Enable nullable (#2392)

* Enable nullable

* Several nullable fixes

* Fix dot-dsl

* calculator-conundrum: fix nullable

* developer-privileges: fix nullable

* face-id2: fix

* zebra-puzzle: fix

* pov: fix

* zipper: fix

* tournament: fix

* simple-linked-list: fix

* sgf-parsing: fix

* rest-api: fix

* react: fix

* robot-name: fix

* say: fix

* satellite: fix

* change: fix

* custom-set: fix

* grep: fix

* binary-search-tree: fix

* linked-list: fix

* alphametics: fix

* hangman: fix

* wizards-and-warriors-2: fix

* remote-control-cleanup: fix

* land-grab-in-space: fix

* instruments-of-texas: fix

* markdown: fix

* Dont remove nullable in new exercise

* More fixes

* remote-control: fix

[no important files changed]

exercises/concept/annalyns-infiltration/AnnalynsInfiltration.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/attack-of-the-trolls/AttackOfTheTrolls.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/authentication-system/AuthenticationSystem.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/beauty-salon-goes-global/BeautySalonGoesGlobal.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/bird-watcher/BirdWatcher.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/booking-up-for-beauty/BookingUpForBeauty.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/building-telemetry/BuildingTelemetry.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/calculator-conundrum/CalculatorConundrum.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/cars-assemble/CarsAssemble.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/developer-privileges/DeveloperPrivileges.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/elons-toys/ElonsToys.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/faceid-2/Faceid2.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/high-school-sweethearts/HighSchoolSweethearts.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/hyper-optimized-telemetry/HyperOptimizedTelemetry.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/hyperia-forex/HyperiaForex.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/hyperinflation-hits-hyperia/HyperinflationHitsHyperia.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/instruments-of-texas/InstrumentsOfTexas.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/interest-is-interesting/InterestIsInteresting.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/international-calling-connoisseur/InternationalCallingConnoisseur.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/land-grab-in-space/LandGrabInSpace.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/log-analysis/LogAnalysis.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/log-levels/LogLevels.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/logs-logs-logs/LogsLogsLogs.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/lucians-luscious-lasagna/LuciansLusciousLasagna.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/need-for-speed/NeedForSpeed.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/object-relational-mapping/ObjectRelationalMapping.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/orm-in-one-go/OrmInOneGo.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/parsing-log-files/ParsingLogFiles.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/phone-number-analysis/PhoneNumberAnalysis.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/red-vs-blue-darwin-style/RedVsBlueDarwinStyle.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/remote-control-cleanup/RemoteControlCleanup.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/remote-control-competition/RemoteControlCompetition.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/roll-the-die/RollTheDie.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/secure-munchester-united/SecureMunchesterUnited.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/squeaky-clean/SqueakyClean.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/the-weather-in-deather/TheWeatherInDeather.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/tracks-on-tracks-on-tracks/TracksOnTracksOnTracks.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/weighing-machine/WeighingMachine.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/wizards-and-warriors-2/WizardsAndWarriors2.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/concept/wizards-and-warriors/WizardsAndWarriors.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/accumulate/Accumulate.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/acronym/Acronym.csproj

@@ -6,6 +6,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/affine-cipher/AffineCipher.csproj

@@ -6,6 +6,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/all-your-base/AllYourBase.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/allergies/Allergies.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/alphametics/Alphametics.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/anagram/Anagram.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/armstrong-numbers/ArmstrongNumbers.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/atbash-cipher/AtbashCipher.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>
 

exercises/practice/bank-account/BankAccount.csproj

@@ -5,6 +5,7 @@
     <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
     <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
     <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
   </PropertyGroup>