Add regression test for ICE with undefined type in async fn

tests/ui/mir/gvn-opt-138225.rs

@@ -0,0 +1,16 @@
+//! Regression test for <https://github.com/rust-lang/rust/issues/138225>
+
+pub struct A {
+    name: NestedOption<Option<String>>,
+    //~^ ERROR cannot find type `NestedOption` in this scope
+}
+
+impl A {
+    pub async fn func1() -> &'static A {
+        //~^ ERROR `async fn` is not permitted in Rust 2015
+        static RES: A = A { name: None };
+        &RES
+    }
+}
+
+fn main() {}

tests/ui/mir/gvn-opt-138225.stderr

@@ -0,0 +1,19 @@
+error[E0670]: `async fn` is not permitted in Rust 2015
+  --> $DIR/gvn-opt-138225.rs:9:9
+   |
+LL |     pub async fn func1() -> &'static A {
+   |         ^^^^^ to use `async fn`, switch to Rust 2018 or later
+   |
+   = help: pass `--edition 2024` to `rustc`
+   = note: for more on editions, read https://doc.rust-lang.org/edition-guide
+
+error[E0425]: cannot find type `NestedOption` in this scope
+  --> $DIR/gvn-opt-138225.rs:4:11
+   |
+LL |     name: NestedOption<Option<String>>,
+   |           ^^^^^^^^^^^^ not found in this scope
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0425, E0670.
+For more information about an error, try `rustc --explain E0425`.