add regression test for rust-lang#68596

Author: lcnr

src/test/ui/const-generics/issues/issue-68596.rs

@@ -0,0 +1,18 @@
+// check-pass
+#![feature(const_generics)]
+#![allow(incomplete_features)]
+
+pub struct S(u8);
+
+impl S {
+    pub fn get<const A: u8>(&self) -> &u8 {
+        &self.0
+    }
+}
+
+fn main() {
+    const A: u8 = 5;
+    let s = S(0);
+
+    s.get::<A>();
+}