tree-wide: Turn on all revive linters (with exceptions)

25 files changed, 117 insertions, 90 deletions

diff --git a/.golangci.yml b/.golangci.yml
index 06570ba..ba58f21 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -85,8 +85,33 @@ linters-settings:
     allow-no-explanation:
       - dupword
   revive:
+    enable-all-rules: true
     rules:
+      - { name: call-to-gc, disabled: true }
       - { name: exported, disabled: true } # TODO: Add doc comments to exported identifiers
+      - { name: file-header, disabled: true } # TODO: This might actually be useful for copyright
+      - { name: flag-parameter, disabled: true }
+      - { name: modifies-value-receiver, disabled: true }
+      - { name: unexported-return, disabled: true }
+      # Style.
+      - { name: banned-characters, disabled: true }
+      - { name: line-length-limit, disabled: true }
+      - { name: nested-structs, disabled: true }
+      - { name: var-naming, disabled: true }
+      # Complexity; sometimes code is just complex.
+      - { name: argument-limit, disabled: true }
+      - { name: cognitive-complexity, disabled: true }
+      - { name: cyclomatic, disabled: true }
+      - { name: function-length, disabled: true }
+      - { name: function-result-limit, disabled: true }
+      - { name: max-public-structs, disabled: true }
+      # Duplicates.
+      - { name: add-constant, disabled: true } # duplicates gomnd
+      - { name: receiver-naming, disabled: true } # duplicates stylecheck ST1016
+      - { name: unhandled-error, disabled: true } # duplicates errcheck
+      # Buggy.
+      - { name: confusing-naming, disabled: true } # false positive on methods implementing interfaces
+      - { name: import-shadowing, disabled: true } # false positive on methods
   stylecheck:
     checks:
       - "all"
diff --git a/cmd/btrfs-rec/inspect/mount/mount.go b/cmd/btrfs-rec/inspect/mount/mount.go
index 01d667f..0e8faf1 100644
--- a/cmd/btrfs-rec/inspect/mount/mount.go
+++ b/cmd/btrfs-rec/inspect/mount/mount.go
@@ -482,4 +482,4 @@ func (sv *subvolume) GetXattr(_ context.Context, op *fuseops.GetXattrOp) error {
 	return nil
 }
 
-func (sv *subvolume) Destroy() {}
+func (*subvolume) Destroy() {}
diff --git a/cmd/btrfs-rec/inspect/rebuildmappings/scan.go b/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
index f9c3bf3..b88f01c 100644
--- a/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
+++ b/cmd/btrfs-rec/inspect/rebuildmappings/scan.go
@@ -103,7 +103,7 @@ func (scanner *deviceScanner) ScanStats() scanStats {
 	}
 }
 
-func newDeviceScanner(ctx context.Context, sb btrfstree.Superblock, numBytes btrfsvol.PhysicalAddr, numSectors int) btrfsutil.DeviceScanner[scanStats, ScanOneDeviceResult] {
+func newDeviceScanner(_ context.Context, sb btrfstree.Superblock, _ btrfsvol.PhysicalAddr, numSectors int) btrfsutil.DeviceScanner[scanStats, ScanOneDeviceResult] {
 	scanner := new(deviceScanner)
 	scanner.alg = sb.ChecksumType
 	scanner.result.FoundNodes = make(map[btrfsvol.LogicalAddr][]btrfsvol.PhysicalAddr)
@@ -112,7 +112,7 @@ func newDeviceScanner(ctx context.Context, sb btrfstree.Superblock, numBytes btr
 	return scanner
 }
 
-func (scanner *deviceScanner) ScanSector(ctx context.Context, dev *btrfs.Device, paddr btrfsvol.PhysicalAddr) error {
+func (scanner *deviceScanner) ScanSector(_ context.Context, dev *btrfs.Device, paddr btrfsvol.PhysicalAddr) error {
 	sum, err := btrfs.ChecksumPhysical(dev, scanner.alg, paddr)
 	if err != nil {
 		return err
@@ -190,7 +190,7 @@ func (scanner *deviceScanner) ScanNode(ctx context.Context, nodeRef *diskio.Ref[
 	return nil
 }
 
