Specification of Julia Scoping Rule

S indicates the current scope. Some terminologies(as well as interfaces provided in NameResolution.jl) :

LHS: left-hide-side
RHS: right-hide-side
pseudo scope: a scope but does not introduce free variables in its parent scope. I don't know how to call it actually, pseudo scope is a tentative name.
LOCAL: to mark a symbol as local, instead of resolving it automatically
GLOBAL: to mark a symbol as global, instead of resolving it automatically

For Loop

for i = I, j in J
    body
end

i is LHS in in S/for1, I is RHS in S.

j is LHS in S/for1/for2, J is RHS in S/for1.

body is RHS in S/for1/for2.

$f = a

If $f is a function calling expression, it's treated as function $f; a end . See [Function Definition](#Function Definition).

Otherwise, all symbols(except heads of expressions) of $f are LHS in S, a is RHS in S.

function f(x::A{T}=default_value) where T
    body
end

f is LHS in S(however the function name should be marked for further analysis, e.g., self recursions).

There's a pseudo scope S/mk-type-params,

The requirement of a symbol in argument type annotations is from the scope S/mk-type-params.

Say,

T in f(x::A{T}=value) is RHS in S/mk-type-params, and
A is RHS in S/mk-type-params(though we know A is from S, pseudo scope doesn't result in free variables).

The function execution has the scope S/mk-type-params/inner and,

Except for

let a = b
    c
end

S/let is a pseudo scope.