if (obj instanceof TypeVariableKey) {
        TypeVariableKey that = (TypeVariableKey) obj;
        return equalsTypeVariable(that.var);
      } else {
        return false;
      }
    }

    @Override
    public String toString() {
      return var.toString();
    }

    /** Wraps {@code t} in a {@code TypeVariableKey} if it's a type variable. */

    TypeResolver resolver =
        new TypeResolver()
            .where(
                ImmutableMap.of(
                    new TypeResolver.TypeVariableKey(typeParam.typeVariable), typeArg.runtimeType));
    // If there's any type error, we'd report now rather than later.
    return new SimpleTypeToken<>(resolver.resolveType(runtimeType));
  }

  /**