Move generic type arg check from TemplateTypeVariance to VarTagTypeRuleHelper

Revert the TemplateTypeVariance hack that treated template types as equal
to their bounds for invariant checks - this was conceptually wrong since
invariant means exact type equality.

Instead, fix VarTagTypeRuleHelper::checkType() to compare generic object
type arguments individually (covariantly) when both types are the same
generic class. This correctly allows @var tags like `@var IRepository<E>`
or `@var IRepository<Foo>` when the expression type is `IRepository<IEntity>`
and E/Foo are subtypes of IEntity.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

phpstan-baseline.neon

@@ -726,7 +726,7 @@ parameters:
 		-
 			rawMessage: Doing instanceof PHPStan\Type\Generic\GenericObjectType is error-prone and deprecated.
 			identifier: phpstanApi.instanceofType
-			count: 1
+			count: 3
 			path: src/Rules/PhpDoc/VarTagTypeRuleHelper.php
 
 		-

src/Rules/PhpDoc/VarTagTypeRuleHelper.php

@@ -177,6 +177,23 @@ private function shouldVarTagTypeBeReported(Scope $scope, Node\Expr $expr, Type
 
 	private function checkType(Scope $scope, Type $type, Type $varTagType, int $depth = 0): bool
 	{
+		if (
+			$type instanceof GenericObjectType
+			&& $varTagType instanceof GenericObjectType
+			&& $type->getClassName() === $varTagType->getClassName()
+		) {
+			$typeArgs = $type->getTypes();
+			$varTagArgs = $varTagType->getTypes();
+			if (count($typeArgs) === count($varTagArgs)) {
+				foreach ($typeArgs as $i => $typeArg) {
+					if ($this->checkType($scope, $typeArg, $varTagArgs[$i], $depth + 1)) {
+						return true;
+					}
+				}
+				return false;
+			}
+		}
+
 		if ($this->strictWideningCheck) {
 			return !$this->isSuperTypeOfVarType($scope, $type, $varTagType);
 		}

src/Type/Generic/TemplateTypeVariance.php

@@ -177,9 +177,6 @@ public function isValidVariance(TemplateType $templateType, Type $a, Type $b): I
 
 		if ($this->invariant()) {
 			$result = $a->equals($b);
-			if (!$result && $b instanceof TemplateType && $a->equals($b->getBound())) {
-				$result = true;
-			}
 			$reasons = [];
 			if (!$result) {
 				if (