6ac836fbb3
I'm about to start introducing usages of TypeParameterType.bound, and nearly all of the usage sites will need to fall back on TypeParameter.bound if there is no bound stored in the TypeParameterType. This CL places the fallback behavior in the TypeParameterType.bound getter so that we won't have to duplicate it at every usage site (and risk making mistakes). The few call sites that don't want the fallback behavior (such as the one in ast_to_binary.dart) can avoid it by referring to TypeParameterType.promotedBound directly. R=ahe@google.com Review-Url: https://codereview.chromium.org/2952883003 .