cleanup

11 files changed, 141 insertions, 116 deletions

diff --git a/changelog.md b/changelog.md
index a1a8825f..88df6e35 100644
--- a/changelog.md
+++ b/changelog.md
@@ -168,6 +168,7 @@ server will generate `doc.json` and `doc.md` in `LOGPATH`.
 
 [#1153]: https://github.com/sumneko/lua-language-server/issues/1153
 [#1177]: https://github.com/sumneko/lua-language-server/issues/1177
+[#1201]: https://github.com/sumneko/lua-language-server/issues/1201
 [#1202]: https://github.com/sumneko/lua-language-server/issues/1202
 [#1332]: https://github.com/sumneko/lua-language-server/issues/1332
 [#1344]: https://github.com/sumneko/lua-language-server/issues/1344
diff --git a/locale/en-us/script.lua b/locale/en-us/script.lua
index 9fceac00..51f1c4eb 100644
--- a/locale/en-us/script.lua
+++ b/locale/en-us/script.lua
@@ -139,7 +139,7 @@ DIAG_REDUNDANT_RETURN_VALUE_RANGE     =
 DIAG_MISSING_RETURN                   =
 'Return value is required here.'
 DIAG_RETURN_TYPE_MISMATCH             =
-'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.'
+'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.\n{err}'
 DIAG_UNKNOWN_OPERATOR                 =
 'Unknown operator `{}`.'
 DIAG_UNREACHABLE_CODE                 =
diff --git a/locale/pt-br/script.lua b/locale/pt-br/script.lua
index a6adc651..2e0b0aa6 100644
--- a/locale/pt-br/script.lua
+++ b/locale/pt-br/script.lua
@@ -139,7 +139,7 @@ DIAG_REDUNDANT_RETURN_VALUE_RANGE     = -- TODO: need translate!
 DIAG_MISSING_RETURN                   = -- TODO: need translate!
 'Return value is required here.'
 DIAG_RETURN_TYPE_MISMATCH             = -- TODO: need translate!
-'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.'
+'The type of the {index} return value is `{def}`, but the actual return is `{ref}`.\n{err}'
 DIAG_UNKNOWN_OPERATOR                 = -- TODO: need translate!
 'Unknown operator `{}`.'
 DIAG_UNREACHABLE_CODE                 = -- TODO: need translate!
diff --git a/locale/zh-cn/script.lua b/locale/zh-cn/script.lua
index 86815da3..9a7a76d8 100644
--- a/locale/zh-cn/script.lua
+++ b/locale/zh-cn/script.lua
@@ -139,7 +139,7 @@ DIAG_REDUNDANT_RETURN_VALUE_RANGE     =
 DIAG_MISSING_RETURN                   =
 '此处需要返回值。'
 DIAG_RETURN_TYPE_MISMATCH             =
-'第 {index} 个返回值的类型为 `{def}` ，但实际返回的是 `{ref}`。'
+'第 {index} 个返回值的类型为 `{def}` ，但实际返回的是 `{ref}`。\n{err}'
 DIAG_UNKNOWN_OPERATOR                 =
 '未知的运算符 `{}`。'
 DIAG_UNREACHABLE_CODE                 =
diff --git a/locale/zh-tw/script.lua b/locale/zh-tw/script.lua
index 060ae8ab..a31c0d67 100644
--- a/locale/zh-tw/script.lua
+++ b/locale/zh-tw/script.lua
@@ -139,7 +139,7 @@ DIAG_REDUNDANT_RETURN_VALUE_RANGE     =
 DIAG_MISSING_RETURN                   =
 '此處需要回傳值。'
 DIAG_RETURN_TYPE_MISMATCH             =
-'第 {index} 個回傳值的類型為 `{def}` ，但實際回傳的是 `{ref}`。'
+'第 {index} 個回傳值的類型為 `{def}` ，但實際回傳的是 `{ref}`。\n{err}'
 DIAG_UNKNOWN_OPERATOR                 = -- TODO: need translate!
 'Unknown operator `{}`.'
 DIAG_UNREACHABLE_CODE                 = -- TODO: need translate!
diff --git a/script/core/diagnostics/assign-type-mismatch.lua b/script/core/diagnostics/assign-type-mismatch.lua
index 2bbceebb..6f68a543 100644
--- a/script/core/diagnostics/assign-type-mismatch.lua
+++ b/script/core/diagnostics/assign-type-mismatch.lua
@@ -96,8 +96,8 @@ return function (uri, callback)
         end
 
