unique: panic when calling unique.Make with string casted as any

[ALX99]

Go version

go version go1.23.0 linux/amd64

Output of go env in your module/workspace:

Go playground

What did you do?

Casting a string to any and passing it to unique.Make seems to cause issues.

package main

import "unique"

func main() {
	unique.Make(any(""))
}

Example crash 1 unexpected fault address 0x912c08: https://go.dev/play/p/vZWwiXU6YXL
Example crash 2 panic: interface conversion: interface {} is *unique.uniqueMap[string], not *unique.uniqueMap[interface {}]: https://go.dev/play/p/U8JvXsqXpJQ

What did you see happen?

For it not to crash

What did you expect to see?

I expected to see nothing and the program not to crash

[gabyhelp]

Related Issues and Documentation

• go/types, types2: go generic assert compile escape #52228 (closed)
• cmd/compile/internal/types2: panic when type function selector is not instantiated #48048 (closed)
• go/types: crash in assignment between "unexported" named interface types #5512 (closed)
• runtime: SIGBUS in initItab (write to readonly ITab.Fun) on unchecked type assertion with generics #65962 (closed)
• go/types, govet: panics when encountering (string constant) + string(rune constant) #4982 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[ianlancetaylor]

CC @mknyszek

[mknyszek]

Looking into it.

[mknyszek]

I see the general problem -- it's a classic reflection mistake when trying to get the type of a value (via TypeOf). This package doesn't use reflection directly, but does something reflect-like to extract the type.

Easy fix, apologies for the breakage.

[gopherbot]

Change https://go.dev/cl/607355 mentions this issue: unique: use TypeFor instead of TypeOf to get type in Make

[mknyszek]

@gopherbot Please open a backport issue for Go 1.23.

This problem accidentally limits what types the unique package can work with, and results in panics. Also, the fix is very simple and low risk.

[gopherbot]

Backport issue(s) opened: #68992 (for 1.23).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://go.dev/wiki/MinorReleases.

[ALX99]

Appreciate the insanely quick response.
Thank you for your contributions to Go!

[gopherbot]

Change https://go.dev/cl/607435 mentions this issue: [release-branch.go1.23] unique: use TypeFor instead of TypeOf to get type in Make