diff --git a/src/Module.ts b/src/Module.ts
index b54f1d990da..a7de14f23f9 100644
--- a/src/Module.ts
+++ b/src/Module.ts
@@ -15,7 +15,7 @@ import { isLiteral } from './ast/nodes/Literal';
 import MetaProperty from './ast/nodes/MetaProperty';
 import * as NodeType from './ast/nodes/NodeType';
 import Program from './ast/nodes/Program';
-import { GenericEsTreeNode, Node, NodeBase } from './ast/nodes/shared/Node';
+import { Node, NodeBase } from './ast/nodes/shared/Node';
 import { isTemplateLiteral } from './ast/nodes/TemplateLiteral';
 import ModuleScope from './ast/scopes/ModuleScope';
 import { EntityPathTracker } from './ast/utils/EntityPathTracker';
@@ -129,24 +129,6 @@ function tryParse(module: Module, parse: IParse, acornOptions: AcornOptions) {
 	}
 }
 
-function includeFully(node: Node) {
-	node.included = true;
-	if (node.variable && !node.variable.included) {
-		node.variable.include();
-	}
-	for (const key of node.keys) {
-		const value = (<GenericEsTreeNode>node)[key];
-		if (value === null) continue;
-		if (Array.isArray(value)) {
-			for (const child of value) {
-				if (child !== null) includeFully(child);
-			}
-		} else {
-			includeFully(value);
-		}
-	}
-}
-
 function handleMissingExport(
 	exportName: string,
 	importingModule: Module,
@@ -618,7 +600,7 @@ export default class Module {
 	}
 
 	includeAllInBundle() {
-		includeFully(this.ast);
+		this.ast.include(true);
 	}
 
 	isIncluded() {
@@ -627,7 +609,7 @@ export default class Module {
 
 	include(): boolean {
 		this.needsTreeshakingPass = false;
-		if (this.ast.shouldBeIncluded()) this.ast.include();
+		if (this.ast.shouldBeIncluded()) this.ast.include(false);
 		return this.needsTreeshakingPass;
 	}
 
diff --git a/src/ast/nodes/AwaitExpression.ts b/src/ast/nodes/AwaitExpression.ts
index a147f5c2c0c..ebd63ac99f0 100644
--- a/src/ast/nodes/AwaitExpression.ts
+++ b/src/ast/nodes/AwaitExpression.ts
@@ -11,8 +11,8 @@ export default class AwaitExpression extends NodeBase {
 	type: NodeType.tAwaitExpression;
 	argument: ExpressionNode;
 
-	include() {
-		super.include();
+	include(includeAllChildrenRecursively: boolean) {
+		super.include(includeAllChildrenRecursively);
 		if (!this.context.usesTopLevelAwait) {
 			let parent = this.parent;
 			do {
diff --git a/src/ast/nodes/BlockStatement.ts b/src/ast/nodes/BlockStatement.ts
index e539105a03d..c4fd9d0a2d7 100644
--- a/src/ast/nodes/BlockStatement.ts
+++ b/src/ast/nodes/BlockStatement.ts
@@ -34,10 +34,11 @@ export default class BlockStatement extends StatementBase {
 		}
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (const node of this.body) {
-			if (node.shouldBeIncluded()) node.include();
+			if (includeAllChildrenRecursively || node.shouldBeIncluded())
+				node.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/CallExpression.ts b/src/ast/nodes/CallExpression.ts
index a6351ac8116..5a8dab171c4 100644
--- a/src/ast/nodes/CallExpression.ts
+++ b/src/ast/nodes/CallExpression.ts
@@ -180,10 +180,10 @@ export default class CallExpression extends NodeBase implements DeoptimizableEnt
 		);
 	}
 
