diff --git a/lib/std/Build/Serialize.zig b/lib/std/Build/Serialize.zig
index fed47eb2fc100ff54d00ef97c6cc731225f72de7..4261c233c11383a254afada9dcebe150f6d75b0e 100644
--- a/lib/std/Build/Serialize.zig
+++ b/lib/std/Build/Serialize.zig
@@ -39,13 +39,17 @@ pub fn write(b: *std.Build, wc: *Configuration.Wip, writer: *std.Io.Writer) !voi
     // instance. Otherwise, addModule may access a package instance that hasn't
     // been created yet with packageInstanceFromBuilder.
 
-    s.package_instance_map.putAssumeCapacityNoClobber(b, {});
-    var iter = b.graph.dependency_cache.valueIterator();
-    while (iter.next()) |dep| s.package_instance_map.putAssumeCapacityNoClobber(dep.*.builder, {});
+    {
+        s.package_instance_map.putAssumeCapacityNoClobber(b, {});
+        var it = b.graph.dependency_cache.valueIterator();
+        while (it.next()) |dep| s.package_instance_map.putAssumeCapacityNoClobber(dep.*.builder, {});
+    }
 
-    try s.addPackageInstance(b);
-    var iter2 = b.graph.dependency_cache.valueIterator();
-    while (iter2.next()) |dep| try s.addPackageInstance(dep.*.builder);
+    {
+        try s.addPackageInstance(b);
+        var it = b.graph.dependency_cache.valueIterator();
+        while (it.next()) |dep| try s.addPackageInstance(dep.*.builder);
+    }
 
     try wc.path_deps.ensureTotalCapacityPrecise(gpa, graph.configure_dependencies.items.len);
     for (