-func (scanner *deviceScanner) ScanDone(ctx context.Context) (ScanOneDeviceResult, error) {
+func (scanner *deviceScanner) ScanDone(_ context.Context) (ScanOneDeviceResult, error) {
 	scanner.result.Checksums.Sums = btrfssum.ShortSum(scanner.sums.String())
 	return scanner.result, nil
 }
diff --git a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild.go b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild.go
index 364dfa0..ca1ce8c 100644
--- a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild.go
+++ b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild.go
@@ -286,7 +286,7 @@ func (o *rebuilder) processSettledItemQueue(ctx context.Context) error {
 			ctx := dlog.WithField(ctx, "btrfs.inspect.rebuild-trees.rebuild.process.item", item.keyAndTree)
 			o.curKey.TreeID = item.TreeID
 			o.curKey.Key.Val = item.Key
-			btrfscheck.HandleItem(o, ctx, item.TreeID, btrfstree.Item{
+			btrfscheck.HandleItem(ctx, o, item.TreeID, btrfstree.Item{
 				Key:  item.Key,
 				Body: item.Body,
 			})
diff --git a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_treecb.go b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_treecb.go
index e6a0777..a422a47 100644
--- a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_treecb.go
+++ b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_treecb.go
@@ -14,7 +14,7 @@ import (
 )
 
 // AddedItem implements btrfsutil.RebuiltForrestCallbacks.
-func (o *rebuilder) AddedItem(ctx context.Context, tree btrfsprim.ObjID, key btrfsprim.Key) {
+func (o *rebuilder) AddedItem(_ context.Context, tree btrfsprim.ObjID, key btrfsprim.Key) {
 	o.addedItemQueue.Insert(keyAndTree{
 		TreeID: tree,
 		Key:    key,
@@ -22,7 +22,7 @@ func (o *rebuilder) AddedItem(ctx context.Context, tree btrfsprim.ObjID, key btr
 }
 
 // AddedRoot implements btrfsutil.RebuiltForrestCallbacks.
-func (o *rebuilder) AddedRoot(ctx context.Context, tree btrfsprim.ObjID, root btrfsvol.LogicalAddr) {
+func (o *rebuilder) AddedRoot(_ context.Context, tree btrfsprim.ObjID, _ btrfsvol.LogicalAddr) {
 	if retries := o.retryItemQueue[tree]; retries != nil {
 		o.addedItemQueue.InsertFrom(retries)
 	}
diff --git a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_wantcb.go b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_wantcb.go
index 4a5029e..704f4ee 100644
--- a/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_wantcb.go
+++ b/cmd/btrfs-rec/inspect/rebuildtrees/rebuild_wantcb.go
@@ -20,7 +20,7 @@ import (
 )
 
 // FSErr implements btrfscheck.GraphCallbacks.
-func (o *rebuilder) FSErr(ctx context.Context, e error) {
+func (*rebuilder) FSErr(ctx context.Context, e error) {
 	dlog.Errorf(ctx, "filesystem error: %v", e)
 }
 
diff --git a/cmd/btrfs-rec/main.go b/cmd/btrfs-rec/main.go
index 15f1964..e433654 100644
--- a/cmd/btrfs-rec/main.go
+++ b/cmd/btrfs-rec/main.go
@@ -2,6 +2,8 @@
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+// Command btrfs-rec is used to recover (data from) a broken btrfs
+// filesystem.
 package main
 
 import (
diff --git a/lib/btrfs/btrfsprim/key.go b/lib/btrfs/btrfsprim/key.go
index 2930782..5580c52 100644
--- a/lib/btrfs/btrfsprim/key.go
+++ b/lib/btrfs/btrfsprim/key.go
@@ -42,12 +42,11 @@ func (key Key) Format(tree ObjID) string {
 			return fmt.Sprintf("(%v %v -1)",
 				key.ObjectID.Format(tree),
 				key.ItemType)
-		} else {
-			return fmt.Sprintf("(%v %v %v)",
-				key.ObjectID.Format(tree),
-				key.ItemType,
-				key.Offset)
 		}
+		return fmt.Sprintf("(%v %v %v)",
+			key.ObjectID.Format(tree),
+			key.ItemType,
+			key.Offset)
 	}
 }
 