-	include() {
-		super.include();
+	include(includeAllChildrenRecursively: boolean) {
+		super.include(includeAllChildrenRecursively);
 		if (!this.returnExpression.included) {
-			this.returnExpression.include();
+			this.returnExpression.include(false);
 		}
 	}
 
diff --git a/src/ast/nodes/ConditionalExpression.ts b/src/ast/nodes/ConditionalExpression.ts
index 10b85108779..be693bcfc67 100644
--- a/src/ast/nodes/ConditionalExpression.ts
+++ b/src/ast/nodes/ConditionalExpression.ts
@@ -129,14 +129,14 @@ export default class ConditionalExpression extends NodeBase implements Deoptimiz
 		this.expressionsToBeDeoptimized = [];
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		if (this.usedBranch === null || this.test.shouldBeIncluded()) {
-			this.test.include();
-			this.consequent.include();
-			this.alternate.include();
+		if (includeAllChildrenRecursively || this.usedBranch === null || this.test.shouldBeIncluded()) {
+			this.test.include(includeAllChildrenRecursively);
+			this.consequent.include(includeAllChildrenRecursively);
+			this.alternate.include(includeAllChildrenRecursively);
 		} else {
-			this.usedBranch.include();
+			this.usedBranch.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/ForInStatement.ts b/src/ast/nodes/ForInStatement.ts
index 790755c25e4..824f83d265e 100644
--- a/src/ast/nodes/ForInStatement.ts
+++ b/src/ast/nodes/ForInStatement.ts
@@ -40,12 +40,12 @@ export default class ForInStatement extends StatementBase {
 		);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		this.left.includeWithAllDeclaredVariables();
+		this.left.includeWithAllDeclaredVariables(includeAllChildrenRecursively);
 		this.left.deoptimizePath(EMPTY_PATH);
-		this.right.include();
-		this.body.include();
+		this.right.include(includeAllChildrenRecursively);
+		this.body.include(includeAllChildrenRecursively);
 	}
 
 	render(code: MagicString, options: RenderOptions) {
diff --git a/src/ast/nodes/ForOfStatement.ts b/src/ast/nodes/ForOfStatement.ts
index 7014e76eee3..d03861dcfba 100644
--- a/src/ast/nodes/ForOfStatement.ts
+++ b/src/ast/nodes/ForOfStatement.ts
@@ -41,12 +41,12 @@ export default class ForOfStatement extends StatementBase {
 		);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		this.left.includeWithAllDeclaredVariables();
+		this.left.includeWithAllDeclaredVariables(includeAllChildrenRecursively);
 		this.left.deoptimizePath(EMPTY_PATH);
-		this.right.include();
-		this.body.include();
+		this.right.include(includeAllChildrenRecursively);
+		this.body.include(includeAllChildrenRecursively);
 	}
 
 	render(code: MagicString, options: RenderOptions) {
diff --git a/src/ast/nodes/Identifier.ts b/src/ast/nodes/Identifier.ts
index 45d892fea7f..b512dd83b09 100644
--- a/src/ast/nodes/Identifier.ts
+++ b/src/ast/nodes/Identifier.ts
@@ -108,7 +108,7 @@ export default class Identifier extends NodeBase {
 		return !this.variable || this.variable.hasEffectsWhenCalledAtPath(path, callOptions, options);
 	}
 
