Make pub strong-mode clean.

lib/src/solver/solve_report.dart

Index: lib/src/solver/solve_report.dart
diff --git a/lib/src/solver/solve_report.dart b/lib/src/solver/solve_report.dart
index 367d963a255a84a69ba7a965a08997ceeb2e61d0..20f40a9034bdc5fe60e655d78fa23f29a2046d3d 100644
--- a/lib/src/solver/solve_report.dart
+++ b/lib/src/solver/solve_report.dart
@@ -104,9 +104,9 @@ class SolveReport {
     removed.removeAll(names);
     if (removed.isNotEmpty) {
       _output.writeln("These packages are no longer being depended on:");
-      removed = removed.toList();
-      removed.sort();
-      removed.forEach((name) => _reportPackage(name, alwaysShow: true));
+      for (var name in ordered(removed)) {
+        _reportPackage(name, alwaysShow: true);
+      }
     }
 
     log.message(_output);