all: remove unused fields, functions and add missing error handling

Credit to staticcheck.io.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/internal/egl/egl.go

@@ -36,12 +36,11 @@ type eglContext struct {
 }
 
 var (
-	nilEGLDisplay          _EGLDisplay
+	nilEGLDisplay       _EGLDisplay
-	nilEGLSurface          _EGLSurface
+	nilEGLSurface       _EGLSurface
-	nilEGLContext          _EGLContext
+	nilEGLContext       _EGLContext
-	nilEGLConfig           _EGLConfig
+	nilEGLConfig        _EGLConfig
-	nilEGLNativeWindowType NativeWindowType
+	EGL_DEFAULT_DISPLAY NativeDisplayType
-	EGL_DEFAULT_DISPLAY    NativeDisplayType
 )
 
 const (

app/internal/window/os_wayland.go

@@ -1001,13 +1001,6 @@ func (w *window) isAnimating() bool {
 	return w.animating || w.fling.anim.Active()
 }
 
-func (w *window) kill(err error) {
-	if w.pendingErr == nil {
-		w.pendingErr = err
-	}
-	w.dead = true
-}
-
 func (w *window) draw(sync bool) {
 	w.flushScroll()
 	w.mu.Lock()

app/internal/window/os_x11.go

@@ -203,11 +203,9 @@ func (w *x11Window) atom(name string, onlyIfExists bool) C.Atom {
 // in x11window.loop.
 //
 type x11EventHandler struct {
-	w      *x11Window
+	w    *x11Window
-	text   []byte
+	text []byte
-	xev    *C.XEvent
+	xev  *C.XEvent
-	status C.Status
-	keysym C.KeySym
 }
 
 // handleEvents returns true if the window needs to be redrawn.

gpu/gpu.go

@@ -272,11 +272,6 @@ const (
 	materialTexture
 )
 
-const (
-	attribPos = 0
-	attribUV  = 1
-)
-
 func New(ctx backend.Device) (*GPU, error) {
 	defFBO := ctx.CurrentFramebuffer()
 	g := &GPU{

gpu/path.go

@@ -107,14 +107,6 @@ const (
 	pathBatchSize = 10000
 )
 
-const (
-	attribPathCorner = 0
-	attribPathMaxY   = 1
-	attribPathFrom   = 2
-	attribPathCtrl   = 3
-	attribPathTo     = 4
-)
-
 func newPather(ctx backend.Device) *pather {
 	return &pather{
 		ctx:       ctx,
@@ -217,6 +209,9 @@ func (s *fboSet) resize(ctx backend.Device, sizes []image.Point) {
 			}
 			tex, err := ctx.NewTexture(backend.TextureFormatFloat, sz.X, sz.Y, backend.FilterNearest, backend.FilterNearest,
 				backend.BufferBindingTexture|backend.BufferBindingFramebuffer)
+			if err != nil {
+				panic(err)
+			}
 			fbo, err := ctx.NewFramebuffer(tex, 0)
 			if err != nil {
 				panic(err)

io/system/system.go

@@ -23,9 +23,6 @@ type FrameEvent struct {
 	// Frame replaces the window's frame with the new
 	// frame.
 	Frame func(frame *op.Ops)
-	// Whether this draw is system generated and needs a complete
-	// frame before proceeding.
-	sync bool
 }
 
 // Config defines the essential properties of
@@ -96,7 +93,7 @@ func (l Stage) String() string {
 	}
 }
 
-func (_ FrameEvent) ImplementsEvent()    {}
+func (FrameEvent) ImplementsEvent()    {}
-func (_ StageEvent) ImplementsEvent()    {}
+func (StageEvent) ImplementsEvent()    {}
-func (_ *CommandEvent) ImplementsEvent() {}
+func (*CommandEvent) ImplementsEvent() {}
-func (_ DestroyEvent) ImplementsEvent()  {}
+func (DestroyEvent) ImplementsEvent()  {}

layout/flex.go

@@ -36,8 +36,6 @@ type FlexChild struct {
 // Spacing determine the spacing mode for a Flex.
 type Spacing uint8
 
-type flexMode uint8
-
 const (
 	// SpaceEnd leaves space at the end.
 	SpaceEnd Spacing = iota

op/op.go

@@ -95,11 +95,10 @@ type Ops struct {
 // StackOp saves and restores the operation state
 // in a stack-like manner.
 type StackOp struct {
-	stackDepth int
+	id      stackID
-	id         stackID
+	macroID int
-	macroID    int
+	active  bool
-	active     bool
+	ops     *Ops
-	ops        *Ops
 }
 
 // MacroOp records a list of operations for later use.

widget/material/button.go

@@ -132,13 +132,6 @@ func toPointF(p image.Point) f32.Point {
 	return f32.Point{X: float32(p.X), Y: float32(p.Y)}
 }
 
-func toRectF(r image.Rectangle) f32.Rectangle {
-	return f32.Rectangle{
-		Min: toPointF(r.Min),
-		Max: toPointF(r.Max),
-	}
-}
-
 func drawInk(gtx *layout.Context, c widget.Click) {
 	d := gtx.Now().Sub(c.Time)
 	t := float32(d.Seconds())

widget/material/icon.go

@@ -17,7 +17,6 @@ import (
 type Icon struct {
 	Color color.RGBA
 	src   []byte
-	size  unit.Value
 	// Cached values.
 	op       paint.ImageOp
 	imgSize  int