package main

func main() {
	var value = new(Demo)
	UseFunc[value.(type)]()
}

type Demo struct{}

func UseFunc[T any]() {}

produces 3 errors :

./prog.go:4:6: value declared and not used
./prog.go:5:10: value.(type) is not a type
./prog.go:5:10: invalid syntax tree: use of .(type) outside type switch

仅应呈现第二个错误。
来自 #58608 。