-	include() {
+	include(_includeAllChildrenRecursively: boolean) {
 		if (!this.included) {
 			this.included = true;
 			if (this.variable !== null && !this.variable.included) {
diff --git a/src/ast/nodes/IfStatement.ts b/src/ast/nodes/IfStatement.ts
index 68665d56f58..c2eda61bffb 100644
--- a/src/ast/nodes/IfStatement.ts
+++ b/src/ast/nodes/IfStatement.ts
@@ -42,22 +42,28 @@ export default class IfStatement extends StatementBase implements DeoptimizableE
 			: this.alternate !== null && this.alternate.hasEffects(options);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		if (this.testValue === UNKNOWN_VALUE || this.test.shouldBeIncluded()) {
-			this.test.include();
+		if (includeAllChildrenRecursively) {
+			this.test.include(true);
+			this.consequent.include(true);
+			if (this.alternate !== null) {
+				this.alternate.include(true);
+			}
+			return;
 		}
-		if (
-			(this.testValue === UNKNOWN_VALUE || this.testValue) &&
-			this.consequent.shouldBeIncluded()
-		) {
-			this.consequent.include();
+		const hasUnknownTest = this.testValue === UNKNOWN_VALUE;
+		if (hasUnknownTest || this.test.shouldBeIncluded()) {
+			this.test.include(false);
+		}
+		if ((hasUnknownTest || this.testValue) && this.consequent.shouldBeIncluded()) {
+			this.consequent.include(false);
 		}
 		if (
 			this.alternate !== null &&
-			((this.testValue === UNKNOWN_VALUE || !this.testValue) && this.alternate.shouldBeIncluded())
+			((hasUnknownTest || !this.testValue) && this.alternate.shouldBeIncluded())
 		) {
-			this.alternate.include();
+			this.alternate.include(false);
 		}
 	}
 
diff --git a/src/ast/nodes/LogicalExpression.ts b/src/ast/nodes/LogicalExpression.ts
index 8c5129c70b3..91caf81426e 100644
--- a/src/ast/nodes/LogicalExpression.ts
+++ b/src/ast/nodes/LogicalExpression.ts
@@ -122,13 +122,17 @@ export default class LogicalExpression extends NodeBase implements Deoptimizable
 		return this.usedBranch.hasEffectsWhenCalledAtPath(path, callOptions, options);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		if (this.usedBranch === null || this.unusedBranch.shouldBeIncluded()) {
-			this.left.include();
-			this.right.include();
+		if (
+			includeAllChildrenRecursively ||
+			this.usedBranch === null ||
+			this.unusedBranch.shouldBeIncluded()
+		) {
+			this.left.include(includeAllChildrenRecursively);
+			this.right.include(includeAllChildrenRecursively);
 		} else {
-			this.usedBranch.include();
+			this.usedBranch.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/MemberExpression.ts b/src/ast/nodes/MemberExpression.ts
index e981cf5fbf2..b4cfc8a685a 100644
--- a/src/ast/nodes/MemberExpression.ts
+++ b/src/ast/nodes/MemberExpression.ts
@@ -176,7 +176,7 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 		);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		if (!this.included) {
 			this.included = true;
 			if (this.variable !== null && !this.variable.included) {
@@ -184,8 +184,8 @@ export default class MemberExpression extends NodeBase implements DeoptimizableE
 				this.context.requestTreeshakingPass();
 			}
 		}
-		this.object.include();
-		this.property.include();
+		this.object.include(includeAllChildrenRecursively);
+		this.property.include(includeAllChildrenRecursively);
 	}
 
 	initialise() {
diff --git a/src/ast/nodes/Program.ts b/src/ast/nodes/Program.ts
index 0ad7243e9c5..06952c8912b 100644
--- a/src/ast/nodes/Program.ts
+++ b/src/ast/nodes/Program.ts
@@ -15,10 +15,11 @@ export default class Program extends NodeBase {
 		}
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (const node of this.body) {
-			if (node.shouldBeIncluded()) node.include();
+			if (includeAllChildrenRecursively || node.shouldBeIncluded())
+				node.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/SequenceExpression.ts b/src/ast/nodes/SequenceExpression.ts
index 47a6585f281..d06aae78965 100644
--- a/src/ast/nodes/SequenceExpression.ts
+++ b/src/ast/nodes/SequenceExpression.ts
@@ -63,13 +63,14 @@ export default class SequenceExpression extends NodeBase {
 		);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (let i = 0; i < this.expressions.length - 1; i++) {
 			const node = this.expressions[i];
-			if (node.shouldBeIncluded()) node.include();
+			if (includeAllChildrenRecursively || node.shouldBeIncluded())
+				node.include(includeAllChildrenRecursively);
 		}
-		this.expressions[this.expressions.length - 1].include();
+		this.expressions[this.expressions.length - 1].include(includeAllChildrenRecursively);
 	}
 
