use mail.ParseAddress to cover missing email validations (#1395)

## Fixes Or Enhances


**Make sure that you've checked the boxes below before you submit PR:**
- [x] Tests exist or have been written that cover this particular
change.

@go-playground/validator-maintainers

---------

Co-authored-by: Benitah <[email protected]>

Author: eladb2011

baked_in.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io/fs"
 	"net"
+	"net/mail"
 	"net/url"
 	"os"
 	"reflect"
@@ -1693,6 +1694,10 @@ func isE164(fl FieldLevel) bool {
 
 // isEmail is the validation function for validating if the current field's value is a valid email address.
 func isEmail(fl FieldLevel) bool {
+	_, err := mail.ParseAddress(fl.Field().String())
+	if err != nil {
+		return false
+	}
 	return emailRegex().MatchString(fl.Field().String())
 }
 

validator_test.go

@@ -8725,6 +8725,20 @@ func TestEmail(t *testing.T) {
 	NotEqual(t, errs, nil)
 	AssertError(t, errs, "", "", "", "", "email")
 
+	s = "[email protected]."
+	errs = validate.Var(s, "email")
+	NotEqual(t, errs, nil)
+	AssertError(t, errs, "", "", "", "", "email")
+
+	s = "[email protected]."
+	errs = validate.Var(s, "email")
+	NotEqual(t, errs, nil)
+	AssertError(t, errs, "", "", "", "", "email")
+
+	s = "Foo Bar <[email protected]>"
+	errs = validate.Var(s, "email")
+	NotEqual(t, errs, nil)
+
 	s = ""
 	errs = validate.Var(s, "email")
 	NotEqual(t, errs, nil)