wip

compiler/can/src/def.rs

@@ -91,6 +91,7 @@ pub enum Declaration {
         Vec<Located<Ident>>,
         Vec<(Region /* pattern */, Region /* expr */)>,
     ),
+    Builtin(Def),
 }
 
 impl Declaration {
@@ -100,6 +101,7 @@ impl Declaration {
             Declare(_) => 1,
             DeclareRec(defs) => defs.len(),
             InvalidCycle(_, _) => 0,
+            Builtin(_) => 0,
         }
     }
 }
@@ -1249,6 +1251,10 @@ fn decl_to_let(
         Declaration::InvalidCycle(symbols, regions) => {
             Expr::RuntimeError(RuntimeError::CircularDef(symbols, regions))
         }
+        Declaration::Builtin(_) => {
+            // Builtins should only be added to top-level decls, not to let-exprs!
+            unreachable!()
+        }
     }
 }
 

compiler/can/src/module.rs

@@ -151,6 +151,7 @@ pub fn canonicalize_module_defs<'a>(
         (Ok(declarations), output) => {
             use crate::def::Declaration::*;
 
+            // Record the variables for all exposed symbols.
             let mut exposed_vars_by_symbol = Vec::with_capacity(exposed_symbols.len());
 
             for decl in declarations.iter() {
@@ -193,6 +194,14 @@ pub fn canonicalize_module_defs<'a>(
                     InvalidCycle(identifiers, _) => {
                         panic!("TODO gracefully handle potentially attempting to expose invalid cyclic defs {:?}" , identifiers);
                     }
+                    Builtin(def) => {
+                        // Builtins cannot be exposed in module declarations.
+                        // This should never happen!
+                        debug_assert!(def
+                            .pattern_vars
+                            .iter()
+                            .all(|(symbol, _)| !exposed_symbols.contains(symbol)));
+                    }
                 }
             }