Docker panic when merging volume configs #2916

panic: reflect: reflect.Value.Set using unaddressable value

goroutine 1 [running]:
reflect.flag.mustBeAssignableSlow(0x95)
	reflect/value.go:260 +0x13f
reflect.flag.mustBeAssignable(...)
	reflect/value.go:247
reflect.Value.Set(0x55b2de3046e0, 0xc0000a5b50, 0x95, 0x55b2de3046e0, 0xc000579cb0, 0x15)
	reflect/value.go:1558 +0x3d
github.com/docker/cli/vendor/github.com/imdario/mergo.deepMerge(0x55b2de3046e0, 0xc0000a5b50, 0x95, 0x55b2de3046e0, 0xc0000a5b00, 0x95, 0xc000131660, 0x2, 0xc00059a0e0, 0x0, ...)
	github.com/docker/cli/vendor/github.com/imdario/mergo/merge.go:90 +0x1646
github.com/docker/cli/vendor/github.com/imdario/mergo.deepMerge(0x55b2de466160, 0xc0000a5b30, 0x99, 0x55b2de466160, 0xc0000a5ae0, 0x99, 0xc000131660, 0x1, 0xc00059a0e0, 0x0, ...)
	github.com/docker/cli/vendor/github.com/imdario/mergo/merge.go:79 +0x27f9
github.com/docker/cli/vendor/github.com/imdario/mergo.deepMerge(0x55b2de302460, 0xc000118e70, 0x195, 0x55b2de302460, 0xc000118e78, 0x195, 0xc000131660, 0x0, 0xc00059a0e0, 0x195, ...)
	github.com/docker/cli/vendor/github.com/imdario/mergo/merge.go:122 +0xa3b
github.com/docker/cli/vendor/github.com/imdario/mergo._map(0x55b2de230940, 0xc000118e70, 0x55b2de230940, 0xc000118e78, 0xc000131890, 0x1, 0x1, 0x0, 0x0)
	github.com/docker/cli/vendor/github.com/imdario/mergo/map.go:160 +0x3be
github.com/docker/cli/vendor/github.com/imdario/mergo.Map(...)
	github.com/docker/cli/vendor/github.com/imdario/mergo/map.go:133
github.com/docker/cli/cli/compose/loader.mergeVolumes(...)
	github.com/docker/cli/cli/compose/loader/merge.go:241
github.com/docker/cli/cli/compose/loader.merge(0xc000590c60, 0x2, 0x2, 0x1, 0x2, 0xc000590c60)
	github.com/docker/cli/cli/compose/loader/merge.go:31 +0x20d
github.com/docker/cli/cli/compose/loader.Load(0xc000412b90, 0x3, 0xc0000525c0, 0x12, 0xc0001346f0, 0x2, 0x2, 0xc000134720, 0x0, 0x0, ...)
	github.com/docker/cli/cli/compose/loader/loader.go:125 +0x40e
github.com/docker/cli/cli/command/stack/loader.LoadComposefile(0x55b2de6210a0, 0xc0000b2dd0, 0xc000382280, 0x2, 0x2, 0x7ffcb538c598, 0x4, 0x55b2ddf3bda2, 0x6, 0x0, ...)
	github.com/docker/cli/cli/command/stack/loader/loader.go:28 +0x175
github.com/docker/cli/cli/command/stack.newDeployCommand.func1(0xc000329340, 0xc00033e0a0, 0x1, 0x5, 0x0, 0x0)
	github.com/docker/cli/cli/command/stack/deploy.go:28 +0x145
github.com/docker/cli/vendor/github.com/spf13/cobra.(*Command).execute(0xc000329340, 0xc0001b5670, 0x5, 0x5, 0xc000329340, 0xc0001b5670)
	github.com/docker/cli/vendor/github.com/spf13/cobra/command.go:850 +0x47c
github.com/docker/cli/vendor/github.com/spf13/cobra.(*Command).ExecuteC(0xc00021a2c0, 0xc0001b5650, 0x7, 0x7)
	github.com/docker/cli/vendor/github.com/spf13/cobra/command.go:958 +0x375
github.com/docker/cli/vendor/github.com/spf13/cobra.(*Command).Execute(...)
	github.com/docker/cli/vendor/github.com/spf13/cobra/command.go:895
main.runDocker(0xc0000b2dd0, 0x55b2de5ac740, 0xc000010020)
	github.com/docker/cli/cmd/docker/docker.go:287 +0x1de
main.main()
	github.com/docker/cli/cmd/docker/docker.go:298 +0xf3

Client:
 Version:           20.10.2
 API version:       1.40
 Go version:        go1.15.6
 Git commit:        2291f610ae
 Built:             Tue Jan  5 19:56:21 2021
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server:
 Engine:
  Version:          19.03.13-ce
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.15.2
  Git commit:       4484c46d9d
  Built:            Sat Sep 26 12:03:35 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.4.1.m
  GitCommit:        c623d1b36f09f8ef6536a057bd658b3aa8632828.m
 runc:
  Version:          1.0.0-rc92
  GitCommit:        ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Build with BuildKit (Docker Inc., v0.5.1-tp-docker)

Server:
 Containers: 1
  Running: 0
  Paused: 0
  Stopped: 1
 Images: 19
 Server Version: 19.03.13-ce
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: c623d1b36f09f8ef6536a057bd658b3aa8632828.m
 runc version: ff819c7e9184c13b7c2607fe6c30ae19403a7aff
 init version: de40ad0 (expected: fec3683)
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 5.8.12-arch1-1
 Operating System: Arch Linux
 OSType: linux
 Architecture: x86_64
 CPUs: 2
 Total Memory: 1.927GiB
 Name: atomic
 ID: UD2B:QCM7:RAWT:32DF:MY6W:MME2:UXTL:IDN4:PYAN:ZAOQ:AQ6Z:ZEH6
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false