Generally, the goal of auto is to create a variable whose purpose is to store a value of the type you have: you called a function, got a constant reference, but to store that you need a concrete value. Generally, the goal of decltype is to compute a type based on other code whose type you don't already know: a simple canonical example is to make a function that does something and transparently returns the result "as if" it were the original code. These are two drastically different use cases and, given the semantics of the various qualifiers, it makes sense to strip them for one and not for the other, lending to two different syntaxes. If you find yourself needing to transparently store the result of an expression, in C++14 you can use "decltype(auto) ;P".