Accept a reference instead of owned value

src/uniqueness/mod.rs

@@ -39,7 +39,7 @@ pub fn constrain_declaration(
     home: ModuleId,
     var_store: &VarStore,
     region: Region,
-    loc_expr: Located<Expr>,
+    loc_expr: &Located<Expr>,
     _declared_idents: &ImMap<Ident, (Symbol, Region)>,
     expected: Expected<Type>,
 ) -> Constraint {

tests/helpers/mod.rs

@@ -114,7 +114,7 @@ pub fn uniq_expr_with(
         home,
         &var_store,
         Region::zero(),
-        loc_expr,
+        &loc_expr,
         declared_idents,
         expected2,
     );