 	deoptimizePath(path: ObjectPath) {
diff --git a/src/ast/nodes/SwitchCase.ts b/src/ast/nodes/SwitchCase.ts
index a4a91d4ebf7..30068eaf487 100644
--- a/src/ast/nodes/SwitchCase.ts
+++ b/src/ast/nodes/SwitchCase.ts
@@ -12,11 +12,12 @@ export default class SwitchCase extends NodeBase {
 	test: ExpressionNode | null;
 	consequent: StatementNode[];
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
-		if (this.test) this.test.include();
+		if (this.test) this.test.include(includeAllChildrenRecursively);
 		for (const node of this.consequent) {
-			if (node.shouldBeIncluded()) node.include();
+			if (includeAllChildrenRecursively || node.shouldBeIncluded())
+				node.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/UnknownNode.ts b/src/ast/nodes/UnknownNode.ts
index 06ee462c461..7dca98101eb 100644
--- a/src/ast/nodes/UnknownNode.ts
+++ b/src/ast/nodes/UnknownNode.ts
@@ -5,4 +5,8 @@ export default class UnknownNode extends NodeBase {
 	hasEffects(_options: ExecutionPathOptions) {
 		return true;
 	}
+
+	include() {
+		super.include(true);
+	}
 }
diff --git a/src/ast/nodes/VariableDeclaration.ts b/src/ast/nodes/VariableDeclaration.ts
index e146bfe726d..36216bb4cda 100644
--- a/src/ast/nodes/VariableDeclaration.ts
+++ b/src/ast/nodes/VariableDeclaration.ts
@@ -35,17 +35,18 @@ export default class VariableDeclaration extends NodeBase {
 		return false;
 	}
 
-	includeWithAllDeclaredVariables() {
+	includeWithAllDeclaredVariables(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (const declarator of this.declarations) {
-			declarator.include();
+			declarator.include(includeAllChildrenRecursively);
 		}
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (const declarator of this.declarations) {
-			if (declarator.shouldBeIncluded()) declarator.include();
+			if (includeAllChildrenRecursively || declarator.shouldBeIncluded())
+				declarator.include(includeAllChildrenRecursively);
 		}
 	}
 
diff --git a/src/ast/nodes/shared/Expression.ts b/src/ast/nodes/shared/Expression.ts
index 7626a6da816..7c4eb07559e 100644
--- a/src/ast/nodes/shared/Expression.ts
+++ b/src/ast/nodes/shared/Expression.ts
@@ -29,5 +29,5 @@ export interface ExpressionEntity extends WritableEntity {
 		callOptions: CallOptions,
 		options: ExecutionPathOptions
 	): boolean;
-	include(): void;
+	include(includeAllChildrenRecursively: boolean): void;
 }
diff --git a/src/ast/nodes/shared/FunctionNode.ts b/src/ast/nodes/shared/FunctionNode.ts
index ec54155f7e1..3ae5c3ce695 100644
--- a/src/ast/nodes/shared/FunctionNode.ts
+++ b/src/ast/nodes/shared/FunctionNode.ts
@@ -60,9 +60,9 @@ export default class FunctionNode extends NodeBase {
 		return this.body.hasEffects(innerOptions);
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.scope.variables.arguments.include();
-		super.include();
+		super.include(includeAllChildrenRecursively);
 	}
 
 	initialise() {
diff --git a/src/ast/nodes/shared/Node.ts b/src/ast/nodes/shared/Node.ts
index ee7fb7e401e..b79725d3339 100644
--- a/src/ast/nodes/shared/Node.ts
+++ b/src/ast/nodes/shared/Node.ts
@@ -49,19 +49,18 @@ export interface Node extends Entity {
 	hasEffects(options: ExecutionPathOptions): boolean;
 
