diff --git a/cmd/stdiscosrv/main.go b/cmd/stdiscosrv/main.go
index eafa1dda9..8ef7ace17 100644
--- a/cmd/stdiscosrv/main.go
+++ b/cmd/stdiscosrv/main.go
@@ -88,11 +88,6 @@ var (
 )
 
 func main() {
-	const (
-		cleanIntv = 1 * time.Hour
-		statsIntv = 5 * time.Minute
-	)
-
 	var listen string
 	var dir string
 	var metricsListen string
diff --git a/cmd/stindex/idxck.go b/cmd/stindex/idxck.go
index 974dd6cbd..88d5b2eb5 100644
--- a/cmd/stindex/idxck.go
+++ b/cmd/stindex/idxck.go
@@ -167,8 +167,8 @@ func idxck(ldb *db.Lowlevel) (success bool) {
 		if needsLocally(vl) {
 			_, ok := needs[gk]
 			if !ok {
-				dev, _ := deviceToIDs[string(vl.Versions[0].Device)]
-				fi, _ := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
+				dev := deviceToIDs[string(vl.Versions[0].Device)]
+				fi := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
 				if !fi.IsDeleted() && !fi.IsIgnored() {
 					fmt.Printf("Missing need entry for needed file %q, folder %q\n", gk.name, folder)
 				}
diff --git a/cmd/strelaypoolsrv/stats.go b/cmd/strelaypoolsrv/stats.go
index 068b77335..ae4a8a751 100644
--- a/cmd/strelaypoolsrv/stats.go
+++ b/cmd/strelaypoolsrv/stats.go
@@ -126,7 +126,7 @@ func refreshStats() {
 		go func(rel *relay) {
 			t0 := time.Now()
 			stats := fetchStats(rel)
-			duration := time.Now().Sub(t0).Seconds()
+			duration := time.Since(t0).Seconds()
 			result := "success"
 			if stats == nil {
 				result = "failed"
diff --git a/cmd/strelaysrv/session.go b/cmd/strelaysrv/session.go
index cf381e340..0221434bd 100644
--- a/cmd/strelaysrv/session.go
+++ b/cmd/strelaysrv/session.go
@@ -22,7 +22,7 @@ import (
 var (
 	sessionMut      = sync.RWMutex{}
 	activeSessions  = make([]*session, 0)
-	pendingSessions = make(map[string]*session, 0)
+	pendingSessions = make(map[string]*session)
 	numProxies      int64
 	bytesProxied    int64
 )
diff --git a/cmd/syncthing/auditservice_test.go b/cmd/syncthing/auditservice_test.go
index f3951f5e0..fcdae4d4f 100644
--- a/cmd/syncthing/auditservice_test.go
+++ b/cmd/syncthing/auditservice_test.go
@@ -37,7 +37,7 @@ func TestAuditService(t *testing.T) {
 	// This event should not be logged, since we have stopped.
 	events.Default.Log(events.ConfigSaved, "the third event")
 
-	result := string(buf.Bytes())
+	result := buf.String()
 	t.Log(result)
 
 	if strings.Contains(result, "first event") {
diff --git a/cmd/syncthing/gui.go b/cmd/syncthing/gui.go
index 6c40b8ceb..0b3ffe118 100644
--- a/cmd/syncthing/gui.go
+++ b/cmd/syncthing/gui.go
@@ -531,7 +531,6 @@ func corsMiddleware(next http.Handler, allowFrameLoading bool) http.Handler {
 
 		// For everything else, pass to the next handler
 		next.ServeHTTP(w, r)
-		return
 	})
 }
 
diff --git a/cmd/syncthing/locations.go b/cmd/syncthing/locations.go
index 916d9d126..94a329471 100644
--- a/cmd/syncthing/locations.go
+++ b/cmd/syncthing/locations.go
@@ -22,17 +22,17 @@ type locationEnum string
 // more meaningful.
 const (
 	locConfigFile    locationEnum = "config"
-	locCertFile                   = "certFile"
-	locKeyFile                    = "keyFile"
-	locHTTPSCertFile              = "httpsCertFile"
-	locHTTPSKeyFile               = "httpsKeyFile"
-	locDatabase                   = "database"
-	locLogFile                    = "logFile"
-	locCsrfTokens                 = "csrfTokens"
-	locPanicLog                   = "panicLog"
-	locAuditLog                   = "auditLog"
-	locGUIAssets                  = "GUIAssets"
-	locDefFolder                  = "defFolder"
+	locCertFile      locationEnum = "certFile"
+	locKeyFile       locationEnum = "keyFile"
+	locHTTPSCertFile locationEnum = "httpsCertFile"
+	locHTTPSKeyFile  locationEnum = "httpsKeyFile"
+	locDatabase      locationEnum = "database"
+	locLogFile       locationEnum = "logFile"
+	locCsrfTokens    locationEnum = "csrfTokens"
+	locPanicLog      locationEnum = "panicLog"
+	locAuditLog      locationEnum = "auditLog"
+	locGUIAssets     locationEnum = "GUIAssets"
+	locDefFolder     locationEnum = "defFolder"
 )
 
