Redeclaration of const should throw SyntaxError

You can do attempt to change a const variable without any error. For example, it should throw an error SyntaxError: redeclaration of const y instead of silently not reassigning y in this code

const y = 2;
y = 4;
print(y); // prints 2

I see an error is thrown when strict mode is enabled.

Is there a reason why you're checking for strict mode before throwing an error for const?