 	/**
-	 * Includes the node in the bundle. Children are usually included if they are
-	 * necessary for this node (e.g. a function body) or if they have effects.
-	 * Necessary variables need to be included as well. Should return true if any
-	 * nodes or variables have been added that were missing before.
+	 * Includes the node in the bundle. If the flag is not set, children are usually included
+	 * if they are necessary for this node (e.g. a function body) or if they have effects.
+	 * Necessary variables need to be included as well.
 	 */
-	include(): void;
+	include(includeAllChildrenRecursively: boolean): void;
 
 	/**
 	 * Alternative version of include to override the default behaviour of
 	 * declarations to only include nodes for declarators that have an effect. Necessary
 	 * for for-loops that do not use a declared loop variable.
 	 */
-	includeWithAllDeclaredVariables(): void;
+	includeWithAllDeclaredVariables(includeAllChildrenRecursively: boolean): void;
 	render(code: MagicString, options: RenderOptions, nodeRenderOptions?: NodeRenderOptions): void;
 
 	/**
@@ -177,23 +176,23 @@ export class NodeBase implements ExpressionNode {
 		return true;
 	}
 
-	include() {
+	include(includeAllChildrenRecursively: boolean) {
 		this.included = true;
 		for (const key of this.keys) {
 			const value = (<GenericEsTreeNode>this)[key];
 			if (value === null) continue;
 			if (Array.isArray(value)) {
 				for (const child of value) {
-					if (child !== null) child.include();
+					if (child !== null) child.include(includeAllChildrenRecursively);
 				}
 			} else {
-				value.include();
+				value.include(includeAllChildrenRecursively);
 			}
 		}
 	}
 
-	includeWithAllDeclaredVariables() {
-		this.include();
+	includeWithAllDeclaredVariables(includeAllChildrenRecursively: boolean) {
+		this.include(includeAllChildrenRecursively);
 	}
 
 	/**
diff --git a/src/ast/variables/LocalVariable.ts b/src/ast/variables/LocalVariable.ts
index 7896842687f..efd9fa95ff2 100644
--- a/src/ast/variables/LocalVariable.ts
+++ b/src/ast/variables/LocalVariable.ts
@@ -153,7 +153,7 @@ export default class LocalVariable extends Variable {
 			this.included = true;
 			for (const declaration of this.declarations) {
 				// If node is a default export, it can save a tree-shaking run to include the full declaration now
-				if (!declaration.included) declaration.include();
+				if (!declaration.included) declaration.include(false);
 				let node = <Node>declaration.parent;
 				while (!node.included) {
 					// We do not want to properly include parents in case they are part of a dead branch
diff --git a/test/form/samples/no-treeshake/_expected/amd.js b/test/form/samples/no-treeshake/_expected/amd.js
index 5a10b8c64a2..ecb358c7923 100644
--- a/test/form/samples/no-treeshake/_expected/amd.js
+++ b/test/form/samples/no-treeshake/_expected/amd.js
@@ -1,24 +1,36 @@
 define(['exports', 'external'], function (exports, external) { 'use strict';
 
-	var foo = 'unused';
+	var foo = 13;
 
 	const quux = 1;
 
 	const other = () => quux;
 
-	function bar () {
-		return foo;
+	function baz() {
+		return foo + external.value;
 	}
 
-	function baz () {
-		return 13 + external.value;
+	var create = Object.create,
+		getPrototypeOf = Object.getPrototypeOf;
+
+	function unusedButIncluded() {
+		const unusedConst = 'unused';
+		if (true) {
+			true ? 'first' : 'second';
+		} else {
+			(true && 'first') || 'second';
+		}
+		'sequence', 'expression';
+		switch ('test') {
+			case 'test':
+				(() => {})();
+			case 'other':
+				'no effect';
+			default:
+				const ignored = 2;
+		}
 	}
 
