switch t := x.typ.(type) {
	case *Alias, *Named:
		if isGeneric(t) {
			what = "type"
		}
	case *Signature:
		if t.tparams != nil {
			if enableReverseTypeInference && T != nil {
				check.funcInst(T, x.Pos(), x, nil, true)
				return
			}
			what = "function"
		}
	}
	if what != "" {
		check.errorf(x.expr, WrongTypeArgCount, "cannot use generic %s %s without instantiation", what, x.expr)

	switch t := x.typ.(type) {
	case *Alias, *Named:
		if isGeneric(t) {
			what = "type"
		}
	case *Signature:
		if t.tparams != nil {
			if enableReverseTypeInference && T != nil {
				check.funcInst(T, x.Pos(), x, nil, true)
				return
			}
			what = "function"
		}
	}
	if what != "" {
		check.errorf(x.expr, WrongTypeArgCount, "cannot use generic %s %s without instantiation", what, x.expr)

			px.X = x
			x = px
		}
		return x

	case _Func:
		pos := p.pos()
		p.next()
		_, ftyp := p.funcType("function type")
		if p.tok == _Lbrace {
			p.xnest++

			f := new(FuncLit)
			f.pos = pos
			f.Type = ftyp
			f.Body = p.funcBody()

			p.xnest--
			return f
		}
		return ftyp

	case _Lbrack, _Chan, _Map, _Struct, _Interface: