Although p{} in the example below is an rvalue, I get an error "cannot bind ‘p’ lvalue to ‘p&&’."

It does compile if I don't use braces, and change p{} to p().

struct p {};
struct b { b( p && ) {} };
struct d : b { using b::b; };

d o( p{} );


In the original, full program, it doesn't mention a value category, and changing the braces to () doesn't work around the issue.