diff --git a/src/generators/nodes/Component.ts b/src/generators/nodes/Component.ts
index 661bfd7d15..1fc249e960 100644
--- a/src/generators/nodes/Component.ts
+++ b/src/generators/nodes/Component.ts
@@ -137,27 +137,21 @@ export default class Component extends Node {
 				block.addVariable(name_updating, '{}');
 				statements.push(`var ${name_initial_data} = ${initialPropString};`);
 
-				const setParentFromChildOnChange = new CodeBuilder();
-				const setParentFromChildOnInit = new CodeBuilder();
+				let hasLocalBindings = false;
+				let hasStoreBindings = false;
 
-				const setStoreFromChildOnChange = new CodeBuilder();
-				const setStoreFromChildOnInit = new CodeBuilder();
+				const builder = new CodeBuilder();
 
 				bindings.forEach((binding: Binding) => {
 					let { name: key } = getObject(binding.value);
 
-					const isStoreProp = generator.options.store && key[0] === '$';
-					if (isStoreProp) key = key.slice(1);
-					const newState = isStoreProp ? 'newStoreState' : 'newState';
-
 					binding.contexts.forEach(context => {
 						allContexts.add(context);
 					});
 
 					let setFromChild;
 
-					if (!isStoreProp && block.contexts.has(key)) {
-						const prop = binding.dependencies[0];
+					if (block.contexts.has(key)) {
 						const computed = isComputed(binding.value);
 						const tail = binding.value.type === 'MemberExpression' ? getTailSnippet(binding.value) : '';
 
@@ -167,20 +161,38 @@ export default class Component extends Node {
 							list[index]${tail} = childState.${binding.name};
 
 							${binding.dependencies
-								.map((prop: string) => `${newState}.${prop} = state.${prop};`)
-								.join('\n')}
-						`;
-					}
+								.map((name: string) => {
+									const isStoreProp = generator.options.store && name[0] === '$';
+									const prop = isStoreProp ? name.slice(1) : name;
+									const newState = isStoreProp ? 'newStoreState' : 'newState';
 
-					else if (binding.value.type === 'MemberExpression') {
-						setFromChild = deindent`
-							${binding.snippet} = childState.${binding.name};
-							${binding.dependencies.map((prop: string) => `${newState}.${prop} = state.${prop};`).join('\n')}
+									if (isStoreProp) hasStoreBindings = true;
+									else hasLocalBindings = true;
+
+									return `${newState}.${prop} = state.${name};`;
+								})
+								.join('\n')}
 						`;
 					}
 
 					else {
-						setFromChild = `${newState}.${key} = childState.${binding.name};`;
+						const isStoreProp = generator.options.store && key[0] === '$';
+						const prop = isStoreProp ? key.slice(1) : key;
+						const newState = isStoreProp ? 'newStoreState' : 'newState';
+
+						if (isStoreProp) hasStoreBindings = true;
+						else hasLocalBindings = true;
+
+						if (binding.value.type === 'MemberExpression') {
+							setFromChild = deindent`
+								${binding.snippet} = childState.${binding.name};
+								${newState}.${prop} = state.${key};
+							`;
+						}
+
+						else {
+							setFromChild = `${newState}.${prop} = childState.${binding.name};`;
+						}
 					}
 
 					statements.push(deindent`
@@ -190,16 +202,11 @@ export default class Component extends Node {
 						}`
 					);
 
-					(isStoreProp ? setStoreFromChildOnChange : setParentFromChildOnChange).addConditional(
+					builder.addConditional(
 						`!${name_updating}.${binding.name} && changed.${binding.name}`,
 						setFromChild
 					);
 
