Error in validating map[string]interface{} struct field

[dex80526]

Bug Report

The following struct:

type S struct {
Props map[string]interface{} `valid:"required"`
}
d := S{props: map[string]interface{}{"field": "test"}
result, err := valid.ValidateStruct(d)
...

With the above code, it gets an error: "function only accepts structs; got string;"

However, if the field of Props is private (i.e., props), the validation is skipped.

Q	A
Version(s)	v0.0.0-20200428143746-21a406dcc535

Summary

The validator does not handle required field of map[string]interface{} correctly.

Current behavior

The current result: false with the error msg of "function only accepts structs; got string;"

How to reproduce

See the above sample code.

Expected behavior

The expected validation result: true (no error)