Is there something special required to use Appender.clear

[Ellie Harper]

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