diff --git a/lib/btrfs/btrfstree/btree_tree.go b/lib/btrfs/btrfstree/btree_tree.go
index df58c0c..1e3c789 100644
--- a/lib/btrfs/btrfstree/btree_tree.go
+++ b/lib/btrfs/btrfstree/btree_tree.go
@@ -188,7 +188,8 @@ func (fs TreeOperatorImpl) treeSearch(treeRoot TreeRoot, fn func(btrfsprim.Key,
 			return nil, nil, err
 		}
 
-		if node.Data.Head.Level > 0 {
+		switch {
+		case node.Data.Head.Level > 0:
 			// interior node
 
 			// Search for the right-most node.Data.BodyInterior item for which
@@ -220,7 +221,7 @@ func (fs TreeOperatorImpl) treeSearch(treeRoot TreeRoot, fn func(btrfsprim.Key,
 				ToMaxKey:         toMaxKey,
 			})
 			FreeNodeRef(node)
-		} else {
+		default:
 			// leaf node
 
 			// Search for a member of node.Data.BodyLeaf for which
diff --git a/lib/btrfs/btrfstree/path.go b/lib/btrfs/btrfstree/path.go
index dc2fc1d..b9ab5bc 100644
--- a/lib/btrfs/btrfstree/path.go
+++ b/lib/btrfs/btrfstree/path.go
@@ -101,23 +101,22 @@ func (elem TreePathElem) writeNodeTo(w io.Writer) {
 func (path TreePath) String() string {
 	if len(path) == 0 {
 		return "(empty-path)"
+	}
+	var ret strings.Builder
+	fmt.Fprintf(&ret, "%s->", path[0].FromTree.Format(btrfsprim.ROOT_TREE_OBJECTID))
+	if len(path) == 1 && path[0] == (TreePathElem{FromTree: path[0].FromTree, FromItemSlot: -1}) {
+		ret.WriteString("(empty-path)")
 	} else {
-		var ret strings.Builder
-		fmt.Fprintf(&ret, "%s->", path[0].FromTree.Format(btrfsprim.ROOT_TREE_OBJECTID))
-		if len(path) == 1 && path[0] == (TreePathElem{FromTree: path[0].FromTree, FromItemSlot: -1}) {
-			ret.WriteString("(empty-path)")
-		} else {
-			path[0].writeNodeTo(&ret)
-		}
-		for _, elem := range path[1:] {
-			fmt.Fprintf(&ret, "[%v]", elem.FromItemSlot)
-			if elem.ToNodeAddr != 0 {
-				ret.WriteString("->")
-				elem.writeNodeTo(&ret)
-			}
+		path[0].writeNodeTo(&ret)
+	}
+	for _, elem := range path[1:] {
+		fmt.Fprintf(&ret, "[%v]", elem.FromItemSlot)
+		if elem.ToNodeAddr != 0 {
+			ret.WriteString("->")
+			elem.writeNodeTo(&ret)
 		}
-		return ret.String()
 	}
+	return ret.String()
 }
 
 func (path TreePath) DeepCopy() TreePath {
diff --git a/lib/btrfs/btrfstree/types_node.go b/lib/btrfs/btrfstree/types_node.go
index c770fe8..8295ccb 100644
--- a/lib/btrfs/btrfstree/types_node.go
+++ b/lib/btrfs/btrfstree/types_node.go
@@ -113,20 +113,22 @@ type NodeHeader struct {
 // .Head.NumItems.
 func (node Node) MaxItems() uint32 {
 	bodyBytes := node.Size - uint32(nodeHeaderSize)
-	if node.Head.Level > 0 {
+	switch {
+	case node.Head.Level > 0:
 		return bodyBytes / uint32(keyPointerSize)
-	} else {
+	default:
 		return bodyBytes / uint32(itemHeaderSize)
 	}
 }
 
