Interning Orchid string literals

src/systems/stl/panic.rs

@@ -1,4 +1,5 @@
 use std::fmt::Display;
+use std::rc::Rc;
 
 use crate::foreign::ExternError;
 use crate::systems::cast_exprinst::with_str;
@@ -6,7 +7,7 @@ use crate::{define_fn, ConstTree, Interner};
 
 /// An unrecoverable error in Orchid land. Because Orchid is lazy, this only
 /// invalidates expressions that reference the one that generated it.
-pub struct OrchidPanic(String);
+pub struct OrchidPanic(Rc<String>);
 
 impl Display for OrchidPanic {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -18,7 +19,10 @@ impl ExternError for OrchidPanic {}
 
 define_fn! {
   /// Takes a message, returns an [ExternError] unconditionally.
-  Panic = |x| with_str(x, |s| Err(OrchidPanic(s.clone()).into_extern()))
+  Panic = |x| with_str(x, |s| {
+    let msg = Rc::new(s.get_string());
+    Err(OrchidPanic(msg).into_extern())
+  })
 }
 
 pub fn panic(i: &Interner) -> ConstTree {