Mock interface which has an un-exported method

[miparnisari]

Actual behavior I'm not able to cast a mocked struct to the actual interface, if it has an un-exported method:

./main_test.go:19:64: cannot use mocks.NewMockTraceServiceServer(mockController) (value of type *mocks.MockTraceServiceServer) as "go.opentelemetry.io/proto/otlp/collector/trace/v1".TraceServiceServer value in variable declaration: *mocks.MockTraceServiceServer does not implement "go.opentelemetry.io/proto/otlp/collector/trace/v1".TraceServiceServer (missing method mustEmbedUnimplementedTraceServiceServer)
FAIL    github.com/miparnisari/mockGo [build failed]

Expected behavior I'm able to cast a mocked struct to the actual interface, if it has an un-exported method, e.g.

type TraceServiceServer interface {
    Export(context.Context, *ExportTraceServiceRequest) (*ExportTraceServiceResponse, error)
    mustEmbedUnimplementedTraceServiceServer()
}

To Reproduce

1. git clone git@github.com:miparnisari/mockGO.git
2. go generate && go test .

Additional Information

• gomock mode (reflect or source): reflect
• gomock version or git ref: n/a
• golang version: 1.20