5 files changed, 80 insertions, 9 deletions
diff --git a/script/core/diagnostics/assign-type-mismatch.lua b/script/core/diagnostics/assign-type-mismatch.lua
index aae4cccb..89ae0a61 100644
--- a/script/core/diagnostics/assign-type-mismatch.lua
+++ b/script/core/diagnostics/assign-type-mismatch.lua
@@ -16,7 +16,7 @@ local checkTypes = {
 
 ---@async
 return function (uri, callback)
-    if not PREVIEW then
+    if not PREVIEW and not TEST then
         return
     end
     local state = files.getState(uri)
diff --git a/script/core/diagnostics/cast-field-type.lua b/script/core/diagnostics/cast-field-type.lua
new file mode 100644
index 00000000..24299649
--- /dev/null
+++ b/script/core/diagnostics/cast-field-type.lua
@@ -0,0 +1,70 @@
+local files = require 'files'
+local lang  = require 'language'
+local guide = require 'parser.guide'
+local vm    = require 'vm'
+local await = require 'await'
+
+---@async
+return function (uri, callback)
+    if not PREVIEW and not TEST then
+        return
+    end
+    local state = files.getState(uri)
+    if not state then
+        return
+    end
+
+    local fieldNodeCache = {}
+
+    local function getParentField(parent, key)
+        if parent.type == 'getlocal' then
+            parent = parent.node
+        end
+        if not fieldNodeCache[parent] then
+            fieldNodeCache[parent] = {}
+        end
+        if fieldNodeCache[parent][key] then
+            return fieldNodeCache[parent][key]
+        end
+        local fieldNode = vm.createNode()
+        fieldNodeCache[parent][key] = fieldNode
+        for _, class in ipairs(vm.getDefs(parent)) do
+            if class.type == 'doc.class' then
+                vm.getClassFields(uri, vm.getGlobal('type', class.class[1]), key, false, function (def)
+                    if def.type == 'doc.field' then
+                        fieldNode:merge(vm.compileNode(def))
+                    end
+                end)
+            end
+        end
+        return fieldNode
+    end
+
+    ---@async
+    guide.eachSourceTypes(state.ast, { 'setfield', 'setindex', 'setmethod', 'tablefield', 'tableindex' }, function (ref)
+        await.delay()
+        if not ref.value then
+            return
+        end
+        local key = guide.getKeyName(ref)
+        if not key then
+            return nil
+        end
+        local parent = ref.node
+        local fieldNode = getParentField(parent, key)
+        if not fieldNode or fieldNode:isEmpty() then
+            return
+        end
+        if vm.canCastType(uri, fieldNode, vm.compileNode(ref.value)) then
+            return
+        end
+        callback {
+            start   = ref.start,
+            finish  = ref.finish,
+            message = lang.script('DIAG_CAST_LOCAL_TYPE', {
+                def = vm.getInfer(fieldNode):view(uri),
+                ref = vm.getInfer(ref.value):view(uri),
+            }),
+        }
+    end)
+end
diff --git a/script/core/diagnostics/cast-local-type.lua b/script/core/diagnostics/cast-local-type.lua
index 0a236084..dd3a37e8 100644
--- a/script/core/diagnostics/cast-local-type.lua
+++ b/script/core/diagnostics/cast-local-type.lua
@@ -6,7 +6,7 @@ local await = require 'await'
 
 ---@async
 return function (uri, callback)
-    if not PREVIEW then
+    if not PREVIEW and not TEST then
         return
     end
     local state = files.getState(uri)
diff --git a/script/core/diagnostics/init.lua b/script/core/diagnostics/init.lua
index 746052b0..efd23bf4 100644
--- a/script/core/diagnostics/init.lua
+++ b/script/core/diagnostics/init.lua
@@ -8,12 +8,13 @@ local util   = require 'utility'
 -- 把耗时最长的诊断放到最后面
 local diagSort = {
     ['redundant-value']      = 100,
-    ['not-yieldable']        = 101,
-    ['deprecated']           = 102,
-    ['undefined-field']      = 103,
-    ['redundant-parameter']  = 104,
-    ['cast-local-type']      = 105,
-    ['assign-type-mismatch'] = 106,
+    ['not-yieldable']        = 100,
+    ['deprecated']           = 100,
+    ['undefined-field']      = 110,
+    ['redundant-parameter']  = 110,
+    ['cast-local-type']      = 120,
+    ['cast-field-type']      = 120,
+    ['assign-type-mismatch'] = 120,
 }
 
 local diagList = {}
diff --git a/script/core/find-source.lua b/script/core/find-source.lua
index 26a411e5..99013b31 100644
--- a/script/core/find-source.lua
+++ b/script/core/find-source.lua
@@ -21,7 +21,7 @@ return function (ast, position, accept)
             end
         end
         local start, finish = guide.getStartFinish(source)
-        if finish - start < len and accept[source.type] then
+        if finish - start <= len and accept[source.type] then
             result = source
             len = finish - start
         end