unreachable-code

13 files changed, 227 insertions, 92 deletions

diff --git a/changelog.md b/changelog.md
index 702b06f6..758eb61a 100644
--- a/changelog.md
+++ b/changelog.md
@@ -13,6 +13,7 @@
   ```
 * `NEW` diagnostics:
   * `unknown-operator`
+  * `unreachable-code`
 * `NEW` settings:
   * `diagnostics.unusedLocalExclude`
 * `CHG` support multi-type:
diff --git a/doc/en-us/config.md b/doc/en-us/config.md
index 3f483650..137793cc 100644
--- a/doc/en-us/config.md
+++ b/doc/en-us/config.md
@@ -205,9 +205,9 @@ Array<string>
 * ``"newfield-call"``
 * ``"err-assign-as-eq"``
 * ``"undefined-doc-param"``
-* ``"param-type-mismatch"``
+* ``"undefined-global"``
 * ``"global-in-nil-env"``
-* ``"unused-vararg"``
+* ``"redundant-return-value"``
 * ``"miss-sep-in-table"``
 * ``"unknown-cast-variable"``
 * ``"unknown-operator"``
@@ -222,66 +222,67 @@ Array<string>
 * ``"redundant-value"``
 * ``"duplicate-doc-alias"``
 * ``"doc-field-no-class"``
-* ``"no-visible-label"``
 * ``"miss-loop-min"``
-* ``"miss-exp"``
+* ``"no-visible-label"``
 * ``"miss-loop-max"``
+* ``"miss-exp"``
+* ``"unicode-name"``
 * ``"miss-name"``
 * ``"empty-block"``
-* ``"unused-local"``
 * ``"err-then-as-do"``
-* ``"duplicate-doc-field"``
 * ``"redefined-label"``
+* ``"duplicate-doc-field"``
 * ``"exp-in-action"``
 * ``"set-const"``
-* ``"circle-doc-class"``
 * ``"unexpect-lfunc-name"``
-* ``"unsupport-symbol"``
-* ``"unused-label"``
+* ``"circle-doc-class"``
 * ``"action-after-return"``
+* ``"miss-space-between"``
+* ``"unused-label"``
 * ``"unexpect-dots"``
-* ``"redundant-return-value"``
+* ``"duplicate-index"``
+* ``"miss-field"``
 * ``"jump-local-scope"``
 * ``"close-non-object"``
-* ``"miss-field"``
+* ``"unexpect-symbol"``
 * ``"count-down-loop"``
 * ``"cast-type-mismatch"``
 * ``"newline-call"``
-* ``"unexpect-symbol"``
+* ``"missing-parameter"``
 * ``"block-after-else"``
-* ``"unicode-name"``
 * ``"miss-exponent"``
 * ``"err-esc"``
 * ``"local-limit"``
+* ``"unsupport-symbol"``
 * ``"trailing-space"``
 * ``"err-c-long-comment"``
-* ``"undefined-global"``
-* ``"undefined-doc-name"``
+* ``"unbalanced-assignments"``
+* ``"duplicate-doc-param"``
 * ``"ambiguity-1"``
 * ``"deprecated"``
 * ``"codestyle-check"``
 * ``"missing-return"``
-* ``"missing-parameter"``
+* ``"code-after-break"``
 * ``"unused-function"``
 * ``"cast-local-type"``
 * ``"assign-type-mismatch"``
 * ``"duplicate-set-field"``
-* ``"no-unknown"``
+* ``"unused-vararg"``
 * ``"need-check-nil"``
 * ``"keyword"``
+* ``"unused-local"``
 * ``"unknown-diag-code"``
-* ``"return-type-mismatch"``
 * ``"err-comment-prefix"``
 * ``"lowercase-global"``
-* ``"unbalanced-assignments"``
 * ``"redefined-local"``
-* ``"code-after-break"``
-* ``"duplicate-index"``
-* ``"duplicate-doc-param"``
+* ``"undefined-doc-name"``
+* ``"no-unknown"``
+* ``"unreachable-code"``
+* ``"param-type-mismatch"``
 * ``"index-in-func-name"``
 * ``"miss-symbol"``
 * ``"undefined-field"``
-* ``"miss-space-between"``
+* ``"return-type-mismatch"``
 
 ## default
 
@@ -450,6 +451,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -568,6 +570,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -737,6 +740,7 @@ object<string, string>
     "unknown-cast-variable": "Any",
     "unknown-diag-code": "Any",
     "unknown-operator": "Any",
+    "unreachable-code": "Opened",
     /*
     Enable unused function diagnostics.