 func (node Node) MinItem() (btrfsprim.Key, bool) {
-	if node.Head.Level > 0 {
+	switch {
+	case node.Head.Level > 0:
 		if len(node.BodyInterior) == 0 {
 			return btrfsprim.Key{}, false
 		}
 		return node.BodyInterior[0].Key, true
-	} else {
+	default:
 		if len(node.BodyLeaf) == 0 {
 			return btrfsprim.Key{}, false
 		}
@@ -135,12 +137,13 @@ func (node Node) MinItem() (btrfsprim.Key, bool) {
 }
 
 func (node Node) MaxItem() (btrfsprim.Key, bool) {
-	if node.Head.Level > 0 {
+	switch {
+	case node.Head.Level > 0:
 		if len(node.BodyInterior) == 0 {
 			return btrfsprim.Key{}, false
 		}
 		return node.BodyInterior[len(node.BodyInterior)-1].Key, true
-	} else {
+	default:
 		if len(node.BodyLeaf) == 0 {
 			return btrfsprim.Key{}, false
 		}
@@ -221,15 +224,15 @@ func (node Node) MarshalBinary() ([]byte, error) {
 
 	buf := make([]byte, node.Size)
 
-	if bs, err := binstruct.Marshal(node.Head); err != nil {
+	bs, err := binstruct.Marshal(node.Head)
+	if err != nil {
 		return buf, err
-	} else {
-		if len(bs) != nodeHeaderSize {
-			return nil, fmt.Errorf("header is %v bytes but expected %v",
-				len(bs), nodeHeaderSize)
-		}
-		copy(buf, bs)
 	}
+	if len(bs) != nodeHeaderSize {
+		return nil, fmt.Errorf("header is %v bytes but expected %v",
+			len(bs), nodeHeaderSize)
+	}
+	copy(buf, bs)
 
 	if node.Head.Level > 0 {
 		if err := node.marshalInteriorTo(buf[nodeHeaderSize:]); err != nil {
diff --git a/lib/btrfs/io4_fs.go b/lib/btrfs/io4_fs.go
index e146739..b1a1232 100644
--- a/lib/btrfs/io4_fs.go
+++ b/lib/btrfs/io4_fs.go
@@ -122,7 +122,7 @@ func (sv *Subvolume) LoadBareInode(inode btrfsprim.ObjID) (*BareInode, error) {
 		})
 		if err != nil {
 			val.Errs = append(val.Errs, err)
-			return
+			return val
 		}
 
 		switch itemBody := item.Body.(type) {
@@ -135,7 +135,7 @@ func (sv *Subvolume) LoadBareInode(inode btrfsprim.ObjID) (*BareInode, error) {
 			panic(fmt.Errorf("should not happen: INODE_ITEM has unexpected item type: %T", itemBody))
 		}
 
-		return
+		return val
 	})
 	if val.InodeItem == nil {
 		return nil, val.Errs
@@ -156,7 +156,7 @@ func (sv *Subvolume) LoadFullInode(inode btrfsprim.ObjID) (*FullInode, error) {
 		if err != nil {
 			val.Errs = append(val.Errs, err)
 			if len(items) == 0 {
-				return
+				return val
 			}
 		}
 		for _, item := range items {
@@ -190,7 +190,7 @@ func (sv *Subvolume) LoadFullInode(inode btrfsprim.ObjID) (*FullInode, error) {
 				val.OtherItems = append(val.OtherItems, item)
 			}
 		}
-		return
+		return val
 	})
 	if val.InodeItem == nil && val.OtherItems == nil {
 		return nil, val.Errs
@@ -205,12 +205,12 @@ func (sv *Subvolume) LoadDir(inode btrfsprim.ObjID) (*Dir, error) {
 		fullInode, err := sv.LoadFullInode(inode)
 		if err != nil {
 			val.Errs = append(val.Errs, err)
-			return
+			return val
 		}
 		val.FullInode = *fullInode
 		val.SV = sv
 		val.populate()
-		return
+		return val
 	})
 	if val.Inode == 0 {
 		return nil, val.Errs
@@ -342,12 +342,12 @@ func (sv *Subvolume) LoadFile(inode btrfsprim.ObjID) (*File, error) {
 		fullInode, err := sv.LoadFullInode(inode)
 		if err != nil {
 			val.Errs = append(val.Errs, err)
-			return
+			return val
 		}
 		val.FullInode = *fullInode
 		val.SV = sv
 		val.populate()
-		return
+		return val
 	})
 	if val.Inode == 0 {
 		return nil, val.Errs
diff --git a/lib/btrfscheck/graph.go b/lib/btrfscheck/graph.go
index ae6d1ec..806f609 100644
--- a/lib/btrfscheck/graph.go
+++ b/lib/btrfscheck/graph.go
@@ -47,7 +47,7 @@ func HandleItemWouldBeNoOp(typ btrfsprim.ItemType) bool {
 	}
 }
 
