Add regression tests

tests/cases/compiler/tupleTypeInference2.ts

@@ -0,0 +1,25 @@
+// @strict: true
+
+// Repro from #22564
+
+type A<R> = [R] | [R, string];
+declare function f<T>(x: A<T>): T;
+f([undefined, ''] as [never, string]); // T: never
+f([undefined, ''] as [void, string]); // T: void
+
+// Repro from #22563
+
+type B<R, S> = [R] | [R, S];
+declare function g<T, U>(f: B<T, U>): U;
+g([[]] as [void[]]); // U: {}
+
+type C<R, S> = [R[]] | [R[], S];
+declare function h<T, U>(f: C<T, U>): U;
+h([[]] as [void[]]); // U: {}
+
+// Repro from #22562
+
+type C2<R> = [R[]] | [R[], void];
+declare function h2<T>(f: C2<T>): T;
+h2([[]] as [never[]]); // T: never
+h2([[]] as [void[]]); // T: void