diff --git a/app/window.go b/app/window.go
index 62c3d0ba..116a38d2 100644
--- a/app/window.go
+++ b/app/window.go
@@ -71,7 +71,6 @@ type Window struct {
 	animating    bool
 	hasNextFrame bool
 	nextFrame    time.Time
-	delayedDraw  *time.Timer
 	// viewport is the latest frame size with insets applied.
 	viewport image.Rectangle
 	// metric is the metric from the most recent frame.
@@ -147,7 +146,7 @@ func NewWindow(options ...Option) *Window {
 
 	w := &Window{
 		out:              make(chan event.Event),
-		immediateRedraws: make(chan struct{}, 0),
+		immediateRedraws: make(chan struct{}),
 		redraws:          make(chan struct{}, 1),
 		scheduledRedraws: make(chan time.Time, 1),
 		frames:           make(chan *op.Ops),
diff --git a/font/opentype/internal/shaping.go b/font/opentype/internal/shaping.go
index 99bbc525..7abff196 100644
--- a/font/opentype/internal/shaping.go
+++ b/font/opentype/internal/shaping.go
@@ -100,7 +100,6 @@ func computeGlyphClusters(l *text.Layout) {
 		clusters = append(clusters, newlineCluster)
 	}
 	l.Clusters = clusters
-	return
 }
 
 // langConfig describes the language and writing system of a body of text.
@@ -396,10 +395,6 @@ func toGioGlyphs(in []shaping.Glyph) []text.Glyph {
 
 // ToLine converts the output into a text.Line
 func (o output) ToLine() text.Line {
-	advances := make([]fixed.Int26_6, 0, len(o.Shaped.Glyphs))
-	for _, glyph := range o.Shaped.Glyphs {
-		advances = append(advances, glyph.XAdvance)
-	}
 	layout := text.Layout{
 		Glyphs:    toGioGlyphs(o.Shaped.Glyphs),
 		Runes:     o.RuneRange,
@@ -458,11 +453,7 @@ func Document(shaper Shaper, face font.Face, ppem fixed.Int26_6, maxWidth int, l
 			}
 			paragraphText = append(paragraphText, r)
 			script := language.LookupScript(r)
-			if _, ok := langs[script]; ok {
-				langs[script]++
-			} else {
-				langs[script] = 1
-			}
+			langs[script]++
 			bytes += sz
 			runes++
 			if r == '\n' {
diff --git a/font/opentype/internal/shaping_test.go b/font/opentype/internal/shaping_test.go
index 8912b676..f3eaa259 100644
--- a/font/opentype/internal/shaping_test.go
+++ b/font/opentype/internal/shaping_test.go
@@ -890,7 +890,6 @@ func TestEngineLineWrap(t *testing.T) {
 func TestEngineDocument(t *testing.T) {
 	const doc = `Rutrum quisque non tellus orci ac auctor augue.
 At risus viverra adipiscing at.`
-	const numLines = 2
 	english := system.Locale{
 		Language:  "EN",
 		Direction: system.LTR,
@@ -980,7 +979,6 @@ func TestLayoutComputeClusters(t *testing.T) {
 	type testcase struct {
 		name     string
 		line     text.Layout
-		lastLine bool
 		expected []text.GlyphCluster
 	}
 	for _, tc := range []testcase{
diff --git a/font/opentype/opentype_test.go b/font/opentype/opentype_test.go
index 682c7670..95502302 100644
--- a/font/opentype/opentype_test.go
+++ b/font/opentype/opentype_test.go
@@ -1,23 +1,13 @@
 package opentype
 
 import (
-	"bytes"
-	"compress/gzip"
-	"encoding/binary"
-	"fmt"
-	"io/ioutil"
-	"os"
 	"strings"
 	"testing"
 
 	"golang.org/x/image/font/gofont/goregular"
 	"golang.org/x/image/math/fixed"
 
-	"gioui.org/internal/ops"
 	"gioui.org/io/system"
-	"gioui.org/op"
-	"gioui.org/op/clip"
-	"gioui.org/text"
 )
 
