`invalid syntax (gotoifnot (true) 0)` from return type conversion of an opaque closure

[tkf]

julia> demo(thunk)::Any = Base.Experimental.@opaque () -> true ? 1 : 2
ERROR: syntax: invalid syntax (gotoifnot (true) 0)
Stacktrace:
 [1] top-level scope
   @ REPL[1]:1

julia> VERSION
v"1.9.0-DEV.241"

Meta.@lower throws, so I guess it happens in the frontend?

julia> Meta.@lower demo(thunk)::Any = Base.Experimental.@opaque () -> true ? 1 : 2
:($(Expr(:error, "invalid syntax (gotoifnot (true) 0)")))

But fe throws something else?

> (fe "demo(thunk)::Any = Base.Experimental.@opaque () -> true ? 1 : 2")
error: invalid syntax (call (top getproperty) (call (top getproperty) (outerref Base) (inert Experiment
al)) (inert @opaque)) # none, line 1 begin
    nothing
    begin
        nothing
        #1 = (new #1#2)
        (unnecessary #1)
    end
end
#0 (error ("invalid syntax (call (top getproperty) (call (top getproperty) (outerref Base) (inert Exper
imental)) (inert @opaque)) # none, line 1 begin\n    nothing\n    begin\n        nothing\n        #1 =
(new #1#2)\n        (unnecessary #1)\n    end\nend"))
#1 (compile-body/compile
...

[simeonschaub]

But fe throws something else?

I don't think fe actually does macro expansion, so you'll need to expand the macro from Julia.

[tkf]

Ah, good to know.

> (expand-toplevel-expr '(= (:: (call demo) Any) (block (line 1 strnig) (opaque_closure (-> (tuple) (block (line 1 strnig) (if (true) 1 2)))))) 'none 0)
error: invalid syntax (gotoifnot (true) 0)
#0 (error ("invalid syntax (gotoifnot (true) 0)"))
#1 (compile-body/compile/lambda
 ((gotoifnot (true) 0)
  (return 1) (label 0) (return 2)))
...