foo1.cs

          switch (targetIdentifier.Name)
          {
            case "assembly":
              return AttributeTargets.Assembly;
            case "module":
              return AttributeTargets.Module;
            case "return":
              return AttributeTargets.ReturnValue;
            case "field":
              return AttributeTargets.Field;
            case "event":
              return AttributeTargets.Event;
            case "method":
              return AttributeTargets.Method;
            case "param":
              return AttributeTargets.Parameter;
            case "property":
              return AttributeTargets.Property;
            case "typevar":
              return AttributeTargets.GenericParameter;
          }

foo2.cs

          return targetIdentifier.Name switch {
            "assembly" => AttributeTargets.Assembly,
            "module"   => AttributeTargets.Module,
            "return"   => AttributeTargets.ReturnValue,
            "field"    => AttributeTargets.Field,
            "event"    => AttributeTargets.Event,
            "method"   => AttributeTargets.Method,
            "param"    => AttributeTargets.Parameter,
            "property" => AttributeTargets.Property,
            "typevar"  => AttributeTargets.GenericParameter
          };