is_resource: adjust type specification for truthy context only

stubs/typeCheckingFunctions.stub

@@ -105,7 +105,7 @@ function is_long(mixed $value): bool
 }
 
 /**
- * @phpstan-assert-if-true resource $value
+ * @phpstan-assert-if-true =resource $value
  * @return bool
  */
 function is_resource(mixed $value): bool

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -143,6 +143,8 @@ public function dataFileAsserts(): iterable
 			yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Functions/data/bug-7823.php');
 		}
 
+		yield from $this->gatherAssertTypes(__DIR__ . '/../Analyser/data/is-resource-specified.php');
+
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Arrays/data/bug-7954.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Comparison/data/docblock-assert-equality.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Properties/data/bug-7839.php');

tests/PHPStan/Analyser/data/is-resource-specified.php

@@ -0,0 +1,11 @@
+<?php
+
+use function PHPStan\Testing\assertType;
+
+$resource = fopen('php://memory', 'r');
+
+if (is_resource($resource)) {
+	assertType('resource', $resource);
+} else {
+	assertType('resource|false', $resource); // can be closed resource
+}

tests/PHPStan/Analyser/data/specifiedTypesUsingIsFunctions.php

@@ -41,7 +41,8 @@ function () {
 		throw new \Exception();
 	}
 
-	if (!is_resource($resource)) {
+	$resource = fopen('php://memory', 'r');
+	if ($resource === false) {
 		throw new \Exception();
 	}