all: clean up code, upgrade to modern Go

Signed-off-by: ddkwork

layout/list.go

@@ -308,10 +308,6 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 			cross = (maxCross - sz.Y) / 2
 		}
 		childSize := sz.X
-		min := pos
-		if min < 0 {
-			min = 0
-		}
 		pt := l.Axis.Convert(image.Pt(pos, cross))
 		trans := op.Offset(pt).Push(ops)
 		child.call.Add(ops)

layout/list_test.go

@@ -88,7 +88,8 @@ func TestListPosition(t *testing.T) {
 		{label: "1 visible 0 hidden", num: 1, count: 1, last: 10},
 		{label: "2 visible 0 hidden", num: 2, count: 2},
 		{label: "2 visible 1 hidden", num: 3, count: 2},
-		{label: "3 visible 0 hidden small scroll", num: 3, count: 3, offset: 5, last: -5,
+		{
+			label: "3 visible 0 hidden small scroll", num: 3, count: 3, offset: 5, last: -5,
 			scroll: _s(
 				pointer.Event{
 					Source:   pointer.Mouse,
@@ -107,8 +108,10 @@ func TestListPosition(t *testing.T) {
 					Kind:     pointer.Release,
 					Position: f32.Pt(5, 0),
 				},
-			)},
-		{label: "3 visible 0 hidden small scroll 2", num: 3, count: 3, offset: 3, last: -7,
+			),
+		},
+		{
+			label: "3 visible 0 hidden small scroll 2", num: 3, count: 3, offset: 3, last: -7,
 			scroll: _s(
 				pointer.Event{
 					Source:   pointer.Mouse,
@@ -127,8 +130,10 @@ func TestListPosition(t *testing.T) {
 					Kind:     pointer.Release,
 					Position: f32.Pt(5, 0),
 				},
-			)},
-		{label: "2 visible 1 hidden large scroll", num: 3, count: 2, first: 1,
+			),
+		},
+		{
+			label: "2 visible 1 hidden large scroll", num: 3, count: 2, first: 1,
 			scroll: _s(
 				pointer.Event{
 					Source:   pointer.Mouse,
@@ -147,7 +152,8 @@ func TestListPosition(t *testing.T) {
 					Kind:     pointer.Release,
 					Position: f32.Pt(15, 0),
 				},
-			)},
+			),
+		},
 	} {
 		t.Run(tc.label, func(t *testing.T) {
 			gtx.Ops.Reset()

layout/stack_test.go

@@ -17,9 +17,8 @@ func BenchmarkStack(b *testing.B) {
 		},
 	}
 	b.ReportAllocs()
-	b.ResetTimer()
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		gtx.Ops.Reset()
 
 		Stack{}.Layout(gtx,
@@ -41,9 +40,8 @@ func BenchmarkBackground(b *testing.B) {
 		},
 	}
 	b.ReportAllocs()
-	b.ResetTimer()
 
-	for i := 0; i < b.N; i++ {
+	for b.Loop() {
 		gtx.Ops.Reset()
 
 		Background{}.Layout(gtx,