spec: allow record {} <: record {null} #722

	name: Rust
	on:
	push:
	branches:
	- master
	pull_request:

	jobs:
	rust:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Install stable toolchain
	uses: actions-rs/toolchain@v1
	with:
	profile: minimal
	toolchain: stable
	override: true
	components: rustfmt, clippy
	- name: Cache cargo build
	uses: actions/cache@v2
	with:
	path: \|
	~/.cargo/registry
	~/.cargo/git
	target
	key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
	- name: Build
	run: cargo build
	- name: Run tests
	run: cargo test --features all
	- name: fmt
	run: cargo fmt -v -- --check
	- name: lint
	run: cargo clippy --tests -- -D clippy::all
	- name: doc
	run: cargo doc

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