-					(isStoreProp ? setStoreFromChildOnInit : setParentFromChildOnInit).addConditional(
-						`!${name_updating}.${binding.name}`,
-						setFromChild
-					);
-
 					// TODO could binding.dependencies.length ever be 0?
 					if (binding.dependencies.length) {
 						updates.push(deindent`
@@ -215,44 +222,23 @@ export default class Component extends Node {
 
 				const initialisers = [
 					'state = #component.get()',
-					!setParentFromChildOnChange.isEmpty() && 'newState = {}',
-					!setStoreFromChildOnChange.isEmpty() && 'newStoreState = {}',
+					hasLocalBindings && 'newState = {}',
+					hasStoreBindings && 'newStoreState = {}',
 				].filter(Boolean).join(', ');
 
 				componentInitProperties.push(deindent`
 					_bind: function(changed, childState) {
 						var ${initialisers};
-						${!setStoreFromChildOnChange.isEmpty() && deindent`
-							${setStoreFromChildOnChange}
-							${name_updating} = @assign({}, changed);
-							#component.store.set(newStoreState);
-						`}
-						${!setParentFromChildOnChange.isEmpty() && deindent`
-							${setParentFromChildOnChange}
-							${name_updating} = @assign({}, changed);
-							#component._set(newState);
-						`}
+						${builder}
+						${hasStoreBindings && `#component.store.set(newStoreState);`}
+						${hasLocalBindings && `#component._set(newState);`}
 						${name_updating} = {};
 					}
 				`);
 
-				// TODO can `!childState` ever be true?
 				beforecreate = deindent`
 					#component.root._beforecreate.push(function() {
-						var childState = ${name}.get(), ${initialisers};
-						if (!childState) return;
-						${setParentFromChildOnInit}
-						${!setStoreFromChildOnInit.isEmpty() && deindent`
-							${setStoreFromChildOnInit}
-							${name_updating} = { ${bindings.map((binding: Binding) => `${binding.name}: true`).join(', ')} };
-							#component.store.set(newStoreState);
-						`}
-						${!setParentFromChildOnInit.isEmpty() && deindent`
-							${setParentFromChildOnInit}
-							${name_updating} = { ${bindings.map((binding: Binding) => `${binding.name}: true`).join(', ')} };
-							#component._set(newState);
-						`}
-						${name_updating} = {};
+						${name}._bind({ ${bindings.map(b => `${b.name}: 1`).join(', ')} }, ${name}.get());
 					});
 				`;
 			} else if (initialProps.length) {
diff --git a/src/parse/index.ts b/src/parse/index.ts
index c81d2f61b0..91d7c3253d 100644
--- a/src/parse/index.ts
+++ b/src/parse/index.ts
@@ -112,14 +112,14 @@ export class Parser {
 		throw new ParseError(message, this.template, index, this.filename);
 	}
 
-	eat(str: string, required?: boolean) {
+	eat(str: string, required?: boolean, message?: string) {
 		if (this.match(str)) {
 			this.index += str.length;
 			return true;
 		}
 
 		if (required) {
-			this.error(`Expected ${str}`);
+			this.error(message || `Expected ${str}`);
 		}
 
 		return false;
diff --git a/src/parse/state/mustache.ts b/src/parse/state/mustache.ts
index bd1db07460..0a255b1256 100644
--- a/src/parse/state/mustache.ts
+++ b/src/parse/state/mustache.ts
@@ -6,7 +6,7 @@ import { Parser } from '../index';
 import { Node } from '../../interfaces';
 
 function trimWhitespace(block: Node, trimBefore: boolean, trimAfter: boolean) {
-	if (!block.children) return; // AwaitBlock
+	if (!block.children || block.children.length === 0) return; // AwaitBlock
 
 	const firstChild = block.children[0];
 	const lastChild = block.children[block.children.length - 1];
@@ -74,8 +74,6 @@ export default function mustache(parser: Parser) {
 		}
 
 		// strip leading/trailing whitespace as necessary
-		if (block.children && !block.children.length) parser.error(`Empty block`, block.start);
-
 		const charBefore = parser.template[block.start - 1];
 		const charAfter = parser.template[parser.index];
 		const trimBefore = !charBefore || whitespace.test(charBefore);
diff --git a/src/parse/state/tag.ts b/src/parse/state/tag.ts
index 8b701cae1d..57e2b1bbb9 100644
--- a/src/parse/state/tag.ts
+++ b/src/parse/state/tag.ts
@@ -71,7 +71,7 @@ export default function tag(parser: Parser) {
 
 	if (parser.eat('!--')) {
 		const data = parser.readUntil(/-->/);
-		parser.eat('-->');
+		parser.eat('-->', true, 'comment was left open, expected -->');
 
 		parser.current().children.push({
 			start,
diff --git a/src/validate/html/index.ts b/src/validate/html/index.ts
index b2a190696f..9ae50baca1 100644
--- a/src/validate/html/index.ts
+++ b/src/validate/html/index.ts
@@ -12,6 +12,13 @@ const meta = new Map([
 	[':Head', validateHead]
 ]);
 
