diff --git a/build/CHANGELOG.md b/build/CHANGELOG.md
index 8d94de2a5..0d1389077 100644
--- a/build/CHANGELOG.md
+++ b/build/CHANGELOG.md
@@ -1,7 +1,8 @@
 ## 2.4.2-wip
 
 - Bump the min sdk to 3.4.0.
-- Remove some unnecessary casts now that we have private field promotion.
+- Remove some unnecessary casts and non-null assertions now that we have private
+  field promotion.
 
 ## 2.4.1
 
diff --git a/build_runner_core/CHANGELOG.md b/build_runner_core/CHANGELOG.md
index fc7768a66..adaf28682 100644
--- a/build_runner_core/CHANGELOG.md
+++ b/build_runner_core/CHANGELOG.md
@@ -1,6 +1,8 @@
 ## 7.3.1-wip
 
 - Bump the min sdk to 3.4.0.
+- Remove some unnecessary casts and non-null assertions now that we have private
+  field promotion.
 
 ## 7.3.0
 
diff --git a/build_runner_core/lib/src/asset/reader.dart b/build_runner_core/lib/src/asset/reader.dart
index bbf29dbde..33cc66763 100644
--- a/build_runner_core/lib/src/asset/reader.dart
+++ b/build_runner_core/lib/src/asset/reader.dart
@@ -173,7 +173,7 @@ class SingleStepReader implements AssetReader {
     }
     var streamCompleter = StreamCompleter<AssetId>();
 
-    doAfter(_getGlobNode!(glob, _primaryPackage, _phaseNumber),
+    doAfter(_getGlobNode(glob, _primaryPackage, _phaseNumber),
         (GlobAssetNode globNode) {
       assetsRead.add(globNode.id);
       streamCompleter.setSourceStream(Stream.fromIterable(globNode.results!));
diff --git a/build_runner_core/lib/src/generate/build_impl.dart b/build_runner_core/lib/src/generate/build_impl.dart
index ec088770d..f5a27cf96 100644
--- a/build_runner_core/lib/src/generate/build_impl.dart
+++ b/build_runner_core/lib/src/generate/build_impl.dart
@@ -266,7 +266,7 @@ class _SingleBuild {
       var invalidated = await _assetGraph.updateAndInvalidate(
           _buildPhases, updates, _packageGraph.root.name, _delete, _reader);
       if (_reader is CachingAssetReader) {
-        (_reader as CachingAssetReader).invalidate(invalidated);
+        _reader.invalidate(invalidated);
       }
     });
   }
@@ -306,7 +306,7 @@ class _SingleBuild {
         assert(result.performance != null);
         var now = DateTime.now();
         var logPath = p.join(
-            _logPerformanceDir!,
+            _logPerformanceDir,
             '${now.year}-${_twoDigits(now.month)}-${_twoDigits(now.day)}'
             '_${_twoDigits(now.hour)}-${_twoDigits(now.minute)}-'
             '${_twoDigits(now.second)}');