I think that the matcher method on its own doesn't give much context.  Instead, I think it's better if the deprecation included a matcher expression, e.g.:

``` ruby
expression = if @negative_expectation
  RSpec::Expectations::Syntax.negative_expression(cardinality_expression(query_method), old_matcher_expression)
else
  RSpec::Expectations::Syntax.positive_expression(cardinality_expression(query_method), old_matcher_expression)
end

RSpec.deprecate("`#{expression}`", :replacement => deprecation_message)
```

The `negative_expression` and `positive_expression` methods take care of constructing a `.should` or `expect` expression based on configured settings.