value-of<T> over a template parameterkey-of case: a generic function
takes T of array and returns one of its values, so value-of<T> is
evaluated at the call site from the inferred T. Without the evaluation the
return is mixed, which satisfies everything silently — so the probe is a
parameter the projected value type cannot satisfy, and the precision probe
is a literal union only an unwidened T can satisfy.
References:
- PHPStan phpdoc-types: value-of over template parameters
- Psalm utility_types.md: value-of with templates| Analyzer | Version | Result | Diagnostics |
|---|---|---|---|
| phan | 6.0.7Phan 6.0.7 php-ast version 1.1.3 PHP version used to run Phan: 8.5.9 | Enforced | phpdoc_advanced_fallback_value_of_template.php:62: Argument 1 ($value) is firstValue(['low'=>1,'high'=>10]) of type int (value: 1)|int (value: 10) but \Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString() takes string defined at /Users/megurine/repo/php/php-typing-conformance/conformance/tests/phpdoc_advanced_fallback_value_of_template.php:43 [PhanTypeMismatchArgument]
|
| phpstan | 2.2.8PHPStan - PHP Static Analysis Tool 2.2.8 | Enforced reported Lv.5+ | phpdoc_advanced_fallback_value_of_template.php:62: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString expects string, int given. [identifier=argument.type] [reported-from-level=5] With strict-rulesphpdoc_advanced_fallback_value_of_template.php:62: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString expects string, int given. [identifier=argument.type]
|
| psalm | 6.16.1Psalm 6.16.1@f1f5de594dc76faf8784e02d3dc4716c91c6f6ac next: 7.0.0-beta19 |
Enforced | phpdoc_advanced_fallback_value_of_template.php:29: Unable to determine the type that $value is being assigned to [MixedAssignment] phpdoc_advanced_fallback_value_of_template.php:33: Could not infer a return type [MixedReturnStatement] phpdoc_advanced_fallback_value_of_template.php:62: Argument 1 of Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString expects string, but 1|10 provided [InvalidScalarArgument]
Expectation diffLine 33: Expected valid value to be accepted, got ["Could not infer a return type [MixedReturnStatement]"] Line 29: Unexpected errors ["Unable to determine the type that $value is being assigned to [MixedAssignment]"] |
| mago | 1.46.0mago 1.46.0 | Enforced ⚠ 1 false positive | phpdoc_advanced_fallback_value_of_template.php:29: Assigning `mixed` type to a variable may lead to unexpected behavior. [mixed-assignment] phpdoc_advanced_fallback_value_of_template.php:62: Invalid argument type for argument #1 of `Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString`: expected `string`, but found `int(1)|int(10)`. [invalid-argument]
Expectation diffLine 29: Unexpected errors ["Assigning `mixed` type to a variable may lead to unexpected behavior. [mixed-assignment]"] |
| mir | 0.70.1mir 0.70.1 | Not enforced | No diagnostics reported.
|
| phpantom | 0.9.0phpantom_lsp 0.9.0 | Incidental (1/1) | phpdoc_advanced_fallback_value_of_template.php:55: Argument 1 ($value) expects int, got value-of<array> [type_mismatch_argument] phpdoc_advanced_fallback_value_of_template.php:59: Argument 1 ($level) expects 1|10, got value-of<array> [type_mismatch_argument] phpdoc_advanced_fallback_value_of_template.php:62: Argument 1 ($value) expects string, got value-of<array> [type_mismatch_argument]
Expectation diffLine 55: Expected valid value to be accepted, got ["Argument 1 ($value) expects int, got value-of<array> [type_mismatch_argument]"] Line 59: Expected valid value to be accepted, got ["Argument 1 ($level) expects 1|10, got value-of<array> [type_mismatch_argument]"] |
| intelephense | 1.18.5intelephense 1.18.5 | Enforced | phpdoc_advanced_fallback_value_of_template.php:62: Expected type 'string'. Found 'int|int'. [P1006]
|
| phpy | 0.2.0phpy 0.2.0 | Not enforced | No diagnostics reported.
