This PR was squashed before being merged into the 3.x branch.
Discussion
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Mark implicit macro argument default values as such with an attribute in AST
This change causes no difference to compiled templates or to macro argument semantics.
Consider the following macro:
```twig
{% macro marco(po, lo = null) %}{% endmacro %}
```
With this change, the `ConstantExpression` for argument `po` will have an attribute `is_implicit`, whose value will be `true`. (Note that `lo` will not have that attribute.)
This allows node visitors to distinguish between arguments that do and those that do not have explicit default values even if the value is `null`.
This is useful for [static code analysis](https://github.com/twigphp/Twig/issues/4003).
For example, a static analysis tool might consider arguments with no explicit default value as non-optional.
Commits
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e83a8028 Mark implicit macro argument default values as such with an attribute in AST
Alexandre Daubois
Alexander M. Turek
Fabien Potencier
Jeroen Versteeg
Jérémy Derussé