Do not tree-shake arguments with side-effects (#2924)

src/ast/scopes/ParameterScope.ts

@@ -58,7 +58,8 @@ export default class ParameterScope extends ChildScope {
 						calledFromTryStatement = true;
 					}
 				}
-			} else if (!argIncluded && arg.shouldBeIncluded()) {
+			}
+			if (!argIncluded && arg.shouldBeIncluded()) {
 				argIncluded = true;
 			}
 			if (argIncluded) {

test/form/samples/treeshake-excess-arguments/argument-side-effects/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'retains arguments that have side-effects'
+};

test/form/samples/treeshake-excess-arguments/argument-side-effects/_expected.js

@@ -0,0 +1,10 @@
+function sideEffects() {
+	console.log('print message');
+	return true;
+}
+
+function hola(a, b) {
+	console.log(a);
+}
+
+hola(1, sideEffects());

test/form/samples/treeshake-excess-arguments/argument-side-effects/main.js

@@ -0,0 +1,10 @@
+function sideEffects() {
+	console.log('print message');
+	return true;
+}
+
+function hola(a, b) {
+	console.log(a);
+}
+
+hola(1, sideEffects());