Add regresstion test for rust-lang#90024.

Uses 2 MCVEs from the issue tracker that test opposite sides of the problem.

Author: JakobDegen

src/test/ui/closures/2229_closure_analysis/migrations/issue-90024-adt-correct-subst.rs

@@ -0,0 +1,37 @@
+// Test that rustc doesn't ICE as in #90024.
+// check-pass
+// edition=2018
+
+#![warn(rust_2021_incompatible_closure_captures)]
+
+// Checks there's no double-subst into the generic args, otherwise we get OOB
+// MCVE by @lqd
+pub struct Graph<N, E, Ix> {
+    _edges: E,
+    _nodes: N,
+    _ix: Vec<Ix>,
+}
+fn graph<N, E>() -> Graph<N, E, i32> {
+    todo!()
+}
+fn first_ice() {
+    let g = graph::<i32, i32>();
+    let _ = || g;
+}
+
+// Checks that there is a subst into the fields, otherwise we get normalization error
+// MCVE by @cuviper
+use std::iter::Empty;
+struct Foo<I: Iterator> {
+    data: Vec<I::Item>,
+}
+pub fn second_ice() {
+    let v = Foo::<Empty<()>> { data: vec![] };
+
+    (|| v.data[0])();
+}
+
+pub fn main() {
+    first_ice();
+    second_ice();
+}