`omitempty` unexpectedly omits a member when the member is a struct with a non-zero unexported member

[hajimehoshi]

Issue tracker is used for reporting bugs and discussing new features. Please use
Discord or stackoverflow for supporting
issues.

Here is the minimum test case: https://go.dev/play/p/3FvUksIAooa

Expected Behavior

Nothing is printed

Current Behavior

got: "", want: "str"

Possible Solution

omitempty should not ignore a struct value which is with a non-zero unexported member. This should be possible by comparing with a zero value.

Steps to Reproduce

Context (Environment)

Detailed Description

Possible Implementation