Is there something special required to use Appender.clear

[Ellie Harper via Digitalmars-d-learn]

Sorry if this is a stupid question, but is there something 
special required to call Appender.clear?  When I attempt even 
just a simple use I am getting compile errors relating to 
`template object.clear`.

When I try:
    import std.array;

    void main(string[] args){
      auto foo = appender!string;
      foo.clear;
    }

I receive the following output:

    $ ldc2 source/tmp.d
    source/tmp.d(5): Error: template object.clear cannot deduce 
function from argument types !()(Appender!string), candidates are:
    /usr/local/include/d/ldc/object.d(2041):        
object.clear(T : Value[Key], Value, Key)(T aa)
    /usr/local/include/d/ldc/object.d(2046):        
object.clear(T : Value[Key], Value, Key)(T* aa)

    $ dmd source/tmp.d
    source/tmp.d(5): Error: template object.clear cannot deduce 
function from argument types !()(Appender!string), candidates are:
    /usr/include/dmd/druntime/import/object.d(1983):        
object.clear(T : Value[Key], Value, Key)(T aa)
    /usr/include/dmd/druntime/import/object.d(1988):        
object.clear(T : Value[Key], Value, Key)(T* aa)


versions:

    $ dmd --version
    DMD64 D Compiler v2.078.0
    Copyright (c) 1999-2017 by The D Language Foundation written 
by Walter Bright

    $ ldc2 --version
    LDC - the LLVM D compiler (1.8.0git-921bb7f):
      based on DMD v2.078.3 and LLVM 4.0.1
      built with DMD64 D Compiler v2.078.0


Is there something I am missing here?

Thanks