restriction about default capture mode and 'this' in C++ lambda-expression

Question

I\'m wondering why = capture-default mode prohibits this in capture-list of C++ lambda expression.

That is,

Answer 1

this can only be captured by copy and never by reference. Even if you specify only [&], this can be implicitly captured by copy if odr-used. Therefore, [=, this] is an error because = would already implicitly capture this by copy while the & in [&, this] signifies capture by reference and does not implicitly capture this (unless it is odr-used)