diff --git a/src/generators/Generator.ts b/src/generators/Generator.ts
index 6c1c365f2e..9ce1f8b39e 100644
--- a/src/generators/Generator.ts
+++ b/src/generators/Generator.ts
@@ -50,6 +50,7 @@ export default class Generator {
 		parsed: Parsed,
 		source: string,
 		name: string,
+		stylesheet: Stylesheet,
 		options: CompileOptions
 	) {
 		this.ast = clone(parsed);
@@ -76,7 +77,7 @@ export default class Generator {
 		this.usesRefs = false;
 
 		// styles
-		this.stylesheet = new Stylesheet(source, parsed, options.filename, options.cascade !== false);
+		this.stylesheet = stylesheet;
 
 		// TODO this is legacy — just to get the tests to pass during the transition
 		this.css = this.stylesheet.render(options.cssOutputFilename).css;
diff --git a/src/generators/Selector.ts b/src/generators/Selector.ts
index b5e2941d1c..ee95236a39 100644
--- a/src/generators/Selector.ts
+++ b/src/generators/Selector.ts
@@ -1,5 +1,6 @@
 import MagicString from 'magic-string';
-import { groupSelectors, isGlobalSelector } from '../utils/css';
+import { groupSelectors } from '../utils/css';
+import { Validator } from '../validate/index';
 import { Node } from '../interfaces';
 
 export default class Selector {
@@ -72,6 +73,35 @@ export default class Selector {
 			}
 		});
 	}
+
+	validate(validator: Validator) {
+		this.blocks.forEach((block) => {
+			let i = block.selectors.length;
+			while (i-- > 1) {
+				const part = block.selectors[i];
+				if (part.type === 'PseudoClassSelector' && part.name === 'global') {
+					validator.error(`:global(...) must be the first element in a compound selector`, part.start);
+				}
+			}
+		});
+
+		let start = 0;
+		let end = this.blocks.length;
+
+		for (; start < end; start += 1) {
+			if (!this.blocks[start].global) break;
+		}
+
+		for (; end > start; end -= 1) {
+			if (!this.blocks[end - 1].global) break;
+		}
+
+		for (let i = start; i < end; i += 1) {
+			if (this.blocks[i].global) {
+				validator.error(`:global(...) can be at the start or end of a selector sequence, but not in the middle`, this.blocks[i].selectors[0].start);
+			}
+		}
+	}
 }
 
 function isDescendantSelector(selector: Node) {
diff --git a/src/generators/Stylesheet.ts b/src/generators/Stylesheet.ts
index 69159e1509..fab27aa051 100644
--- a/src/generators/Stylesheet.ts
+++ b/src/generators/Stylesheet.ts
@@ -3,6 +3,7 @@ import { walk } from 'estree-walker';
 import { getLocator } from 'locate-character';
 import Selector from './Selector';
 import getCodeFrame from '../utils/getCodeFrame';
+import { Validator } from '../validate/index';
 import { Node, Parsed } from '../interfaces';
 
 class Rule {
@@ -193,6 +194,14 @@ export default class Stylesheet {
 		};
 	}
 
+	validate(validator: Validator) {
+		this.rules.forEach(rule => {
+			rule.selectors.forEach(selector => {
+				selector.validate(validator);
+			});
+		});
+	}
+
 	warnOnUnusedSelectors(onwarn) {
 		if (this.cascade) return;
 
diff --git a/src/generators/dom/index.ts b/src/generators/dom/index.ts
index 63fefb6687..01cd6cc568 100644
--- a/src/generators/dom/index.ts
+++ b/src/generators/dom/index.ts
@@ -9,6 +9,7 @@ import CodeBuilder from '../../utils/CodeBuilder';
 import visit from './visit';
 import shared from './shared';
 import Generator from '../Generator';
+import Stylesheet from '../Stylesheet';
 import preprocess from './preprocess';
 import Block from './Block';
 import { Parsed, CompileOptions, Node } from '../../interfaces';
@@ -28,9 +29,10 @@ export class DomGenerator extends Generator {
 		parsed: Parsed,
 		source: string,
 		name: string,
+		stylesheet: Stylesheet,
 		options: CompileOptions
 	) {
-		super(parsed, source, name, options);
+		super(parsed, source, name, stylesheet, options);
 		this.blocks = [];
 
 		this.readonly = new Set();
@@ -45,11 +47,12 @@ export class DomGenerator extends Generator {
 export default function dom(
 	parsed: Parsed,
 	source: string,
+	stylesheet: Stylesheet,
 	options: CompileOptions
 ) {
 	const format = options.format || 'es';
 