-func HandleItem(o GraphCallbacks, ctx context.Context, treeID btrfsprim.ObjID, item btrfstree.Item) {
+func HandleItem(ctx context.Context, o GraphCallbacks, treeID btrfsprim.ObjID, item btrfstree.Item) {
 	// Notionally, just express the relationships shown in
 	// https://btrfs.wiki.kernel.org/index.php/File:References.png (from the page
 	// https://btrfs.wiki.kernel.org/index.php/Data_Structures )
diff --git a/lib/btrfsutil/listnodes.go b/lib/btrfsutil/listnodes.go
index 16300da..5505d23 100644
--- a/lib/btrfsutil/listnodes.go
+++ b/lib/btrfsutil/listnodes.go
@@ -30,7 +30,7 @@ func (s nodeStats) String() string {
 
 var _ DeviceScanner[nodeStats, containers.Set[btrfsvol.LogicalAddr]] = (*nodeScanner)(nil)
 
-func newNodeScanner(ctx context.Context, sb btrfstree.Superblock, numBytes btrfsvol.PhysicalAddr, numSectors int) DeviceScanner[nodeStats, containers.Set[btrfsvol.LogicalAddr]] {
+func newNodeScanner(context.Context, btrfstree.Superblock, btrfsvol.PhysicalAddr, int) DeviceScanner[nodeStats, containers.Set[btrfsvol.LogicalAddr]] {
 	s := new(nodeScanner)
 	s.nodes = make(containers.Set[btrfsvol.LogicalAddr])
 	return s
@@ -40,16 +40,16 @@ func (s *nodeScanner) ScanStats() nodeStats {
 	return nodeStats{numNodes: len(s.nodes)}
 }
 
-func (*nodeScanner) ScanSector(ctx context.Context, dev *btrfs.Device, paddr btrfsvol.PhysicalAddr) error {
+func (*nodeScanner) ScanSector(context.Context, *btrfs.Device, btrfsvol.PhysicalAddr) error {
 	return nil
 }
 
-func (s *nodeScanner) ScanNode(ctx context.Context, nodeRef *diskio.Ref[btrfsvol.PhysicalAddr, btrfstree.Node]) error {
+func (s *nodeScanner) ScanNode(_ context.Context, nodeRef *diskio.Ref[btrfsvol.PhysicalAddr, btrfstree.Node]) error {
 	s.nodes.Insert(nodeRef.Data.Head.Addr)
 	return nil
 }
 
-func (s *nodeScanner) ScanDone(ctx context.Context) (containers.Set[btrfsvol.LogicalAddr], error) {
+func (s *nodeScanner) ScanDone(_ context.Context) (containers.Set[btrfsvol.LogicalAddr], error) {
 	return s.nodes, nil
 }
 
diff --git a/lib/btrfsutil/print_addrspace.go b/lib/btrfsutil/print_addrspace.go
index c9c51f0..ae2c492 100644
--- a/lib/btrfsutil/print_addrspace.go
+++ b/lib/btrfsutil/print_addrspace.go
@@ -49,7 +49,7 @@ func PrintPhysicalSpace(out io.Writer, fs *btrfs.FS) {
 		return mappings[i].PAddr.Compare(mappings[j].PAddr) < 0
 	})
 
