diff --git a/pubspec.yaml b/pubspec.yaml
index 4a67b5e..683250c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -55,6 +55,10 @@
     git:
       url: git://github.com/dart-lang/stack_trace.git
       ref: null_safety
+  string_scanner:
+    git:
+      url: git://github.com/dart-lang/string_scanner.git
+      ref: null_safety
   term_glyph:
     git:
       url: git://github.com/dart-lang/term_glyph.git