     */
@@ -872,6 +876,7 @@ object<string, string>
     "unknown-cast-variable": "Warning",
     "unknown-diag-code": "Warning",
     "unknown-operator": "Warning",
+    "unreachable-code": "Hint",
     /*
     Enable unused function diagnostics.
     */
@@ -1271,6 +1276,8 @@ object<string, string>
     "package": "default",
     "string": "default",
     "table": "default",
+    "table.clear": "default",
+    "table.new": "default",
     "utf8": "default"
 }
 ```
diff --git a/doc/pt-br/config.md b/doc/pt-br/config.md
index f888efea..97a01630 100644
--- a/doc/pt-br/config.md
+++ b/doc/pt-br/config.md
@@ -205,9 +205,9 @@ Array<string>
 * ``"newfield-call"``
 * ``"err-assign-as-eq"``
 * ``"undefined-doc-param"``
-* ``"param-type-mismatch"``
+* ``"undefined-global"``
 * ``"global-in-nil-env"``
-* ``"unused-vararg"``
+* ``"redundant-return-value"``
 * ``"miss-sep-in-table"``
 * ``"unknown-cast-variable"``
 * ``"unknown-operator"``
@@ -222,66 +222,67 @@ Array<string>
 * ``"redundant-value"``
 * ``"duplicate-doc-alias"``
 * ``"doc-field-no-class"``
-* ``"no-visible-label"``
 * ``"miss-loop-min"``
-* ``"miss-exp"``
+* ``"no-visible-label"``
 * ``"miss-loop-max"``
+* ``"miss-exp"``
+* ``"unicode-name"``
 * ``"miss-name"``
 * ``"empty-block"``
-* ``"unused-local"``
 * ``"err-then-as-do"``
-* ``"duplicate-doc-field"``
 * ``"redefined-label"``
+* ``"duplicate-doc-field"``
 * ``"exp-in-action"``
 * ``"set-const"``
-* ``"circle-doc-class"``
 * ``"unexpect-lfunc-name"``
-* ``"unsupport-symbol"``
-* ``"unused-label"``
+* ``"circle-doc-class"``
 * ``"action-after-return"``
+* ``"miss-space-between"``
+* ``"unused-label"``
 * ``"unexpect-dots"``
-* ``"redundant-return-value"``
+* ``"duplicate-index"``
+* ``"miss-field"``
 * ``"jump-local-scope"``
 * ``"close-non-object"``
-* ``"miss-field"``
+* ``"unexpect-symbol"``
 * ``"count-down-loop"``
 * ``"cast-type-mismatch"``
 * ``"newline-call"``
-* ``"unexpect-symbol"``
+* ``"missing-parameter"``
 * ``"block-after-else"``
-* ``"unicode-name"``
 * ``"miss-exponent"``
 * ``"err-esc"``
 * ``"local-limit"``
+* ``"unsupport-symbol"``
 * ``"trailing-space"``
 * ``"err-c-long-comment"``
-* ``"undefined-global"``
-* ``"undefined-doc-name"``
+* ``"unbalanced-assignments"``
+* ``"duplicate-doc-param"``
 * ``"ambiguity-1"``
 * ``"deprecated"``
 * ``"codestyle-check"``
 * ``"missing-return"``
-* ``"missing-parameter"``
+* ``"code-after-break"``
 * ``"unused-function"``
 * ``"cast-local-type"``
 * ``"assign-type-mismatch"``
 * ``"duplicate-set-field"``
-* ``"no-unknown"``
+* ``"unused-vararg"``
 * ``"need-check-nil"``
 * ``"keyword"``
+* ``"unused-local"``
 * ``"unknown-diag-code"``
-* ``"return-type-mismatch"``
 * ``"err-comment-prefix"``
 * ``"lowercase-global"``
-* ``"unbalanced-assignments"``
 * ``"redefined-local"``
-* ``"code-after-break"``
-* ``"duplicate-index"``
-* ``"duplicate-doc-param"``
+* ``"undefined-doc-name"``
+* ``"no-unknown"``
+* ``"unreachable-code"``
+* ``"param-type-mismatch"``
 * ``"index-in-func-name"``
 * ``"miss-symbol"``
 * ``"undefined-field"``
-* ``"miss-space-between"``
+* ``"return-type-mismatch"``
 
 ## default
 
@@ -450,6 +451,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -568,6 +570,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -737,6 +740,7 @@ object<string, string>