-	const moreExternal = external.more;
-
-	var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
-
-	exports.baz = baz;
 	exports.create = create;
 	exports.getPrototypeOf = getPrototypeOf;
 	exports.strange = quux;
diff --git a/test/form/samples/no-treeshake/_expected/cjs.js b/test/form/samples/no-treeshake/_expected/cjs.js
index 53fce965345..c8f47529115 100644
--- a/test/form/samples/no-treeshake/_expected/cjs.js
+++ b/test/form/samples/no-treeshake/_expected/cjs.js
@@ -4,25 +4,37 @@ Object.defineProperty(exports, '__esModule', { value: true });
 
 var external = require('external');
 
-var foo = 'unused';
+var foo = 13;
 
 const quux = 1;
 
 const other = () => quux;
 
-function bar () {
-	return foo;
+function baz() {
+	return foo + external.value;
 }
 
-function baz () {
-	return 13 + external.value;
+var create = Object.create,
+	getPrototypeOf = Object.getPrototypeOf;
+
+function unusedButIncluded() {
+	const unusedConst = 'unused';
+	if (true) {
+		true ? 'first' : 'second';
+	} else {
+		(true && 'first') || 'second';
+	}
+	'sequence', 'expression';
+	switch ('test') {
+		case 'test':
+			(() => {})();
+		case 'other':
+			'no effect';
+		default:
+			const ignored = 2;
+	}
 }
 
-const moreExternal = external.more;
-
-var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
-
-exports.baz = baz;
 exports.create = create;
 exports.getPrototypeOf = getPrototypeOf;
 exports.strange = quux;
diff --git a/test/form/samples/no-treeshake/_expected/es.js b/test/form/samples/no-treeshake/_expected/es.js
index 48e3035d91b..28b4f47617f 100644
--- a/test/form/samples/no-treeshake/_expected/es.js
+++ b/test/form/samples/no-treeshake/_expected/es.js
@@ -1,21 +1,34 @@
-import { value, more } from 'external';
+import { value } from 'external';
 
-var foo = 'unused';
+var foo = 13;
 
 const quux = 1;
 
 const other = () => quux;
 
-function bar () {
-	return foo;
+function baz() {
+	return foo + value;
 }
 
-function baz () {
-	return 13 + value;
+var create = Object.create,
+	getPrototypeOf = Object.getPrototypeOf;
+
+function unusedButIncluded() {
+	const unusedConst = 'unused';
+	if (true) {
+		true ? 'first' : 'second';
+	} else {
+		(true && 'first') || 'second';
+	}
+	'sequence', 'expression';
+	switch ('test') {
+		case 'test':
+			(() => {})();
+		case 'other':
+			'no effect';
+		default:
+			const ignored = 2;
+	}
 }
 
-const moreExternal = more;
-
-var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
-
-export { baz, create, getPrototypeOf, quux as strange };
+export { create, getPrototypeOf, quux as strange };
diff --git a/test/form/samples/no-treeshake/_expected/iife.js b/test/form/samples/no-treeshake/_expected/iife.js
index 060a647e7d8..a8294f43882 100644
--- a/test/form/samples/no-treeshake/_expected/iife.js
+++ b/test/form/samples/no-treeshake/_expected/iife.js
@@ -1,25 +1,37 @@
 var stirred = (function (exports,external) {
 	'use strict';
 
-	var foo = 'unused';
+	var foo = 13;
 
 	const quux = 1;
 
 	const other = () => quux;
 
-	function bar () {
-		return foo;
+	function baz() {
+		return foo + external.value;
 	}
 
-	function baz () {
-		return 13 + external.value;
+	var create = Object.create,
+		getPrototypeOf = Object.getPrototypeOf;
+
+	function unusedButIncluded() {
+		const unusedConst = 'unused';
+		if (true) {
+			true ? 'first' : 'second';
+		} else {
+			(true && 'first') || 'second';
+		}
+		'sequence', 'expression';
+		switch ('test') {
+			case 'test':
+				(() => {})();
+			case 'other':
+				'no effect';
+			default:
+				const ignored = 2;
+		}
 	}
 
