[BCB] Remove ArrayType::generalizeKeys()

Author: ondrejmirtes

UPGRADING.md

@@ -232,3 +232,4 @@ Instead of `PHPStanTestCase::createBroker()`, call `PHPStanTestCase::createRefle
 * `Type::getSmallerType()`, `Type::getSmallerOrEqualType()`, `Type::getGreaterType()`, `Type::getGreaterOrEqualType()`, `Type::isSmallerThan()`, `Type::isSmallerThanOrEqual()` now require [`PhpVersion`](https://apiref.phpstan.org/2.0.x/PHPStan.Php.PhpVersion.html) as argument.
 * `CompoundType::isGreaterThan()`, `CompoundType::isGreaterThanOrEqual()` now require [`PhpVersion`](https://apiref.phpstan.org/2.0.x/PHPStan.Php.PhpVersion.html) as argument.
 * Removed `ReflectionProvider::supportsAnonymousClasses()` (all reflection providers support anonymous classes)
+* Remove `ArrayType::generalizeKeys()`

src/Type/ArrayType.php

@@ -183,14 +183,6 @@ function () use ($level, $isMixedKeyType, $isMixedItemType): string {
 		);
 	}
 
-	/**
-	 * @deprecated
-	 */
-	public function generalizeKeys(): self
-	{
-		return new self($this->keyType->generalize(GeneralizePrecision::lessSpecific()), $this->itemType);
-	}
-
 	public function generalizeValues(): self
 	{
 		return new self($this->keyType, $this->itemType->generalize(GeneralizePrecision::lessSpecific()));