> the invariant that c<motion> is equivalent to d<motion>i
Nit: that invariant also doesn’t work when the motion takes you to the end of the line because of how the cursor is one character wide in normal mode and zero characters wide in insert mode. On a buffer “asdf jkl” with the cursor on the letter f, c$x gets you “asd|” (| representing the cursor location), whereas d$ix gets you “as|d”.
Nit: that invariant also doesn’t work when the motion takes you to the end of the line because of how the cursor is one character wide in normal mode and zero characters wide in insert mode. On a buffer “asdf jkl” with the cursor on the letter f, c$x gets you “asd|” (| representing the cursor location), whereas d$ix gets you “as|d”.