This is a piece of the upcoming strong mode-based type propagation.
The new type propagator will build its inference graph based on the
subtyping constraints found during type checking.
This type checker is not intended to report type errors to end-users.
In its current form, it is quite redundant with the front end's type
checker, but this will not be the case once we augment kernel's type
system.
The internals of "dart:" libraries are not type checked -- they are
simply assumed to satisfy the type annotations on their interfaces.
BUG=
R=kmillikin@google.com
Review URL: https://codereview.chromium.org/2465893002 .
Asger Feldthaus
ca5bb64dc0