 var english = system.Locale{
@@ -53,99 +43,3 @@ func TestEmptyString(t *testing.T) {
 		t.Errorf("got bounds %+v for empty string; expected %+v", got, exp)
 	}
 }
-
-func decompressFontFile(name string) (*Font, []byte, error) {
-	f, err := os.Open(name)
-	if err != nil {
-		return nil, nil, fmt.Errorf("could not open file for reading: %s: %v", name, err)
-	}
-	defer f.Close()
-	gz, err := gzip.NewReader(f)
-	if err != nil {
-		return nil, nil, fmt.Errorf("font file contains invalid gzip data: %v", err)
-	}
-	src, err := ioutil.ReadAll(gz)
-	if err != nil {
-		return nil, nil, fmt.Errorf("failed to decompress font file: %v", err)
-	}
-	fnt, err := Parse(src)
-	if err != nil {
-		return nil, nil, fmt.Errorf("file did not contain a valid font: %v", err)
-	}
-	return fnt, src, nil
-}
-
-// mergeFonts produces a trivial OpenType Collection (OTC) file for two source fonts.
-// It makes many assumptions and is not meant for general use.
-// For file format details, see https://docs.microsoft.com/en-us/typography/opentype/spec/otff
-// For a robust tool to generate these files, see https://pypi.org/project/afdko/
-func mergeFonts(ttf1, ttf2 []byte) []byte {
-	// Locations to place the two embedded fonts. All of the offsets to the fonts' internal tables will need to be
-	// shifted from the start of the file by the appropriate amount, and then everything will work as expected.
-	offset1 := uint32(20) // Length of OpenType collection headers
-	offset2 := offset1 + uint32(len(ttf1))
-
-	var buf bytes.Buffer
-	_, _ = buf.Write([]byte("ttcf\x00\x01\x00\x00\x00\x00\x00\x02"))
-	_ = binary.Write(&buf, binary.BigEndian, offset1)
-	_ = binary.Write(&buf, binary.BigEndian, offset2)
-
-	// Inline function to copy a font into the collection verbatim, except for adding an offset to all of the font's
-	// table positions.
-	copyOffsetTTF := func(ttf []byte, offset uint32) {
-		_, _ = buf.Write(ttf[:12])
-		numTables := binary.BigEndian.Uint16(ttf[4:6])
-		for i := uint16(0); i < numTables; i++ {
-			p := 12 + 16*i
-			_, _ = buf.Write(ttf[p : p+8])
-			tblLoc := binary.BigEndian.Uint32(ttf[p+8:p+12]) + offset
-			_ = binary.Write(&buf, binary.BigEndian, tblLoc)
-			_, _ = buf.Write(ttf[p+12 : p+16])
-		}
-		_, _ = buf.Write(ttf[12+16*numTables:])
-	}
-	copyOffsetTTF(ttf1, offset1)
-	copyOffsetTTF(ttf2, offset2)
-
-	return buf.Bytes()
-}
-
-// shapeRune uses a given Face to shape exactly one rune at a fixed size, then returns the resulting shape data.
-func shapeRune(f text.Face, r rune) (clip.PathSpec, error) {
-	ppem := fixed.I(200)
-	lines, err := f.Layout(ppem, 2000, english, strings.NewReader(string(r)))
-	if err != nil {
-		return clip.PathSpec{}, err
-	}
-	if len(lines) != 1 {
-		return clip.PathSpec{}, fmt.Errorf("unexpected rendering for \"U+%08X\": got %d lines (expected: 1)", r, len(lines))
-	}
-	return f.Shape(ppem, lines[0].Layout), nil
-}
-
-// areShapesEqual returns true iff both given text shapes are produced with identical operations.
-func areShapesEqual(shape1, shape2 clip.PathSpec) bool {
-	var ops1, ops2 op.Ops
-	clip.Outline{Path: shape1}.Op().Push(&ops1).Pop()
-	clip.Outline{Path: shape2}.Op().Push(&ops2).Pop()
-	var r1, r2 ops.Reader
-	r1.Reset(&ops1.Internal)
-	r2.Reset(&ops2.Internal)
-	for {
-		encOp1, ok1 := r1.Decode()
-		encOp2, ok2 := r2.Decode()
-		if ok1 != ok2 {
-			return false
-		}
-		if !ok1 {
-			break
-		}
-		if len(encOp1.Refs) > 0 || len(encOp2.Refs) > 0 {
-			panic("unexpected ops with refs in font shaping test")
-		}
-		if !bytes.Equal(encOp1.Data, encOp2.Data) {
-			return false
-		}
-	}
-	return true
-}
diff --git a/gpu/compute.go b/gpu/compute.go
index 83196a74..242a8c5b 100644
--- a/gpu/compute.go
+++ b/gpu/compute.go
@@ -265,7 +265,6 @@ type clipState struct {
 	path      []byte
 	pathKey   ops.Key
 	intersect f32.Rectangle
-	push      bool
 
 	clipKey
 }
@@ -308,11 +307,6 @@ type encoder struct {
 	ntrans   int
 }
 
-type encodeState struct {
-	trans f32.Affine2D
-	clip  f32.Rectangle
-}
-
 // sizedBuffer holds a GPU buffer, or its equivalent CPU memory.
 type sizedBuffer struct {
 	size   int
@@ -1612,13 +1606,6 @@ func (e *encoder) numElements() int {
 	return len(e.scene)
 }
 
