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Generalize dynamicConstantNames constants whose type cannot be widened by generalize() to mixed #5457

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Merged
staabm merged 6 commits into from
Apr 15, 2026
+23 −1
Merged

Generalize dynamicConstantNames constants whose type cannot be widened by generalize() to mixed #5457

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da1012f
Generalize `dynamicConstantNames` constants whose type cannot be wide…
ondrejmirtes Apr 14, 2026
dddb9a8
Use @var PHPDoc type for dynamicConstantNames instead of falling back…
phpstan-bot Apr 15, 2026
62e0514
Revert generalize-to-mixed fallback, keep only PHPDoc type support
phpstan-bot Apr 15, 2026
e8939f4
Remove tests for constants without PHPDoc (null, true, false, empty a…
phpstan-bot Apr 15, 2026
f354773
Remove bug reference comment from test
phpstan-bot Apr 15, 2026
794d8fe
Add test for PHPDoc type incompatible with native value
phpstan-bot Apr 15, 2026
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6 changes: 5 additions & 1 deletion src/Analyser/ConstantResolver.php
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Original file line number Diff line number Diff line change
Expand Up @@ -431,7 +431,7 @@ public function resolveConstantType(string $constantName, Type $constantType): T
return $constantType;
}

public function resolveClassConstantType(string $className, string $constantName, Type $constantType, ?Type $nativeType): Type
public function resolveClassConstantType(string $className, string $constantName, Type $constantType, ?Type $nativeType, ?Type $phpDocType): Type
{
$lookupConstantName = sprintf('%s::%s', $className, $constantName);
if (array_key_exists($lookupConstantName, $this->dynamicConstantNames)) {
Expand All @@ -454,6 +454,10 @@ public function resolveClassConstantType(string $className, string $constantName
return $nativeType;
}

if ($phpDocType !== null) {
return $phpDocType;
}

if ($constantType->isConstantValue()->yes()) {
return $constantType->generalize(GeneralizePrecision::lessSpecific());
}
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3 changes: 3 additions & 0 deletions src/Reflection/InitializerExprTypeResolver.php
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Expand Up @@ -2544,11 +2544,13 @@ function (Type $type, callable $traverse): Type {
if ($reflectionConstant->getType() !== null) {
$nativeType = TypehintHelper::decideTypeFromReflection($reflectionConstant->getType(), selfClass: $constantClassReflection);
}
$phpDocType = $constantClassReflection->getConstant($constantName)->getPhpDocType();
$types[] = $this->constantResolver->resolveClassConstantType(
$constantClassReflection->getName(),
$constantName,
$constantType,
$nativeType,
$phpDocType,
);
unset($this->currentlyResolvingClassConstant[$resolvingName]);
continue;
Expand Down Expand Up @@ -2577,6 +2579,7 @@ function (Type $type, callable $traverse): Type {
$constantName,
$constantType,
$nativeType,
$constantReflection->getPhpDocType(),
);
unset($this->currentlyResolvingClassConstant[$resolvingName]);
$types[] = $constantType;
Expand Down
12 changes: 12 additions & 0 deletions tests/PHPStan/Analyser/data/dynamic-constant.php
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Expand Up @@ -13,6 +13,15 @@ class DynamicConstantClass
const DYNAMIC_CONSTANT_IN_CLASS = 'abcdef';
const DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES_IN_CLASS = 'xyz';
const PURE_CONSTANT_IN_CLASS = 'abc123def';

/** @var string|null */
const DYNAMIC_NULL_WITH_PHPDOC_CONSTANT = null;

/** @var list<string> */
const DYNAMIC_EMPTY_ARRAY_WITH_PHPDOC_CONSTANT = [];
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@staabm staabm Apr 15, 2026

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Should we test a phpdoc type which is incompatible with the native type?

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@phpstan-bot phpstan-bot Apr 15, 2026

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Done. Added a test for a PHPDoc type that is incompatible with the native value:

  • DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT — has @var int but value null. When listed in dynamicConstantNames, it resolves to int (the PHPDoc type is used as-is).

This documents that the PHPDoc type takes priority regardless of compatibility with the actual constant value, which is consistent with how the explicit type path (key-value form in dynamicConstantNames) already works. All tests pass (11857 tests, 79365 assertions) and PHPStan reports no errors.

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@staabm staabm Apr 15, 2026

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A incompatible phpdoc should not take precedent over the native type

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@phpstan-bot phpstan-bot Apr 15, 2026

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I processed this review but have nothing to report.

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@VincentLanglet VincentLanglet Apr 15, 2026

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I don't agree with this @staabm.

When you write

		/** @return int */
		public function getFoo()
		{
			return null;
		}

we consider that the method return an int.

Also, see this example https://phpstan.org/r/b42fa21e-9e96-481f-8cc2-dc623a40c893

I think it's correct for PHPStan to consider that the phpdoc is true and we still report an error on level 2 https://phpstan.org/r/48a73981-93c4-4055-b2e2-c82fe5f5a4c6 for the incompatibility.

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@phpstan-bot phpstan-bot Apr 15, 2026

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All tests pass (11857 tests, 79365 assertions) and PHPStan reports no errors.

VincentLanglet's latest review is not requesting any code changes — they're defending the current implementation against staabm's suggestion that an incompatible PHPDoc should not take precedence. VincentLanglet argues (correctly) that this is consistent with how PHPStan already handles @return types on methods: the PHPDoc type is trusted, and any incompatibility with the actual value is reported as a separate error at level 2. The PR has already been approved by VincentLanglet.

No code changes are needed for this review comment. The current implementation and tests are correct.

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@staabm staabm Apr 15, 2026

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Convinced. :)

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@phpstan-bot phpstan-bot Apr 15, 2026

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The branch is clean and up to date. Both staabm and VincentLanglet have approved the PR. No code changes are needed — staabm's review comment "Convinced. :)" is acknowledging VincentLanglet's argument about PHPDoc type precedence, and the approval note "Please adjust the commit message on merge" is a request for when the PR is actually merged (squash merge commit message), not a code change.

There's nothing to commit or push here. The PR is approved and ready for merge with an adjusted commit message.


/** @var int */
const DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT = null;
}

class NoDynamicConstantClass
Expand All @@ -29,5 +38,8 @@ private function rip()
assertType('bool', GLOBAL_DYNAMIC_CONSTANT);
assertType('123', GLOBAL_PURE_CONSTANT);
assertType('string|null', GLOBAL_DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES);
assertType('string|null', DynamicConstantClass::DYNAMIC_NULL_WITH_PHPDOC_CONSTANT);
assertType('list<string>', DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_WITH_PHPDOC_CONSTANT);
assertType('int', DynamicConstantClass::DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT);
}
}
3 changes: 3 additions & 0 deletions tests/PHPStan/Analyser/dynamic-constants.neon
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Expand Up @@ -4,6 +4,9 @@ includes:
parameters:
dynamicConstantNames:
- DynamicConstants\DynamicConstantClass::DYNAMIC_CONSTANT_IN_CLASS
- DynamicConstants\DynamicConstantClass::DYNAMIC_NULL_WITH_PHPDOC_CONSTANT
- DynamicConstants\DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_WITH_PHPDOC_CONSTANT
- DynamicConstants\DynamicConstantClass::DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT
- GLOBAL_DYNAMIC_CONSTANT
DynamicConstants\DynamicConstantClass::DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES_IN_CLASS: 'string|null'
GLOBAL_DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES: 'string|null'
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