credentials of the first party.
     if (_credential != null &&
-        _credential!.canAuthenticate(request.url.toString())) {
+        _credential.canAuthenticate(request.url.toString())) {
       request.headers[HttpHeaders.authorizationHeader] =
-          await _credential!.getAuthorizationHeaderValue();
+          await _credential.getAuthorizationHeaderValue();
     }
 
     final response = await _inner.send(request);
diff --git a/lib/src/command/outdated.dart b/lib/src/command/outdated.dart
index 124a99a83..d60e49aa5 100644
--- a/lib/src/command/outdated.dart
+++ b/lib/src/command/outdated.dart
@@ -952,8 +952,8 @@ class _MarkedVersionDetails implements _Details {
 
     var jsonExplanation = _jsonExplanation;
     return jsonExplanation == null
-        ? _versionDetails!.toJson()
-        : (_versionDetails!.toJson()..addEntries([jsonExplanation]));
+        ? _versionDetails.toJson()
+        : (_versionDetails.toJson()..addEntries([jsonExplanation]));
   }
 }
 
diff --git a/lib/src/solver/package_lister.dart b/lib/src/solver/package_lister.dart
index 35c97f370..d67352685 100644
--- a/lib/src/solver/package_lister.dart
+++ b/lib/src/solver/package_lister.dart
@@ -131,7 +131,7 @@ class PackageLister {
 
   /// Returns the number of versions of this package that match [constraint].
   Future<int> countVersions(VersionConstraint constraint) async {
-    if (_locked != null && constraint.allows(_locked!.version)) return 1;
+    if (_locked != null && constraint.allows(_locked.version)) return 1;
     try {
       return (await _versions)
           .where((id) => constraint.allows(id.version))
@@ -226,7 +226,7 @@ class PackageLister {
 
     if (_cachedVersions == null &&
         _locked != null &&
-        id.version == _locked!.version) {
+        id.version == _locked.version) {
       if (_listedLockedVersion) return const [];
 
       var depender = id.toRange();
diff --git a/pubspec.yaml b/pubspec.yaml
index c58a4aaa4..863422924 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,7 +1,7 @@
 name: pub
 
 environment:
-  sdk: ^3.0.0
+  sdk: ^3.2.0
 
 dependencies:
   analyzer: ^6.2.0