Disallow uninitialized non-nullable variables

pkg/analyzer/lib/src/task/strong/checker.dart

Index: pkg/analyzer/lib/src/task/strong/checker.dart
diff --git a/pkg/analyzer/lib/src/task/strong/checker.dart b/pkg/analyzer/lib/src/task/strong/checker.dart
index 8f2f12cf4926712a2392ae339ff6f5ce2cbaa234..b20d702e71f4f1c4fa53b9c4974e48b22260857e 100644
--- a/pkg/analyzer/lib/src/task/strong/checker.dart
+++ b/pkg/analyzer/lib/src/task/strong/checker.dart
@@ -629,6 +629,20 @@ class CodeChecker extends RecursiveAstVisitor {
   }
 
   @override
+  Object visitVariableDeclaration(VariableDeclaration node) {
+    if (!node.isConst &&
+        !node.isFinal &&
+        node.initializer == null &&
+        rules.isNonNullableType(node?.element?.type)) {
+      _recordMessage(
+          node,
+          StaticTypeWarningCode.NON_NULLABLE_FIELD_NOT_INITIALIZED,
+          [node.name, node?.element?.type]);
+    }
+    return super.visitVariableDeclaration(node);
+  }
+
+  @override
   void visitWhileStatement(WhileStatement node) {
     checkBoolean(node.condition);
     node.visitChildren(this);