// hasDots reports whether the last argument in the call is followed by ...
func hasDots(call *ast.CallExpr) bool { return call.Ellipsis.IsValid() }

// dddErrPos returns the positioner for reporting an invalid ... use in a call.
func dddErrPos(call *ast.CallExpr) positioner { return atPos(call.Ellipsis) }

// argErrPos returns positioner for reporting an invalid argument count.

	//     37  .  .  .  .  .  .  .  .  .  Kind: STRING
	//     38  .  .  .  .  .  .  .  .  .  Value: "\"Hello, World!\""
	//     39  .  .  .  .  .  .  .  .  }
	//     40  .  .  .  .  .  .  .  }
	//     41  .  .  .  .  .  .  .  Ellipsis: -
	//     42  .  .  .  .  .  .  .  Rparen: 4:25
	//     43  .  .  .  .  .  .  }
	//     44  .  .  .  .  .  }
	//     45  .  .  .  .  }
	//     46  .  .  .  .  Rbrace: 5:1
	//     47  .  .  .  }

			Walk(v, n.Tag)
		}
		if n.Comment != nil {
			Walk(v, n.Comment)
		}

	case *FieldList:
		walkList(v, n.List)

	// Expressions
	case *BadExpr, *Ident, *BasicLit:
		// nothing to do

	case *Ellipsis:
		if n.Elt != nil {
			Walk(v, n.Elt)
		}

	case *FuncLit:
		Walk(v, n.Type)
		Walk(v, n.Body)

	case *CompositeLit:
		if n.Type != nil {
			Walk(v, n.Type)
		}
		walkList(v, n.Elts)