What you're missing is that storing to an object doesn't "access it's stored value". Once you've stored to the malloced memory through an int-typed lvalue, it'

What you're missing is that storing to an object doesn't "access it's stored value". Once you've stored to the malloced memory through an int-typed lvalue, it's effective type becomes int, and you can't access it (ie. read it) through a double-typed lvalue. But you can then write to it through a double-typed lvalue, because that doesn't access it's stored value - it overwrites it, and changes its effective type to double.