Move readonly-for-loop-vars check from diagnostic to parser stage

Co-authored-by: CppCXY <[email protected]>

Author: Copilot

locale/en-us/script.lua

@@ -24,8 +24,6 @@ DIAG_UNUSED_VARARG      =
 'Unused vararg.'
 DIAG_REDEFINED_LOCAL    =
 'Redefined local `{}`.'
-DIAG_READONLY_FOR_LOOP_VAR =
-'Cannot assign to for-loop variable `{}` (read-only in Lua 5.5).'
 DIAG_DUPLICATE_INDEX    =
 'Duplicate index `{}`.'
 DIAG_DUPLICATE_METHOD   =
@@ -295,6 +293,8 @@ PARSER_MISS_SEP_IN_TABLE =
 'Miss symbol `,` or `;` .'
 PARSER_SET_CONST         =
 'Assignment to const variable.'
+PARSER_SET_FOR_LOOP_VAR  =
+'Cannot assign to for-loop variable `{}` (read-only in Lua 5.5).'
 PARSER_UNICODE_NAME      =
 'Contains Unicode characters.'
 PARSER_ERR_NONSTANDARD_SYMBOL =

locale/es-419/script.lua

@@ -291,6 +291,8 @@ PARSER_MISS_SEP_IN_TABLE =
 'Falta el símbolo `,` ó `;` .'
 PARSER_SET_CONST         =
 'Asignación de valor a una variable constante.'
+PARSER_SET_FOR_LOOP_VAR  =
+'No se puede asignar a la variable de bucle for `{}` (solo lectura en Lua 5.5).'
 PARSER_UNICODE_NAME      =
 'Contiene caracteres Unicode.'
 PARSER_ERR_NONSTANDARD_SYMBOL =

locale/ja-jp/script.lua

@@ -293,6 +293,8 @@ PARSER_MISS_SEP_IN_TABLE =
 '区切りには `,` または `;` が必要です。'
 PARSER_SET_CONST         =
 '定数に値を代入できません。'
+PARSER_SET_FOR_LOOP_VAR  =
+'forループ変数`{}`に代入できません（Lua 5.5では読み取り専用）。'
 PARSER_UNICODE_NAME      =
 'Unicode 文字が含まれています。'
 PARSER_ERR_NONSTANDARD_SYMBOL =

locale/pt-br/script.lua

@@ -293,6 +293,8 @@ PARSER_MISS_SEP_IN_TABLE =
 'Falta o símbolo `,` ou `;` .'
 PARSER_SET_CONST         =
 'Atribuição à variável constante.'
+PARSER_SET_FOR_LOOP_VAR  =
+'Não é possível atribuir à variável de loop for `{}` (somente leitura no Lua 5.5).'
 PARSER_UNICODE_NAME      =
 'Contém caracteres Unicode.'
 PARSER_ERR_NONSTANDARD_SYMBOL =

locale/zh-cn/script.lua

@@ -295,6 +295,8 @@ PARSER_MISS_SEP_IN_TABLE =
 '需要用`,`或`;`进行分割。'
 PARSER_SET_CONST         =
 '不能对常量赋值。'
+PARSER_SET_FOR_LOOP_VAR  =
+'不能对for循环变量`{}`赋值（在Lua 5.5中只读）。'
 PARSER_UNICODE_NAME      =
 '包含了 Unicode 字符。'
 PARSER_ERR_NONSTANDARD_SYMBOL =

locale/zh-tw/script.lua

@@ -293,6 +293,8 @@ PARSER_MISS_SEP_IN_TABLE =
 '需要用 `,` 或 `;` 進行分割。'
 PARSER_SET_CONST         =
 '不能對常數賦值。'
+PARSER_SET_FOR_LOOP_VAR  =
+'不能對for迴圈變數`{}`賦值（在Lua 5.5中唯讀）。'
 PARSER_UNICODE_NAME      =
 '包含了 Unicode 字元。'
 PARSER_ERR_NONSTANDARD_SYMBOL =

script/core/diagnostics/readonly-for-loop-vars.lua

@@ -263,6 +263,36 @@ local function addSpecial(name, obj)
     obj.special = name
 end
 
+---@param local parser.object
+---@return boolean
+local function isForLoopVariable(local_)
+    -- Check if this local is a for-loop variable
+    if not local_ or local_.type ~= 'local' then
+        return false
+    end
+    
+    local parent = local_.parent
+    if not parent then
+        return false
+    end
+    
+    -- Check if parent is a numeric for-loop
+    if parent.type == 'loop' and parent.loc == local_ then
+        return true
+    end
+    
+    -- Check if parent is a for-in loop
+    if parent.type == 'in' and parent.keys then
+        for i = 1, #parent.keys do
+            if parent.keys[i] == local_ then
+                return true
+            end
+        end
+    end
+    
+    return false
+end
+
 ---@param offset integer
 ---@param leftOrRight '"left"'|'"right"'
 local function getPosition(offset, leftOrRight)
@@ -2921,6 +2951,15 @@ local function bindValue(n, v, index, lastValue, isLocal, isSet)
                     start  = n.start,
                     finish = n.finish,
                 }
+            elseif State.version == 'Lua 5.5' and isForLoopVariable(loc) then
+                pushError {
+                    type   = 'SET_FOR_LOOP_VAR',
+                    start  = n.start,
+                    finish = n.finish,
+                    info   = {
+                        name = loc[1],
+                    },
+                }
             end
         end
     end
@@ -4011,6 +4050,15 @@ function parseAction()
                         start  = name.start,
                         finish = name.finish,
                     }
+                elseif State.version == 'Lua 5.5' and isForLoopVariable(loc) then
+                    pushError {
+                        type   = 'SET_FOR_LOOP_VAR',
+                        start  = name.start,
+                        finish = name.finish,
+                        info   = {
+                            name = loc[1],
+                        },
+                    }
                 end
             end
             pushActionIntoCurrentChunk(name)

script/parser/compile.lua

@@ -174,14 +174,6 @@ m.register {
     status   = 'Opened',
 }
 
-m.register {
-    'readonly-for-loop-vars',
-} {
-    group    = 'readonly',
-    severity = 'Error',
-    status   = 'Opened',
-}
-
 m.register {
     'undefined-global',
     'global-in-nil-env',

script/proto/diagnostic.lua

@@ -1,26 +1,27 @@
 -- Test for readonly for-loop variables in Lua 5.5
+-- Note: These now produce parser errors instead of diagnostics
 
 TEST [[
 ---@language Lua 5.5
 for i = 1, 10 do
-    <!i!> = 5  -- Error: Cannot assign to for-loop variable
+    i = 5  -- This is now a parser error, so no diagnostic
 end
 ]]
 
 TEST [[
 ---@language Lua 5.5
 for k, v in pairs(t) do
-    <!k!> = "new"  -- Error: Cannot assign to for-loop variable
-    <!v!> = 123    -- Error: Cannot assign to for-loop variable
+    k = "new"  -- This is now a parser error, so no diagnostic
+    v = 123    -- This is now a parser error, so no diagnostic
 end
 ]]
 
 TEST [[
 ---@language Lua 5.5
 for i = 1, 10 do
     for j = 1, 5 do
-        <!i!> = j  -- Error: Cannot assign to outer for-loop variable
-        <!j!> = i  -- Error: Cannot assign to inner for-loop variable
+        i = j  -- This is now a parser error, so no diagnostic
+        j = i  -- This is now a parser error, so no diagnostic
     end
 end
 ]]