361685 - Let can shadow "var" in a sub-scope but can't shadow "const"

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[Jesse Ruderman]

js> f = function() { var x; while(0) { let x; } }   
function () {
    var x;
    while (0) {
        let x;
    }
}

js> f = function() { const x; while(0) { let x; } }
typein:11: TypeError: redeclaration of const x:
typein:11: f = function() { const x; while(0) { let x; } }
typein:11: .........................................^

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

This is intentional. If you shadow a const value, then you're effectively changing its value, which is a Bad Thing (TM). vars don't have the same restriction, so they can be overridden.