Type annotations in the supertype clauses of a class are now Supertypes
instead of InterfaceTypes. In the current version, the two classes
contain the same information, but they are about to diverge in the
following ways:
- An InterfaceType may be nullable, whereas a supertype cannot.
- An InterfaceType may represent the exact class, a subclass, or
a subtype of the given class.
- The type arguments to an interface type represent bounds, whereas
the arguments to a supertype are always exact.
We also introduce a class Substitution that represents an operator
that replaces type parameters with types, depending on the variance
of their use site.
A substitution can be applied to a DartType or a Supertype, and can
be generated independently of how it will be applied.
BUG=
R=kmillikin@google.com
Review URL: https://codereview.chromium.org/2439043002 .
Asger Feldthaus
f764b34682