vm: fix errors not being returned

vm/stack.go

@@ -32,9 +32,9 @@ func (st *Stack) useGas(gasToUse uint64) {
 }
 
 func (st *Stack) setErr(err error) {
-	if *st.err != nil {
-		*st.err = err
-	}
+	//if *st.err != nil {
+	*st.err = err
+	//}
 }
 
 func (st *Stack) Push(d Word256) {

vm/vm.go

@@ -659,7 +659,7 @@ func (vm *VM) call(caller, callee *Account, code, input []byte, value uint64, ga
 		case RETURN: // 0xF3
 			offset, size := stack.Pop64(), stack.Pop64()
 			ret, ok := subslice(memory, offset, size, false)
-			if !ok {
+			if !ok || err != nil {
 				return nil, firstErr(err, ErrMemoryOutOfBounds)
 			}
 			dbg.Printf(" => [%v, %v] (%d) 0x%X\n", offset, size, len(ret), ret)