all: Use some Go 1.21 features (#9409)

13 files changed, 23 insertions, 72 deletions

diff --git a/go.mod b/go.mod
index a0a0e94b0..6a3954339 100644
--- a/go.mod
+++ b/go.mod
@@ -39,7 +39,6 @@ require (
 	github.com/vitrun/qart v0.0.0-20160531060029-bf64b92db6b0
 	github.com/willabides/kongplete v0.4.0
 	golang.org/x/crypto v0.19.0
-	golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3
 	golang.org/x/net v0.21.0
 	golang.org/x/sys v0.17.0
 	golang.org/x/text v0.14.0
@@ -69,6 +68,7 @@ require (
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.6 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/nxadm/tail v1.4.11 // indirect
 	github.com/onsi/ginkgo/v2 v2.15.0 // indirect
 	github.com/onsi/gomega v1.31.1 // indirect
@@ -80,13 +80,13 @@ require (
 	github.com/prometheus/client_model v0.5.0 // indirect
 	github.com/prometheus/common v0.46.0 // indirect
 	github.com/prometheus/procfs v0.12.0 // indirect
-	github.com/quic-go/qtls-go1-20 v0.4.1 // indirect
 	github.com/riywo/loginshell v0.0.0-20200815045211-7d26008be1ab // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
 	github.com/stretchr/objx v0.5.1 // indirect
 	github.com/stretchr/testify v1.8.4 // indirect
 	github.com/yusufpapurcu/wmi v1.2.4 // indirect
 	go.uber.org/mock v0.4.0 // indirect
+	golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3 // indirect
 	golang.org/x/mod v0.15.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
diff --git a/go.sum b/go.sum
index bcdbd13e2..ef909d96e 100644
--- a/go.sum
+++ b/go.sum
@@ -34,6 +34,7 @@ github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMn
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/cpuguy83/go-md2man/v2 v2.0.3 h1:qMCsGGgs+MAzDFyp9LpAe1Lqy/fY/qCovCm0qnXZOBM=
 github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/d4l3k/messagediff v1.2.1 h1:ZcAIMYsUg0EAp9X+tt8/enBE/Q8Yd5kzPynLyKptt9U=
 github.com/d4l3k/messagediff v1.2.1/go.mod h1:Oozbb1TVXFac9FtSIxHBMnBCq2qeH/2KkEQxENCrlLo=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -86,8 +87,6 @@ github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeN
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/pprof v0.0.0-20210407192527-94a9f03dee38/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
-github.com/google/pprof v0.0.0-20240130152714-0ed6a68c8d9e h1:E+3PBMCXn0ma79O7iCrne0iUpKtZ7rIcZvoz+jNtNtw=
-github.com/google/pprof v0.0.0-20240130152714-0ed6a68c8d9e/go.mod h1:czg5+yv1E0ZGTi6S6vVK1mke0fV+FaUhNGcd6VRS9Ik=
 github.com/google/pprof v0.0.0-20240207164012-fb44976bdcd5 h1:E/LAvt58di64hlYjx7AsNS6C/ysHWYo+2qPCZKTQhRo=
 github.com/google/pprof v0.0.0-20240207164012-fb44976bdcd5/go.mod h1:czg5+yv1E0ZGTi6S6vVK1mke0fV+FaUhNGcd6VRS9Ik=
 github.com/google/uuid v1.3.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
@@ -107,8 +106,6 @@ github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUq
 github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-github.com/jackpal/gateway v1.0.10 h1:7g3fDo4Cd3RnTu6PzAfw6poO4Y81uNxrxFQFsBFSzJM=
-github.com/jackpal/gateway v1.0.10/go.mod h1:+uPBgIllrbkwYCAoDkGSZbjvpre/bGYAFCYIcrH+LHs=
 github.com/jackpal/gateway v1.0.13 h1:fJccMvawxx0k7S1q7Fy/SXFE0R3hMXkMuw8y9SofWAk=
 github.com/jackpal/gateway v1.0.13/go.mod h1:6c8LjW+FVESFmwxaXySkt7fU98Yv806ADS3OY6Cvh2U=
 github.com/jackpal/go-nat-pmp v1.0.2 h1:KzKSgb7qkJvOUTqYl9/Hg/me3pWgBmERKrTGD7BdWus=
@@ -121,6 +118,10 @@ github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/cpuid/v2 v2.2.6 h1:ndNyv040zDGIDh8thGkXYjnFtiN02M1PVVF+JE/48xc=
 github.com/klauspost/cpuid/v2 v2.2.6/go.mod h1:Lcz8mBdAVJIBVzewtcLocK12l3Y+JytZYpaMropDUws=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/lib/pq v1.10.9 h1:YXG7RB+JIjhP29X+OtkiDnYaXQwpS4JEWq7dtCCRUEw=
 github.com/lib/pq v1.10.9/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/lufia/plan9stats v0.0.0-20211012122336-39d0f177ccd0/go.mod h1:zJYVVT2jmtg6P3p1VtQj7WsuWi/y4VnjVBn7F8KPB3I=
@@ -177,22 +178,18 @@ github.com/prometheus/common v0.46.0 h1:doXzt5ybi1HBKpsZOL0sSkaNHJJqkyfEWZGGqqSc
 github.com/prometheus/common v0.46.0/go.mod h1:Tp0qkxpb9Jsg54QMe+EAmqXkSV7Evdy1BTn+g2pa/hQ=
