Ok, so strictly speaking there is no bug. Both gc and gccgo are
spec-compliant; gc just opts not to raise an error in this case. (One
might say it is a bug that gc doesn't raise the error consistently, but I
don't think the spec says anything about consistency, only optionality.)
In any case, I
More generally, this is https://github.com/golang/go/issues/10989.
Such ineffectual assignments can be detected
using https://github.com/gordonklaus/ineffassign.
An analysis showed that only a small fraction of such were bugs, making the
backwards-incompatible language change not worthwhile.
@