+function isEmptyBlock(node: Node) {
+	if (!/Block$/.test(node.type) || !node.children) return false;
+	if (node.children.length > 1) return false;
+	const child = node.children[0];
+	return !child || (child.type === 'Text' && !/\S/.test(child.data));
+}
+
 export default function validateHtml(validator: Validator, html: Node) {
 	const refs = new Map();
 	const refCallees: Node[] = [];
@@ -58,6 +65,10 @@ export default function validateHtml(validator: Validator, html: Node) {
 			}
 		}
 
+		if (validator.options.dev && isEmptyBlock(node)) {
+			validator.warn('Empty block', node.start);
+		}
+
 		if (node.children) {
 			if (node.type === 'Element') elementStack.push(node);
 			stack.push(node);
diff --git a/src/validate/index.ts b/src/validate/index.ts
index b57f2b0c2a..da603a437b 100644
--- a/src/validate/index.ts
+++ b/src/validate/index.ts
@@ -93,7 +93,7 @@ export default function validate(
 	stylesheet: Stylesheet,
 	options: CompileOptions
 ) {
-	const { onwarn, onerror, name, filename, store } = options;
+	const { onwarn, onerror, name, filename, store, dev } = options;
 
 	try {
 		if (name && !/^[a-zA-Z_$][a-zA-Z_$0-9]*$/.test(name)) {
@@ -114,7 +114,8 @@ export default function validate(
 			onwarn,
 			name,
 			filename,
-			store
+			store,
+			dev
 		});
 
