Advanced search does not work as advertised for the Subject field

The Advanced Search page says:

You may search for whole sentences using "sentence goes here" or omit certain words by prepending a - to them, such as: apples -oranges to search for apples but exclude emails with oranges.

This is true for the quick query box, but not for the subject box, which only appears to support search by substring (case-blind)

Also, quoted search strings also work for phrases, not just sentences.

Start at the Advanced Search page and compare how the quick query box and subject box parse quoted terms and terms prefixed with '-'. Verify the subject field supports phrase and exclusion searches, and update the help text so it describes phrases rather than only sentences.

Written by the indexing model from the issue text.