iter 22b.2.1: add Constraint struct, Type::Forall.constraints

crates/ailang-codegen/src/subst.rs

@@ -191,8 +191,9 @@ pub(crate) fn qualify_local_types_codegen(
             param_modes: vec![],
             ret_mode: ParamMode::Implicit,
         },
-        Type::Forall { vars, body } => Type::Forall {
+        Type::Forall { vars, constraints, body } => Type::Forall {
             vars: vars.clone(),
+            constraints: constraints.clone(),
             body: Box::new(qualify_local_types_codegen(body, owner_module, owner_local_types)),
         },
         Type::Var { .. } => t.clone(),
@@ -216,7 +217,7 @@ pub(crate) fn apply_subst_to_type(t: &Type, subst: &BTreeMap<String, Type>) -> T
             param_modes: vec![],
             ret_mode: ParamMode::Implicit,
         },
-        Type::Forall { vars, body } => {
+        Type::Forall { vars, constraints, body } => {
             // Inner forall shadows: don't substitute re-bound names.
             let inner: BTreeMap<String, Type> = subst
                 .iter()
@@ -225,6 +226,7 @@ pub(crate) fn apply_subst_to_type(t: &Type, subst: &BTreeMap<String, Type>) -> T
                 .collect();
             Type::Forall {
                 vars: vars.clone(),
+                constraints: constraints.clone(),
                 body: Box::new(apply_subst_to_type(body, &inner)),
             }
         }