I have read the following sentence in a French language learning tool:
Elle vend un ancien chapeau.
According to https://about-france.com/french/adjectives.htm, the adjective "ancien" means "former" when it precedes a noun and "ancient" / "old" when it comes after it. Larousse examples in the definition of the adjective "ancien" seem to confirm it. As "a former hat" makes no sense, is the sentence above incorrect?