On Wed, Jan 18, 2023 at 5:52 PM Andrew Athan <andrew...@gmail.com> wrote:
> (Possibly related to issues such as those discussed in > https://groups.google.com/g/golang-nuts/c/pO2sclKEoQs/m/5JYjveKgCQAJ ?) > > If I do: > > ``` > func Foo[V any](v V)bool { > return v==v > } > ``` > > golang 1.19 reports: > > ``` > invalid operation: v == v (incomparable types in type set) > ``` > > There are two issues with this in my mind: (1) It is ambiguous in that I > cannot be sure, as a new user, whether what's being indicated is an > incompatibility between the actual types on either side of the equality > test or between the set of possible types that COULD be on either side of > the equality test due to V's any type constraing in either the case where > the left and right side are same or different types (2) In this case, the > type V appears to be determinable at compile time and yet it is claimed > this equality test is in some way problematic. > > I'm sure I'm misunderstanding something about golang generics. > > Can someone comment on this? > > Thanks in advance :) > The problem here is that a type constraint is different from a type, but the same identifier is overloaded in the language so "any" as a type constraint means something else from "any" as a type. The error is there, because without that Foo([]string{}) would satisfy the constraint but it is still a compile error. Foo[V comparable)(v V) bool is the correct declaration. > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/7134400e-ed5e-4c9f-bacd-4b739daf0e0bn%40googlegroups.com > <https://groups.google.com/d/msgid/golang-nuts/7134400e-ed5e-4c9f-bacd-4b739daf0e0bn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAMV2Rqo_nrhZfvJ_9qykTkg%3DTxbgdZMC7zFHx1rNnGcdgQk8cA%40mail.gmail.com.