     "unknown-cast-variable": "Any",
     "unknown-diag-code": "Any",
     "unknown-operator": "Any",
+    "unreachable-code": "Opened",
     /*
     未使用的函数
     */
@@ -872,6 +876,7 @@ object<string, string>
     "unknown-cast-variable": "Warning",
     "unknown-diag-code": "Warning",
     "unknown-operator": "Warning",
+    "unreachable-code": "Hint",
     /*
     未使用的函数
     */
@@ -1271,6 +1276,8 @@ object<string, string>
     "package": "default",
     "string": "default",
     "table": "default",
+    "table.clear": "default",
+    "table.new": "default",
     "utf8": "default"
 }
 ```
diff --git a/doc/zh-cn/config.md b/doc/zh-cn/config.md
index 3e2b1246..888cb25e 100644
--- a/doc/zh-cn/config.md
+++ b/doc/zh-cn/config.md
@@ -205,9 +205,9 @@ Array<string>
 * ``"newfield-call"``
 * ``"err-assign-as-eq"``
 * ``"undefined-doc-param"``
-* ``"param-type-mismatch"``
+* ``"undefined-global"``
 * ``"global-in-nil-env"``
-* ``"unused-vararg"``
+* ``"redundant-return-value"``
 * ``"miss-sep-in-table"``
 * ``"unknown-cast-variable"``
 * ``"unknown-operator"``
@@ -222,66 +222,67 @@ Array<string>
 * ``"redundant-value"``
 * ``"duplicate-doc-alias"``
 * ``"doc-field-no-class"``
-* ``"no-visible-label"``
 * ``"miss-loop-min"``
-* ``"miss-exp"``
+* ``"no-visible-label"``
 * ``"miss-loop-max"``
+* ``"miss-exp"``
+* ``"unicode-name"``
 * ``"miss-name"``
 * ``"empty-block"``
-* ``"unused-local"``
 * ``"err-then-as-do"``
-* ``"duplicate-doc-field"``
 * ``"redefined-label"``
+* ``"duplicate-doc-field"``
 * ``"exp-in-action"``
 * ``"set-const"``
-* ``"circle-doc-class"``
 * ``"unexpect-lfunc-name"``
-* ``"unsupport-symbol"``
-* ``"unused-label"``
+* ``"circle-doc-class"``
 * ``"action-after-return"``
+* ``"miss-space-between"``
+* ``"unused-label"``
 * ``"unexpect-dots"``
-* ``"redundant-return-value"``
+* ``"duplicate-index"``
+* ``"miss-field"``
 * ``"jump-local-scope"``
 * ``"close-non-object"``
-* ``"miss-field"``
+* ``"unexpect-symbol"``
 * ``"count-down-loop"``
 * ``"cast-type-mismatch"``
 * ``"newline-call"``
-* ``"unexpect-symbol"``
+* ``"missing-parameter"``
 * ``"block-after-else"``
-* ``"unicode-name"``
 * ``"miss-exponent"``
 * ``"err-esc"``
 * ``"local-limit"``
+* ``"unsupport-symbol"``
 * ``"trailing-space"``
 * ``"err-c-long-comment"``
-* ``"undefined-global"``
-* ``"undefined-doc-name"``
+* ``"unbalanced-assignments"``
+* ``"duplicate-doc-param"``
 * ``"ambiguity-1"``
 * ``"deprecated"``
 * ``"codestyle-check"``
 * ``"missing-return"``
-* ``"missing-parameter"``
+* ``"code-after-break"``
 * ``"unused-function"``
 * ``"cast-local-type"``
 * ``"assign-type-mismatch"``
 * ``"duplicate-set-field"``
-* ``"no-unknown"``
+* ``"unused-vararg"``
 * ``"need-check-nil"``
 * ``"keyword"``
+* ``"unused-local"``
 * ``"unknown-diag-code"``
-* ``"return-type-mismatch"``
 * ``"err-comment-prefix"``
 * ``"lowercase-global"``
-* ``"unbalanced-assignments"``
 * ``"redefined-local"``
-* ``"code-after-break"``
-* ``"duplicate-index"``
-* ``"duplicate-doc-param"``
+* ``"undefined-doc-name"``
+* ``"no-unknown"``
+* ``"unreachable-code"``
+* ``"param-type-mismatch"``