 github.com/prometheus/procfs v0.12.0 h1:jluTpSng7V9hY0O2R9DzzJHYb2xULk9VTR1V1R/k6Bo=
 github.com/prometheus/procfs v0.12.0/go.mod h1:pcuDEFsWDnvcgNzo4EEweacyhjeA9Zk3cnaOZAZEfOo=
-github.com/quic-go/qtls-go1-20 v0.4.1 h1:D33340mCNDAIKBqXuAvexTNMUByrYmFYVfKfDN5nfFs=
-github.com/quic-go/qtls-go1-20 v0.4.1/go.mod h1:X9Nh97ZL80Z+bX/gUXMbipO6OxdiDi58b/fMC9mAL+k=
-github.com/quic-go/quic-go v0.40.1 h1:X3AGzUNFs0jVuO3esAGnTfvdgvL4fq655WaOi1snv1Q=
-github.com/quic-go/quic-go v0.40.1/go.mod h1:PeN7kuVJ4xZbxSv/4OX6S1USOX8MJvydwpTx31vx60c=
 github.com/quic-go/quic-go v0.41.0 h1:aD8MmHfgqTURWNJy48IYFg2OnxwHT3JL7ahGs73lb4k=
 github.com/quic-go/quic-go v0.41.0/go.mod h1:qCkNjqczPEvgsOnxZ0eCD14lv+B2LHlFAB++CNOh9hA=
 github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475 h1:N/ElC8H3+5XpJzTSTfLsJV/mx9Q9g7kxmchpfZyxgzM=
 github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475/go.mod h1:bCqnVzQkZxMG4s8nGwiZ5l3QUCyqpo9Y+/ZMZ9VjZe4=
 github.com/riywo/loginshell v0.0.0-20200815045211-7d26008be1ab h1:ZjX6I48eZSFetPb41dHudEyVr5v953N15TsNZXlkcWY=
 github.com/riywo/loginshell v0.0.0-20200815045211-7d26008be1ab/go.mod h1:/PfPXh0EntGc3QAAyUaviy4S9tzy4Zp0e2ilq4voC6E=
+github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/sclevine/spec v1.4.0 h1:z/Q9idDcay5m5irkZ28M7PtQM4aOISzOpj4bUPkDee8=
 github.com/sclevine/spec v1.4.0/go.mod h1:LvpgJaFyvQzRvc1kaDs0bulYwzC70PbiYjC4QnFHkOM=
-github.com/shirou/gopsutil/v3 v3.23.11 h1:i3jP9NjCPUz7FiZKxlMnODZkdSIp2gnzfrvsu9CuWEQ=
-github.com/shirou/gopsutil/v3 v3.23.11/go.mod h1:1FrWgea594Jp7qmjHUUPlJDTPgcsb9mGnXDxavtikzM=
 github.com/shirou/gopsutil/v3 v3.24.1 h1:R3t6ondCEvmARp3wxODhXMTLC/klMa87h2PHUw5m7QI=
 github.com/shirou/gopsutil/v3 v3.24.1/go.mod h1:UU7a2MSBQa+kW1uuDq8DeEBS8kmrnQwsv2b5O513rwU=
 github.com/shoenig/go-m1cpu v0.1.6/go.mod h1:1JJMcUBvfNwpq05QDQVAnx3gUHr9IYF7GNg9SUEw2VQ=
@@ -239,20 +236,14 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
-golang.org/x/crypto v0.18.0 h1:PGVlW0xEltQnzFZ55hkuX5+KLyrMYhHld1YHO4AKcdc=
-golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/crypto v0.19.0 h1:ENy+Az/9Y1vSrlrvBSyna3PITt4tiZLf7sgCjZBX7Wo=
 golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
-golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=
-golang.org/x/exp v0.0.0-20240119083558-1b970713d09a/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
 golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3 h1:/RIbNt/Zr7rVhIkQhooTxCxFcdWLGIKnZA4IXNFSrvo=
 golang.org/x/exp v0.0.0-20240205201215-2c58cdc269a3/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/mod v0.14.0 h1:dGoOF9QVLYng8IHTm7BAyWqCqSheQ5pYWGhzW00YJr0=
-golang.org/x/mod v0.14.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/mod v0.15.0 h1:SernR4v+D55NyBH2QiEQrlBAnj1ECL6AGrA5+dPaMY8=
 golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -268,8 +259,6 @@ golang.org/x/net v0.0.0-20220607020251-c690dde0001d/go.mod h1:XRhObCWvk6IyKnWLug
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.10.0/go.mod h1:0qNGK6F8kojg2nk9dLZ2mShWaEBan6FAoqfSigmmuDg=
-golang.org/x/net v0.20.0 h1:aCL9BSgETF1k+blQaYUBx9hJ9LOGP3gAVemcZlf1Kpo=
-golang.org/x/net v0.20.0/go.mod h1:z8BVo6PvndSri0LbOE3hAn0apkU+1YvI6E70E9jsnvY=
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
@@ -309,8 +298,6 @@ golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/sys v0.16.0 h1:xWw16ngr6ZMtmxDyKyIgsE93KNKz5HKmMa3b8ALHidU=
 golang.org/x/sys v0.16.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
 golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
@@ -355,6 +342,8 @@ google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQ
 google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
 google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 h1:uRGJdciOHaEIrze2W8Q3AKkepLTh2hOroT7a+7czfdQ=
 gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
diff --git a/lib/api/api_auth.go b/lib/api/api_auth.go
index cee0397ad..b24ad7950 100644
--- a/lib/api/api_auth.go
+++ b/lib/api/api_auth.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"slices"
 	"strings"
 	"time"
 