-	const generator = new DomGenerator(parsed, source, options.name || 'SvelteComponent', options);
+	const generator = new DomGenerator(parsed, source, options.name || 'SvelteComponent', stylesheet, options);
 
 	const {
 		computations,
diff --git a/src/generators/server-side-rendering/index.ts b/src/generators/server-side-rendering/index.ts
index c755b63adc..9bd68dcbf2 100644
--- a/src/generators/server-side-rendering/index.ts
+++ b/src/generators/server-side-rendering/index.ts
@@ -1,5 +1,6 @@
 import deindent from '../../utils/deindent';
 import Generator from '../Generator';
+import Stylesheet from '../Stylesheet';
 import Block from './Block';
 import preprocess from './preprocess';
 import visit from './visit';
@@ -15,9 +16,10 @@ export class SsrGenerator extends Generator {
 		parsed: Parsed,
 		source: string,
 		name: string,
+		stylesheet: Stylesheet,
 		options: CompileOptions
 	) {
-		super(parsed, source, name, options);
+		super(parsed, source, name, stylesheet, options);
 		this.bindings = [];
 		this.renderCode = '';
 		this.elementDepth = 0;
@@ -63,11 +65,12 @@ export class SsrGenerator extends Generator {
 export default function ssr(
 	parsed: Parsed,
 	source: string,
+	stylesheet: Stylesheet,
 	options: CompileOptions
 ) {
 	const format = options.format || 'cjs';
 
-	const generator = new SsrGenerator(parsed, source, options.name || 'SvelteComponent', options);
+	const generator = new SsrGenerator(parsed, source, options.name || 'SvelteComponent', stylesheet, options);
 
 	const { computations, name, hasJs, templateProperties } = generator;
 
diff --git a/src/index.ts b/src/index.ts
index 5c9d98992f..78696bc3a4 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,6 +4,7 @@ import generate from './generators/dom/index';
 import generateSSR from './generators/server-side-rendering/index';
 import { assign } from './shared/index.js';
 import { version } from '../package.json';
+import Stylesheet from './generators/Stylesheet';
 import { Parsed, CompileOptions, Warning } from './interfaces';
 
 function normalizeOptions(options: CompileOptions): CompileOptions {
@@ -44,11 +45,13 @@ export function compile(source: string, _options: CompileOptions) {
 		return;
 	}
 
-	validate(parsed, source, options);
+	const stylesheet = new Stylesheet(source, parsed, options.filename, options.cascade !== false);
+
+	validate(parsed, source, stylesheet, options);
 
 	const compiler = options.generate === 'ssr' ? generateSSR : generate;
 
-	return compiler(parsed, source, options);
+	return compiler(parsed, source, stylesheet, options);
 }
 
 export function create(source: string, _options: CompileOptions = {}) {
diff --git a/src/utils/css.ts b/src/utils/css.ts
index 1e00d657e4..b398956760 100644
--- a/src/utils/css.ts
+++ b/src/utils/css.ts
@@ -1,9 +1,5 @@
 import { Node } from '../interfaces';
 
-export function isGlobalSelector(block: Node[]) {
-	return block[0].type === 'PseudoClassSelector' && block[0].name === 'global';
-}
-
 export function groupSelectors(selector: Node) {
 	let block = {
 		global: selector.children[0].type === 'PseudoClassSelector' && selector.children[0].name === 'global',
diff --git a/src/validate/css/index.ts b/src/validate/css/index.ts
index 57c13a7716..658b3631bb 100644
--- a/src/validate/css/index.ts
+++ b/src/validate/css/index.ts
@@ -1,4 +1,4 @@
-import { groupSelectors, isGlobalSelector, walkRules } from '../../utils/css';
+import { groupSelectors, walkRules } from '../../utils/css';
 import { Validator } from '../index';
 import { Node } from '../../interfaces';
 
diff --git a/src/validate/index.ts b/src/validate/index.ts
index 62cb9e614d..4e5fe1caa4 100644
--- a/src/validate/index.ts
+++ b/src/validate/index.ts
@@ -4,6 +4,7 @@ import validateHtml from './html/index';
 import { getLocator, Location } from 'locate-character';
 import getCodeFrame from '../utils/getCodeFrame';
 import CompileError from '../utils/CompileError';
+import Stylesheet from '../generators/Stylesheet';
 import { Node, Parsed, CompileOptions, Warning } from '../interfaces';
 
 class ValidationError extends CompileError {
@@ -73,6 +74,7 @@ export class Validator {
 export default function validate(
 	parsed: Parsed,
 	source: string,
+	stylesheet: Stylesheet,
 	options: CompileOptions
 ) {
 	const { onwarn, onerror, name, filename } = options;
@@ -103,7 +105,7 @@ export default function validate(
 		}
 
 		if (parsed.css) {
-			validateCss(validator, parsed.css);
+			stylesheet.validate(validator);
 		}
 
 		if (parsed.html) {
diff --git a/test/validator/index.js b/test/validator/index.js
index 5a63958c9c..e41e18a1da 100644
--- a/test/validator/index.js
+++ b/test/validator/index.js
@@ -18,12 +18,10 @@ describe("validate", () => {
 			const input = fs.readFileSync(filename, "utf-8").replace(/\s+$/, "");
 
 			try {
-				const parsed = svelte.parse(input);
-
 				const errors = [];
 				const warnings = [];
 
-				svelte.validate(parsed, input, {
+				svelte.compile(input, {
 					onerror(error) {
 						errors.push({
 							message: error.message,