Non-null Types and Non-null By Default (NNBD)

Dart Enhancement Process (DEP) proposal for non-null types and non-null by default. The full proposal is available in two formats:

PDF, or
markdown (autogenerated, DO NOT EDIT).

Original markdown sources for the proposal are under doc-src.

If you make changes and want to generate the PDF, then follow these instructions. (When submitting a Pull Request, there is no need to submit the PDF or .md under doc.)

To build the proposal you will need Pandoc, which can be installed as a brew cask as follows:
```
$ brew cask install pandoc
```
(The pandoc cask takes minutes to install, against hours for the homebrew pandoc Formula.)
We also have a simple custom Pandoc filter that requires a node package so run:
```
$ npm install
```
To generate a PDF run:
```
$ make
```

chalin/DEP-non-null

Non-null Types and Non-null By Default (NNBD)