alias overloading strange error

[vitus via Digitalmars-d-learn]

//Why expression 'foobar(1);' doesn't work?


void foo()(){}
void bar(int){}

alias foobar = foo;
alias foobar = bar;

void main(){
        .foobar(1);             //OK
        foobar(1);              //Error: overload alias 'foo' is not a variable

}