May 9, 2025 · May 9, 2025
diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst
 .. code-block:: python

   attributes = {"src": "shrubbery.jpg", "alt": "looks nice"}
   template = t"<img {attributes} />"
   assert html(template) == '<img src="shrubbery.jpg" alt="looks nice" class="looks-nice" />'
   template = t"<img {attributes}>"
   assert html(template) == '<img src="shrubbery.jpg" alt="looks nice" class="looks-nice">'

 Unlike f-strings, the ``html`` function has access to template attributes
 Compared to using an f-string, the ``html`` function has access to template attributes
 containing the original information: static strings, interpolations, and values
 from the original scope. Unlike existing templating approaches, t-strings build
 from the well-known f-string syntax and rules. Template systems thus benefit
 In Python 3.14, the behavior of code using ``from __future__ import annotations``
 is unchanged.

 .. seealso::
   :pep:`649`.


 Improved error messages
 -----------------------
                     ^^^^^^
   SyntaxError: cannot use subscript as import target

 .. seealso::
   :pep:`649`.
 * Improved error message when trying to add an instance of an unhashable type to
  a :class:`dict` or :class:`set`. (Contributed by CF Bolz-Tereick and Victor Stinner
  in :gh:`132828`.)

  .. code-block:: pycon

     >>> s = set()
     >>> s.add({'pages': 12, 'grade': 'A'})
     Traceback (most recent call last):
       File "<python-input-1>", line 1, in <module>
         s.add({'pages': 12, 'grade': 'A'})
         ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     TypeError: cannot use 'dict' as a set element (unhashable type: 'dict')
     >>> d = {}
     >>> l = [1, 2, 3]
     >>> d[l] = 12
     Traceback (most recent call last):
       File "<python-input-4>", line 1, in <module>
         d[l] = 12
         ~^^^
     TypeError: cannot use 'list' as a dict key (unhashable type: 'list')


 .. _whatsnew314-pep741:
Original file line number	Diff line number	Diff line change
Expand Up		@@ -153,10 +153,10 @@ As another example, generating HTML attributes from data:
		.. code-block:: python

		attributes = {"src": "shrubbery.jpg", "alt": "looks nice"}
		template = t"<img {attributes} />"
		assert html(template) == '<img src="shrubbery.jpg" alt="looks nice" class="looks-nice" />'
		template = t"<img {attributes}>"
		assert html(template) == '<img src="shrubbery.jpg" alt="looks nice" class="looks-nice">'

		Unlike f-strings, the ``html`` function has access to template attributes
		Compared to using an f-string, the ``html`` function has access to template attributes
		containing the original information: static strings, interpolations, and values
		from the original scope. Unlike existing templating approaches, t-strings build
		from the well-known f-string syntax and rules. Template systems thus benefit
Expand DownExpand Up		@@ -443,6 +443,9 @@ Python without deferred evaluation of annotations, reaches its end of life in 20
		In Python 3.14, the behavior of code using ``from __future__ import annotations``
		is unchanged.

		.. seealso::
		:pep:`649`.


		Improved error messages
		-----------------------
Expand DownExpand Up		@@ -584,8 +587,27 @@ Improved error messages
		^^^^^^
		SyntaxError: cannot use subscript as import target

		.. seealso::
		:pep:`649`.
		* Improved error message when trying to add an instance of an unhashable type to
		a :class:`dict` or :class:`set`. (Contributed by CF Bolz-Tereick and Victor Stinner
		in :gh:`132828`.)

		.. code-block:: pycon

		>>> s = set()
		>>> s.add({'pages': 12, 'grade': 'A'})
		Traceback (most recent call last):
		File "<python-input-1>", line 1, in <module>
		s.add({'pages': 12, 'grade': 'A'})
		~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
		TypeError: cannot use 'dict' as a set element (unhashable type: 'dict')
		>>> d = {}
		>>> l = [1, 2, 3]
		>>> d[l] = 12
		Traceback (most recent call last):
		File "<python-input-4>", line 1, in <module>
		d[l] = 12
		~^^^
		TypeError: cannot use 'list' as a dict key (unhashable type: 'list')


		.. _whatsnew314-pep741:
Expand Down