instanceof narrowing no longer widens specific types.

Author: AJenbo

docs/CHANGELOG.md

@@ -37,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Inherited `@method` and `@property` tags.** Virtual members declared via `@method` or `@property` on a parent class now appear on child classes. Previously only the declaring class itself surfaced these members.
 - **Class constant and enum case assignment resolution.** Assigning from a class constant (`$x = Foo::SOME_CONST`) or enum case (`$x = Status::Active`) now resolves the variable's type correctly for subsequent completion.
 - **Sequential assert narrowing.** Multiple `assert($x instanceof A); assert($x instanceof B);` statements now accumulate, showing members from both types. Previously only the last assertion's narrowing applied.
+- **`instanceof` narrowing no longer widens specific types.** `assert($zoo instanceof ZooBase)` after `$zoo = new Zoo()` (where `Zoo extends ZooBase`) no longer replaces the type with the less-specific parent. The narrower `Zoo` type is preserved because it already satisfies the check. Previously this produced false-positive "unknown member" warnings for `@property` and `@method` members declared on the child class.
 - **Arrow function parameter completion with incomplete expressions.** Typing `$foo->` inside an arrow function body (e.g. `fn(Foo $foo) => $foo->`) now resolves the parameter type even when the expression is incomplete. The parser recovery inserts a dummy token so the surrounding arrow function structure is recognized.