add regression test

src/test/ui/generics/issue-94923.rs

@@ -0,0 +1,49 @@
+// run-pass
+// regression test for issue #94923
+// min-llvm-version: 15.0.0
+// compile-flags: -C opt-level=3
+
+fn f0<T>(mut x: usize) -> usize {
+    for _ in 0..1000 {
+        x *= 123;
+        x %= 99
+    }
+    x + 321 // function composition is not just longer iteration
+}
+
+fn f1<T>(x: usize) -> usize {
+    f0::<(i8, T)>(f0::<(u8, T)>(x))
+}
+
+fn f2<T>(x: usize) -> usize {
+    f1::<(i8, T)>(f1::<(u8, T)>(x))
+}
+
+fn f3<T>(x: usize) -> usize {
+    f2::<(i8, T)>(f2::<(u8, T)>(x))
+}
+
+fn f4<T>(x: usize) -> usize {
+    f3::<(i8, T)>(f3::<(u8, T)>(x))
+}
+
+fn f5<T>(x: usize) -> usize {
+    f4::<(i8, T)>(f4::<(u8, T)>(x))
+}
+
+fn f6<T>(x: usize) -> usize {
+    f5::<(i8, T)>(f5::<(u8, T)>(x))
+}
+
+fn f7<T>(x: usize) -> usize {
+    f6::<(i8, T)>(f6::<(u8, T)>(x))
+}
+
+fn f8<T>(x: usize) -> usize {
+    f7::<(i8, T)>(f7::<(u8, T)>(x))
+}
+
+fn main() {
+    let y = f8::<()>(1);
+    assert_eq!(y, 348);
+}