Fixed handling tuples when they are part of union/intersection

src/transformer.ts

@@ -296,6 +296,13 @@ function createTransformerFactory(program: ts.Program, options?: Partial<RenameO
 					return true;
 				}
 
+				if (objectType.objectFlags & ts.ObjectFlags.Reference) {
+					const target = (objectType as ts.TypeReference).target;
+					if (target !== objectType && isTypePropertyExternal(target, typePropertyName)) {
+						return true;
+					}
+				}
+
 				// in case when we can't get where a property come from in mapped types
 				// let's check the whole type explicitly
 				// thus in case of when property doesn't have a declaration let's treat any property of a mapped type as "external" if its parent type is external

tests/test-cases/tuple-complex/input.ts

@@ -0,0 +1,15 @@
+type TwoItems = [number, number];
+type FourItems = [number, number, number, number];
+type TupleOrNumber = number | TwoItems | FourItems;
+
+function drawRoundRect(tupleOrNumber: TupleOrNumber): void {
+	if (!Array.isArray(tupleOrNumber)) {
+		console.log(tupleOrNumber.toExponential());
+	} else if (tupleOrNumber.length === 2) {
+		const [first, second] = tupleOrNumber;
+		console.log(first.toExponential(), second.toExponential());
+	} else if (tupleOrNumber.length === 4) {
+		const [first, second, third, fourth] = tupleOrNumber;
+		console.log(first.toExponential(), second.toExponential(), third.toExponential(), fourth.toExponential());
+	}
+}

tests/test-cases/tuple-complex/output.js

@@ -0,0 +1,13 @@
+function drawRoundRect(tupleOrNumber) {
+    if (!Array.isArray(tupleOrNumber)) {
+        console.log(tupleOrNumber.toExponential());
+    }
+    else if (tupleOrNumber.length === 2) {
+        var first = tupleOrNumber[0], second = tupleOrNumber[1];
+        console.log(first.toExponential(), second.toExponential());
+    }
+    else if (tupleOrNumber.length === 4) {
+        var first = tupleOrNumber[0], second = tupleOrNumber[1], third = tupleOrNumber[2], fourth = tupleOrNumber[3];
+        console.log(first.toExponential(), second.toExponential(), third.toExponential(), fourth.toExponential());
+    }
+}