-	var prevDev btrfsvol.DeviceID = 0
+	var prevDev btrfsvol.DeviceID
 	var prevEnd btrfsvol.PhysicalAddr
 	var sumHole, sumExt btrfsvol.AddrDelta
 	for _, mapping := range mappings {
diff --git a/lib/containers/intervaltree.go b/lib/containers/intervaltree.go
index 7b96526..d2e2732 100644
--- a/lib/containers/intervaltree.go
+++ b/lib/containers/intervaltree.go
@@ -39,7 +39,7 @@ type IntervalTree[K Ordered[K], V any] struct {
 	inner RBTree[intervalValue[K, V]]
 }
 
-func (t *IntervalTree[K, V]) attrFn(node *RBNode[intervalValue[K, V]]) {
+func (*IntervalTree[K, V]) attrFn(node *RBNode[intervalValue[K, V]]) {
 	max := node.Value.ValSpan.Max
 	if node.Left != nil && node.Left.Value.ChildSpan.Max.Compare(max) > 0 {
 		max = node.Left.Value.ChildSpan.Max
diff --git a/lib/containers/optional.go b/lib/containers/optional.go
index c0e7b32..5bb7bb6 100644
--- a/lib/containers/optional.go
+++ b/lib/containers/optional.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -19,11 +19,10 @@ var (
 )
 
 func (o Optional[T]) MarshalJSON() ([]byte, error) {
-	if o.OK {
-		return json.Marshal(o.Val)
-	} else {
+	if !o.OK {
 		return []byte("null"), nil
 	}
+	return json.Marshal(o.Val)
 }
 
 func (o *Optional[T]) UnmarshalJSON(dat []byte) error {
diff --git a/lib/containers/rbtree.go b/lib/containers/rbtree.go
index 6182150..59f63aa 100644
--- a/lib/containers/rbtree.go
+++ b/lib/containers/rbtree.go
@@ -167,9 +167,8 @@ func (t *RBTree[T]) Subrange(rangeFn func(T) int, handleFn func(*RBNode[T]) bool
 	_, node := t.root.search(func(v T) int {
 		if rangeFn(v) <= 0 {
 			return -1
-		} else {
-			return 1
 		}
+		return 1
 	})
 	for node != nil && rangeFn(node.Value) > 0 {
 		node = node.Next()
diff --git a/lib/containers/rbtree_test.go b/lib/containers/rbtree_test.go
index d2fe931..c6e7a3b 100644
--- a/lib/containers/rbtree_test.go
+++ b/lib/containers/rbtree_test.go
@@ -108,25 +108,25 @@ func checkRBTree[T constraints.Ordered](t *testing.T, expectedSet Set[T], tree *
 }
 
 func FuzzRBTree(f *testing.F) {
-	Ins := uint8(0b0100_0000)
-	Del := uint8(0)
+	ins := uint8(0b0100_0000)
+	del := uint8(0)
 
 	f.Add([]uint8{})
-	f.Add([]uint8{Ins | 5, Del | 5})
-	f.Add([]uint8{Ins | 5, Del | 6})
-	f.Add([]uint8{Del | 6})
+	f.Add([]uint8{ins | 5, del | 5})
+	f.Add([]uint8{ins | 5, del | 6})
+	f.Add([]uint8{del | 6})
 
 	f.Add([]uint8{ // CLRS Figure 14.4
-		Ins | 1,
-		Ins | 2,
-		Ins | 5,
-		Ins | 7,
-		Ins | 8,
-		Ins | 11,
-		Ins | 14,
-		Ins | 15,
-
-		Ins | 4,
+		ins | 1,
+		ins | 2,
+		ins | 5,
+		ins | 7,
+		ins | 8,
+		ins | 11,
+		ins | 14,
+		ins | 15,
+
+		ins | 4,
 	})
 
 	f.Fuzz(func(t *testing.T, dat []uint8) {
diff --git a/lib/diskio/file_blockbuf.go b/lib/diskio/file_blockbuf.go
index b7db849..0bb3156 100644
--- a/lib/diskio/file_blockbuf.go
+++ b/lib/diskio/file_blockbuf.go
@@ -99,5 +99,5 @@ func (bf *bufferedFile[A]) WriteAt(dat []byte, off A) (n int, err error) {
 		bf.blockCache.Delete(blockOffset)
 	}
 
