Request for input on #7253: Top-level bindings in GHCI

I'm thinking of working on this ticket ( https://ghc.haskell.org/trac/ghc/ticket/7253), so, as per mpickering's suggestion (https://phabricator.haskell.org/chatlog/channel/3/?at=1353572), I'm emailing the list to solicit input. My first instinct was to treat declarations like "a = 1" in GHCI as equivalent to "let a = 1"; this would be a straightforward matter of parsing. On the other hand, as thoughtpolice comments, let-bound variables are treated subtly differently than top-level bindings, so the proper solution may be more involved. Comments?