anchor.diff:  # IE: programs coupled with the compiler
   , allowGoReference ? false
   
  -, meta ? {}, ... } @ args':
  +, meta ? {}, ... } @ args:
   
   if disabled
     then throw "${name} not supported for go ${go.meta.branch}"
  
positive.code:     optionalString
      ;
  
    args = filterAttrs (name: _: name != "extraSrcs") args';
  
    removeReferences = [
      go
    ];
  
negative.code: 
    disallowedReferences = optional (!allowGoReference) go;
  
    passthru = passthru // optionalAttrs (goPackageAliases != []) { inherit goPackageAliases; } // {
      inherit extraSrcs;
    };
  
    # I prefer to call this dev but propagatedBuildInputs expects $out to exist
    outputs = [ "out" "bin" ];
  