-	return
+	return n, err
 }
diff --git a/lib/diskio/file_state_test.go b/lib/diskio/file_state_test.go
index 3f0c119..32ca705 100644
--- a/lib/diskio/file_state_test.go
+++ b/lib/diskio/file_state_test.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -21,11 +21,11 @@ func (r byteReaderWithName) Name() string {
 	return r.name
 }
 
-func (r byteReaderWithName) Close() error {
+func (byteReaderWithName) Close() error {
 	return nil
 }
 
-func (r byteReaderWithName) WriteAt([]byte, int64) (int, error) {
+func (byteReaderWithName) WriteAt([]byte, int64) (int, error) {
 	panic("not implemented")
 }
 
diff --git a/lib/fmtutil/fmt_test.go b/lib/fmtutil/fmt_test.go
index 2c63c2e..6d21b3e 100644
--- a/lib/fmtutil/fmt_test.go
+++ b/lib/fmtutil/fmt_test.go
@@ -1,4 +1,4 @@
-// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+// Copyright (C) 2022-2023  Luke Shumaker <lukeshu@lukeshu.com>
 //
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -53,11 +53,11 @@ func (st FmtState) Flag(b int) bool {
 	return false
 }
 
-func (st FmtState) Write([]byte) (int, error) {
+func (FmtState) Write([]byte) (int, error) {
 	panic("not implemented")
 }
 
-func (dst *FmtState) Format(src fmt.State, verb rune) {
+func (dst *FmtState) Format(src fmt.State, _ rune) {
 	if width, ok := src.Width(); ok {
 		dst.MWidth = width
 	}
diff --git a/lib/profile/cobra.go b/lib/profile/cobra.go
index 3094015..9bc55dd 100644
--- a/lib/profile/cobra.go
+++ b/lib/profile/cobra.go
@@ -67,7 +67,7 @@ func (fv *flagValue) Set(filename string) error {
 }
 
 // Type implements pflag.Value.
-func (fv *flagValue) Type() string { return "filename" }
+func (*flagValue) Type() string { return "filename" }
 
 func pStart(name string) startFunc {
 	return func(w io.Writer) (StopFunc, error) {
diff --git a/lib/streamio/runescanner.go b/lib/streamio/runescanner.go
index 947efeb..203439f 100644
--- a/lib/streamio/runescanner.go
+++ b/lib/streamio/runescanner.go
@@ -89,7 +89,7 @@ func (rs *runeScanner) ReadRune() (r rune, size int, err error) {
 			rs.progressWriter.Set(rs.progress)
 		}
 	}
-	return
+	return r, size, err
 }
 
 // ReadRune implements io.RuneScanner.
diff --git a/lib/textui/log.go b/lib/textui/log.go
index 6cf9abe..9aff364 100644
--- a/lib/textui/log.go
+++ b/lib/textui/log.go
@@ -35,7 +35,7 @@ type LogLevelFlag struct {
 var _ pflag.Value = (*LogLevelFlag)(nil)
 
 // Type implements pflag.Value.
-func (lvl *LogLevelFlag) Type() string { return "loglevel" }
+func (*LogLevelFlag) Type() string { return "loglevel" }
 
 // Set implements pflag.Value.
 func (lvl *LogLevelFlag) Set(str string) error {
@@ -94,7 +94,7 @@ func NewLogger(out io.Writer, lvl dlog.LogLevel) dlog.Logger {
 }
 
 // Helper implements dlog.Logger.
-func (l *logger) Helper() {}
+func (*logger) Helper() {}
 
 // WithField implements dlog.Logger.
 func (l *logger) WithField(key string, value any) dlog.Logger {
@@ -127,7 +127,7 @@ func (l *logger) StdLogger(lvl dlog.LogLevel) *log.Logger {
 }
 
 // Log implements dlog.Logger.
-func (l *logger) Log(lvl dlog.LogLevel, msg string) {
+func (*logger) Log(dlog.LogLevel, string) {
 	panic("should not happen: optimized log methods should be used instead")
 }