```coffeescript
applyDependencies = (services, resolver) ->
  wrappedServices = {}
  for serviceName, serviceDef of services
    dependencies = {}
    
    # we will create keys for any declared dependency types
    # and have them map to resolved dependencies
    for dependencyType of serviceDef.dependencies
      # initialize sub-object for this dependencyType
      dependencies[dependencyType] = {}
      
      # populate it with resolved service references
      for dependencyName in serviceDef.dependencies[dependencyType]
        dependencies[dependencyType][dependencyName] = resolver[dependencyType] dependencyName
    
    makeWrapper = (serviceName, serviceDef, dependencies) ->
      wrapper = (args, done) ->
        serviceDef args, done, dependencies
      for key in Object.keys serviceDef
        wrapper[key] = serviceDef[key]
      wrapper.dependencies = dependencies
      f = wrapper.callStack[wrapper.callStack.length-1]
      wrapper.callStack[wrapper.callStack.length-1] = (args, done) ->
        f args, done, wrapper.dependencies
      return wrapper

    wrapper = makeWrapper serviceName, serviceDef, dependencies
    wrappedServices[serviceName] = wrapper
  return wrappedServices

module.exports = applyDependencies```

Remove unnecessary manual copying, add comments
user
```coffeescript
applyDependencies = (services, resolver) ->
  wrappedServices = {}
  for serviceName, serviceDef of services
    dependencies = {}
    
    # we will create keys for any declared dependency types
    # and have them map to resolved dependencies
    for dependencyType of serviceDef.dependencies
      # initialize sub-object for this dependencyType
      dependencies[dependencyType] = {}
      
      # populate it with resolved service references
      for dependencyName in serviceDef.dependencies[dependencyType]
        dependencies[dependencyType][dependencyName] = resolver[dependencyType] dependencyName
    
    makeWrapper = (serviceName, serviceDef, dependencies) ->
      # start with a copy of the service up until now
      wrapper = serviceDef

      # add a handle to our newly-resolved dependencies
      wrapper.dependencies = dependencies

      # grab a reference to the raw service as-defined
      f = wrapper.callStack[wrapper.callStack.length-1]
      
      # pseudo-right curry to inject the `dependencies` reference and
      # ensure the signature is chain-friendly throughout `callStack`
      wrapper.callStack[wrapper.callStack.length-1] = (args, done) ->
        f args, done, wrapper.dependencies
        
      return wrapper

    wrapper = makeWrapper serviceName, serviceDef, dependencies
    wrappedServices[serviceName] = wrapper
    
  return wrappedServices

module.exports = applyDependencies```
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