add regression test

Author: lcnr

src/test/ui/mir/mir-inlining/ice-issue-68347.rs

@@ -0,0 +1,28 @@
+// run-pass
+// compile-flags:-Zmir-opt-level=2
+pub fn main() {
+    let _x: fn() = handle_debug_column;
+}
+
+fn handle_debug_column() {
+    let sampler = sample_columns();
+
+    let foo = || {
+        sampler.get(17);
+    };
+    foo();
+}
+
+fn sample_columns() -> impl Sampler {
+    ColumnGen {}
+}
+
+struct ColumnGen {}
+
+trait Sampler {
+    fn get(&self, index: i32);
+}
+
+impl Sampler for ColumnGen {
+    fn get(&self, _index: i32) {}
+}