Actual behavior A clear and concise description of what the bug is.

# gogen.go
package src

//go:generate mockgen -source=gogen.go -destination=gogen_mock.go -package=src_test

type Base[M any] interface {
	Get() M
}

type MyInterface interface {
	Base[int]
}

type IntInterface = Base[int]

type MyInterface2 interface {
	IntInterface
}

Mockgen is able to generate MyInterface successfully, but not able to generate MyInterface2, and returns following bug

2025/07/28 10:05:40 Loading input failed: gogen.go:18:2: unknown embedded interface interview/src.IntInterface
gogen.go:3: running "mockgen": exit status 1

Expected behavior A clear and concise description of what you expected to
happen.

Mockgen should be able to generate MyInterface2 since the interface should be exactally same as MyInterface

To Reproduce Steps to reproduce the behavior

1. run go generage ./...

Additional Information

• gomock mode (reflect or source): source
• gomock version or git ref: v0.5.2
• golang version: 1.24.4

Triage Notes for the Maintainers