-func (e *encoder) append(e2 encoder) {
-	e.scene = append(e.scene, e2.scene...)
-	e.npath += e2.npath
-	e.npathseg += e2.npathseg
-	e.ntrans += e2.ntrans
-}
-
 func (e *encoder) transform(m f32.Affine2D) {
 	e.scene = append(e.scene, scene.Transform(m))
 	e.ntrans++
@@ -1666,11 +1653,6 @@ func (e *encoder) line(start, end f32.Point) {
 	e.npathseg++
 }
 
-func (e *encoder) quad(start, ctrl, end f32.Point) {
-	e.scene = append(e.scene, scene.Quad(start, ctrl, end))
-	e.npathseg++
-}
-
 func (c *collector) reset() {
 	c.prevFrame, c.frame = c.frame, c.prevFrame
 	c.profile = false
diff --git a/gpu/internal/opengl/opengl.go b/gpu/internal/opengl/opengl.go
index 73b9fffd..7148e930 100644
--- a/gpu/internal/opengl/opengl.go
+++ b/gpu/internal/opengl/opengl.go
@@ -49,7 +49,6 @@ type Backend struct {
 type glState struct {
 	drawFBO     gl.Framebuffer
 	readFBO     gl.Framebuffer
-	renderBuf   gl.Renderbuffer
 	vertAttribs [5]struct {
 		obj        gl.Buffer
 		enabled    bool
@@ -154,11 +153,6 @@ type uniformLocation struct {
 	size    int
 }
 
-type inputLayout struct {
-	inputs []shader.InputLocation
-	layout []driver.InputDesc
-}
-
 // textureTriple holds the type settings for
 // a TexImage2D call.
 type textureTriple struct {
@@ -426,13 +420,6 @@ func (s *glState) activeTexture(f *gl.Functions, unit gl.Enum) {
 	}
 }
 
-func (s *glState) bindRenderbuffer(f *gl.Functions, target gl.Enum, r gl.Renderbuffer) {
-	if !r.Equal(s.renderBuf) {
-		f.BindRenderbuffer(gl.RENDERBUFFER, r)
-		s.renderBuf = r
-	}
-}
-
 func (s *glState) bindTexture(f *gl.Functions, unit int, t gl.Texture) {
 	s.activeTexture(f, gl.TEXTURE0+gl.Enum(unit))
 	if !t.Equal(s.texUnits.binds[unit]) {
@@ -448,13 +435,6 @@ func (s *glState) bindVertexArray(f *gl.Functions, a gl.VertexArray) {
 	}
 }
 
-func (s *glState) deleteRenderbuffer(f *gl.Functions, r gl.Renderbuffer) {
-	f.DeleteRenderbuffer(r)
-	if r.Equal(s.renderBuf) {
-		s.renderBuf = gl.Renderbuffer{}
-	}
-}
-
 func (s *glState) deleteFramebuffer(f *gl.Functions, fbo gl.Framebuffer) {
 	f.DeleteFramebuffer(fbo)
 	if fbo.Equal(s.drawFBO) {
diff --git a/gpu/path.go b/gpu/path.go
index e0662843..8b5beace 100644
--- a/gpu/path.go
+++ b/gpu/path.go
@@ -58,7 +58,6 @@ type coverUniforms struct {
 	uvCoverTransform [4]float32
 	uvTransformR1    [4]float32
 	uvTransformR2    [4]float32
-	z                float32
 }
 
 type stenciler struct {
@@ -239,6 +238,9 @@ func newStenciler(ctx driver.Device) *stenciler {
 		Topology:    driver.TopologyTriangleStrip,
 	})
 	st.ipipeline.pipeline = &pipeline{ipipe, vertUniforms}
+	if err != nil {
+		panic(err)
+	}
 	return st
 }
 
diff --git a/internal/stroke/stroke.go b/internal/stroke/stroke.go
index 34f656f0..20fd5914 100644
--- a/internal/stroke/stroke.go
+++ b/internal/stroke/stroke.go
@@ -69,12 +69,6 @@ type strokeState struct {
 
 type StrokeQuads []StrokeQuad
 
-func (qs *StrokeQuads) setContour(n uint32) {
-	for i := range *qs {
-		(*qs)[i].Contour = n
-	}
-}
-
 func (qs *StrokeQuads) pen() f32.Point {
 	return (*qs)[len(*qs)-1].Quad.To
 }
@@ -330,8 +324,7 @@ func strokePathNorm(p0, p1, p2 f32.Point, t, d float32) f32.Point {
 	panic("impossible")
 }
 
