diff --git a/plugins/commands/serve/client/project.rb b/plugins/commands/serve/client/project.rb
index 5a224580c..329776f01 100644
--- a/plugins/commands/serve/client/project.rb
+++ b/plugins/commands/serve/client/project.rb
@@ -54,7 +54,7 @@ module VagrantPlugins
           resp.path
         end
 
-        def default_provider(opts)
+        def default_provider(opts={})
           req = ::Hashicorp::Vagrant::Sdk::Project::DefaultProviderRequest.new(
             exclude: opts.fetch(:exclude, []),
             force_default: opts.fetch(:force_default, true),
diff --git a/plugins/commands/serve/mappers/proc.rb b/plugins/commands/serve/mappers/proc.rb
index a712dc377..631ab2548 100644
--- a/plugins/commands/serve/mappers/proc.rb
+++ b/plugins/commands/serve/mappers/proc.rb
@@ -19,7 +19,7 @@ module VagrantPlugins
             end
 
             # If this is already stored, return existing ID
-            idx = @stored.index(value)
+            idx = @stored.key(value)
             return idx if idx
 
             # Create a new ID and store