class Sprockets::Context

def annotate_exception!(exception)

the exception was raised in.
Annotates exception backtrace with the original template that

def annotate_exception!(exception)
  location = pathname.to_s
  location << ":#{@__LINE__}" if @__LINE__
  exception.extend(Sprockets::EngineError)
  exception.sprockets_annotation = "  (in #{location})"
end