 		if (parsed.js) {
diff --git a/test/parser/samples/error-comment-unclosed/error.json b/test/parser/samples/error-comment-unclosed/error.json
new file mode 100644
index 0000000000..f392e12fa1
--- /dev/null
+++ b/test/parser/samples/error-comment-unclosed/error.json
@@ -0,0 +1,8 @@
+{
+	"message": "comment was left open, expected -->",
+	"loc": {
+		"line": 1,
+		"column": 24
+	},
+	"pos": 24
+}
diff --git a/test/parser/samples/error-comment-unclosed/input.html b/test/parser/samples/error-comment-unclosed/input.html
new file mode 100644
index 0000000000..725cf9be60
--- /dev/null
+++ b/test/parser/samples/error-comment-unclosed/input.html
@@ -0,0 +1 @@
+<!-- an unclosed comment
diff --git a/test/runtime/samples/store-component-binding-deep/TextInput.html b/test/runtime/samples/store-component-binding-deep/TextInput.html
new file mode 100644
index 0000000000..f24d608cd5
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-deep/TextInput.html
@@ -0,0 +1 @@
+<input bind:value>
\ No newline at end of file
diff --git a/test/runtime/samples/store-component-binding-deep/_config.js b/test/runtime/samples/store-component-binding-deep/_config.js
new file mode 100644
index 0000000000..66ae5ac4ae
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-deep/_config.js
@@ -0,0 +1,42 @@
+import { Store } from '../../../../store.js';
+
+const store = new Store({
+	name: {
+		value: 'world'
+	}
+});
+
+export default {
+	store,
+
+	html: `
+		<h1>Hello world!</h1>
+		<input>
+	`,
+
+	test(assert, component, target, window) {
+		const input = target.querySelector('input');
+		const event = new window.Event('input');
+
+		const changeRecord = [];
+		store.onchange((state, changes) => {
+			changeRecord.push({ state, changes });
+		});
+
+		input.value = 'everybody';
+		input.dispatchEvent(event);
+
+		assert.equal(store.get('name').value, 'everybody');
+		assert.htmlEqual(target.innerHTML, `
+			<h1>Hello everybody!</h1>
+			<input>
+		`);
+
+		assert.deepEqual(changeRecord, [
+			{
+				state: { name: { value: 'everybody' } },
+				changes: { name: true }
+			}
+		]);
+	}
+};
\ No newline at end of file
diff --git a/test/runtime/samples/store-component-binding-deep/main.html b/test/runtime/samples/store-component-binding-deep/main.html
new file mode 100644
index 0000000000..f77016b549
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-deep/main.html
@@ -0,0 +1,10 @@
+<h1>Hello {{$name.value}}!</h1>
+<TextInput bind:value=$name.value/>
+
+<script>
+	import TextInput from './TextInput.html';
+
+	export default {
+		components: { TextInput }
+	};
+</script>
\ No newline at end of file
diff --git a/test/runtime/samples/store-component-binding-each/Widget.html b/test/runtime/samples/store-component-binding-each/Widget.html
new file mode 100644
index 0000000000..f24d608cd5
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-each/Widget.html
@@ -0,0 +1 @@
+<input bind:value>
\ No newline at end of file
diff --git a/test/runtime/samples/store-component-binding-each/_config.js b/test/runtime/samples/store-component-binding-each/_config.js
new file mode 100644
index 0000000000..5d6e6889ae
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-each/_config.js
@@ -0,0 +1,30 @@
+import { Store } from '../../../../store.js';
+
+const store = new Store({
+	a: ['foo', 'bar', 'baz']
+});
+
+export default {
+	store,
+
+	html: `
+		<input><input><input>
+		<p>foo, bar, baz</p>
+	`,
+
+	test(assert, component, target, window) {
+		const event = new window.MouseEvent('input');
+		const inputs = target.querySelectorAll('input');
+
+		inputs[0].value = 'blah';
+		inputs[0].dispatchEvent(event);
+
+		assert.deepEqual(store.get('a'), ['blah', 'bar', 'baz']);
+		assert.htmlEqual(target.innerHTML, `
+			<input><input><input>
+			<p>blah, bar, baz</p>
+		`);
+
+		component.destroy();
+	},
+};
diff --git a/test/runtime/samples/store-component-binding-each/main.html b/test/runtime/samples/store-component-binding-each/main.html
new file mode 100644
index 0000000000..e150c57af8
--- /dev/null
+++ b/test/runtime/samples/store-component-binding-each/main.html
@@ -0,0 +1,15 @@
+{{#each $a as x}}
+	<Widget bind:value='x'/>
+{{/each}}
+
+<p>{{$a.join(', ')}}</p>
+
+<script>
+	import Widget from './Widget.html';
+
+	export default {
+		components: {
+			Widget
+		}
+	};
+</script>
diff --git a/test/runtime/samples/store-component-binding/_config.js b/test/runtime/samples/store-component-binding/_config.js
index aefc4ec652..1d2beab7a7 100644
--- a/test/runtime/samples/store-component-binding/_config.js
+++ b/test/runtime/samples/store-component-binding/_config.js
@@ -16,6 +16,11 @@ export default {
 		const input = target.querySelector('input');
 		const event = new window.Event('input');
 
+		const changeRecord = [];
+		store.onchange((state, changes) => {
+			changeRecord.push({ state, changes });
+		});
+
 		input.value = 'everybody';
 		input.dispatchEvent(event);
 
@@ -24,5 +29,12 @@ export default {
 			<h1>Hello everybody!</h1>
 			<input>
 		`);
+
+		assert.deepEqual(changeRecord, [
+			{
+				state: { name: 'everybody' },
+				changes: { name: true }
+			}
+		]);
 	}
 };
\ No newline at end of file
diff --git a/test/validator/index.js b/test/validator/index.js
index 176d060faf..0a132a7c9e 100644
--- a/test/validator/index.js
+++ b/test/validator/index.js
@@ -1,6 +1,6 @@
 import * as fs from "fs";
 import assert from "assert";
-import { svelte, tryToLoadJson } from "../helpers.js";
+import { svelte, loadConfig, tryToLoadJson } from "../helpers.js";
 
 describe("validate", () => {
 	fs.readdirSync("test/validator/samples").forEach(dir => {
@@ -15,6 +15,7 @@ describe("validate", () => {
 		}
 
