fix repeated docname

Author: sumneko

script/core/completion/completion.lua

@@ -1671,24 +1671,32 @@ end
 
 local function tryluaDocByErr(state, position, err, docState, results)
     if     err.type == 'LUADOC_MISS_CLASS_EXTENDS_NAME' then
+        local used = {}
         for _, doc in ipairs(vm.getDocSets(state.uri)) do
             if  doc.type == 'doc.class'
+            and not used[doc.class[1]]
             and doc.class[1] ~= docState.class[1] then
+                used[doc.class[1]] = true
                 results[#results+1] = {
                     label       = doc.class[1],
                     kind        = define.CompletionItemKind.Class,
                 }
             end
         end
     elseif err.type == 'LUADOC_MISS_TYPE_NAME' then
+        local used = {}
         for _, doc in ipairs(vm.getDocSets(state.uri)) do
-            if doc.type == 'doc.class' then
+            if  doc.type == 'doc.class'
+            and not used[doc.class[1]] then
+                used[doc.class[1]] = true
                 results[#results+1] = {
                     label       = doc.class[1],
                     kind        = define.CompletionItemKind.Class,
                 }
             end
-            if doc.type == 'doc.alias' then
+            if  doc.type == 'doc.alias'
+            and not used[doc.alias[1]] then
+                used[doc.alias[1]] = true
                 results[#results+1] = {
                     label       = doc.alias[1],
                     kind        = define.CompletionItemKind.Class,

test/completion/common.lua

@@ -3292,3 +3292,22 @@ local t = x[<??>]
         assert(res.label ~= 'do')
     end
 end)
+
+TEST [[
+---@class ZZZZZ.XXXX
+---@class ZZZZZ.XXXX
+---@class ZZZZZ.XXXX
+---@class ZZZZZ.XXXX
+---@class ZZZZZ.XXXX
+
+---@type <??>
+]]
+(function (results)
+    local count = 0
+    for _, res in ipairs(results) do
+        if res.label == 'ZZZZZ.XXXX' then
+            count = count + 1
+        end
+    end
+    assert(count == 1)
+end)