stage2 修复语义问题

stage2/sema.spl

@@ -367,6 +367,10 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
 
     var saved = self.current_aggregate_lang;
     self.current_aggregate_lang = agg_lang;
+    // 聚合体自成命名空间：成员类型可引用同体声明的嵌套类型（裸名）。
+    var saved_scope = self.scope.current_scope;
+    var agg_scope = Scope.alloc(&self.scope);
+    self.scope.current_scope = agg_scope;
 
     var members = Vec.blank(@sizeof(Member), @alignof(Member));
     var methods = Vec.blank(@sizeof(LangMethod), @alignof(LangMethod));
@@ -376,19 +380,15 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
         .TypeAggregate(&x) => { mlist = x.members; },
         _ => {},
     }
+
+    // 第一遍：登记嵌套类型/函数的 def，挂进 methods 与聚合作用域。成员类型可能引用它们，
+    // 必须早于成员类型推断，否则限定名（经 methods）与裸名（经作用域）都解析不到。
     var i: usize = 0;
     while i < mlist.len {
         var mref = list_at(mlist, i);
         var mn = node(self, mref);
         if mn != null {
             match mn.body {
-                .MemberDecl(md) => {
-                    var mtid: usize = 0;
-                    if md.type_expr != 0 { mtid = infer(self, md.type_expr); }
-                    var mm = Member { .name = md.name, .type_id = ir_of(self, mtid),
-                                      .ast_node_ref = mref };
-                    Vec.push(&members, &mm as *u8);
-                },
                 .FnDecl(fd) => {
                     var fn_def = mn.resolved_def_id;
                     if fn_def == 0 {
@@ -400,6 +400,8 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
                     if fn_d != null { fn_d.owner_def = owner_def_id; }
                     var meth = LangMethod { .name = fd.name, .def_id = fn_def };
                     Vec.push(&methods, &meth as *u8);
+                    Scope.insert(&self.scope, agg_scope,
+                                 Symbol { .name = fd.name, .kind = .Fn, .node = fn_def });
                 },
                 .TypeDecl(td) => {
                     var tpat = node(self, td.pattern);
@@ -416,6 +418,8 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
                         }
                         var meth = LangMethod { .name = tname, .def_id = tdef };
                         Vec.push(&methods, &meth as *u8);
+                        Scope.insert(&self.scope, agg_scope,
+                                     Symbol { .name = tname, .kind = .Type, .node = tdef });
                     }
                 },
                 _ => {},
@@ -424,6 +428,33 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
         i = i + 1;
     }
 
+    var lslot = LangType.lang_node(&self.types, agg_lang);
+    if lslot != null {
+        Vec.drop(&lslot.methods);
+        lslot.methods = methods;
+    }
+
+    // 第二遍：成员（字段/变体）类型推断；此时嵌套名字已可解析。
+    i = 0;
+    while i < mlist.len {
+        var mref = list_at(mlist, i);
+        var mn = node(self, mref);
+        if mn != null {
+            match mn.body {
+                .MemberDecl(md) => {
+                    var mtid: usize = 0;
+                    if md.type_expr != 0 { mtid = infer(self, md.type_expr); }
+                    var mm = Member { .name = md.name, .type_id = ir_of(self, mtid),
+                                      .ast_node_ref = mref };
+                    Vec.push(&members, &mm as *u8);
+                },
+                _ => {},
+            }
+        }
+        i = i + 1;
+    }
+
+    self.scope.current_scope = saved_scope;
     self.current_aggregate_lang = saved;
 
     // IR 节点
@@ -445,11 +476,6 @@ fn build_aggregate(self: *Sema, te: *Node, owner_def_id: usize): usize {
     }
     TypeTable.define(&self.types.ir, agg_ir, &tk);
 
-    var lslot = LangType.lang_node(&self.types, agg_lang);
-    if lslot != null {
-        Vec.drop(&lslot.methods);
-        lslot.methods = methods;
-    }
     ret agg_lang;
 }