@@ -19,7 +20,6 @@ import (
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/rand"
-	"golang.org/x/exp/slices"
 )
 
 const (
diff --git a/lib/api/api_test.go b/lib/api/api_test.go
index 9b053a340..8fac8a84d 100644
--- a/lib/api/api_test.go
+++ b/lib/api/api_test.go
@@ -18,6 +18,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"slices"
 	"strconv"
 	"strings"
 	"testing"
@@ -46,7 +47,6 @@ import (
 	"github.com/syncthing/syncthing/lib/tlsutil"
 	"github.com/syncthing/syncthing/lib/ur"
 	"github.com/thejerf/suture/v4"
-	"golang.org/x/exp/slices"
 )
 
 var (
diff --git a/lib/api/tokenmanager.go b/lib/api/tokenmanager.go
index d03c75923..73ba8425e 100644
--- a/lib/api/tokenmanager.go
+++ b/lib/api/tokenmanager.go
@@ -7,12 +7,12 @@
 package api
 
 import (
+	"slices"
 	"time"
 
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/sync"
-	"golang.org/x/exp/slices"
 )
 
 type tokenManager struct {
diff --git a/lib/connections/service.go b/lib/connections/service.go
index c08a47c95..359dcff4d 100644
--- a/lib/connections/service.go
+++ b/lib/connections/service.go
@@ -22,14 +22,12 @@ import (
 	"math"
 	"net"
 	"net/url"
+	"slices"
 	"sort"
 	"strings"
 	stdsync "sync"
 	"time"
 
-	"golang.org/x/exp/constraints"
-	"golang.org/x/exp/slices"
-
 	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/connections/registry"
@@ -1468,20 +1466,3 @@ func newConnectionID(t0, t1 int64) string {
 	// from the random. We want the timestamp part deterministic.
 	return enc.EncodeToString(buf[:8]) + enc.EncodeToString(buf[8:])
 }
-
-// temporary implementations of min and max, to be removed once we can use
-// Go 1.21 builtins. :)
-
-func min[T constraints.Ordered](a, b T) T {
-	if a < b {
-		return a
-	}
-	return b
-}
-
-func max[T constraints.Ordered](a, b T) T {
-	if a > b {
-		return a
-	}
-	return b
-}
diff --git a/lib/locations/locations_test.go b/lib/locations/locations_test.go
index 286476916..4c9208bf2 100644
--- a/lib/locations/locations_test.go
+++ b/lib/locations/locations_test.go
@@ -10,10 +10,9 @@ package locations
 