 		(solo ? it.only : skip ? it.skip : it)(dir, () => {
+			const config = loadConfig(`./validator/samples/${dir}/_config.js`);
 			const filename = `test/validator/samples/${dir}/input.html`;
 			const input = fs.readFileSync(filename, "utf-8").replace(/\s+$/, "");
 
@@ -32,7 +33,8 @@ describe("validate", () => {
 							pos: warning.pos,
 							loc: warning.loc
 						});
-					}
+					},
+					dev: config.dev
 				});
 
 				assert.deepEqual(warnings, expectedWarnings);
diff --git a/test/validator/samples/each-block-multiple-children/_config.js b/test/validator/samples/each-block-multiple-children/_config.js
new file mode 100644
index 0000000000..e26996239d
--- /dev/null
+++ b/test/validator/samples/each-block-multiple-children/_config.js
@@ -0,0 +1,3 @@
+export default {
+	dev: true
+};
\ No newline at end of file
diff --git a/test/validator/samples/each-block-multiple-children/input.html b/test/validator/samples/each-block-multiple-children/input.html
new file mode 100644
index 0000000000..9d996a3acf
--- /dev/null
+++ b/test/validator/samples/each-block-multiple-children/input.html
@@ -0,0 +1,10 @@
+{{#each things as thing}}
+	<span>this only exists...</span>
+	<span>...to increase test coverage</span>
+{{/each}}
+
+{{#each things as thing}}{{soDoesThis}}{{/each}}
+
+{{#each things as thing}}
+	andThis
+{{/each}}
\ No newline at end of file
diff --git a/test/validator/samples/each-block-multiple-children/warnings.json b/test/validator/samples/each-block-multiple-children/warnings.json
new file mode 100644
index 0000000000..0637a088a0
--- /dev/null
+++ b/test/validator/samples/each-block-multiple-children/warnings.json
@@ -0,0 +1 @@
+[]
\ No newline at end of file
diff --git a/test/validator/samples/empty-block-dev/_config.js b/test/validator/samples/empty-block-dev/_config.js
new file mode 100644
index 0000000000..e26996239d
--- /dev/null
+++ b/test/validator/samples/empty-block-dev/_config.js
@@ -0,0 +1,3 @@
+export default {
+	dev: true
+};
\ No newline at end of file
diff --git a/test/validator/samples/empty-block-dev/input.html b/test/validator/samples/empty-block-dev/input.html
new file mode 100644
index 0000000000..32b892d470
--- /dev/null
+++ b/test/validator/samples/empty-block-dev/input.html
@@ -0,0 +1,5 @@
+{{#each things as thing}}
+
+{{/each}}
+
+{{#each things as thing}}{{/each}}
\ No newline at end of file
diff --git a/test/validator/samples/empty-block-dev/warnings.json b/test/validator/samples/empty-block-dev/warnings.json
new file mode 100644
index 0000000000..54584bf135
--- /dev/null
+++ b/test/validator/samples/empty-block-dev/warnings.json
@@ -0,0 +1,18 @@
+[
+	{
+		"message": "Empty block",
+		"loc": {
+			"line": 1,
+			"column": 0
+		},
+		"pos": 0
+	},
+	{
+		"message": "Empty block",
+		"loc": {
+			"line": 5,
+			"column": 0
+		},
+		"pos": 38
+	}
+]
\ No newline at end of file
diff --git a/test/validator/samples/empty-block-prod/input.html b/test/validator/samples/empty-block-prod/input.html
new file mode 100644
index 0000000000..32b892d470
--- /dev/null
+++ b/test/validator/samples/empty-block-prod/input.html
@@ -0,0 +1,5 @@
+{{#each things as thing}}
+
+{{/each}}
+
+{{#each things as thing}}{{/each}}
\ No newline at end of file
diff --git a/test/validator/samples/empty-block-prod/warnings.json b/test/validator/samples/empty-block-prod/warnings.json
new file mode 100644
index 0000000000..0637a088a0
--- /dev/null
+++ b/test/validator/samples/empty-block-prod/warnings.json
@@ -0,0 +1 @@
+[]
\ No newline at end of file