How to invoke a repl that loads your local swift package?

I was following along with this older blog post on loading a swift REPL for a package, and found that path no longer appears to work.

When I invoke it, it does the build and attempts to load a REPL, but then fails out:

Running the command swift run --repl results in a "you got the command wrong" kind of response:

Launching Swift REPL with arguments: -I/Users/heckj/src/Scale/.build/arm64-apple-macosx/debug -L/Users/heckj/src/Scale/.build/arm64-apple-macosx/debug -lscale__REPL -I/Users/heckj/src/Scale/.build/checkouts/swift-numerics/Sources/_NumericsShims/include

Welcome to Swift!


  swift build      Build Swift packages
  swift package    Create and work on packages
  swift run        Run a program from a package
  swift test       Run package tests
  swift repl       Experiment with Swift code interactively

  Use `swift --help` for descriptions of available options and flags.

  Use `swift help <subcommand>` for more information about a subcommand.

When I invoke swift repl directly, that works - but my local package isn't loaded. Is there still a fast-path to set up a REPL that can use a local swift package?

(When I combine the details from swift run --repl into the CLI arguments for swift repl - that DOES seem to work)