MemoryStateChange (@Nullable MemoryStateChange previous, @NotNull Instruction instruction, @NotNull Map<DfaVariableValue, Change> result, @NotNull DfaValue value) { if (result.isEmpty() && DfaTypeValue.isUnknown(value)) { return previous; } return new MemoryStateChange(ContainerUtil.createMaybeSingletonList(previous), instruction, result, value, Collections.emptyMap()); }