-	const moreExternal = external.more;
-
-	var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
-
-	exports.baz = baz;
 	exports.create = create;
 	exports.getPrototypeOf = getPrototypeOf;
 	exports.strange = quux;
diff --git a/test/form/samples/no-treeshake/_expected/system.js b/test/form/samples/no-treeshake/_expected/system.js
index 1bbfb5fb64c..426db5b89f8 100644
--- a/test/form/samples/no-treeshake/_expected/system.js
+++ b/test/form/samples/no-treeshake/_expected/system.js
@@ -1,33 +1,43 @@
 System.register('stirred', ['external'], function (exports, module) {
 	'use strict';
-	var value, more;
+	var value;
 	return {
 		setters: [function (module) {
 			value = module.value;
-			more = module.more;
 		}],
 		execute: function () {
 
-			exports('baz', baz);
-
-			var foo = 'unused';
+			var foo = 13;
 
 			const quux = exports('strange', 1);
 
 			const other = () => quux;
 
-			function bar () {
-				return foo;
+			function baz() {
+				return foo + value;
 			}
 
-			function baz () {
-				return 13 + value;
+			var create = exports('create', Object.create),
+				getPrototypeOf = exports('getPrototypeOf', Object.getPrototypeOf);
+
+			function unusedButIncluded() {
+				const unusedConst = 'unused';
+				if (true) {
+					true ? 'first' : 'second';
+				} else {
+					(true && 'first') || 'second';
+				}
+				'sequence', 'expression';
+				switch ('test') {
+					case 'test':
+						(() => {})();
+					case 'other':
+						'no effect';
+					default:
+						const ignored = 2;
+				}
 			}
 
-			const moreExternal = more;
-
-			var create = exports('create', Object.create), getPrototypeOf = exports('getPrototypeOf', Object.getPrototypeOf);
-
 		}
 	};
 });
diff --git a/test/form/samples/no-treeshake/_expected/umd.js b/test/form/samples/no-treeshake/_expected/umd.js
index 05f355ea6c2..92caa73a32f 100644
--- a/test/form/samples/no-treeshake/_expected/umd.js
+++ b/test/form/samples/no-treeshake/_expected/umd.js
@@ -4,25 +4,37 @@
 	(factory((global.stirred = {}),global.external));
 }(this, (function (exports,external) { 'use strict';
 
-	var foo = 'unused';
+	var foo = 13;
 
 	const quux = 1;
 
 	const other = () => quux;
 
-	function bar () {
-		return foo;
+	function baz() {
+		return foo + external.value;
 	}
 
-	function baz () {
-		return 13 + external.value;
+	var create = Object.create,
+		getPrototypeOf = Object.getPrototypeOf;
+
+	function unusedButIncluded() {
+		const unusedConst = 'unused';
+		if (true) {
+			true ? 'first' : 'second';
+		} else {
+			(true && 'first') || 'second';
+		}
+		'sequence', 'expression';
+		switch ('test') {
+			case 'test':
+				(() => {})();
+			case 'other':
+				'no effect';
+			default:
+				const ignored = 2;
+		}
 	}
 
-	const moreExternal = external.more;
-
-	var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
-
-	exports.baz = baz;
 	exports.create = create;
 	exports.getPrototypeOf = getPrototypeOf;
 	exports.strange = quux;
diff --git a/test/form/samples/no-treeshake/foo.js b/test/form/samples/no-treeshake/foo.js
index e4c7f512867..e9ac6f7b062 100644
--- a/test/form/samples/no-treeshake/foo.js
+++ b/test/form/samples/no-treeshake/foo.js
@@ -1 +1 @@
-export default 'unused';
+export default 13;
diff --git a/test/form/samples/no-treeshake/main.js b/test/form/samples/no-treeshake/main.js
index 154a571059f..2a6361ba2b7 100644
--- a/test/form/samples/no-treeshake/main.js
+++ b/test/form/samples/no-treeshake/main.js
@@ -1,15 +1,28 @@
 import * as external from 'external';
-import foo from './foo.js'
+import foo from './foo.js';
 export { quux as strange } from './quux.js';
 
