[6.x] Skip trait in getMethodMutations when storage is missing (fixes "Could not get class storage")

[alies-dev]

Fixes #8953

Psalm 6.x crashes with InvalidArgumentException: Could not get class storage for illuminate\console\concerns\promptsformissinginput when analyzing Laravel projects containing classes that extend Illuminate\Console\Command.

Root cause: ClassLikeAnalyzer::getMethodMutations() iterates AST TraitUse nodes unconditionally. A trait may be registered via reflection (present in existing_traits) but absent from ClassLikeStorageProvider::$storage. The call to getTraitNode() → classlike_storage_provider->get() throws InvalidArgumentException.
Fix: Add a 4-line has() guard before accessing trait storage, same pattern as the interface fix in 03037f7.
Real-world trigger: Any Laravel class extending Illuminate\Console\Command (which uses PromptsForMissingInput trait) with an uninitialized typed property that triggers collect_initializations → getMethodMutations → crash.

Stack Trace

InvalidArgumentException: Could not get class storage for illuminate\console\concerns\promptsformissinginput
  at src/Psalm/Internal/Provider/ClassLikeStorageProvider.php:45
  ClassLikes.php:771       → getTraitNode("Illuminate\Console\Concerns\PromptsForMissingInput")
  ClassLikeAnalyzer.php:141 → getTraitNode(...)        ← CRASH SITE
  FileAnalyzer.php:409     → getMethodMutations(...)
  ProjectAnalyzer.php:1205 → getMethodMutations(...)
  FileAnalyzer.php:372     → analyzing ExportMakeCommand.php

Test

php vendor/bin/phpunit tests/IncludeTest.php --filter=testGetMethodMutationsDoesNotCrashWhenTraitStorageMissing

It failed with:

InvalidArgumentException: Could not get class storage for foo\mytrait
  at src/Psalm/Internal/Analyzer/ClassLikeAnalyzer.php:137

The stack trace matched the expected crash path through ClassLikeAnalyzer::getMethodMutations() → ClassLikeStorageProvider::get().

Notes

Follows the same guard pattern as the interface fix in 03037f7 (#11760)

---

Note

Medium Risk
Touches core mutation-tracking logic for traits; while the change is a small guard, it can alter analysis behavior by silently skipping unscanned traits and should be validated against real-world projects.

Overview
Prevents ClassLikeAnalyzer::getMethodMutations() from throwing when encountering a TraitUse whose ClassLikeStorage is missing by adding a classlike_storage_provider->has() guard and skipping that trait.

Adds a regression test in IncludeTest that simulates a trait registered via reflection but absent from storage (by removing it from ClassLikeStorageProvider::$storage) and asserts analyzing a child class no longer crashes.

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