checker: require unsafe for Struct(voidptr) casts

examples/sokol/drawing.v

@@ -35,9 +35,8 @@ fn init(user_data voidptr) {
 	sgl.setup(&sgl_desc)
 }
 
-fn frame(user_data voidptr) {
+fn frame(state &AppState) {
 	// println('frame')
-	state := &AppState(user_data)
 	draw()
 	gfx.begin_default_pass(&state.pass_action, sapp.width(), sapp.height())
 	sgl.draw()

examples/sokol/fonts.v

@@ -55,8 +55,7 @@ fn init(mut state AppState) {
 	}
 }
 
-fn frame(user_data voidptr) {
-	mut state := &AppState(user_data)
+fn frame(mut state AppState) {
 	state.render_font()
 	gfx.begin_default_pass(&state.pass_action, sapp.width(), sapp.height())
 	sgl.draw()

examples/sokol/freetype_raven.v

@@ -91,8 +91,7 @@ fn main() {
 	sapp.run(&desc)
 }
 
-fn init(user_data voidptr) {
-	mut state := &AppState(user_data)
+fn init(mut state AppState) {
 	desc := sapp.create_desc()
 	gfx.setup(&desc)
 	s := &sgl.Desc{}
@@ -107,8 +106,7 @@ fn init(user_data voidptr) {
 	}
 }
 
-fn frame(user_data voidptr) {
-	mut state := &AppState(user_data)
+fn frame(mut state AppState) {
 	state.render_font()
 	gfx.begin_default_pass(&state.pass_action, sapp.width(), sapp.height())
 	sgl.draw()

examples/sokol/particles/particles.v

@@ -73,8 +73,7 @@ fn (a App) draw() {
 	a.ps.draw()
 }
 
-fn init(user_data voidptr) {
-	mut app := &App(user_data)
+fn init(mut app App) {
 	desc := sapp.create_desc()
 	gfx.setup(&desc)
 	sgl_desc := sgl.Desc{
@@ -96,14 +95,12 @@ fn init(user_data voidptr) {
 	app.alpha_pip = sgl.make_pipeline(&pipdesc)
 }
 
-fn cleanup(user_data voidptr) {
-	mut app := &App(user_data)
+fn cleanup(mut app App) {
 	app.cleanup()
 	gfx.shutdown()
 }
 
-fn frame(user_data voidptr) {
-	mut app := &App(user_data)
+fn frame(mut app App) {
 	app.width = sapp.width()
 	app.height = sapp.height()
 	t := time.ticks()