1 files changed, 7 insertions, 1 deletions
diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index cc7569e1..574ebd4a 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -346,7 +346,13 @@ type constr = spanned[constr_];
 
 type arg = rec(mode mode, @ty ty, ident ident, def_id id);
 type fn_decl = rec(vec[arg] inputs,
-                   @ty output);
+                   @ty output,
+                   purity purity);
+tag purity {
+    pure_fn;   // declared with "pred"
+    impure_fn; // declared with "fn"
+}
+
 type _fn = rec(fn_decl decl,
                proto proto,
                block body);