 // Platform dependent directories
diff --git a/cmd/syncthing/usage_report.go b/cmd/syncthing/usage_report.go
index e9d2059f0..be7ca2eed 100644
--- a/cmd/syncthing/usage_report.go
+++ b/cmd/syncthing/usage_report.go
@@ -190,7 +190,7 @@ func reportData(cfg configIntf, m modelIntf, connectionsService connectionsIntf,
 	res["upgradeAllowedPre"] = !(upgrade.DisabledByCompilation || noUpgradeFromEnv) && opts.AutoUpgradeIntervalH > 0 && opts.UpgradeToPreReleases
 
 	if version >= 3 {
-		res["uptime"] = int(time.Now().Sub(startTime).Seconds())
+		res["uptime"] = int(time.Since(startTime).Seconds())
 		res["natType"] = connectionsService.NATType()
 		res["alwaysLocalNets"] = len(opts.AlwaysLocalNets) > 0
 		res["cacheIgnoredFiles"] = opts.CacheIgnoredFiles
diff --git a/lib/connections/service.go b/lib/connections/service.go
index aac8df980..9c192ca21 100644
--- a/lib/connections/service.go
+++ b/lib/connections/service.go
@@ -35,8 +35,8 @@ import (
 )
 
 var (
-	dialers   = make(map[string]dialerFactory, 0)
-	listeners = make(map[string]listenerFactory, 0)
+	dialers   = make(map[string]dialerFactory)
+	listeners = make(map[string]listenerFactory)
 )
 
 var (
diff --git a/lib/db/set_test.go b/lib/db/set_test.go
index 2abc32966..8f4ce711d 100644
--- a/lib/db/set_test.go
+++ b/lib/db/set_test.go
@@ -418,10 +418,7 @@ func TestUpdateToInvalid(t *testing.T) {
 	})
 
 	if !f.Iterate([]string{folder}, localHave[4].Blocks[0].Hash, func(folder, file string, index int32) bool {
-		if file == localHave[4].Name {
-			return true
-		}
-		return false
+		return file == localHave[4].Name
 	}) {
 		t.Errorf("First block of un-invalidated file is missing from blockmap")
 	}
diff --git a/lib/fs/basicfs_test.go b/lib/fs/basicfs_test.go
index 08e501eab..88e9ce826 100644
--- a/lib/fs/basicfs_test.go
+++ b/lib/fs/basicfs_test.go
@@ -82,7 +82,7 @@ func TestChownFile(t *testing.T) {
 	}
 	fd.Close()
 
-	info, err := fs.Lstat("file")
+	_, err = fs.Lstat("file")
 	if err != nil {
 		t.Error("Unexpected error:", err)
 	}
@@ -94,7 +94,7 @@ func TestChownFile(t *testing.T) {
 		t.Error("Unexpected error:", err)
 	}
 
-	info, err = fs.Lstat("file")
+	info, err := fs.Lstat("file")
 	if err != nil {
 		t.Error("Unexpected error:", err)
 	}
diff --git a/lib/fs/fakefs.go b/lib/fs/fakefs.go
index e19b76de5..986f9585b 100644
--- a/lib/fs/fakefs.go
+++ b/lib/fs/fakefs.go
@@ -500,7 +500,7 @@ func (fs *fakefs) URI() string {
 }
 
 func (fs *fakefs) SameFile(fi1, fi2 FileInfo) bool {
-	return fi1.Name() == fi1.Name()
+	return fi1.Name() == fi2.Name()
 }
 
 // fakeFile is the representation of an open file. We don't care if it's
diff --git a/lib/fs/fakefs_test.go b/lib/fs/fakefs_test.go
index 52e683dd4..a42dc592e 100644
--- a/lib/fs/fakefs_test.go
+++ b/lib/fs/fakefs_test.go
@@ -8,8 +8,8 @@ package fs
 
 import (
 	"bytes"
+	"io"
 	"io/ioutil"
-	"os"
 	"testing"
 )
 
