WriteExpr(buf, x.X)
		buf.WriteByte('.')
		buf.WriteString(x.Sel.Name)

	case *ast.IndexExpr, *ast.IndexListExpr:
		ix := typeparams.UnpackIndexExpr(x)
		WriteExpr(buf, ix.X)
		buf.WriteByte('[')
		writeExprList(buf, ix.Indices)
		buf.WriteByte(']')

	case *ast.SliceExpr:
		WriteExpr(buf, x.X)
		buf.WriteByte('[')
		if x.Low != nil {
			WriteExpr(buf, x.Low)
		}
		buf.WriteByte(':')
		if x.High != nil {

		case token.Pos:
			if fset != nil {
				arg = fset.Position(a).String()
			}
		case ast.Expr:
			arg = ExprString(a)
		case []ast.Expr:
			var buf bytes.Buffer
			buf.WriteByte('[')
			writeExprList(&buf, a)
			buf.WriteByte(']')
			arg = buf.String()
		case Object:
			arg = ObjectString(a, qf)
		case Type:
			var buf bytes.Buffer
			w := newTypeWriter(&buf, qf)
			w.tpSubscripts = tpSubscripts