id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
37050	Improve simple_tag / simple_block_tag error message when as is used without a variable name	Shima Fallah	Shima Fallah	"When using Library.simple_tag() or Library.simple_block_tag(), templates that end with as but omit the target variable currently raise a generic argument error. This is valid behavior (it fails), but the message is unclear for template authors.

**Examples**
{% load custom %}{% one_param 37 as %}
{% load custom %}{% div as %}content{% enddiv %}
Current behavior
A generic TemplateSyntaxError is raised from argument parsing, which does not clearly explain that the variable name after as is missing.

Expected behavior
Raise a clear, direct error, e.g.:

'one_param' tag requires a variable name after 'as'
'div' tag requires a variable name after 'as'
What this change does

Adds an explicit check in both compile paths (simple_tag and simple_block_tag) for trailing as without a following variable.
Raises a specific TemplateSyntaxError message before normal argument parsing.
Tests
Adds 4 regression tests covering invalid trailing as usage:

simple tag without args: {% no_params as %}
simple tag with args: {% one_param 37 as %}
simple block tag without args: {% div as %}...{% enddiv %}
simple block tag with args: {% one_param_block 37 as %}...{% endone_param_block %}

These tests verify the new explicit error messages."	Cleanup/optimization	assigned	Template system	6.0	Normal			Shima Fallah	Unreviewed	1	0	0	0	1	0