message: Treat mergeInFieldsFromFragmentSpreads as false in Swift codegen when flag isn't specified
  Fixes
diff: @@ -300,7 +300,7 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
  ) {
  const typeCase = typeCaseForSelectionSet(
  selectionSet,
  - this.context.options.mergeInFieldsFromFragmentSpreads
  + !!this.context.options.mergeInFieldsFromFragmentSpreads
  );
  this.structDeclarationForVariant(
  @@ -384,7 +384,7 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
  const fields = collectAndMergeFields(
  variant,
  - this.context.options.mergeInFieldsFromFragmentSpreads
  + !!this.context.options.mergeInFieldsFromFragmentSpreads
  ).map(field => this.helpers.propertyFromField(field as Field));
  const fragmentSpreads = variant.fragmentSpreads.map(fragmentSpread => {
  