@@ -23,7 +23,7 @@ func TestFakeFS(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	info, err := fs.Stat("dira/dirb")
+	_, err = fs.Stat("dira/dirb")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -33,7 +33,7 @@ func TestFakeFS(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	info, err = fs.Stat("dira/dirb/dirc")
+	_, err = fs.Stat("dira/dirb/dirc")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -51,7 +51,7 @@ func TestFakeFS(t *testing.T) {
 	}
 
 	// Stat on fd
-	info, err = fd.Stat()
+	info, err := fd.Stat()
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -75,7 +75,7 @@ func TestFakeFS(t *testing.T) {
 	}
 
 	// Seek
-	_, err = fd.Seek(1, os.SEEK_SET)
+	_, err = fd.Seek(1, io.SeekStart)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -90,7 +90,7 @@ func TestFakeFS(t *testing.T) {
 	}
 
 	// Read again, same data hopefully
-	_, err = fd.Seek(0, os.SEEK_SET)
+	_, err = fd.Seek(0, io.SeekStart)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -133,7 +133,7 @@ func TestFakeFSRead(t *testing.T) {
 	_ = fd.Truncate(3 * 1 << randomBlockShift)
 
 	// Read
-	_, _ = fd.Seek(0, 0)
+	_, _ = fd.Seek(0, io.SeekStart)
 	bs0, err := ioutil.ReadAll(fd)
 	if err != nil {
 		t.Fatal(err)
@@ -143,7 +143,7 @@ func TestFakeFSRead(t *testing.T) {
 	}
 
 	// Read again, starting at an odd offset
-	_, _ = fd.Seek(0, 0)
+	_, _ = fd.Seek(0, io.SeekStart)
 	buf0 := make([]byte, 12345)
 	n, _ := fd.Read(buf0)
 	if n != len(buf0) {
diff --git a/lib/ignore/ignore_test.go b/lib/ignore/ignore_test.go
index f2c27d28a..e7254a90e 100644
--- a/lib/ignore/ignore_test.go
+++ b/lib/ignore/ignore_test.go
@@ -9,6 +9,7 @@ package ignore
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -507,7 +508,7 @@ func TestCacheReload(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	_, err = fd.Seek(0, os.SEEK_SET)
+	_, err = fd.Seek(0, io.SeekStart)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/lib/model/model.go b/lib/model/model.go
index 4b54e3517..78808e908 100644
--- a/lib/model/model.go
+++ b/lib/model/model.go
@@ -115,7 +115,7 @@ type Model struct {
 type folderFactory func(*Model, config.FolderConfiguration, versioner.Versioner, fs.Filesystem) service
 
 var (
-	folderFactories = make(map[config.FolderType]folderFactory, 0)
+	folderFactories = make(map[config.FolderType]folderFactory)
 )
 
 var (
@@ -489,12 +489,8 @@ func (m *Model) UsageReportingStats(version int, preview bool) map[string]interf
 				}
 
 				// Noops, remove
-				if strings.HasSuffix(line, "**") {
-					line = line[:len(line)-2]
-				}
-				if strings.HasPrefix(line, "**/") {
-					line = line[3:]
-				}
+				line = strings.TrimSuffix(line, "**")
+				line = strings.TrimPrefix(line, "**/")
 
 				if strings.HasPrefix(line, "/") {
 					ignoreStats["rooted"] += 1
@@ -508,7 +504,7 @@ func (m *Model) UsageReportingStats(version int, preview bool) map[string]interf
 				if strings.Contains(line, "**") {
 					ignoreStats["doubleStars"] += 1
 					// Remove not to trip up star checks.
-					strings.Replace(line, "**", "", -1)
+					line = strings.Replace(line, "**", "", -1)
 				}
 
 				if strings.Contains(line, "*") {
@@ -2392,6 +2388,11 @@ func (m *Model) GetFolderVersions(folder string) (map[string][]versioner.FileVer
 			return nil
 		}
 
+		// Skip walking if we cannot walk...
+		if err != nil {
+			return err
+		}
+
 		// Ignore symlinks
 		if f.IsSymlink() {
 			return fs.SkipDir
diff --git a/lib/model/model_test.go b/lib/model/model_test.go
index 076ab6266..9787b4494 100644
--- a/lib/model/model_test.go
+++ b/lib/model/model_test.go
@@ -2572,7 +2572,7 @@ func TestIssue2782(t *testing.T) {
 	}
 