 import (
 	"path/filepath"
+	"slices"
 	"testing"
 	"time"
-
-	"golang.org/x/exp/slices"
 )
 
 func TestUnixConfigDir(t *testing.T) {
diff --git a/lib/logger/logger.go b/lib/logger/logger.go
index a60856e12..919a5fcf4 100644
--- a/lib/logger/logger.go
+++ b/lib/logger/logger.go
@@ -12,11 +12,10 @@ import (
 	"io"
 	"log"
 	"os"
+	"slices"
 	"strings"
 	"sync"
 	"time"
-
-	"golang.org/x/exp/slices"
 )
 
 // This package uses stdlib sync as it may be used to debug syncthing/lib/sync
diff --git a/lib/model/queue_test.go b/lib/model/queue_test.go
index 34ff67fd8..a49f2c70f 100644
--- a/lib/model/queue_test.go
+++ b/lib/model/queue_test.go
@@ -9,11 +9,11 @@ package model
 import (
 	"fmt"
 	"math/rand"
+	"slices"
 	"testing"
 	"time"
 
 	"github.com/d4l3k/messagediff"
-	"golang.org/x/exp/slices"
 )
 
 func TestJobQueue(t *testing.T) {
diff --git a/lib/nat/service.go b/lib/nat/service.go
index cc93e933a..8ff66a380 100644
--- a/lib/nat/service.go
+++ b/lib/nat/service.go
@@ -12,6 +12,7 @@ import (
 	"hash/fnv"
 	"math/rand"
 	"net"
+	"slices"
 	stdsync "sync"
 	"time"
 
@@ -411,21 +412,11 @@ func addrSetsEqual(a []Address, b []Address) bool {
 		return false
 	}
 
-	// TODO: Rewrite this using slice.Contains once Go 1.21 is the minimum Go version.
-	for _, aElem := range a {
-		aElemFound := false
-		for _, bElem := range b {
-			if bElem.Equal(aElem) {
-				aElemFound = true
-				break
-			}
-		}
-		if !aElemFound {
-			// Found element in a that is not in b.
+	for _, v := range a {
+		if !slices.ContainsFunc(b, v.Equal) {
 			return false
 		}
 	}
 
-	// b contains all elements of a and their lengths are equal, so the sets are equal.
 	return true
 }
diff --git a/lib/protocol/vector.go b/lib/protocol/vector.go
index 74a8bd42a..fefb88aa9 100644
--- a/lib/protocol/vector.go
+++ b/lib/protocol/vector.go
@@ -43,13 +43,6 @@ func (v Vector) updateWithNow(id ShortID, now uint64) Vector {
 	})}
 }
 
-func max(a, b uint64) uint64 {
-	if a > b {
-		return a
-	}
-	return b
-}
-
 // Merge returns the vector containing the maximum indexes from v and b. If it
 // is possible, the vector v is updated and returned. If it is not, a copy
 // will be created, updated and returned.
diff --git a/lib/sliceutil/sliceutil_test.go b/lib/sliceutil/sliceutil_test.go
index 41387cd2b..cf3ecf711 100644
--- a/lib/sliceutil/sliceutil_test.go
+++ b/lib/sliceutil/sliceutil_test.go
@@ -7,10 +7,10 @@
 package sliceutil_test
 
 import (
+	"slices"
 	"testing"
 
 	"github.com/syncthing/syncthing/lib/sliceutil"
-	"golang.org/x/exp/slices"
 )
 
 func TestRemoveAndZero(t *testing.T) {
diff --git a/lib/versioner/simple_test.go b/lib/versioner/simple_test.go
index 3b3abb436..5e540e48a 100644
--- a/lib/versioner/simple_test.go
+++ b/lib/versioner/simple_test.go
@@ -7,7 +7,6 @@
 package versioner
 
 import (
-	"math"
 	"os"
 	"path/filepath"
 	"strings"
@@ -88,7 +87,7 @@ func TestSimpleVersioningVersionCount(t *testing.T) {
 			t.Error(err)
 		}
 
-		if float64(len(n)) != math.Min(float64(i), 2) {
+		if len(n) != min(i, 2) {
 			t.Error("Wrong count")
 		}