Suppress `property.nonObject` and `method.nonObject` errors when `property_exists()`/`method_exists()` guard is present by phpstan-bot · Pull Request #5729 · phpstan/phpstan-src

phpstan-bot · 2026-05-21T08:44:38Z

Summary

When property_exists($mixed, 'prop') is used as a guard and then $mixed->prop is accessed, PHPStan incorrectly reported "Cannot access property $prop on class-string|object." This happened because property_exists() narrows mixed to class-string|(object&hasProperty(prop)), and the class-string member of the union causes canAccessProperties() to return maybe(), triggering the property.nonObject error. The same issue existed for method_exists() with canCallMethods().

PR #5544 added property_exists() guard handling in AccessStaticPropertiesCheck but missed the instance property access case in AccessPropertiesCheck, and also missed the analogous method_exists() case in MethodCallCheck.

Changes

src/Type/Php/PropertyExistsTypeSpecifyingExtension.php: In the !isObject()->yes() branch, also store the property_exists() call result as true (via createFuncCallSpec) in addition to narrowing the argument type. This enables synthetic call checks to find the stored specification.
src/Type/Php/MethodExistsTypeSpecifyingExtension.php: Same fix for the generic (non-string) branch.
src/Rules/Properties/AccessPropertiesCheck.php: Add a synthetic property_exists() call check before the canAccessProperties() error (line 122). Also extend the existing property_exists() guard check for undefined properties (previously only handled Expr names) to also handle Identifier names by constructing a String_ node.
src/Rules/Methods/MethodCallCheck.php: Add a synthetic method_exists() call check before the canCallMethods() error. Also extend the existing method_exists() guard check for undefined methods to handle Identifier names.
tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php: Remove the assertion for the now-suppressed false positive "Cannot call method foo() on class-string|object."

Analogous cases probed

Static property access (AccessStaticPropertiesCheck): Already fixed by PR Suppress undefined static property error when property_exists() guard is present #5544. Verified no regression.
Property access in assignment (AccessPropertiesInAssignRule): Uses AccessPropertiesCheck, automatically covered. Added dedicated test.
Object-type branch in type specifiers: When the first argument IS already an object, the narrowed type is object&hasProperty(prop) (no class-string union), so canAccessProperties() returns yes() and no false positive occurs. No fix needed.
Static method calls (CallStaticMethodsRule): Not affected — static method calls on class-strings are valid PHP and handled differently.

Root cause

Two independent issues combined to produce the false positive:

PropertyExistsTypeSpecifyingExtension (and MethodExistsTypeSpecifyingExtension) narrowed the argument type for mixed to class-string|(object&hasProperty(…)) but did NOT store the function call result as true. This meant synthetic property_exists()/method_exists() call checks in rule code could not detect the guard.
AccessPropertiesCheck (and MethodCallCheck) did not check for property_exists()/method_exists() guards before reporting the canAccessProperties()/canCallMethods() error. The existing guard checks only applied to the "undefined property/method" errors and only for dynamic (Expr) names.

Test

tests/PHPStan/Rules/Properties/data/bug-14667.php — Tests instance property access after property_exists() with mixed, explicit mixed, object|string, object, $this, self, and chained conditions.
tests/PHPStan/Rules/Properties/data/bug-14667-assign.php — Tests property assignment after property_exists() with mixed, explicit mixed, and object|string.
tests/PHPStan/Analyser/nsrt/bug-14667.php — Verifies type narrowing produces class-string|(object&hasProperty(prop)) for mixed.
tests/PHPStan/Rules/Methods/data/bug-14667.php — Tests method call after method_exists() with mixed, explicit mixed, object|string, object, and chained conditions.

