From 47beee7d7085af35f6869cb349e27dd09b82e7a4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9C=80=E8=90=8C=E5=B0=8F=E6=B1=90?= <sumneko@hotmail.com>
Date: Thu, 16 Jun 2022 20:57:50 +0800
Subject: infer `nil` as redundant return value

---
 script/vm/compiler.lua | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'script/vm/compiler.lua')

diff --git a/script/vm/compiler.lua b/script/vm/compiler.lua
index 29de39ae..65df3a1d 100644
--- a/script/vm/compiler.lua
+++ b/script/vm/compiler.lua
@@ -667,7 +667,7 @@ local function selectNode(source, list, index)
             if list[i] then
                 local last = list[i]
                 if last.type == 'call'
-                or last.type == '...' then
+                or last.type == 'varargs' then
                     index = index - i + 1
                     exp = last
                 end
@@ -1376,9 +1376,11 @@ local compilerSwitch = util.switch()
         local hasMarkDoc
         if func.bindDocs then
             local sign = getObjectSign(func)
+            local lastReturn
             for _, doc in ipairs(func.bindDocs) do
                 if doc.type == 'doc.return' then
                     for _, rtn in ipairs(doc.returns) do
+                        lastReturn = rtn
                         if rtn.returnIndex == index then
                             hasMarkDoc = true
                             local hasGeneric
@@ -1396,12 +1398,18 @@ local compilerSwitch = util.switch()
                     end
                 end
             end
+            if lastReturn and not hasMarkDoc and lastReturn.types[1][1] == '...' then
+                vm.setNode(source, vm.getGlobal('type', 'unknown'))
+            end
         end
         if func.returns and not hasMarkDoc then
             for _, rtn in ipairs(func.returns) do
                 selectNode(source, rtn, index)
             end
         end
+        if vm.getNode(source):isEmpty() then
+            vm.setNode(source, vm.getGlobal('type', 'nil'))
+        end
     end)
     : case 'main'
     : call(function (source)
-- 
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