room for improvement with undefined var error message

[IainNZ]

function foo(x)
    return x^2
end

function bar(y)
    fizz = foo(y)
    # Many lines of code
    foo = fizz + 1
    # ...
    return foo
end

println(bar(5))

produces

ERROR: foo not defined
 in bar at /home/idunning/.julia/v0.3/JuMP/test/foo.jl:6
 in include at boot.jl:240
while loading /home/idunning/.julia/v0.3/JuMP/test/foo.jl, in expression starting on line 13

The error message, if you read as "foo not defined yet", would maybe point you to the fact foo is later used in the function as a variable, but I would find it confusing because the meaning of foo at that point is unambiguous, and is in fact defined in two places (not nowhere, as the message implies)

[JeffBezanson]

I guess the message could identify whether it is a local or global variable. That would probably help in this case. In some cases I can also give a more specific message if the variable is provably used before it even could have been assigned, e.g. print(x); x = 1.

[KristofferC]

Closing in favour of #17062