cmd/compile: //go:build file version ignored when using generic function from package "slices" in Go 1.21 [1.21 backport] #66326
Description
@cherrymui requested issue #66064 to be considered for backport to the next 1.21 minor release.
@gopherbot please backport this to Go 1.21 release. This causes build failure for valid Go code. We'll re-apply CL 571075.