Error message for variable with same name as function could be more explicit

[antoine-levitt]

julia> f(x) = 2
f (generic function with 1 method)

julia> let
       f = f(2)
       end
ERROR: UndefVarError: f not defined
Stacktrace:
 [1] top-level scope at REPL[7]:2

[StefanKarpinski]

The outer function definition is a red herring here though—it's irrelevant. The issue is that inside of the let block it's an undefined local variable and you're accessing it before it's defined.

[antoine-levitt]

Sure, the problem is that the variable shadows the function name. If I write g = f(2) I'm fine, and if I write f = g(2) it's OK too, it's just this particular conflicting case that's a bit tricky to find out. This is pretty frequent in numerical code, when you use quantity(x) as a function that computes quantity, and so you want to do quantity = quantity(x); quantity + quantity^2 or something.

[antoine-levitt]

To clarify: I know this is invalid code and I understand why julia is giving this message, I just wish it could be more helpful

[vtjnash]

Duplicate of #17062