The `c` command should handle generic dependencies gracefully

[eriksvedang]

Somewhat related to #1347 (comment), the c command (defined in Eval.hs, function commandC on line 975) spits out a lot of errors if a definition generates generic functions as dependencies.

Example:

鲤 (defn f [] (fn [x] x))
鲤 (c f)

I found an unresolved generic type `(Fn [t2] t2 t4)` for the expression `(defn <> _Lambda_f_7_env__?_? [x] x)` at line 2, column 12 in 'REPL', can't print resulting code.
I found an unresolved generic type `(Fn [t2] t2 t4)` for the expression `(defn <> _Lambda_f_7_env__?_? [x] x)` at line 2, column 12 in 'REPL', can't print resulting code.
I found an unresolved generic type `(Fn [(Fn [t2] t2 t4)] ())` for the expression `(instantiate Function.delete__?_?)` at unknown line, unknown column in 'Function.delete__?_? template', can't print resulting code.
I found an unresolved generic type `(Fn [] (Fn [a] a b))` for the expression `(defn f [] (fn <> [x] x))` at line 2, column 2 in 'REPL', can't print resulting code.

A better behaviour would be to simply not try print generic dependencies.

[hellerve]

I can add this to #1373 or open a new PR with this functionality.

[hellerve]

I played around with this a bit. The offending function is this one:

Carp/src/Eval.hs

Lines 1005 to 1011 in 330dc52

	printC :: XObj -> String
	printC xobj =
	case checkForUnresolvedSymbols xobj of
	Left e ->
	strWithColor Red (show e ++ ", can't print resulting code.\n")
	Right _ ->
	strWithColor Green (toC All (Binder emptyMeta xobj))

It’s clearly part of it’s intended behavior to show these errors. We can instead ignore those errors and just not print anything, of course, but that might mean that we swallow too much; what do you think?

[eriksvedang]

I think this function should only be called for the function passed to c, for the dependencies we can check if it's generic and only print if not. Makes sense?

[hellerve]

Somewhat, but it’s important to note that C works with arbitrary forms:

> (defdynamic x '(Int.+ 1 1))
> (c x)
int _3 = Int__PLUS_(1, 1);

[eriksvedang]

Sure, whatever is passed to c should still have the warning, but generic deps should be filtered out.