add System.Collections.Generic using to generator

Author: ash.blade

samples/EnumClass.RawEnumComparison/Program.cs

@@ -23,8 +23,7 @@ void PrintEnumClassComparison(string representationName, PetKind enumClassKind,
 
  var result = enumClassKind.Switch(2, 2,
  static (dog, i, j) => i + j * 2,
- // static (cat, i, j) => cat.CalculateValue(i, j),
- static (cat, i, j) => 0,
+ static (cat, i, j) => cat.CalculateValue(i, j),
  static (parrot, i, j) => i * j + 1,
  static (hamster, i, j) => i + j);
  Console.WriteLine($"It says that 2+2 is {result}");

src/EnumClass.Generator/EnumClassIncrementalGenerator.cs

@@ -30,6 +30,10 @@ private static void GenerateAllEnumClasses(Compilation
  ImmutableArray<EnumDeclarationSyntax> enums,
  SourceProductionContext context)
  {
+ // Do not use EnumInfoFactory that accepts compilation, 
+ // because it will search for all enums in all assemblies
+ // but we need only enums from this assembly
+ 
  // Why do i need to compile? Skip!
  if (enums.IsDefaultOrEmpty)
  {
@@ -56,6 +60,7 @@ private static void GenerateAllEnumClasses(Compilation
  builder.Append("#nullable enable\n\n");
  }
  builder.AppendLine("using System;");
+ builder.AppendLine("using System.Collections.Generic;");
  builder.AppendLine("using System.Runtime.CompilerServices;");
  builder.AppendLine();
  builder.AppendFormat("namespace {0}\n{{\n", enumInfo.Namespace);