diff --git a/src/Module.ts b/src/Module.ts
index fa498192d3b..80eeb58d547 100644
--- a/src/Module.ts
+++ b/src/Module.ts
@@ -1061,14 +1061,16 @@ export default class Module {
 			variable.include();
 			this.graph.needsTreeshakingPass = true;
 			const variableModule = variable.module;
-			if (variableModule && variableModule !== this && variableModule instanceof Module) {
+			if (variableModule && variableModule instanceof Module) {
 				if (!variableModule.isExecuted) {
 					markModuleAndImpureDependenciesAsExecuted(variableModule);
 				}
-				const sideEffectModules = getAndExtendSideEffectModules(variable, this);
-				for (const module of sideEffectModules) {
-					if (!module.isExecuted) {
-						markModuleAndImpureDependenciesAsExecuted(module);
+				if (variableModule !== this) {
+					const sideEffectModules = getAndExtendSideEffectModules(variable, this);
+					for (const module of sideEffectModules) {
+						if (!module.isExecuted) {
+							markModuleAndImpureDependenciesAsExecuted(module);
+						}
 					}
 				}
 			}
diff --git a/src/ast/nodes/shared/Node.ts b/src/ast/nodes/shared/Node.ts
index 38e72ee3296..a7a1656aebd 100644
--- a/src/ast/nodes/shared/Node.ts
+++ b/src/ast/nodes/shared/Node.ts
@@ -286,5 +286,5 @@ export function locateNode(node: Node) {
 }
 
 export function logNode(node: Node) {
-	console.log(node.context.code.slice(node.start, node.end));
+	return node.context.code.slice(node.start, node.end);
 }
diff --git a/test/function/samples/side-effect-free-module-function/_config.js b/test/function/samples/side-effect-free-module-function/_config.js
new file mode 100644
index 00000000000..7338de6c86e
--- /dev/null
+++ b/test/function/samples/side-effect-free-module-function/_config.js
@@ -0,0 +1,11 @@
+module.exports = {
+	description:
+		'correctly include functions with side effects from side-effect-free modules (#3942)',
+	options: {
+		plugins: {
+			transform() {
+				return { moduleSideEffects: false };
+			}
+		}
+	}
+};
diff --git a/test/function/samples/side-effect-free-module-function/curry.js b/test/function/samples/side-effect-free-module-function/curry.js
new file mode 100644
index 00000000000..c4e015c5001
--- /dev/null
+++ b/test/function/samples/side-effect-free-module-function/curry.js
@@ -0,0 +1,4 @@
+export function curry(fn, args = []) {
+	return (..._args) =>
+		(rest => (rest.length >= fn.length ? fn(...rest) : curry(fn, rest)))([...args, ..._args]);
+}
diff --git a/test/function/samples/side-effect-free-module-function/main.js b/test/function/samples/side-effect-free-module-function/main.js
new file mode 100644
index 00000000000..12ab0b1a92b
--- /dev/null
+++ b/test/function/samples/side-effect-free-module-function/main.js
@@ -0,0 +1,11 @@
+import { curry } from './curry';
+let result;
+
+function foo() {
+	result = 'foo';
+}
+
+var fooc = curry(foo);
+fooc();
+
+assert.strictEqual(result, 'foo');