 * ``"index-in-func-name"``
 * ``"miss-symbol"``
 * ``"undefined-field"``
-* ``"miss-space-between"``
+* ``"return-type-mismatch"``
 
 ## default
 
@@ -450,6 +451,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -568,6 +570,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -737,6 +740,7 @@ object<string, string>
     "unknown-cast-variable": "Any",
     "unknown-diag-code": "Any",
     "unknown-operator": "Any",
+    "unreachable-code": "Opened",
     /*
     未使用的函数
     */
@@ -871,6 +875,7 @@ object<string, string>
     "unknown-cast-variable": "Warning",
     "unknown-diag-code": "Warning",
     "unknown-operator": "Warning",
+    "unreachable-code": "Hint",
     /*
     未使用的函数
     */
@@ -1270,6 +1275,8 @@ object<string, string>
     "package": "default",
     "string": "default",
     "table": "default",
+    "table.clear": "default",
+    "table.new": "default",
     "utf8": "default"
 }
 ```
diff --git a/doc/zh-tw/config.md b/doc/zh-tw/config.md
index dcd44d63..adf09ae6 100644
--- a/doc/zh-tw/config.md
+++ b/doc/zh-tw/config.md
@@ -205,9 +205,9 @@ Array<string>
 * ``"newfield-call"``
 * ``"err-assign-as-eq"``
 * ``"undefined-doc-param"``
-* ``"param-type-mismatch"``
+* ``"undefined-global"``
 * ``"global-in-nil-env"``
-* ``"unused-vararg"``
+* ``"redundant-return-value"``
 * ``"miss-sep-in-table"``
 * ``"unknown-cast-variable"``
 * ``"unknown-operator"``
@@ -222,66 +222,67 @@ Array<string>
 * ``"redundant-value"``
 * ``"duplicate-doc-alias"``
 * ``"doc-field-no-class"``
-* ``"no-visible-label"``
 * ``"miss-loop-min"``
-* ``"miss-exp"``
+* ``"no-visible-label"``
 * ``"miss-loop-max"``
+* ``"miss-exp"``
+* ``"unicode-name"``
 * ``"miss-name"``
 * ``"empty-block"``
-* ``"unused-local"``
 * ``"err-then-as-do"``
-* ``"duplicate-doc-field"``
 * ``"redefined-label"``
+* ``"duplicate-doc-field"``
 * ``"exp-in-action"``
 * ``"set-const"``
-* ``"circle-doc-class"``
 * ``"unexpect-lfunc-name"``
-* ``"unsupport-symbol"``
-* ``"unused-label"``
+* ``"circle-doc-class"``
 * ``"action-after-return"``
+* ``"miss-space-between"``
+* ``"unused-label"``
 * ``"unexpect-dots"``
-* ``"redundant-return-value"``
+* ``"duplicate-index"``
+* ``"miss-field"``
 * ``"jump-local-scope"``
 * ``"close-non-object"``
-* ``"miss-field"``
+* ``"unexpect-symbol"``
 * ``"count-down-loop"``
 * ``"cast-type-mismatch"``
 * ``"newline-call"``
-* ``"unexpect-symbol"``
+* ``"missing-parameter"``
 * ``"block-after-else"``
-* ``"unicode-name"``
 * ``"miss-exponent"``
 * ``"err-esc"``
 * ``"local-limit"``
+* ``"unsupport-symbol"``
 * ``"trailing-space"``
 * ``"err-c-long-comment"``
-* ``"undefined-global"``
-* ``"undefined-doc-name"``
+* ``"unbalanced-assignments"``
+* ``"duplicate-doc-param"``
 * ``"ambiguity-1"``
 * ``"deprecated"``
 * ``"codestyle-check"``
 * ``"missing-return"``
-* ``"missing-parameter"``
+* ``"code-after-break"``
 * ``"unused-function"``
 * ``"cast-local-type"``
 * ``"assign-type-mismatch"``
 * ``"duplicate-set-field"``
-* ``"no-unknown"``
+* ``"unused-vararg"``
 * ``"need-check-nil"``
 * ``"keyword"``
+* ``"unused-local"``
 * ``"unknown-diag-code"``
-* ``"return-type-mismatch"``
 * ``"err-comment-prefix"``
 * ``"lowercase-global"``
-* ``"unbalanced-assignments"``
