Preloading with foreignKey and references overwrite does not work

[cstaud]

GORM Playground Link

go-gorm/playground#671

Description

When using a belongs-to relation with foreignKey and references overwrites preloading does not work.
Without the overwrite it works as expected.

type Country1 struct {
	Name string `gorm:"primaryKey"`
}

type Country2 struct {
	CName string `gorm:"primaryKey"`
}

type Address1 struct {
	CountryName string
	Country     Country1
}

type Address2 struct {
	CName   string
	Country Country2 `gorm:"foreignKey:CName;references:CName"`
}

type Org struct {
	ID        int
	Adress1_1 Address1 `gorm:"embedded;embeddedPrefix:address1_1_"`
	Adress1_2 Address1 `gorm:"embedded;embeddedPrefix:address1_2_"`
	Adress2_1 Address2 `gorm:"embedded;embeddedPrefix:address2_1_"`
	Adress2_2 Address2 `gorm:"embedded;embeddedPrefix:address2_2_"`
}

In the example above Address1 does not overwrite foreignKey nor references, and preloading works as expected.
Address2 overwrites foreignKey and references, preloading does not work.

	c1_1 := Country1{Name: "c1_1"}
	c1_2 := Country1{Name: "c1_2"}
	c2_1 := Country2{CName: "c2_1"}
	c2_2 := Country2{CName: "c2_2"}

	org := Org{
		Adress1_1: Address1{Country: c1_1},
		Adress1_2: Address1{Country: c1_2},
		Adress2_1: Address2{Country: c2_1},
		Adress2_2: Address2{Country: c2_2},
	}
	DB.Create(&org)

	var result Org
	DB.Preload(clause.Associations).First(&result)

	if result.Adress1_1.Country.Name != "c1_1" {
		t.Error("Adress1_1 country has not been resolved")
	}
	if result.Adress1_2.Country.Name != "c1_2" {
		t.Error("Adress1_2 country has not been resolved")
	}
	if result.Adress2_1.Country.CName != "c2_1" {
		t.Error("Adress2_1 country has not been resolved")
	}
	if result.Adress2_2.Country.CName != "c2_2" {
		t.Error("Adress2_2 country has not been resolved")
	}

Fails with: Adress2_1 country has not been resolved && Adress2_2 country has not been resolved

Hint:
Only overwriting the reference and auto detecting the foreignKey works as expected.
Example:

type Address3 struct {
	CountryID   string
	Country Country2 `gorm:"references:CName"`
}

[a631807682]

#5793 (comment)