fix type for collection->whereNotNull (#1332)

extension.neon

@@ -277,6 +277,10 @@ services:
         class: NunoMaduro\Larastan\ReturnTypes\CollectionFilterDynamicReturnTypeExtension
         tags:
             - phpstan.broker.dynamicMethodReturnTypeExtension
+    -
+        class: NunoMaduro\Larastan\ReturnTypes\CollectionWhereNotNullDynamicReturnTypeExtension
+        tags:
+            - phpstan.broker.dynamicMethodReturnTypeExtension
 
     -
         class: NunoMaduro\Larastan\ReturnTypes\CollectionGenericStaticMethodDynamicMethodReturnTypeExtension

src/ReturnTypes/CollectionWhereNotNullDynamicReturnTypeExtension.php

@@ -0,0 +1,51 @@
+<?php
+
+declare(strict_types=1);
+
+namespace NunoMaduro\Larastan\ReturnTypes;
+
+use Illuminate\Support\Enumerable;
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\Generic\GenericObjectType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+
+class CollectionWhereNotNullDynamicReturnTypeExtension implements DynamicMethodReturnTypeExtension
+{
+    public function getClass(): string
+    {
+        return Enumerable::class;
+    }
+
+    public function isMethodSupported(MethodReflection $methodReflection): bool
+    {
+        return $methodReflection->getName() === 'whereNotNull';
+    }
+
+    public function getTypeFromMethodCall(
+        MethodReflection $methodReflection,
+        MethodCall $methodCall,
+        Scope $scope
+    ): Type {
+        $calledOnType = $scope->getType($methodCall->var);
+
+        if (! $calledOnType instanceof \PHPStan\Type\Generic\GenericObjectType) {
+            return ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+        }
+
+        $keyType = $methodReflection->getDeclaringClass()->getActiveTemplateTypeMap()->getType('TKey');
+        $valueType = $methodReflection->getDeclaringClass()->getActiveTemplateTypeMap()->getType('TValue');
+
+        if ($keyType === null || $valueType === null) {
+            return ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+        }
+
+        $nonFalseyTypes = TypeCombinator::removeNull($valueType);
+
+        return new GenericObjectType($calledOnType->getClassName(), [$keyType, $nonFalseyTypes]);
+    }
+}

tests/Type/CollectionDynamicReturnTypeExtensionTest.php

@@ -12,6 +12,7 @@ class CollectionDynamicReturnTypeExtensionTest extends \PHPStan\Testing\TypeInfe
     public function dataFileAsserts(): iterable
     {
         yield from $this->gatherAssertTypes(__DIR__.'/data/collection-filter.php');
+        yield from $this->gatherAssertTypes(__DIR__.'/data/collection-where-not-null.php');
 
         if (PHP_VERSION_ID >= 70400) {
             yield from $this->gatherAssertTypes(__DIR__.'/data/collection-filter-arrow-function.php');

tests/Type/data/collection-where-not-null.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace CollectionWhereNotNull;
+
+use Illuminate\Database\Eloquent\Collection as EloquentCollection;
+use function PHPStan\Testing\assertType;
+
+assertType('Illuminate\Support\Collection<int, int|string>', collect([1, 2, null, '', 'hello'])->whereNotNull());
+assertType('Illuminate\Support\Collection<int, int|string>', collect([1, 2, null, '', 'hello'])->whereNotNull());
+
+/** @param \Illuminate\Database\Eloquent\Collection<int, \App\User> $foo */
+function objectAndParam(EloquentCollection $foo): void
+{
+    assertType("Illuminate\Database\Eloquent\Collection<int, App\User>", $foo->whereNotNull('blocked'));
+}
+
+/** @param \Illuminate\Database\Eloquent\Collection<int, ?\App\User> $foo */
+function objectOrNullAndParam(EloquentCollection $foo): void
+{
+    assertType("Illuminate\Database\Eloquent\Collection<int, App\User>", $foo->whereNotNull('blocked'));
+}
+
+/** @param \Illuminate\Database\Eloquent\Collection<int, ?\App\User> $foo */
+function objectOrNull(EloquentCollection $foo): void
+{
+    assertType("Illuminate\Database\Eloquent\Collection<int, App\User>", $foo->whereNotNull());
+}