Check well-formedness of constraints

Check that the operand in a constraint is an explicit name,
and that the operands are all local variables or literals. Still need
to check that the name refers to a pure function.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index 1f123f74..cc7569e1 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -563,6 +563,20 @@ fn is_call_expr(@expr e) -> bool {
     }
 }
 
+fn is_constraint_arg(@expr e) -> bool {
+    alt (e.node) {
+        case (expr_lit(_,_)) {
+            ret true;
+        }
+        case (expr_path(_, option.some[def](def_local(_)), _)) {
+            ret true;
+        }
+        case (_) {
+            ret false;
+        }
+    }
+}
+
 //
 // Local Variables:
 // mode: rust