message: Fix 6 more Flow errors by using assertAbstractType
  Down to 131.
diff: @@ -25,6 +25,7 @@ import {
  SchemaMetaFieldDef,
  TypeMetaFieldDef,
  TypeNameMetaFieldDef,
  + assertAbstractType,
  doTypesOverlap,
  getNamedType,
  getNullableType,
  @@ -225,9 +226,10 @@ function getSuggestionsForFragmentTypeConditions(
  let possibleTypes;
  if (typeInfo.parentType) {
  if (isAbstractType(typeInfo.parentType)) {
  + const abstractType = assertAbstractType(typeInfo.parentType);
  // Collect both the possible Object types as well as the interfaces
  // they implement.
  - const possibleObjTypes = schema.getPossibleTypes(typeInfo.parentType);
  + const possibleObjTypes = schema.getPossibleTypes(abstractType);
  const possibleIfaceMap = Object.create(null);
  possibleObjTypes.forEach(type => {
  type.getInterfaces().forEach(iface => {
  