         local varNode = vm.compileNode(source)
-        local suc, errs = vm.canCastType(uri, varNode, valueNode)
-        if suc then
+        local errs = {}
+        if vm.canCastType(uri, varNode, valueNode, errs) then
             return
         end
 
@@ -108,8 +108,6 @@ return function (uri, callback)
             end
         end
 
-        assert(errs)
-
         callback {
             start   = source.start,
             finish  = source.finish,
diff --git a/script/core/diagnostics/cast-local-type.lua b/script/core/diagnostics/cast-local-type.lua
index 42271e91..cde4ac40 100644
--- a/script/core/diagnostics/cast-local-type.lua
+++ b/script/core/diagnostics/cast-local-type.lua
@@ -34,10 +34,8 @@ return function (uri, callback)
                     refNode = refNode:copy():setTruthy()
                 end
 
-                local suc, errs = vm.canCastType(uri, locNode, refNode)
-
-                if not suc then
-                    assert(errs)
+                local errs = {}
+                if not vm.canCastType(uri, locNode, refNode, errs) then
                     callback {
                         start   = ref.start,
                         finish  = ref.finish,
diff --git a/script/core/diagnostics/cast-type-mismatch.lua b/script/core/diagnostics/cast-type-mismatch.lua
index 34b12559..c4809338 100644
--- a/script/core/diagnostics/cast-type-mismatch.lua
+++ b/script/core/diagnostics/cast-type-mismatch.lua
@@ -26,8 +26,8 @@ return function (uri, callback)
                     for _, cast in ipairs(doc.casts) do
                         if not cast.mode and cast.extends then
                             local refNode = vm.compileNode(cast.extends)
-                            local suc, errs = vm.canCastType(uri, defNode, refNode)
-                            if not suc then
+                            local errs = {}
+                            if not vm.canCastType(uri, defNode, refNode, errs) then
                                 assert(errs)
                                 callback {
                                     start   = cast.extends.start,
diff --git a/script/core/diagnostics/param-type-mismatch.lua b/script/core/diagnostics/param-type-mismatch.lua
index 9b2fbc6a..d3ff350d 100644
--- a/script/core/diagnostics/param-type-mismatch.lua
+++ b/script/core/diagnostics/param-type-mismatch.lua
@@ -100,8 +100,8 @@ return function (uri, callback)
                 -- 因此将假值移除再进行检查
                 refNode = refNode:copy():setTruthy()
             end
-            local suc, errs = vm.canCastType(uri, defNode, refNode)
-            if not suc then
+            local errs = {}
+            if not vm.canCastType(uri, defNode, refNode, errs) then
                 local rawDefNode = getRawDefNode(funcNode, i)
                 assert(errs)
                 callback {
diff --git a/script/core/diagnostics/return-type-mismatch.lua b/script/core/diagnostics/return-type-mismatch.lua
index 1f335e9d..092b44fc 100644
--- a/script/core/diagnostics/return-type-mismatch.lua
+++ b/script/core/diagnostics/return-type-mismatch.lua
@@ -61,13 +61,15 @@ return function (uri, callback)
                     retNode = retNode:copy():removeOptional()
                 end
             end
-            if not vm.canCastType(uri, docRet, retNode) then
+            local errs = {}
+            if not vm.canCastType(uri, docRet, retNode, errs) then
                 callback {
                     start   = exp.start,
                     finish  = exp.finish,
                     message = lang.script('DIAG_RETURN_TYPE_MISMATCH', {
                         def   = vm.getInfer(docRet):view(uri),
                         ref   = vm.getInfer(retNode):view(uri),
+                        err   = vm.viewTypeErrorMessage(uri, errs),
                         index = i,
                     }),
                 }
diff --git a/script/vm/type.lua b/script/vm/type.lua
index c60978e5..05b76fc3 100644
--- a/script/vm/type.lua
+++ b/script/vm/type.lua
@@ -50,9 +50,9 @@ end
 ---@param parentName string
 ---@param child      vm.node.object
 ---@param uri        uri
----@param err        typecheck.err[]
+---@param errs?      typecheck.err[]
 ---@return boolean?
-local function checkEnum(parentName, child, uri, err)
+local function checkEnum(parentName, child, uri, errs)
     local parentClass = vm.getGlobal('type', parentName)
     if not parentClass then
         return nil
@@ -74,14 +74,18 @@ local function checkEnum(parentName, child, uri, err)
                 return true
             end
         end
-        err[#err+1] = 'TYPE_ERROR_ENUM_GLOBAL_DISMATCH'
-        err[#err+1] = child
-        err[#err+1] = parentClass
+        if errs then
+            errs[#errs+1] = 'TYPE_ERROR_ENUM_GLOBAL_DISMATCH'
+            errs[#errs+1] = child
+            errs[#errs+1] = parentClass
+        end
         return false
     elseif child.type == 'generic' then
         ---@cast child vm.generic
-        err[#err+1] = 'TYPE_ERROR_ENUM_GENERIC_UNSUPPORTED'
-        err[#err+1] = child
+        if errs then
+            errs[#errs+1] = 'TYPE_ERROR_ENUM_GENERIC_UNSUPPORTED'
+            errs[#errs+1] = child
+        end
         return false
     else
         ---@cast child parser.object
