Add order to BindParams in the ToSql collector

This removes the need for us to do the re-ordering by walking the AST in
ActiveRecord. We're using a block to communicate with the collector,
since the collector needs to be the thing which knows about the index,
while the visitor is the thing that needs to know the syntax. The
BindParam needs to know about neither of these things, so it's been
changed to stop being a subclass of SqlLiteral

I could also see an alternative implementation using format strings if
for some reason blocks cause a problem.

2 files changed, 6 insertions, 3 deletions

diff --git a/lib/arel/nodes/bind_param.rb b/lib/arel/nodes/bind_param.rb
new file mode 100644
index 0000000000..160bc21b91
--- /dev/null
+++ b/lib/arel/nodes/bind_param.rb
@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class BindParam < Node
+    end
+  end
+end
diff --git a/lib/arel/nodes/sql_literal.rb b/lib/arel/nodes/sql_literal.rb
index b43288b29c..2c56644b99 100644
--- a/lib/arel/nodes/sql_literal.rb
+++ b/lib/arel/nodes/sql_literal.rb
@@ -10,8 +10,5 @@ module Arel
         coder.scalar = self.to_s
       end
     end
-
-    class BindParam < SqlLiteral
-    end
   end
 end