QueryResultTypeWalker: precise type inferring

Author: janedbal

Diff for: README.md

@@ -152,6 +152,12 @@ $query->getOneOrNullResult(Query::HYDRATE_OBJECT); // User
 
 This is due to the design of the `Query` class preventing from determining the hydration mode used by these functions unless it is specified explicitly during the call.
 
+### Expression types inferring
+
+Whether `MAX(e.id)` is fetched as `string` or `int` highly [depends on drivers, their setup and PHP version](https://github.com/janedbal/php-database-drivers-fetch-test).
+This extension copies the logic from linked analysis, autodetects your setup and provides accurate results for `pdo_mysql`, `mysqli`, `pdo_sqlite`, `sqlite3`, `pdo_pgsql` and `pgsql`.
+Any other driver will result in union with stringified version, e.g. `numeric-string|int`.
+
 ### Problematic approaches
 
 Not every QueryBuilder can be statically analysed, here are few advices to maximize type inferring:

Diff for: phpstan.neon

@@ -49,3 +49,11 @@ parameters:
 				- '#^Cannot call method getWrappedResourceHandle\(\) on class\-string\|object\.$#'
 			path: tests/Platform/QueryResultTypeWalkerFetchTypeMatrixTest.php
 			reportUnmatched: false
+		-
+			message: '#^Call to function method_exists\(\) with Doctrine\\DBAL\\Connection and ''getNativeConnection'' will always evaluate to true\.$#' # needed for older DBAL versions
+			path: src/Type/Doctrine/Query/QueryResultTypeWalker.php
+		-
+			messages: # needed for older DBAL versions (fails only on PHP 7.3)
+				- '#^Class Doctrine\\DBAL\\Driver\\PgSQL\\Driver not found\.$#'
+				- '#^Class Doctrine\\DBAL\\Driver\\SQLite3\\Driver not found\.$#'
+			path: src/Type/Doctrine/Query/QueryResultTypeWalker.php