 * ``"redefined-local"``
-* ``"code-after-break"``
-* ``"duplicate-index"``
-* ``"duplicate-doc-param"``
+* ``"undefined-doc-name"``
+* ``"no-unknown"``
+* ``"unreachable-code"``
+* ``"param-type-mismatch"``
 * ``"index-in-func-name"``
 * ``"miss-symbol"``
 * ``"undefined-field"``
-* ``"miss-space-between"``
+* ``"return-type-mismatch"``
 
 ## default
 
@@ -450,6 +451,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -568,6 +570,7 @@ object<string, string>
     * empty-block
     * redundant-return
     * trailing-space
+    * unreachable-code
     * unused-function
     * unused-label
     * unused-local
@@ -737,6 +740,7 @@ object<string, string>
     "unknown-cast-variable": "Any",
     "unknown-diag-code": "Any",
     "unknown-operator": "Any",
+    "unreachable-code": "Opened",
     /*
     未使用的函式
     */
@@ -871,6 +875,7 @@ object<string, string>
     "unknown-cast-variable": "Warning",
     "unknown-diag-code": "Warning",
     "unknown-operator": "Warning",
+    "unreachable-code": "Hint",
     /*
     未使用的函式
     */
@@ -1270,6 +1275,8 @@ object<string, string>
     "package": "default",
     "string": "default",
     "table": "default",
+    "table.clear": "default",
+    "table.new": "default",
     "utf8": "default"
 }
 ```
diff --git a/locale/en-us/script.lua b/locale/en-us/script.lua
index c46c83c8..fdaa1428 100644
--- a/locale/en-us/script.lua
+++ b/locale/en-us/script.lua
@@ -142,6 +142,8 @@ DIAG_RETURN_TYPE_MISMATCH             =
 'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.'
 DIAG_UNKNOWN_OPERATOR                 =
 'Unknown operator `{}`.'
+DIAG_UNREACHABLE_CODE                 =
+'Unreachable code.'
 
 MWS_NOT_SUPPORT         =
 '{} does not support multi workspace for now, I may need to restart to support the new workspace ...'
diff --git a/locale/pt-br/script.lua b/locale/pt-br/script.lua
index 908ba8cc..f7ac6d3d 100644
--- a/locale/pt-br/script.lua
+++ b/locale/pt-br/script.lua
@@ -142,6 +142,8 @@ DIAG_RETURN_TYPE_MISMATCH             = -- TODO: need translate!
 'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.'
 DIAG_UNKNOWN_OPERATOR                 = -- TODO: need translate!
 'Unknown operator `{}`.'
+DIAG_UNREACHABLE_CODE                 = -- TODO: need translate!
+'Unreachable code.'
 
 MWS_NOT_SUPPORT         =
 '{} não é suportado múltiplos espaços de trabalho por enquanto, posso precisar reiniciar para estabelecer um novo espaço de trabalho ...'
diff --git a/locale/zh-cn/script.lua b/locale/zh-cn/script.lua
index 02596c04..f50d4b7b 100644
--- a/locale/zh-cn/script.lua
+++ b/locale/zh-cn/script.lua
@@ -142,6 +142,8 @@ DIAG_RETURN_TYPE_MISMATCH             =
 '第 {index} 个返回值的类型为 `{def}` ，但实际返回的是 `{ref}`。'
 DIAG_UNKNOWN_OPERATOR                 =
 '未知的运算符 `{}`。'
+DIAG_UNREACHABLE_CODE                 =
+'不可达的代码。'
 
 MWS_NOT_SUPPORT         =
 '{} 目前还不支持多工作目录，我可能需要重启才能支持新的工作目录...'
diff --git a/locale/zh-tw/script.lua b/locale/zh-tw/script.lua
index 7cf5134d..80733139 100644
--- a/locale/zh-tw/script.lua
+++ b/locale/zh-tw/script.lua
@@ -142,6 +142,8 @@ DIAG_RETURN_TYPE_MISMATCH             =
 '第 {index} 個回傳值的類型為 `{def}` ，但實際回傳的是 `{ref}`。'
 DIAG_UNKNOWN_OPERATOR                 = -- TODO: need translate!
