From e178c42bcb81fbe81599a07432246d5f5a466a95 Mon Sep 17 00:00:00 2001
From: Hisham Muhammad <hisham@gobolinux.org>
Date: Tue, 13 Aug 2024 10:53:48 -0300
Subject: [PATCH] fix: do not close nested types too early

Closes #775.
---
 spec/declaration/record_function_spec.lua | 20 ++++++++++++
 tl.lua                                    | 37 +++++++++++++++++------
 tl.tl                                     | 37 +++++++++++++++++------
 3 files changed, 74 insertions(+), 20 deletions(-)

diff --git a/spec/declaration/record_function_spec.lua b/spec/declaration/record_function_spec.lua
index 290f5e617..75bd616f5 100644
--- a/spec/declaration/record_function_spec.lua
+++ b/spec/declaration/record_function_spec.lua
@@ -107,5 +107,25 @@ describe("record function", function()
       ]], {}, {
          { y = 7, msg = "different number of return values: got 1, expected 0" },
       }))
+
+      it("does not close nested types too early (regression test for #775)", util.check([[
+         -- declare a nested record
+         local record mul
+            record Fil
+               mime: function(Fil)
+            end
+         end
+
+         -- declare an alias
+         local type Fil = mul.Fil
+
+         -- this works
+         function mul.Fil:new_method1(self: Fil)
+         end
+
+         -- should work as well for alias
+         function Fil:new_method2(self: Fil)
+         end
+      ]]))
    end)
 end)
diff --git a/tl.lua b/tl.lua
index 4f135af23..c8a56c598 100644
--- a/tl.lua
+++ b/tl.lua
@@ -12277,22 +12277,38 @@ self:expand_type(node, values, elements) })
       end,
    }
 
+   function TypeChecker:begin_temporary_record_types(typ)
+      self:add_var(nil, "@self", type_at(typ, a_type(typ, "typedecl", { def = typ })))
+
+      for fname, ftype in fields_of(typ) do
+         if ftype.typename == "typealias" then
+            self:resolve_nominal(ftype.alias_to)
+            self:add_var(nil, fname, ftype)
+         elseif ftype.typename == "typedecl" then
+            self:add_var(nil, fname, ftype)
+         end
+      end
+   end
+
+   function TypeChecker:end_temporary_record_types(typ)
+
+
+      local scope = self.st[#self.st]
+      scope.vars["@self"] = nil
+      for fname, ftype in fields_of(typ) do
+         if ftype.typename == "typealias" or ftype.typename == "typedecl" then
+            scope.vars[fname] = nil
+         end
+      end
+   end
+
    local visit_type
    visit_type = {
       cbs = {
          ["record"] = {
             before = function(self, typ)
                self:begin_scope()
-               self:add_var(nil, "@self", type_at(typ, a_type(typ, "typedecl", { def = typ })))
-
-               for fname, ftype in fields_of(typ) do
-                  if ftype.typename == "typealias" then
-                     self:resolve_nominal(ftype.alias_to)
-                     self:add_var(nil, fname, ftype)
-                  elseif ftype.typename == "typedecl" then
-                     self:add_var(nil, fname, ftype)
-                  end
-               end
+               self:begin_temporary_record_types(typ)
             end,
             after = function(self, typ, children)
                local i = 1
@@ -12386,6 +12402,7 @@ self:expand_type(node, values, elements) })
                   end
                end
 
+               self:end_temporary_record_types(typ)
                self:end_scope()
 
                return typ
diff --git a/tl.tl b/tl.tl
index 7d6250047..957b891d4 100644
--- a/tl.tl
+++ b/tl.tl
@@ -12277,22 +12277,38 @@ do
       end,
    }
 
+   function TypeChecker:begin_temporary_record_types(typ: RecordType)
+      self:add_var(nil, "@self", type_at(typ, a_typedecl(typ, typ)))
+
+      for fname, ftype in fields_of(typ) do
+         if ftype is TypeAliasType then
+            self:resolve_nominal(ftype.alias_to)
+            self:add_var(nil, fname, ftype)
+         elseif ftype is TypeDeclType then
+            self:add_var(nil, fname, ftype)
+         end
+      end
+   end
+
+   function TypeChecker:end_temporary_record_types(typ: RecordType)
+      -- drop @self and nested records from scope
+      -- to avoid closing them prematurely in end_scope()
+      local scope = self.st[#self.st]
+      scope.vars["@self"] = nil
+      for fname, ftype in fields_of(typ) do
+         if ftype is TypeAliasType or ftype is TypeDeclType then
+            scope.vars[fname] = nil
+         end
+      end
+   end
+
    local visit_type: Visitor<TypeChecker, TypeName,Type,Type>
    visit_type = {
       cbs = {
          ["record"] = {
             before = function(self: TypeChecker, typ: RecordType)
                self:begin_scope()
-               self:add_var(nil, "@self", type_at(typ, a_typedecl(typ, typ)))
-
-               for fname, ftype in fields_of(typ) do
-                  if ftype is TypeAliasType then
-                     self:resolve_nominal(ftype.alias_to)
-                     self:add_var(nil, fname, ftype)
-                  elseif ftype is TypeDeclType then
-                     self:add_var(nil, fname, ftype)
-                  end
-               end
+               self:begin_temporary_record_types(typ)
             end,
             after = function(self: TypeChecker, typ: RecordType, children: {Type}): Type
                local i = 1
@@ -12386,6 +12402,7 @@ do
                   end
                end
 
+               self:end_temporary_record_types(typ)
                self:end_scope()
 
                return typ