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

Generating mocks with Go 1.25 fails:

❯ go run go.uber.org/mock/mockgen -typed -package quic -self_package github.com/quic-go/quic-go -self_package github.com/quic-go/quic-go -destination mock_packetconn_test.go net PacketConn
# golang.org/x/tools/internal/tokeninternal
../../../../pkg/mod/golang.org/x/tools@v0.22.0/internal/tokeninternal/tokeninternal.go:64:9: invalid array length -delta * delta (constant -256 of type int64)

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

The mock should have generated without any errors.

To Reproduce Steps to reproduce the behavior

Run the command above.

Additional Information

• gomock mode (reflect or source):
• gomock version or git ref: v0.5.2
• golang version: go version go1.25.0 darwin/arm64

Triage Notes for the Maintainers