Fixes phpstan/phpstan#14667

…perty_exists()`/`method_exists()` guard is present - Add synthetic `property_exists()` call check in `AccessPropertiesCheck` before the `canAccessProperties()` error, so `mixed` narrowed to `class-string|(object&hasProperty(…))` no longer triggers a false positive - Extend the existing `property_exists()` guard check for undefined properties to also handle `Identifier` property names (previously only handled `Expr`) - Apply the same fix to `MethodCallCheck` for `method_exists()` guards - Update `PropertyExistsTypeSpecifyingExtension` and `MethodExistsTypeSpecifyingExtension` to also store the function call result as `true` in the `!isObject()->yes()` branch, so synthetic call checks can find the stored specification - Remove the now-incorrect assertion in `CallMethodsRuleTest` that expected the false positive "Cannot call method foo() on class-string|object"

staabm

newly added tests using mixed need a // lint >= 8.0 comment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

phpstan-bot · 2026-05-23T06:21:23Z

Done. Added // lint >= 8.0 to all four bug-14667 test files that use mixed type hints, replacing the declare(strict_types = 1) line. Tests and static analysis both pass. Pushed to the PR branch.

staabm · 2026-05-23T06:25:55Z

 			$context,
 			$scope,
-		);
+		)->unionWith($this->createFuncCallSpec($node, $context, $scope));


why do we not need the same fix at the return in line 68 of this file?

Pushed. Here's a summary of the changes and the answer to staabm's review question:

Why line 68 doesn't need ->unionWith($this->createFuncCallSpec(...)):

The return at line 68 handles the case where the first argument to method_exists() is already a class-string. In this branch, the type narrows to class-string&hasMethod(foo), where canCallMethods() returns No (since ClassStringType returns No and HasMethodType returns Maybe, and lazyMaxMin without any Yes takes the minimum). Instance method calls on class-strings are genuinely invalid PHP — method_exists($className, 'foo') only validates the class has the method, not that $className->foo() is valid. NOT storing the func call spec is intentional so the synthetic check in MethodCallCheck doesn't suppress this legitimate error.

The !isObject()->yes() branch (line 88-99) is different: mixed narrows to class-string|(object&hasProperty(...)), and the object member makes instance access valid. There, the createFuncCallSpec is needed to suppress the false positive caused by the class-string member making canCallMethods() return Maybe.

Bug found and fixed: Investigating this question revealed that PropertyExistsTypeSpecifyingExtension stores the func call spec for ALL string types (including class-strings), which caused the new synthetic check in AccessPropertiesCheck to incorrectly suppress the property.nonObject error for class-strings. Fixed by adding a !$type->canAccessProperties()->no() guard to the synthetic check.

…erties The synthetic `property_exists()` guard check must also verify that instance property access is valid for the type. For class-strings, `property_exists()` checks if the CLASS has the property, but instance property access (`$x->prop`) on a string is invalid PHP regardless of the guard. Added class-string test cases for both property and method access to document that `method.nonObject` and `property.nonObject` errors are correctly reported when the type is a class-string, even inside a `method_exists()`/`property_exists()` guard. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

staabm · 2026-05-23T07:05:58Z

 				$context,
 				$scope,
-			);
+			)->unionWith($this->createFuncCallSpec($node, $context, $scope));


why do we not need the same fix at the return in line 107 of this file?

staabm force-pushed the create-pull-request/patch-jmikw0u branch from e751452 to f407edc Compare May 23, 2026 05:58

staabm requested changes May 23, 2026

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Add // lint >= 8.0 comment to bug-14667 test files using mixed type

92fedf0

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

staabm reviewed May 23, 2026

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Suppress `property.nonObject` and `method.nonObject` errors when `property_exists()`/`method_exists()` guard is present#5729

Suppress `property.nonObject` and `method.nonObject` errors when `property_exists()`/`method_exists()` guard is present#5729
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phpstan:2.1.xfrom
phpstan-bot:create-pull-request/patch-jmikw0u

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phpstan-bot commented May 21, 2026

Summary

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Root cause

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phpstan-bot commented May 23, 2026

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