@@ -97,9 +101,11 @@ local function checkEnum(parentName, child, uri, err)
                     end
                 end
             end
-            err[#err+1] = 'TYPE_ERROR_ENUM_LITERAL_DISMATCH'
-            err[#err+1] = child[1]
-            err[#err+1] = parentClass
+            if errs then
+                errs[#errs+1] = 'TYPE_ERROR_ENUM_LITERAL_DISMATCH'
+                errs[#errs+1] = child[1]
+                errs[#errs+1] = parentClass
+            end
             return false
         elseif childName == 'function'
         or     childName == 'table' then
@@ -110,13 +116,17 @@ local function checkEnum(parentName, child, uri, err)
                     end
                 end
             end
-            err[#err+1] = 'TYPE_ERROR_ENUM_OBJECT_DISMATCH'
-            err[#err+1] = child
-            err[#err+1] = parentClass
+            if errs then
+                errs[#errs+1] = 'TYPE_ERROR_ENUM_OBJECT_DISMATCH'
+                errs[#errs+1] = child
+                errs[#errs+1] = parentClass
+            end
             return false
         end
-        err[#err+1] = 'TYPE_ERROR_ENUM_NO_OBJECT'
-        err[#err+1] = child
+        if errs then
+            errs[#errs+1] = 'TYPE_ERROR_ENUM_NO_OBJECT'
+            errs[#errs+1] = child
+        end
         return false
     end
 end
@@ -124,17 +134,19 @@ end
 ---@param parent vm.node.object
 ---@param child  vm.node.object
 ---@param mark   table
----@param err    typecheck.err[]
+---@param errs?  typecheck.err[]
 ---@return boolean
-local function checkValue(parent, child, mark, err)
+local function checkValue(parent, child, mark, errs)
     if parent.type == 'doc.type.integer' then
         if child.type == 'integer'
         or child.type == 'doc.type.integer'
         or child.type == 'number' then
             if parent[1] ~= child[1] then
-                err[#err+1] = 'TYPE_ERROR_INTEGER_DISMATCH'
-                err[#err+1] = child[1]
-                err[#err+1] = parent[1]
+                if errs then
+                    errs[#errs+1] = 'TYPE_ERROR_INTEGER_DISMATCH'
+                    errs[#errs+1] = child[1]
+                    errs[#errs+1] = parent[1]
+                end
                 return false
             end
         end
@@ -147,9 +159,11 @@ local function checkValue(parent, child, mark, err)
         or child.type == 'doc.type.string'
         or child.type == 'doc.field.name' then
             if parent[1] ~= child[1] then
-                err[#err+1] = 'TYPE_ERROR_STRING_DISMATCH'
-                err[#err+1] = child[1]
-                err[#err+1] = parent[1]
+                if errs then
+                    errs[#errs+1] = 'TYPE_ERROR_STRING_DISMATCH'
+                    errs[#errs+1] = child[1]
+                    errs[#errs+1] = parent[1]
+                end
                 return false
             end
         end
@@ -160,9 +174,11 @@ local function checkValue(parent, child, mark, err)
         if child.type == 'boolean'
         or child.type == 'doc.type.boolean' then
             if parent[1] ~= child[1] then
-                err[#err+1] = 'TYPE_ERROR_BOOLEAN_DISMATCH'
-                err[#err+1] = child[1]
-                err[#err+1] = parent[1]
+                if errs then
+                    errs[#errs+1] = 'TYPE_ERROR_BOOLEAN_DISMATCH'
+                    errs[#errs+1] = child[1]
+                    errs[#errs+1] = parent[1]
+                end
                 return false
             end
         end
@@ -179,16 +195,20 @@ local function checkValue(parent, child, mark, err)
                 local knode = vm.compileNode(pfield.name)
                 local cvalues = vm.getTableValue(uri, tnode, knode, true)
                 if not cvalues then
-                    err[#err+1] = 'TYPE_ERROR_TABLE_NO_FIELD'
-                    err[#err+1] = pfield.name
+                    if errs then
+                        errs[#errs+1] = 'TYPE_ERROR_TABLE_NO_FIELD'
+                        errs[#errs+1] = pfield.name
+                    end
                     return false
                 end
                 local pvalues = vm.compileNode(pfield.extends)
-                if vm.isSubType(uri, cvalues, pvalues, mark, err) == false then
-                    err[#err+1] = 'TYPE_ERROR_TABLE_FIELD_DISMATCH'
-                    err[#err+1] = pfield.name
-                    err[#err+1] = cvalues
-                    err[#err+1] = pvalues
+                if vm.isSubType(uri, cvalues, pvalues, mark, errs) == false then
+                    if errs then
+                        errs[#errs+1] = 'TYPE_ERROR_TABLE_FIELD_DISMATCH'
+                        errs[#errs+1] = pfield.name
+                        errs[#errs+1] = cvalues
+                        errs[#errs+1] = pvalues
+                    end
                     return false
                 end
             end
@@ -219,17 +239,15 @@ end
 ---@param child  vm.node|string|vm.node.object
 ---@param parent vm.node|string|vm.node.object
 ---@param mark?  table
----@param err? typecheck.err[]
+---@param errs? typecheck.err[]
 ---@return boolean|nil
----@return typecheck.err[] # errors
-function vm.isSubType(uri, child, parent, mark, err)
+function vm.isSubType(uri, child, parent, mark, errs)
     mark = mark or {}
-    err  = err  or {}
 