-func rot90CW(p f32.Point) f32.Point  { return f32.Pt(+p.Y, -p.X) }
-func rot90CCW(p f32.Point) f32.Point { return f32.Pt(-p.Y, +p.X) }
+func rot90CW(p f32.Point) f32.Point { return f32.Pt(+p.Y, -p.X) }
 
 // cosPt returns the cosine of the opening angle between p and q.
 func cosPt(p, q f32.Point) float32 {
diff --git a/internal/vk/vulkan.go b/internal/vk/vulkan.go
index 5703cc04..b380e2ba 100644
--- a/internal/vk/vulkan.go
+++ b/internal/vk/vulkan.go
@@ -1750,7 +1750,7 @@ func AllocateDescriptorSets(d Device, pool DescriptorPool, layout DescriptorSetL
 		descriptorSetCount: C.uint32_t(count),
 		pSetLayouts:        &layouts[0],
 	}
-	sets := make([]DescriptorSet, count, count)
+	sets := make([]DescriptorSet, count)
 	if err := vkErr(C.vkAllocateDescriptorSets(funcs.vkAllocateDescriptorSets, d, inf, &sets[0])); err != nil {
 		return nil, fmt.Errorf("vulkan: vkAllocateDescriptorSets: %w", err)
 	}
diff --git a/layout/list.go b/layout/list.go
index 2907b6e4..bb9e320c 100644
--- a/layout/list.go
+++ b/layout/list.go
@@ -283,10 +283,6 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 			cross = (maxCross - sz.Y) / 2
 		}
 		childSize := sz.X
-		max := childSize + pos
-		if max > mainMax {
-			max = mainMax
-		}
 		min := pos
 		if min < 0 {
 			min = 0
diff --git a/text/text.go b/text/text.go
index 7b555e64..822e23d2 100644
--- a/text/text.go
+++ b/text/text.go
@@ -128,27 +128,6 @@ func (l Layout) Slice(start, end int) Layout {
 	return out
 }
 
-// equals returns true when l2 is logically equivalent to l.
-func (l Layout) equals(l2 Layout) bool {
-	if len(l.Glyphs) != len(l2.Glyphs) || len(l.Clusters) != len(l2.Clusters) {
-		return false
-	}
-	if l.Runes != l2.Runes || l.Direction != l2.Direction {
-		return false
-	}
-	for i := range l.Clusters {
-		if l.Clusters[i] != l2.Clusters[i] {
-			return false
-		}
-	}
-	for i := range l.Glyphs {
-		if l.Glyphs[i] != l2.Glyphs[i] {
-			return false
-		}
-	}
-	return true
-}
-
 // Style is the font style.
 type Style int
 
diff --git a/widget/editor.go b/widget/editor.go
index 4bee3fa2..94ec3ed4 100644
--- a/widget/editor.go
+++ b/widget/editor.go
@@ -126,8 +126,6 @@ type maskReader struct {
 	maskBuf [utf8.UTFMax]byte
 	// mask is the utf-8 encoded mask rune.
 	mask []byte
-	// overflow contains excess mask bytes left over after the last Read call.
-	overflow []byte
 }
 
 // combinedPos is a point in the editor.
@@ -198,14 +196,6 @@ type SubmitEvent struct {
 // Editor.SelectedText() (which can be empty).
 type SelectEvent struct{}
 
-type line struct {
-	offset         image.Point
-	clip           clip.Op
-	selected       bool
-	selectionYOffs int
-	selectionSize  image.Point
-}
-
 const (
 	blinksPerSecond  = 1
 	maxBlinkDuration = 10 * time.Second
@@ -1460,14 +1450,6 @@ func sign(n int) int {
 	}
 }
 
-// sortPoints returns a and b sorted such that a2 <= b2.
-func sortPoints(a, b screenPos) (a2, b2 screenPos) {
-	if b.Less(a) {
-		return b, a
-	}
-	return a, b
-}
-
 func nullLayout(rr io.RuneReader) ([]text.Line, error) {
 	var rerr error
 	var n int
diff --git a/widget/editor_test.go b/widget/editor_test.go
index 66e285ef..e1f45e33 100644
--- a/widget/editor_test.go
+++ b/widget/editor_test.go
@@ -993,11 +993,3 @@ func printLines(e *Editor) {
 		fmt.Printf("%d: %s\n", n, text)
 	}
 }
-
-// sortInts returns a and b sorted such that a2 <= b2.
-func sortInts(a, b int) (a2, b2 int) {
-	if b < a {
-		return b, a
-	}
-	return a, b
-}