WEBVTT 00:00.080 --> 00:00.620 Hi everyone. 00:00.620 --> 00:01.160 Welcome back. 00:01.160 --> 00:04.460 In this lecture we will look into the limitations of using VR. 00:04.460 --> 00:09.200 So the number one limitation is that you cannot have var x equal to null. 00:09.290 --> 00:11.870 Because null can be of any type. 00:11.870 --> 00:16.550 You cannot just define null and try to assign that to a var reserved type name. 00:16.550 --> 00:17.630 So this is not allowed. 00:17.630 --> 00:24.020 And another thing is let's say you're going to assign where x equal to ABC. 00:24.140 --> 00:29.120 And then if you try to change a type to something else, let's say if you want to assign x equal to 00:29.150 --> 00:34.700 five, we are trying to change from the string initial info type to another type. 00:34.700 --> 00:37.040 This is also not allowed okay. 00:37.070 --> 00:42.470 And the next thing is that if you go to the top, you cannot use var as an instance variable. 00:42.470 --> 00:45.830 So where in the class properties are not allowed. 00:45.830 --> 00:51.680 So in this case if I try to do this here, the compiler will complain that where is not allowed and 00:51.830 --> 00:54.740 or it cannot even resolve the symbol where. 00:54.770 --> 00:55.130 Okay. 00:55.160 --> 00:55.940 And the. 00:55.940 --> 01:00.500 Another thing is you cannot use where on the function parameters to. 01:00.530 --> 01:05.720 So in this case, let's say if I try to take the string off and try to use where here, this again is 01:05.720 --> 01:09.890 going to give you the same issue cannot resolve symbol where. 01:09.890 --> 01:13.880 So which means where in the function argument is not allowed. 01:13.880 --> 01:18.920 And one more thing which I would like to show you is in the beginning of the lecture I said where is 01:18.920 --> 01:25.320 not a Reserved keywords in this case were equal to Java, so this is still allowed. 01:25.320 --> 01:27.780 So here the compiler is not going to complain. 01:27.780 --> 01:30.390 You cannot use where as a variable. 01:30.540 --> 01:36.120 So these are some of the limitations that you need to be aware of when you are using local variable 01:36.150 --> 01:36.840 type inference. 01:36.840 --> 01:37.830 Using where. 01:37.860 --> 01:40.380 Let me quickly summarize what we have learned so far. 01:40.380 --> 01:46.230 So what I'm going to do, let's go back to the slides and quickly summarize what we have learned as 01:46.230 --> 01:48.000 the limitations of where. 01:48.000 --> 01:54.630 So number one is you cannot have a null value assigned to a where as a type cannot be inferred. 01:54.660 --> 01:56.010 And number two is changing. 01:56.010 --> 01:57.810 The type is not allowed. 01:57.810 --> 02:01.290 Which means if you try to assign a variable to a certain type. 02:01.290 --> 02:06.540 In this case we are assigning where is equal to the hello world, which is a string, and changing that 02:06.540 --> 02:12.300 to a different type is not allowed, and the next thing is where cannot be used as a class property. 02:12.300 --> 02:15.180 Also, you cannot use this at the class level. 02:15.180 --> 02:20.220 So that's one of the reasons why it is named as it is a local variable type inference. 02:20.220 --> 02:26.220 The scope of using where is just local to the functions, and the final one to call out is that where 02:26.250 --> 02:28.260 cannot be used as a function. 02:28.260 --> 02:28.860 Argument two. 02:28.890 --> 02:34.560 So these are the limitations that you need to be aware of anytime you are using where for type inference 02:34.560 --> 02:36.870 or local variable type inference. 02:36.870 --> 02:38.430 This marks the end of this lecture. 02:38.430 --> 02:39.480 Thank you for watching.