     if type(child) == 'string' then
         local global = vm.getGlobal('type', child)
         if not global then
-            return nil, err
+            return nil
         end
         child = global
     elseif child.type == 'vm.node' then
@@ -238,41 +256,45 @@ function vm.isSubType(uri, child, parent, mark, err)
             for n in child:eachObject() do
                 if getNodeName(n) then
                     hasKnownType = hasKnownType + 1
-                    if vm.isSubType(uri, n, parent, mark, err) == true then
-                        return true, err
+                    if vm.isSubType(uri, n, parent, mark, errs) == true then
+                        return true
                     end
                 end
             end
             if hasKnownType > 0 then
-                if hasKnownType > 1 then
-                    err[#err+1] = 'TYPE_ERROR_CHILD_ALL_DISMATCH'
-                    err[#err+1] = child
-                    err[#err+1] = parent
+                if errs and hasKnownType > 1 then
+                    errs[#errs+1] = 'TYPE_ERROR_CHILD_ALL_DISMATCH'
+                    errs[#errs+1] = child
+                    errs[#errs+1] = parent
                 end
-                return false, err
+                return false
             end
-            return true, err
+            return true
         else
             local weakNil = config.get(uri, 'Lua.type.weakNilCheck')
             for n in child:eachObject() do
                 local nodeName = getNodeName(n)
                 if  nodeName
                 and not (nodeName == 'nil' and weakNil)
-                and vm.isSubType(uri, n, parent, mark, err) == false then
-                    err[#err+1] = 'TYPE_ERROR_UNION_DISMATCH'
-                    err[#err+1] = n
-                    err[#err+1] = parent
-                    return false, err
+                and vm.isSubType(uri, n, parent, mark, errs) == false then
+                    if errs then
+                        errs[#errs+1] = 'TYPE_ERROR_UNION_DISMATCH'
+                        errs[#errs+1] = n
+                        errs[#errs+1] = parent
+                    end
+                    return false
                 end
             end
             if not weakNil and child:isOptional() then
-                if vm.isSubType(uri, 'nil', parent, mark, err) == false then
-                    err[#err+1] = 'TYPE_ERROR_OPTIONAL_DISMATCH'
-                    err[#err+1] = parent
-                    return false, err
+                if vm.isSubType(uri, 'nil', parent, mark, errs) == false then
+                    if errs then
+                        errs[#errs+1] = 'TYPE_ERROR_OPTIONAL_DISMATCH'
+                        errs[#errs+1] = parent
+                    end
+                    return false
                 end
             end
-            return true, err
+            return true
         end
     end
 
