occasional error for "using Foo" inside if statement

[stevengj]

Given

module Foo
const foo = 3
end

I get error compiling anonymous: unsupported or misplaced expression using in function anonymous for

if true
    using Foo
    for m in 1:3
        println(m)
    end
end

but on the other hand the following works fine:

if true
    using Foo
    println("ok")
end

I'm don't understand why using would be allowed in one if statement but not in the other.

[JeffBezanson]

Probably same issue as #2586

Due to the introduction of variables with assignments, our scopes can be specified "inside out" --- whether something is a scope can depend on what is inside. This can prevent a block from being at the top level, thereby forbidding top-level-only expressions.

[stevengj]

I thought if statements never introduce a new scope?

[JeffBezanson]

The if statement doesn't really (adding x=1 above the for loop will indeed assign x globally). It's just that the compiler is being lazy and lumping the whole expression into one "non-top-level-thing" even though only the for loop part of it actually creates a scope.

[JeffBezanson]

Closing as dup