Make sure logical expressions always check the left argument for side…

…-effects (#3438)

src/ast/nodes/LogicalExpression.ts

@@ -97,10 +97,13 @@ export default class LogicalExpression extends NodeBase implements Deoptimizable
 	}
 
 	hasEffects(context: HasEffectsContext): boolean {
-		if (this.usedBranch === null) {
-			return this.left.hasEffects(context) || this.right.hasEffects(context);
+		if (this.left.hasEffects(context)) {
+			return true;
+		}
+		if (this.usedBranch !== this.left) {
+			return this.right.hasEffects(context);
 		}
-		return this.usedBranch.hasEffects(context);
+		return false;
 	}
 
 	hasEffectsWhenAccessedAtPath(path: ObjectPath, context: HasEffectsContext): boolean {

test/function/samples/reassigned-return-expression/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'does not bind return expressions before assignments are bound (#3382)'
+};

test/function/samples/reassigned-return-expression/main.js

@@ -0,0 +1,17 @@
+function getIcon() {
+	var icon = undefined;
+	icon = { code: true };
+	return icon;
+}
+
+function main() {
+	var a = getIcon() || {
+		code: undefined
+	};
+	if (!a.code) {
+		return 'broken';
+	}
+	return 'works';
+}
+
+assert.strictEqual(main(), 'works');