From 4b0d634a27ae188c98f839736bad1b8514952467 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: Fri, 10 Feb 2023 16:01:17 +0800
Subject: [PATCH] fix #1889

---
 changelog.md                                 |  2 ++
 script/config/template.lua                   |  1 +
 script/core/diagnostics/missing-return.lua   |  2 +-
 script/core/diagnostics/unreachable-code.lua |  2 +-
 script/parser/compile.lua                    |  6 ++++--
 script/parser/guide.lua                      |  2 +-
 script/vm/tracer.lua                         |  2 +-
 test/type_inference/init.lua                 | 11 +++++++++++
 8 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/changelog.md b/changelog.md
index 321e40b88..a80ed3a9f 100644
--- a/changelog.md
+++ b/changelog.md
@@ -4,9 +4,11 @@
 * `CHG` completion: don't show loading process
 * `FIX` [#1886]
 * `FIX` [#1895]
+* `FIX` [#1889]
 
 [#1886]: https://github.com/LuaLS/lua-language-server/issues/1886
 [#1895]: https://github.com/LuaLS/lua-language-server/issues/1895
+[#1889]: https://github.com/LuaLS/lua-language-server/issues/1889
 
 ## 3.6.10
 `2023-2-7`
diff --git a/script/config/template.lua b/script/config/template.lua
index e93ffa080..7a4d3f1b6 100644
--- a/script/config/template.lua
+++ b/script/config/template.lua
@@ -210,6 +210,7 @@ local template = {
                                                     'assert',
                                                     'error',
                                                     'type',
+                                                    'os.exit',
                                                 }
                                             ),
     ['Lua.runtime.meta']                    = Type.String >> '${version} ${language} ${encoding}',
diff --git a/script/core/diagnostics/missing-return.lua b/script/core/diagnostics/missing-return.lua
index 7333e5e3b..2b5c90d23 100644
--- a/script/core/diagnostics/missing-return.lua
+++ b/script/core/diagnostics/missing-return.lua
@@ -7,7 +7,7 @@ local await  = require 'await'
 ---@param block parser.object
 ---@return boolean
 local function hasReturn(block)
-    if block.hasReturn or block.hasError then
+    if block.hasReturn or block.hasExit then
         return true
     end
     if block.type == 'if' then
diff --git a/script/core/diagnostics/unreachable-code.lua b/script/core/diagnostics/unreachable-code.lua
index 4f0a38b72..cbffe4db4 100644
--- a/script/core/diagnostics/unreachable-code.lua
+++ b/script/core/diagnostics/unreachable-code.lua
@@ -23,7 +23,7 @@ end
 ---@param block parser.object
 ---@return boolean
 local function hasReturn(block)
-    if block.hasReturn or block.hasError then
+    if block.hasReturn or block.hasExit then
         return true
     end
     if block.type == 'if' then
diff --git a/script/parser/compile.lua b/script/parser/compile.lua
index 7cc6f36b2..917a68a47 100644
--- a/script/parser/compile.lua
+++ b/script/parser/compile.lua
@@ -118,6 +118,7 @@ local Specials = {
     ['assert']       = true,
     ['error']        = true,
     ['type']         = true,
+    ['os.exit']      = true,
 }
 
 local UnarySymbol = {
@@ -2899,14 +2900,15 @@ local function compileExpAsAction(exp)
     end
 
     if exp.type == 'call' then
-        if exp.node.special == 'error' then
+        if exp.node.special == 'error'
+        or exp.node.special == 'os.exit' then
             for i = #Chunk, 1, -1 do
                 local block = Chunk[i]
                 if block.type == 'ifblock'
                 or block.type == 'elseifblock'
                 or block.type == 'elseblock'
                 or block.type == 'function' then
-                    block.hasError = true
+                    block.hasExit = true
                     break
                 end
             end
diff --git a/script/parser/guide.lua b/script/parser/guide.lua
index 0b6de77d6..ec5746c13 100644
--- a/script/parser/guide.lua
+++ b/script/parser/guide.lua
@@ -72,7 +72,7 @@ local type         = type
 ---@field hasGoTo?              true
 ---@field hasReturn?            true
 ---@field hasBreak?             true
----@field hasError?             true
+---@field hasExit?              true
 ---@field [integer]             parser.object|any
 ---@field package _root          parser.object
 
diff --git a/script/vm/tracer.lua b/script/vm/tracer.lua
index 6ce57d5c9..a13d00e13 100644
--- a/script/vm/tracer.lua
+++ b/script/vm/tracer.lua
@@ -369,7 +369,7 @@ local lookIntoChild = util.switch()
                 local neverReturn = subBlock.hasReturn
                                 or  subBlock.hasGoTo
                                 or  subBlock.hasBreak
-                                or  subBlock.hasError
+                                or  subBlock.hasExit
                 if neverReturn then
                     mergedNode = true
                 else
diff --git a/test/type_inference/init.lua b/test/type_inference/init.lua
index 5a9e1796b..4e3c9d5bb 100644
--- a/test/type_inference/init.lua
+++ b/test/type_inference/init.lua
@@ -2620,6 +2620,17 @@ end
 print(<?n?>)
 ]]
 
+TEST 'integer' [[
+---@type integer?
+local n
+
+if not n then
+    os.exit()
+end
+
+print(<?n?>)
+]]
+
 TEST 'table' [[
 ---@type table?
 local n