Avoid setAlwaysOverwriteTypes() in specifyOnly statement path

Replace the SpecifiedTypes + setAlwaysOverwriteTypes() construction with a
direct assignExpression() call, which is what the overwrite branch of
filterBySpecifiedTypes() does internally. Functionally identical, but avoids
the bug-prone setAlwaysOverwriteTypes() flag.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: 2 people

src/Analyser/NodeScopeResolver.php

@@ -1153,14 +1153,9 @@ public function processStmtNode(
 			if ($specifiedTypes->shouldSpecifyOnly()) {
 				// Statement counterpart of the specifyOnly handling in filterByTruthyValue():
 				// store the call's true result so a duplicate void assertion statement is
-				// reported as always-true. We overwrite directly (not via TypeSpecifier::create)
-				// because void calls have no return value to protect from the purity check.
-				$scope = $scope->filterBySpecifiedTypes(
-					(new SpecifiedTypes(
-						[$scope->getNodeKey($stmt->expr) => [$stmt->expr, new ConstantBooleanType(true)]],
-						[],
-					))->setAlwaysOverwriteTypes(),
-				);
+				// reported as always-true. We assign directly because void calls have no
+				// return value to protect, and intersecting true with void would produce never.
+				$scope = $scope->assignExpression($stmt->expr, new ConstantBooleanType(true), new ConstantBooleanType(true));
 			}
 			$hasYield = $result->hasYield();
 			$throwPoints = $result->getThrowPoints();