-function bar () {
-	return foo;
+function baz() {
+	return foo + external.value;
 }
 
-export function baz () {
-	return 13 + external.value;
-}
-
-const moreExternal = external.more;
+export var create = Object.create,
+	getPrototypeOf = Object.getPrototypeOf;
 
-export var create = Object.create, getPrototypeOf = Object.getPrototypeOf;
+function unusedButIncluded() {
+	const unusedConst = 'unused';
+	if (true) {
+		true ? 'first' : 'second';
+	} else {
+		(true && 'first') || 'second';
+	}
+	'sequence', 'expression';
+	switch ('test') {
+		case 'test':
+			(() => {})();
+		case 'other':
+			'no effect';
+		default:
+			const ignored = 2;
+	}
+}
diff --git a/test/form/samples/unknown-token-effects/_config.js b/test/form/samples/unknown-token-effects/_config.js
new file mode 100644
index 00000000000..b3be078cdee
--- /dev/null
+++ b/test/form/samples/unknown-token-effects/_config.js
@@ -0,0 +1,28 @@
+module.exports = {
+	description: 'does not tree-shake unknown tokens',
+	options: {
+		acorn: {
+			plugins: { doTestExpressions: true }
+		},
+		acornInjectPlugins: [
+			acorn => {
+				acorn.plugins.doTestExpressions = function doTestExpressions(instance) {
+					instance.extend(
+						'parseExprAtom',
+						superF =>
+							function parseExprAtom(...args) {
+								if (this.type === acorn.tokTypes._do) {
+									this.eat(acorn.tokTypes._do);
+									const node = this.startNode();
+									node.body = this.parseBlock();
+									return this.finishNode(node, 'DoExpression');
+								}
+								return Reflect.apply(superF, this, args);
+							}
+					);
+				};
+				return acorn;
+			}
+		]
+	}
+};
diff --git a/test/form/samples/unknown-token-effects/_expected.js b/test/form/samples/unknown-token-effects/_expected.js
new file mode 100644
index 00000000000..ecb1863985c
--- /dev/null
+++ b/test/form/samples/unknown-token-effects/_expected.js
@@ -0,0 +1,34 @@
+(do {
+	() => console.log('retained');
+}());
+(do {
+	null;
+}.y);
+(do {
+	({ y: () => console.log('retained') });
+}.y());
+(do {
+	({
+		set y(value) {
+			console.log(value);
+		}
+	});
+}.y = 'retained');
+
+const functionUsedInExpr = () => 1;
+const objectUsedInExpr = { value: 2 };
+const valueUsedInExpr = 3;
+
+const exprValue = do {
+	if (unknownCondition1) {
+		functionUsedInExpr();
+	} else if (unknownCondition2) {
+		objectUsedInExpr.value;
+	} else if (unknownCondition3) {
+		valueUsedInExpr;
+	} else {
+		'direct value';
+	}
+};
+
+export { exprValue };
diff --git a/test/form/samples/unknown-token-effects/main.js b/test/form/samples/unknown-token-effects/main.js
new file mode 100644
index 00000000000..6242104883a
--- /dev/null
+++ b/test/form/samples/unknown-token-effects/main.js
@@ -0,0 +1,32 @@
+(do {
+	() => console.log('retained');
+}());
+(do {
+	null;
+}.y);
+(do {
+	({ y: () => console.log('retained') });
+}.y());
+(do {
+	({
+		set y(value) {
+			console.log(value);
+		}
+	});
+}.y = 'retained');
+
+const functionUsedInExpr = () => 1;
+const objectUsedInExpr = { value: 2 };
+const valueUsedInExpr = 3;
+
+export const exprValue = do {
+	if (unknownCondition1) {
+		functionUsedInExpr();
+	} else if (unknownCondition2) {
+		objectUsedInExpr.value;
+	} else if (unknownCondition3) {
+		valueUsedInExpr;
+	} else {
+		'direct value'
+	}
+};