@@ -280,18 +302,18 @@ function vm.isSubType(uri, child, parent, mark, err)
     local childName = getNodeName(child)
     if childName == 'any'
     or childName == 'unknown' then
-        return true, err
+        return true
     end
 
     if not childName
     or isAlias(childName, uri) then
-        return nil, err
+        return nil
     end
 
     if type(parent) == 'string' then
         local global = vm.getGlobal('type', parent)
         if not global then
-            return false, err
+            return false
         end
         parent = global
     elseif parent.type == 'vm.node' then
@@ -299,25 +321,25 @@ function vm.isSubType(uri, child, parent, mark, err)
         for n in parent:eachObject() do
             if getNodeName(n) then
                 hasKnownType = hasKnownType + 1
-                if vm.isSubType(uri, child, n, mark, err) == true then
-                    return true, err
+                if vm.isSubType(uri, child, n, mark, errs) == true then
+                    return true
                 end
             end
         end
         if parent:isOptional() then
-            if vm.isSubType(uri, child, 'nil', mark, err) == true then
-                return true, err
+            if vm.isSubType(uri, child, 'nil', mark, errs) == true then
+                return true
             end
         end
         if hasKnownType > 0 then
-            if hasKnownType > 1 then
-                err[#err+1] = 'TYPE_ERROR_PARENT_ALL_DISMATCH'
-                err[#err+1] = child
-                err[#err+1] = parent
+            if errs and hasKnownType > 1 then
+                errs[#errs+1] = 'TYPE_ERROR_PARENT_ALL_DISMATCH'
+                errs[#errs+1] = child
+                errs[#errs+1] = parent
             end
-            return false, err
+            return false
         end
-        return true, err
+        return true
     end
 
