1 files changed, 82 insertions, 0 deletions
diff --git a/script/core/diagnostics/redundant-parameter.lua b/script/core/diagnostics/redundant-parameter.lua
new file mode 100644
index 00000000..2fae20e8
--- /dev/null
+++ b/script/core/diagnostics/redundant-parameter.lua
@@ -0,0 +1,82 @@
+local files  = require 'files'
+local guide  = require 'parser.guide'
+local vm     = require 'vm'
+local lang   = require 'language'
+local define = require 'proto.define'
+local await  = require 'await'
+
+local function countCallArgs(source)
+    local result = 0
+    if not source.args then
+        return 0
+    end
+    if source.node and source.node.type == 'getmethod' then
+        result = result + 1
+    end
+    result = result + #source.args
+    return result
+end
+
+local function countFuncArgs(source)
+    local result = 0
+    if source.parent and source.parent.type == 'setmethod' then
+        result = result + 1
+    end
+    if not source.args then
+        return result
+    end
+    if source.args[#source.args].type == '...' then
+        return math.maxinteger
+    end
+    result = result + #source.args
+    return result
+end
+
+return function (uri, callback)
+    local ast = files.getAst(uri)
+    if not ast then
+        return
+    end
+
+    guide.eachSourceType(ast.ast, 'call', function (source)
+        local callArgs = countCallArgs(source)
+        if callArgs == 0 then
+            return
+        end
+
+        local func = source.node
+        local funcArgs
+        local defs = vm.getDefs(func)
+        for _, def in ipairs(defs) do
+            if def.value then
+                def = def.value
+            end
+            if def.type == 'function' then
+                local args = countFuncArgs(def)
+                if not funcArgs or args > funcArgs then
+                    funcArgs = args
+                end
+            end
+        end
+
+        if not funcArgs then
+            return
+        end
+
+        local delta = callArgs - funcArgs
+        if delta <= 0 then
+            return
+        end
+        for i = #source.args - delta + 1, #source.args do
+            local arg = source.args[i]
+            if arg then
+                callback {
+                    start   = arg.start,
+                    finish  = arg.finish,
+                    tags    = { define.DiagnosticTag.Unnecessary },
+                    message = lang.script('DIAG_OVER_MAX_ARGS', funcArgs, callArgs)
+                }
+            end
+        end
+    end)
+end