|
| qodana | 262.8665.325Qodana 262.8665.325 | Incidental (0/1) ⚠ 1 false positive | phpdoc_advanced_fallback_value_of_template.php:48: Argument type does not match the declared [PhpDocSignatureInspection]
Expectation diffLine 48: Unexpected errors ["Argument type does not match the declared [PhpDocSignatureInspection]"] |
| noverify | 0.5.5NoVerify, version 0.5.5: built on: 2025.04.22 14:36:46 OS: r-kuchinskas arm64 Commit: 4774b82f8adc53fbef38f95e97af4b953b4d1529 | Unrecognized ⚠ 1 false positive | phpdoc_advanced_fallback_value_of_template.php:27: param $items miss matched with phpdoc type <<T>> [funcParamTypeMissMatch] phpdoc_advanced_fallback_value_of_template.php:50: param $level miss matched with phpdoc type <<1|10>> [funcParamTypeMissMatch]
Expectation diffLine 50: Unexpected errors ["param $level miss matched with phpdoc type <<1|10>> [funcParamTypeMissMatch]"] |
| steins | 0.1.5steins 0.1.5 (2026-08-12 revision 39b4cc1) | Widened to mixed | No diagnostics reported.
Notes: Same project_value_of catch-all as key-of<T>: a @template T type variable lowers to ContractTy::Class("t"), not a shape-bearing arm, so value-of<T> floors to Opaque and the value type is never narrowed from the template parameter. |
| phpstan-strict | 2.2.8PHPStan - PHP Static Analysis Tool 2.2.8 | Enforced | phpdoc_advanced_fallback_value_of_template.php:62: Parameter #1 $value of function Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString expects string, int given. [identifier=argument.type]
|
| psalm-next | 7.0.0-beta19Psalm 7.0.0-beta19@7e751c06a756fa64dc4c759c09fe4a173afcb433 | Enforced ⚠ 1 false positive | phpdoc_advanced_fallback_value_of_template.php:29: Unable to determine the type that $value is being assigned to [MixedAssignment] phpdoc_advanced_fallback_value_of_template.php:33: Could not infer a return type [MixedReturnStatement] phpdoc_advanced_fallback_value_of_template.php:62: Argument 1 of Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate\acceptsString expects string, but 1|10 provided [InvalidScalarArgument]
Expectation diffLine 33: Expected valid value to be accepted, got ["Could not infer a return type [MixedReturnStatement]"] Line 29: Unexpected errors ["Unable to determine the type that $value is being assigned to [MixedAssignment]"] |
<?php
declare(strict_types=1);
namespace Conformance\Tests\PhpdocAdvancedFallbackValueOfTemplate;
/**
* `value-of<T>` over a template parameter
*
* The value-side mirror of the template `key-of` case: a generic function
* takes `T of array` and returns one of its values, so `value-of<T>` is
* evaluated at the call site from the inferred T. Without the evaluation the
* return is `mixed`, which satisfies everything silently — so the probe is a
* parameter the projected value type cannot satisfy, and the precision probe
* is a literal union only an unwidened T can satisfy.
*
* References:
* - PHPStan phpdoc-types: value-of over template parameters
* - Psalm utility_types.md: value-of with templates
*/
/**
* @template T of array<array-key, mixed>
* @param T $items
* @return value-of<T>
*/
function firstValue(array $items) // T: value-of<T>
{
foreach ($items as $value) {
// A tool can evaluate the projection at call sites and still be unable
// to prove this body produces value-of<T>; that limitation surfaces as
// a false positive here, not as an expectation of the test.
return $value; // V
}
throw new \InvalidArgumentException('empty array');
}
function acceptsInt(int $value): void
{
}
function acceptsString(string $value): void
{
}
/**
* @param 1|10 $level
*/
function acceptsLevel(int $level): void
{
}
// With int values, the returned value is an int.
acceptsInt(firstValue(['low' => 1, 'high' => 10])); // V
// More precisely, it is the union of this argument's values: a tool that
// infers T but widens the values to `int` reports a false positive here.
acceptsLevel(firstValue(['low' => 1, 'high' => 10])); // V
// A value of this argument is never a string.
acceptsString(firstValue(['low' => 1, 'high' => 10])); // E?: the values of this argument are ints