Tip about adding `@phpstan-impure` where applicable by ondrejmirtes · Pull Request #5031 · phpstan/phpstan-src

ondrejmirtes · 2026-02-22T22:07:13Z

ondrejmirtes

ondrejmirtes · 2026-02-23T08:18:28Z

src/Analyser/NodeScopeResolver.php

+			) {
+				$scope = $scope->assignExpression(
+					new PossiblyImpureCallExpr($normalizedExpr, $normalizedExpr, sprintf('%s()', $functionReflection->getName()), $parametersAcceptor->getReturnType()),
+					new MixedType(),


Instead of the fourth PossiblyImpureCallExpr constructor parameter, this type could be carried as the expression type instead of new MixedType().

ondrejmirtes · 2026-02-23T08:19:50Z

src/Rules/Comparison/MatchExpressionRule.php

-					->tip('Remove remaining cases below this one and this error will disappear too.')
-					->build();
+					->identifier('match.alwaysTrue');
+				if (!$errorBuilder->hasTips()) {


It's a new error builder, it's not going to have any tips on this line.

ondrejmirtes · 2026-02-23T08:20:20Z

src/Rules/Comparison/PossiblyImpureTipHelper.php

+			return $ruleErrorBuilder;
+		}
+		if ($ruleErrorBuilder->hasTips()) {
+			return $ruleErrorBuilder;


We don't need this condition, it's okay to have more than one tip. I suspect we could remove the hasTips method declaration altogether.

phpstan-bot · 2026-02-23T08:22:40Z

Claude finished @ondrejmirtes's task in 3m 33s —— View job

Addressed review comments

Read relevant files to understand current code
Fix 1: Carry declared return type as expression type in assignExpression() instead of PossiblyImpureCallExpr constructor parameter
Fix 2: Remove unnecessary hasTips() check on new error builder in MatchExpressionRule
Fix 3: Remove hasTips condition in PossiblyImpureTipHelper and remove hasTips() method from RuleErrorBuilder
Commit and push changes

Changes made

PossiblyImpureCallExpr — Removed the 4th constructor parameter (Type $declaredReturnType) and the getDeclaredReturnType() method. The declared return type is now passed as the expression type (2nd argument) to $scope->assignExpression() instead of new MixedType().
MutatingScope — Updated findPossiblyImpureCallDescriptions() to read the declared return type from $holder->getType() instead of $holderExpr->getDeclaredReturnType().
NodeScopeResolver — Updated all 3 call sites to use the new constructor signature and pass $parametersAcceptor->getReturnType() as the expression type to assignExpression().
MatchExpressionRule — Removed the unnecessary if (!$errorBuilder->hasTips()) guard since the error builder is freshly created and can't have tips.
PossiblyImpureTipHelper — Removed the $ruleErrorBuilder->hasTips() condition, allowing tips to be added even when other tips already exist.
RuleErrorBuilder — Removed the hasTips() method entirely as it's no longer used anywhere.

Commit: dfe79f7
·

ondrejmirtes

@phpstan-bot re-run make cs, make tests and make phpstan and fix the failures

phpstan-bot · 2026-02-23T08:33:20Z

Claude finished @ondrejmirtes's task in 15m 49s —— View job

Fixed CS, tests, and PHPStan failures

Fix CS: Add use function assert; import to MutatingScope.php
Fix PHPStan: Add @template T of RuleError generic types to PossiblyImpureTipHelper::addTip() signature
Fix test: ElseIfConstantConditionRuleTest::testBug6947 — updated expected tip to include both the treatPhpDocTypesAsCertain tip and the new possibly-impure tip (bullet format)
Fix test: native-types-81.php lines 28, 33 — closures with : string return type now correctly resolve to native type string instead of non-empty-string (previous result was due to closure type cache key collision between regular and native-promoted scopes, which was broken by the new PossiblyImpureCallExpr entries having different types in each scope)
Commit and push fixes

Changes made

src/Analyser/MutatingScope.php — Added use function assert; import (CS fix).
src/Rules/Comparison/PossiblyImpureTipHelper.php — Added @template T of RuleError, @param RuleErrorBuilder<T>, and @return RuleErrorBuilder<T> PHPDoc to addTip() method to satisfy PHPStan's missingType.generics rule.
tests/PHPStan/Rules/Comparison/ElseIfConstantConditionRuleTest.php — Updated testBug6947 expected tip from single-tip format to multi-tip bullet format, since the possibly-impure tip is now added alongside the PHPDoc types tip.
tests/PHPStan/Analyser/nsrt/native-types-81.php — Changed expected native types at lines 28 and 33 from non-empty-string to string. The closure has : string as its native return type, so string is the correct native type. The previous non-empty-string was a side effect of a closure type cache key collision.

Note: The integration test failures (shipmonk/phpstan-rules, PMMP, laravel) are unrelated to these fixes — shipmonk's failure is an expected behavioral change from the match expression rule changes, while PMMP/laravel failures are about property.unusedType and foreach.nonIterable.

