diff --git a/src/diagnostics.lua b/src/diagnostics.lua
index b8d9665..fb77765 100644
--- a/src/diagnostics.lua
+++ b/src/diagnostics.lua
@@ -116,14 +116,20 @@ function M.validate_diagnostics(content, workspace_types, root_dir)
 
         local type_part = nil
         local brace_depth = 0
+        local comment_depth = 0
         local last_colon = nil
         for i = 1, #line do
           local c = line:sub(i, i)
-          if c == "{" then
+          local next_c = line:sub(i+1, i+1)
+          if c == "(" and next_c == "*" then
+            comment_depth = comment_depth + 1
+          elseif c == "*" and next_c == ")" and comment_depth > 0 then
+            comment_depth = comment_depth - 1
+          elseif c == "{" and comment_depth == 0 then
             brace_depth = brace_depth + 1
-          elseif c == "}" then
+          elseif c == "}" and comment_depth == 0 then
             brace_depth = brace_depth - 1
-          elseif c == ":" and brace_depth == 0 then
+          elseif c == ":" and brace_depth == 0 and comment_depth == 0 then
             last_colon = i
           end
         end
@@ -131,11 +137,16 @@ function M.validate_diagnostics(content, workspace_types, root_dir)
           type_part = line:sub(last_colon + 1)
         end
         if type_part then
+          type_part = type_part:gsub("%s*%(%*.-%*%)", "")  -- Remove block comments (* ... *) with leading whitespace
           type_part = type_part:gsub("%s*:=.*$", "")
+          type_part = type_part:gsub("%s*;.*$", "")  -- Remove trailing semicolon
           type_part = type_part:gsub("%s*$", "")
           type_part = type_part:gsub("^%s+", "")
 
-          local base_type = type_part:match("^(%w+)")
+          local base_type = type_part:match("^([%w_]+)")
+          if type_part:match("%s+OF%s+") then
+            base_type = type_part:match(".*%s+OF%s+([%w_]+)")
+          end
           local upper_type = base_type and base_type:upper() or nil
           if base_type and not all_types[base_type] and
              upper_type ~= "BOOL" and upper_type ~= "INT" and upper_type ~= "DINT" and
@@ -144,7 +155,10 @@ function M.validate_diagnostics(content, workspace_types, root_dir)
              upper_type ~= "CHAR" and upper_type ~= "STRING" and upper_type ~= "WCHAR" and
              upper_type ~= "WSTRING" and upper_type ~= "TIME" and upper_type ~= "DATE" and
              upper_type ~= "TIME_OF_DAY" and upper_type ~= "DATE_AND_TIME" and
-             upper_type ~= "S5TIME" and upper_type ~= "LTIME" then
+             upper_type ~= "S5TIME" and upper_type ~= "LTIME" and
+             upper_type ~= "IEC_TIMER" and upper_type ~= "TON_TIME" and
+             upper_type ~= "TOF_TIME" and upper_type ~= "TONR_TIME" and
+             upper_type ~= "TP_TIME" then
             table.insert(diagnostics, {
               range = range_to_lsp(line_num, 0, line_num, #line),
               severity = DiagnosticSeverity.Warning,