Confusing syntax error for missing comma after import-as target

Bug report

Bug description:

Right now we have:

>>> import a as a  b
  File "<python-input-0>", line 1
    import a as a  b
                ^
SyntaxError: cannot use name as import target

>>> from x import a as a  b
  File "<python-input-1>", line 1
    from x import a as a  b
                       ^
SyntaxError: cannot use name as import target

This happens since these cases match these two rules.

One possible fix would be to add NAME to the list of not-matched tokens so that the current rules don't match this case.

However, I have an idea for a slightly nicer error. PR forthcoming.

cc @pablogsal @lysnikolaou @sobolevn

CPython versions tested on:

3.14, 3.15, CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-146493

Reproduce los dos ejemplos de import-as en la Python REPL y, después, inspecciona las dos reglas coincidentes en Grammar/python.gram alrededor de las líneas 1435 y 1439. Compara el diagnóstico resultante con el comportamiento esperado descrito en el issue; se considera terminado cuando el caso de la coma faltante recibe un error de sintaxis más claro. Ya se ha indicado un PR enlazado.