[Issue 14657] New: can alias auto ref function but only after it's been called before

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14657

          Issue ID: 14657
           Summary: can alias auto ref function but only after it's been
                    called before
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: minor
          Priority: P1
         Component: DMD
          Assignee: nobody at puremagic.com
          Reporter: ag0aep6g at gmail.com

Related to issue 14656 (printing bad "auto") and issue 9204 (can't alias auto
ref function).

This errors out:
----
void unaryFun()(auto ref int a) pure nothrow @safe @nogc {}
void main()
{
    alias u = unaryFun!();
}
----
test.d(1): Error: auto can only be used for template function parameters
test.d(4): Error: template instance test.unaryFun!() error instantiating

But these compile and print different types:
----
void unaryFun()(auto ref int a) pure nothrow @safe @nogc {}
void main()
{
    unaryFun!()(41);
    alias u = unaryFun!();
    pragma(msg, typeof(u)); /* ...(auto int a) */
}
----

----
void unaryFun()(auto ref int a) pure nothrow @safe @nogc {}
void main()
{
    int x;
    unaryFun!()(x);
    alias u = unaryFun!();
    pragma(msg, typeof(u)); /* ...(auto ref int a) */
}
----

I think they should either all error or all print "auto ref int".

--