diff --git a/src/language/ctu/include/ctu/ast.h b/src/language/ctu/include/ctu/ast.h
index 64922aad..e596ad7c 100644
--- a/src/language/ctu/include/ctu/ast.h
+++ b/src/language/ctu/include/ctu/ast.h
@@ -124,7 +124,7 @@ typedef struct ctu_t {
                 /* eCtuDeclVariant */
                 struct {
                     ctu_t *underlying;
-                    vector_t *cases;
+                    const vector_t *cases;
                 };
 
                 /* eCtuVariantCase */
@@ -308,7 +308,7 @@ ctu_t *ctu_decl_typealias(scan_t *scan, where_t where, bool exported, char *name
 ctu_t *ctu_decl_union(scan_t *scan, where_t where, bool exported, char *name, vector_t *fields);
 ctu_t *ctu_decl_struct(scan_t *scan, where_t where, bool exported, char *name, vector_t *fields);
 
-ctu_t *ctu_decl_variant(scan_t *scan, where_t where, bool exported, char *name, ctu_t *underlying, vector_t *cases);
+ctu_t *ctu_decl_variant(scan_t *scan, where_t where, bool exported, char *name, ctu_t *underlying, const vector_t *cases);
 
 ///
 /// internal components
diff --git a/src/language/ctu/src/ast.c b/src/language/ctu/src/ast.c
index 19eed2bc..308c357b 100644
--- a/src/language/ctu/src/ast.c
+++ b/src/language/ctu/src/ast.c
@@ -322,7 +322,7 @@ ctu_t *ctu_decl_struct(scan_t *scan, where_t where, bool exported, char *name, v
     return ast;
 }
 
-ctu_t *ctu_decl_variant(scan_t *scan, where_t where, bool exported, char *name, ctu_t *underlying, vector_t *cases)
+ctu_t *ctu_decl_variant(scan_t *scan, where_t where, bool exported, char *name, ctu_t *underlying, const vector_t *cases)
 {
     ctu_t *ast = ctu_decl(scan, where, eCtuDeclVariant, name, exported);
     ast->underlying = underlying;
diff --git a/src/language/ctu/src/ctu.y b/src/language/ctu/src/ctu.y
index e2c94aba..73943a24 100644
--- a/src/language/ctu/src/ctu.y
+++ b/src/language/ctu/src/ctu.y
@@ -136,12 +136,12 @@ void ctuerror(where_t *where, void *state, scan_t *scan, const char *msg);
     attrib_args
     expr_list
     type_list
-    variant_field_list opt_variant_field_list
+    variant_field_list
     initList
     attribs attrib attrib_body attrib_list
 
 %type<cvector>
-    modspec imports opt_type_list opt_expr_list decls
+    modspec imports opt_type_list opt_expr_list decls opt_variant_field_list
 
 /**
  * order of operations, tightest first
@@ -268,7 +268,7 @@ underlying: %empty { $$ = NULL; }
     | COLON type { $$ = $2; }
     ;
 
-opt_variant_field_list: %empty { $$ = &gEmptyVector; }
+opt_variant_field_list: %empty { $$ = &kEmptyVector; }
     | variant_field_list { $$ = $1; }
     ;
 
diff --git a/src/language/ctu/src/sema/expr.c b/src/language/ctu/src/sema/expr.c
index 5ffca2b3..c2dc90e0 100644
--- a/src/language/ctu/src/sema/expr.c
+++ b/src/language/ctu/src/sema/expr.c
@@ -643,7 +643,8 @@ static tree_t *sema_local(ctu_sema_t *sema, const ctu_t *stmt)
         return tree_stmt_assign(stmt->node, self, value);
     }
 
-    return tree_stmt_block(stmt->node, &gEmptyVector); // TODO: good enough
+    // TODO: maybe a nop node would be better
+    return tree_stmt_block(stmt->node, &kEmptyVector);
 }
 
 static tree_t *sema_stmts(ctu_sema_t *sema, const ctu_t *stmt)
@@ -685,7 +686,7 @@ static tree_t *sema_while(ctu_sema_t *sema, const ctu_t *stmt)
     tree_t *save = ctu_current_loop(sema);
 
     tree_t *cond = ctu_sema_rvalue(sema, stmt->cond, ctu_get_bool_type());
-    tree_t *loop = tree_stmt_loop(stmt->node, cond, tree_stmt_block(stmt->node, &gEmptyVector),
+    tree_t *loop = tree_stmt_loop(stmt->node, cond, tree_stmt_block(stmt->node, &kEmptyVector),
                                   NULL);
 
     if (stmt->name != NULL)
diff --git a/src/language/pl0/src/sema.c b/src/language/pl0/src/sema.c
index 632b9ce9..6a3a8698 100644
--- a/src/language/pl0/src/sema.c
+++ b/src/language/pl0/src/sema.c
@@ -415,11 +415,10 @@ static void sema_proc(tree_t *sema, tree_t *tree, pl0_t *node)
         tree_add_local(tree, it);
     }
 
-    tree_t *ret = tree_stmt_return(node->node, tree_expr_unit(node->node, gVoidType));
-
     vector_t *inner = sema_stmt_vector(nest, node->body);
 
-    vector_push(&inner, inner);
+    // make sure we always have a return statement
+    tree_t *ret = tree_stmt_return(node->node, tree_expr_unit(node->node, gVoidType));
     vector_push(&inner, ret);
 
     // make sure we have a return statement