Check git status before citing line numbers in a code walkthrough

During a multi-turn, line-by-line code explanation, the user's IDE selection showed an interface at lines 39-44 while my earlier explanation cited 95-100 for the same file. git status showed the file had uncommitted edits (reordered with section comments) made between turns. Before citing line numbers or answering about a selected snippet, re-read the current file and run git status on it; otherwise earlier explanations silently point at the wrong lines. Also: an interface method existing 'for testability' may not actually be varied by the fakes — grep the fake before claiming that justification.