     ---@cast parent vm.node.object
@@ -325,54 +347,58 @@ function vm.isSubType(uri, child, parent, mark, err)
     local parentName = getNodeName(parent)
     if parentName == 'any'
     or parentName == 'unknown' then
-        return true, err
+        return true
     end
 
     if not parentName
     or isAlias(parentName, uri) then
-        return nil, err
+        return nil
     end
 
     if childName == parentName then
-        if not checkValue(parent, child, mark, err) then
-            return false, err
+        if not checkValue(parent, child, mark, errs) then
+            return false
         end
-        return true, err
+        return true
     end
 
     if parentName == 'number' and childName == 'integer' then
-        return true, err
+        return true
     end
 
     if parentName == 'integer' and childName == 'number' then
         if config.get(uri, 'Lua.type.castNumberToInteger') then
-            return true, err
+            return true
         end
         if  child.type == 'number'
         and child[1]
         and not math.tointeger(child[1]) then
-            err[#err+1] = 'TYPE_ERROR_NUMBER_LITERAL_TO_INTEGER'
-            err[#err+1] = child[1]
-            return false, err
+            if errs then
+                errs[#errs+1] = 'TYPE_ERROR_NUMBER_LITERAL_TO_INTEGER'
+                errs[#errs+1] = child[1]
+            end
+            return false
         end
         if  child.type == 'global'
         and child.cate == 'type' then
-            err[#err+1] = 'TYPE_ERROR_NUMBER_TYPE_TO_INTEGER'
-            return false, err
+            if errs then
+                errs[#errs+1] = 'TYPE_ERROR_NUMBER_TYPE_TO_INTEGER'
+            end
+            return false
         end
-        return true, err
+        return true
     end
 
-    local isEnum = checkEnum(parentName, child, uri, err)
+    local isEnum = checkEnum(parentName, child, uri, errs)
     if isEnum ~= nil then
-        return isEnum, err
+        return isEnum
     end
 
     if parentName == 'table' and not guide.isBasicType(childName) then
-        return true, err
+        return true
     end
     if childName == 'table' and not guide.isBasicType(parentName) then
-        return true, err
+        return true
     end
 
     -- check class parent
@@ -386,8 +412,8 @@ function vm.isSubType(uri, child, parent, mark, err)
                     for _, ext in ipairs(set.extends) do
                         if  ext.type == 'doc.extends.name'
                         and (not isBasicType or guide.isBasicType(ext[1]))
-                        and vm.isSubType(uri, ext[1], parent, mark, err) == true then
-                            return true, err
+                        and vm.isSubType(uri, ext[1], parent, mark, errs) == true then
+                            return true
                         end
                     end
                 end
@@ -405,13 +431,15 @@ function vm.isSubType(uri, child, parent, mark, err)
     if  guide.isBasicType(childName)
     and guide.isLiteral(child)
     and vm.isSubType(uri, parentName, childName, mark) then
-        return true, err
+        return true
     end
 
-    err[#err+1] = 'TYPE_ERROR_DISMATCH'
-    err[#err+1] = child
-    err[#err+1] = parent
-    return false, err
+    if errs then
+        errs[#errs+1] = 'TYPE_ERROR_DISMATCH'
+        errs[#errs+1] = child
+        errs[#errs+1] = parent
+    end
+    return false
 end
 
 ---@param node string|vm.node|vm.object
@@ -554,9 +582,9 @@ end
 ---@param uri uri
 ---@param defNode vm.node
 ---@param refNode vm.node
+---@param errs typecheck.err[]?
 ---@return boolean
----@return typecheck.err[]?
-function vm.canCastType(uri, defNode, refNode)
+function vm.canCastType(uri, defNode, refNode, errs)
     local defInfer = vm.getInfer(defNode)
     local refInfer = vm.getInfer(refNode)
 
@@ -594,13 +622,11 @@ function vm.canCastType(uri, defNode, refNode)
         end
     end
 
-    local suc, err = vm.isSubType(uri, refNode, defNode)
-
-    if suc then
+    if vm.isSubType(uri, refNode, defNode, {}, errs) then
         return true
     end
 
-    return false, err
+    return false
 end
 
 local ErrorMessageMap = {