Cannot resolve local def

[armic]

Hello,

If I try to write the following:

(defn foo [] (def x 3) x)

I get a warning from cursive saying x cannot be resolved, even though this code runs fine.

[royalaid]

Just want to say that this seems to apply to any def that is not at the "top level" of a namespace.

[cursive-ghost]

Right. Basically, Clojure discourages defining vars in nested scopes, because people (often coming from Scheme) tend to try to use them as local variables. There are some cases where this is acceptable and Cursive tries to support them:

; Closing over a binding
(let [my-val (something)]
  (defn work-with-my-val []
    ...))

; Some macro forms, e.g. clairvoyant
(trace/trace-forms {:tracer trace/default-tracer}
 (defn add [a b]
   (+ a b)))

If you have either of these cases or something similar you'd like to see supported, feel free to let me know here.

[royalaid]

Mostly it has to do with one of the debugging techniques that I use from time to time to capture a value back to the repl for exploring, something along the lines of https://blog.michielborkent.nl/blog/2017/05/25/inline-def-debugging/.

[matj1]

Clojure discourages defining vars in nested scopes, because people (often coming from Scheme) tend to try to use them as local variables.

Then, it is wrong to say that the variable cannot be resolved. There should be an intention to convert it to let or a warning against using def locally, but not that it can't be resolved when it can.

[Heliosmaster]

We use this pattern a lot, at least in our tests, because it makes for good repl debuggability. Please consider supporting its resolution and maybe turn it into its own warning that i can disable?

(deftest foo
  (def bar 1))

Thread on slack: https://clojurians.slack.com/archives/C0744GXCJ/p1738667786396909