fixup! fix(math): Paired open/close atoms shall be forced in a mrow i…

…n TeX-like math

packages/math/texlike.lua

@@ -261,6 +261,9 @@ local compileToStr = function (argEnv, mathlist)
 end
 
 local function isOperatorKind (tree, typeOfAtom, typeOfSymbol)
+   if not tree then
+      return false -- safeguard
+   end
    if tree.command ~= "mo" then
       return false
    end
@@ -363,6 +366,22 @@ local function compileToMathML_aux (_, arg_env, tree)
                if #stack > 0 then
                   children = table.remove(stack)
                end
+            elseif (child.command == "msubsup" or child.command == "msub" or child.command == "msup")
+               and isCloseOperator(child[1]) -- child[1] is the base
+            then
+               if #stack > 0 then
+                  -- Special case for closing operator with sub/superscript:
+                  -- (....)^i must be interpreted as {(....)}^i, not as (...{)}^i
+                  -- Push the closing operator into the mrow
+                  table.insert(children, child[1])
+                  -- Move the mrow into the msubsup, replacing the closing operator
+                  child[1] = children
+                  -- And insert the msubsup into the parent
+                  children = table.remove(stack)
+                  children[#children] = child
+               else
+                  table.insert(children, child)
+               end
             else
                table.insert(children, child)
             end