opportunistic move

should be way faster now

src/systems/stl/panic.rs

@@ -2,8 +2,7 @@ use std::fmt::Display;
 use std::rc::Rc;
 
 use crate::foreign::ExternError;
-use crate::systems::cast_exprinst::with_str;
-use crate::{define_fn, ConstTree, Interner};
+use crate::{define_fn, ConstTree, Interner, OrcString};
 
 /// An unrecoverable error in Orchid land. Because Orchid is lazy, this only
 /// invalidates expressions that reference the one that generated it.
@@ -19,10 +18,10 @@ impl ExternError for OrchidPanic {}
 
 define_fn! {
   /// Takes a message, returns an [ExternError] unconditionally.
-  Panic = |x| with_str(x, |s| {
-    let msg = Rc::new(s.get_string());
+  Panic = |x| {
+    let msg = Rc::new(x.downcast::<OrcString>()?.get_string());
     Err(OrchidPanic(msg).into_extern())
-  })
+  }
 }
 
 pub fn panic(i: &Interner) -> ConstTree {