Update roadmap (#3696)

Remove items that we've finished from the roadmap. Remove
April-June heading. Updated to remaining items.

Author: JukkaL

ROADMAP.md

@@ -9,60 +9,26 @@ core team member that nobody else is working on the same thing.
 on, and everything is subject to change. Near-term plans are likely
 more accurate.
 
-## April-June 2017
-
-- Add more comprehensive testing for `--incremental` and `--quick`
-  modes to improve reliability. At least write more unit tests with
-  focus on areas that have previously had bugs.
-  ([issue](https://github.com/python/mypy/issues/3455))
-
-- Speed up `--quick` mode to better support million+ line codebases
-  through some of these:
-
-  - Make it possible to use remote caching for incremental cache
-    files. This would speed up a cold run with no local cache data.
-    We need to update incremental cache to use hashes to determine
-    whether files have changes to allow
-    [sharing cache data](https://github.com/python/mypy/issues/3403).
-
-  - See if we can speed up deserialization of incremental cache
-    files. Initial experiments aren’t very promising though so there
-    might not be any easy wins left.
-    ([issue](https://github.com/python/mypy/issues/3456))
-
-- Improve support for complex signatures such as `open(fn, 'rb')` and
-  specific complex decorators such as `contextlib.contextmanager`
-  through type checker plugins/hooks.
-  ([issue](https://github.com/python/mypy/issues/1240))
+## July-December 2017
+
+- Fix remaining highest-priority TypedDict issues and make TypedDict
+  an officially supported mypy feature.
 
 - Document basic properties of all type operations used within mypy,
   including compatibility, proper subtyping, joins and meets.
   ([issue](https://github.com/python/mypy/issues/3454))
 
-- Make TypedDict an officially supported mypy feature. This makes it
-  possible to give precise types for dictionaries that represent JSON
-  objects, such as `{"path": "/dir/fnam.ext", "size": 1234}`.
-  ([issue](https://github.com/python/mypy/issues/3453))
-
-- Make error messages more useful and informative.
+- Continue making error messages more useful and informative.
   ([issue](https://github.com/python/mypy/labels/topic-usability))
 
 - Resolve [#2008](https://github.com/python/mypy/issues/2008) (we are
   converging on approach 4).
 
-## July-December 2017
-
 - Invest some effort into systematically filling in missing
   annotations and stubs in typeshed, with focus on features heavily
   used at Dropbox. Better support for ORMs will be a separate
   project.
 
-- Improve opt-in warnings about `Any` types to make it easier to keep
-  code free from unwanted `Any` types. For example, warn about using
-  `list` (instead of `List[x]`) and calling `open` if we can’t infer a
-  precise return type, or using types imported from ignored modules
-  (they are implicitly `Any`).
-
 - Add support for protocols and structural subtyping (PEP 544).
 
 - Switch completely to pytest and remove the custom testing framework.
@@ -73,24 +39,25 @@ more accurate.
   significantly. Even when using the incremental mode, processing a
   large number of files is not cheap.
 
+- Provide much faster, reliable interactive feedback through
+  fine-grained incremental type checking, built on top the daemon
+  mode.
+
 - Refactor and simplify specific tricky parts of mypy internals, such
   as the [conditional type binder](https://github.com/python/mypy/issues/3457),
   [symbol tables](https://github.com/python/mypy/issues/3458) or
   the various [semantic analysis passes](https://github.com/python/mypy/issues/3459).
 
-- Implement a general type system plugin architecture. It should be
-  able to support some typical ORM features at least, such as
-  metaclasses that add methods with automatically inferred signatures
-  and complex descriptors such as those used by Django models.
+- Make the mypy plugin architecture more general and officially
+  supported. It should be able to support some typical ORM features at
+  least, such as metaclasses that add methods with automatically
+  inferred signatures and complex descriptors such as those used by
+  Django models.
   ([issue](https://github.com/python/mypy/issues/1240))
 
 - Add support for statically typed
   [protobufs](https://developers.google.com/protocol-buffers/).
 
-- Provide much faster, reliable interactive feedback through
-  fine-grained incremental type checking, built on top the daemon
-  mode.
-
 - Start work on editor plugins and support for selected IDE features.
 
 - Turn on `--strict-optional` by default.