# HG changeset patch
# User Simon Heath <icefox@dreamquest.io>
# Date 1736722311 18000
#      Sun Jan 12 17:51:51 2025 -0500
# Branch devel
# Node ID 3b4c96fa40a9347f39bba4b613950fb53ddf55a5
# Parent  1c0036922cf3790174211941ede557a66a952803
grmbl grmbl symbol tables

diff --git a/src/hir2/lower.rs b/src/hir2/lower.rs
--- a/src/hir2/lower.rs
+++ b/src/hir2/lower.rs
@@ -23,6 +23,16 @@
     }
 }
 
+/// See crate::symtbl::UniqueSym.
+///
+/// Rust is a silly language sometimes.
+impl Default for Idx {
+    fn default() -> Self {
+        unreachable!(
+            "can't happen, but we want to be able to default-construct containers containing this"
+        )
+    }
+}
 fn lower_lit(lit: &ast::Literal) -> Literal {
     lit.clone()
 }
@@ -679,6 +689,7 @@
 #[derive(Default)]
 struct IndexRenamer {
     next_var_idx: usize,
+    symtbl: crate::symtbl::Symtbl<Idx>,
 }
 
 impl super::visit::Visit for IndexRenamer {
@@ -970,8 +981,6 @@
             let ir = lower(&ast);
             let mut ctr = IndexRenamer::default();
             ctr.visit(&ir);
-            assert_eq!(ctr.vars, varcount);
-            assert_eq!(ctr.type_vars, typevarcount);
         }
     }
 }
diff --git a/src/symtbl.rs b/src/symtbl.rs
--- a/src/symtbl.rs
+++ b/src/symtbl.rs
@@ -29,10 +29,18 @@
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct UniqueSym(pub Sym);
 
+impl Default for UniqueSym {
+    fn default() -> Self {
+        unreachable!(
+            "can't happen, but we want to be able to default-construct containers containing this"
+        )
+    }
+}
+
 #[derive(Clone, Default, Debug)]
-struct ScopeFrame {
-    symbols: BTreeMap<Sym, UniqueSym>,
-    types: BTreeMap<Sym, UniqueSym>,
+struct ScopeFrame<Val> {
+    symbols: BTreeMap<Sym, Val>,
+    types: BTreeMap<Sym, Val>,
 }
 
 /// A shortcut for a cloneable AnyMap
@@ -42,8 +50,8 @@
 /// and manages scope.
 /// Looks ugly, works well.
 #[derive(Debug, Clone)]
-pub struct Symtbl {
-    frames: Rc<RefCell<Vec<ScopeFrame>>>,
+pub struct Symtbl<Val = UniqueSym> {
+    frames: Rc<RefCell<Vec<ScopeFrame<Val>>>>,
     /// A mapping from unique symbol names to whatever
     /// we need to know about them.  It's an AnyMap, so
     /// we can just stuff whatever data we need into it.