 'Unknown operator `{}`.'
+DIAG_UNREACHABLE_CODE                 = -- TODO: need translate!
+'Unreachable code.'
 
 MWS_NOT_SUPPORT         =
 '{} 目前還不支援多工作目錄，我可能需要重新啟動才能支援新的工作目錄...'
diff --git a/script/core/diagnostics/unreachable-code.lua b/script/core/diagnostics/unreachable-code.lua
new file mode 100644
index 00000000..28aee6ea
--- /dev/null
+++ b/script/core/diagnostics/unreachable-code.lua
@@ -0,0 +1,68 @@
+local files  = require 'files'
+local guide  = require 'parser.guide'
+local vm     = require 'vm'
+local lang   = require 'language'
+local await  = require 'await'
+
+---@param block parser.object
+---@return boolean
+local function hasReturn(block)
+    if block.hasReturn or block.hasError then
+        return true
+    end
+    if block.type == 'if' then
+        local hasElse
+        for _, subBlock in ipairs(block) do
+            if not hasReturn(subBlock) then
+                return false
+            end
+            if subBlock.type == 'elseblock' then
+                hasElse = true
+            end
+        end
+        return hasElse == true
+    else
+        if block.type == 'while' then
+            if vm.testCondition(block.filter) then
+                return true
+            end
+        end
+        for _, action in ipairs(block) do
+            if guide.isBlockType(action) then
+                if hasReturn(action) then
+                    return true
+                end
+            end
+        end
+    end
+    return false
+end
+
+---@async
+return function (uri, callback)
+    local state = files.getState(uri)
+    if not state then
+        return
+    end
+
+    ---@async
+    guide.eachSourceTypes(state.ast, {'main', 'function'}, function (source)
+        await.delay()
+        if not source.returns then
+            return
+        end
+        for i, action in ipairs(source) do
+            if  guide.isBlockType(action)
+            and hasReturn(action) then
+                if i < #source then
+                    callback {
+                        start = source[i+1].start,
+                        finish = source[#source].finish,
+                        message = lang.script('DIAG_UNREACHABLE_CODE'),
+                    }
+                end
+                return
+            end
+        end
+    end)
+end
diff --git a/script/proto/diagnostic.lua b/script/proto/diagnostic.lua
index d8312dfe..dc550fac 100644
--- a/script/proto/diagnostic.lua
+++ b/script/proto/diagnostic.lua
@@ -47,6 +47,7 @@ m.register {
     'redundant-return',
     'empty-block',
     'code-after-break',
+    'unreachable-code',
 } {
     group    = 'unused',
     severity = 'Hint',
diff --git a/test/diagnostics/common.lua b/test/diagnostics/common.lua
index fab02caf..1ab6ec5c 100644
--- a/test/diagnostics/common.lua
+++ b/test/diagnostics/common.lua
@@ -1958,3 +1958,31 @@ local <!ll!>
 ]]
 
 config.remove(nil, 'Lua.diagnostics.unusedLocalExclude', 'll_*')
+
+TEST [[
+---@diagnostic disable: undefined-global
+
+if X then
+    return false
+elseif X then
+    return false
+else
+    return false
+end
+<!return true!>
+]]
+
+TEST [[
+---@diagnostic disable: undefined-global
+
+function X()
+    if X then
+        return false
+    elseif X then
+        return false
+    else
+        return false
+    end
+    <!return true!>
+end
+]]
diff --git a/test/type_inference/init.lua b/test/type_inference/init.lua
index 91182af8..30f47900 100644
--- a/test/type_inference/init.lua
+++ b/test/type_inference/init.lua
@@ -3714,3 +3714,4 @@ A.B.C = 1
 
 print(A.B.<?C?>)
 ]]
+