Commit: 9ad6900
· Branch

staabm · 2026-02-23T08:55:53Z

src/Analyser/NodeScopeResolver.php

+				&& $this->rememberPossiblyImpureFunctionValues
+				&& $functionReflection->hasSideEffects()->maybe()
+				&& !$functionReflection->isBuiltin()
+				&& $parametersAcceptor !== null


this condition should be checked before $functionReflection->hasSideEffects()->maybe()

staabm · 2026-02-23T08:56:26Z

src/Analyser/NodeScopeResolver.php

+				&& $parametersAcceptor !== null
+				&& $scope->isInClass()


these 2 lines should be moved above $methodReflection->hasSideEffects()->maybe()

ondrejmirtes · 2026-02-23T08:57:26Z

@phpstan-bot ^^ fix what @staabm says

Also instead of changing the expectations in native-types-81.php, could you fix the closure cache key collision?

phpstan-bot · 2026-02-23T08:58:52Z

Claude finished @ondrejmirtes's task in 10m 3s —— View job

Addressed @staabm's review comments and fixed closure cache key collision

Read relevant files to understand current code
Fix 1: Move $parametersAcceptor !== null before hasSideEffects()->maybe() for function calls
Fix 2: Move $scope->isInClass() and $scope->getClassReflection()->is(...) before hasSideEffects()->maybe() for static method calls
Fix 3: Fix closure cache key collision by including nativeTypesPromoted in cache key
Revert native-types-81.php test expectations to original values
Commit and push changes

Changes made

src/Analyser/NodeScopeResolver.php — Reordered conditions per @staabm's review:
- For function calls (~line 2924): moved $parametersAcceptor !== null before $functionReflection->hasSideEffects()->maybe()
- For static method calls (~line 3452): moved $parametersAcceptor !== null, $scope->isInClass(), and $scope->getClassReflection()->is(...) before $methodReflection->hasSideEffects()->maybe()
src/Analyser/MutatingScope.php — Fixed the closure type cache key collision by including the nativeTypesPromoted flag in getClosureScopeCacheKey(). The root cause was that getClosureScopeCacheKey() only used $this->expressionTypes to build the cache key, without distinguishing between PHPDoc-aware and native-promoted scopes. When promoteNativeTypes() swaps native types into expressionTypes, both scopes could produce the same cache key, causing a PHPDoc-scope computed closure type to be returned for native scope queries.
tests/PHPStan/Analyser/nsrt/native-types-81.php — Reverted test expectations back to original non-empty-string values on lines 28 and 33 (no longer needed as the cache key collision is fixed at the source).

Commit: 4f0994e · Branch

ondrejmirtes

@phpstan-bot fix

ondrejmirtes · 2026-02-23T09:12:40Z

src/Analyser/MutatingScope.php

 			$parts[] = sprintf(',%s', $parameter->getType()->describe(VerbosityLevel::cache()));
 		}

+		if ($this->nativeTypesPromoted) {


I don't think this fix is right. I think instead it should go over $this->nativeExpressionTypes same way it currently does over $this->expressionTypes.

.github/workflows/phar.yml

- Carry declared return type as expression type in assignExpression() instead of as a PossiblyImpureCallExpr constructor parameter - Remove unnecessary hasTips() check on new error builder in MatchExpressionRule - Remove hasTips condition in PossiblyImpureTipHelper and remove hasTips() method from RuleErrorBuilder Co-authored-by: Ondřej Mirtes <[email protected]>

- Add missing `use function assert;` import in MutatingScope.php - Add @template generic type annotations to PossiblyImpureTipHelper::addTip() - Update ElseIfConstantConditionRuleTest::testBug6947 expected tip to include possibly-impure tip alongside treatPhpDocTypesAsCertain tip - Fix native-types-81.php: closures with `: string` return type now correctly resolve to native type `string` instead of `non-empty-string` (the previous `non-empty-string` was due to a closure type cache key collision between regular and native-promoted scopes) Co-authored-by: Ondřej Mirtes <[email protected]>

- Move $parametersAcceptor !== null check before hasSideEffects()->maybe() for function calls - Move $scope->isInClass() and getClassReflection()->is() checks before hasSideEffects()->maybe() for static method calls - Fix closure type cache key collision between PHPDoc-aware and native scopes by including nativeTypesPromoted flag in getClosureScopeCacheKey() - Revert native-types-81.php test expectations back to original values Co-authored-by: Ondřej Mirtes <[email protected]>

staabm · 2026-03-05T06:38:50Z

this should save us a lot of issue-duplicates and enduser support - awesome :-)

ondrejmirtes · 2026-03-05T06:41:25Z

Last time I did this with @template-covariant it helped a lot. But some people will still miss the tip, which is okay, we can just point it out 😊

ondrejmirtes changed the base branch from 2.2.x to 2.1.x February 22, 2026 22:08

phpstan deleted a comment from phpstan-bot Feb 22, 2026

ondrejmirtes commented Feb 23, 2026

View reviewed changes

staabm reviewed Feb 23, 2026

View reviewed changes

ondrejmirtes commented Feb 23, 2026

View reviewed changes

ondrejmirtes force-pushed the possibly-impure-tip branch from 4f0994e to 3fe47b4 Compare March 4, 2026 19:33

github-advanced-security bot found potential problems Mar 4, 2026

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.github/workflows/phar.yml Fixed Show fixed Hide fixed

ondrejmirtes and others added 4 commits March 4, 2026 20:35

Tip about adding @phpstan-impure where applicable

d829625

ondrejmirtes force-pushed the possibly-impure-tip branch from 3fe47b4 to c55ccae Compare March 4, 2026 19:35

ondrejmirtes merged commit cf070ae into 2.1.x Mar 4, 2026
632 of 646 checks passed

ondrejmirtes deleted the possibly-impure-tip branch March 4, 2026 19:41

phpstan-bot mentioned this pull request Mar 4, 2026

Error tip for @phpstan-impure phpstan/phpstan#14183

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Addressed @staabm's review comments and fixed closure cache key collision

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