 	m.fmut.Lock()
-	runner, _ := m.folderRunners["default"]
+	runner := m.folderRunners["default"]
 	m.fmut.Unlock()
 	if err := runner.CheckHealth(); err != nil {
 		t.Error("health check error:", err)
diff --git a/lib/model/progressemitter.go b/lib/model/progressemitter.go
index a06487a48..55f3467a9 100644
--- a/lib/model/progressemitter.go
+++ b/lib/model/progressemitter.go
@@ -167,13 +167,14 @@ func (t *ProgressEmitter) sendDownloadProgressMessages() {
 			// If we fail to find that folder, we tell the state to forget about it
 			// and return us a list of updates which would clean up the state
 			// on the remote end.
-			updates := state.cleanup(folder)
-			if len(updates) > 0 {
-				// XXX: Don't send this now, as the only way we've unshared a folder
-				// is by breaking the connection and reconnecting, hence sending
-				// forget messages for some random folder currently makes no sense.
-				// deviceConns[id].DownloadProgress(folder, updates, 0, nil)
-			}
+			state.cleanup(folder)
+			// updates := state.cleanup(folder)
+			// if len(updates) > 0 {
+			// XXX: Don't send this now, as the only way we've unshared a folder
+			// is by breaking the connection and reconnecting, hence sending
+			// forget messages for some random folder currently makes no sense.
+			// deviceConns[id].DownloadProgress(folder, updates, 0, nil)
+			// }
 		}
 	}
 }
diff --git a/lib/model/progressemitter_test.go b/lib/model/progressemitter_test.go
index 73947bee2..ff26dc509 100644
--- a/lib/model/progressemitter_test.go
+++ b/lib/model/progressemitter_test.go
@@ -193,7 +193,7 @@ func TestSendDownloadProgressMessages(t *testing.T) {
 	v2 := (protocol.Vector{}).Update(1)
 
 	// Requires more than 10 blocks to work.
-	blocks := make([]protocol.BlockInfo, 11, 11)
+	blocks := make([]protocol.BlockInfo, 11)
 
 	state1 := &sharedPullerState{
 		folder: "folder",
diff --git a/lib/model/requests_test.go b/lib/model/requests_test.go
index ea8515bf5..2c27e9172 100644
--- a/lib/model/requests_test.go
+++ b/lib/model/requests_test.go
@@ -471,7 +471,6 @@ func TestIssue4841(t *testing.T) {
 			t.Fatalf(`Sent index with file %v, should be "foo"`, fs[0].Name)
 		}
 		received <- fs[0]
-		return
 	}
 	fc.mut.Unlock()
 
@@ -521,7 +520,6 @@ func TestRescanIfHaveInvalidContent(t *testing.T) {
 			t.Fatalf(`Sent index with file %v, should be "foo"`, fs[0].Name)
 		}
 		received <- fs[0]
-		return
 	}
 	fc.mut.Unlock()
 
@@ -551,7 +549,7 @@ func TestRescanIfHaveInvalidContent(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	res, err = m.Request(device2, "default", "foo", int32(len(payload)), 0, f.Blocks[0].Hash, f.Blocks[0].WeakHash, false)
+	_, err = m.Request(device2, "default", "foo", int32(len(payload)), 0, f.Blocks[0].Hash, f.Blocks[0].WeakHash, false)
 	if err == nil {
 		t.Fatalf("expected failure")
 	}
@@ -586,7 +584,6 @@ func TestParentDeletion(t *testing.T) {
 	fc.mut.Lock()
 	fc.indexFn = func(folder string, fs []protocol.FileInfo) {
 		received <- fs
-		return
 	}
 	fc.mut.Unlock()
 	fc.sendIndexUpdate()
diff --git a/lib/watchaggregator/aggregator_test.go b/lib/watchaggregator/aggregator_test.go
index 5815cbfbc..30df4353e 100644
--- a/lib/watchaggregator/aggregator_test.go
+++ b/lib/watchaggregator/aggregator_test.go
@@ -231,9 +231,7 @@ func TestNoDelay(t *testing.T) {
 func getEventPaths(dir *eventDir, dirPath string, a *aggregator) []string {
 	var paths []string
 	for childName, childDir := range dir.dirs {
-		for _, path := range getEventPaths(childDir, filepath.Join(dirPath, childName), a) {
-			paths = append(paths, path)
-		}
+		paths = append(paths, getEventPaths(childDir, filepath.Join(dirPath, childName), a)...)
 	}
 	for name := range dir.events {
 		paths = append(paths, filepath.Join(dirPath, name))
@@ -264,9 +262,7 @@ func compareBatchToExpected(batch []string, expectedPaths []string) (missing []s
 			missing = append(missing, expected)
 		}
 	}
-	for _, received := range batch {
-		unexpected = append(unexpected, received)
-	}
+	unexpected = append(unexpected, batch...)
 	return missing, unexpected
 }