Just three weeks after PHPStan 2.1.40, this release fixes whopping 87 issues! 🎉

Major new features 🚀

• Main documentation page on phpstan.org is now a dashboard linking the most common problem-solving pages
• All error identifiers reported by PHPStan now have comprehensive documentation.
  • Each page shows a code example reporting the error
  • Followed by an explanation why is it reported
  • And showing one or more ways how to fix it
  • Several awesome examples: ternary.resultUnused, property.onlyRead, return.void
• Documentation about custom extensions now documents all previously-undocumented extension types

Improvements 🔧

• Add option reportIgnoresWithoutComments to report ignores without comments (#5032), Option to disable phpstan-ignore-line and phpstan-ignore-next-line #11340, thanks @calebdw!
  • This disables @phpstan-ignore without comments in parentheses
  • It also disables @phpstan-ignore-line and @phpstan-ignore-next-line completely
  • See: https://phpstan.org/config-reference#reportignoreswithoutcomments
• Tuned how many CPU cores PHPStan uses by default:
  • Diminishing returns beyond 8 CPU cores (phpstan/phpstan-src@23928d9)
  • Different method to compute CPU cores to use (phpstan/phpstan-src@89f1382), Test the new CpuCoreCounter API #11410, Determine actual resources on Kubernetes #7479
  • See docs: https://phpstan.org/config-reference#parallel-processing
• Solve various HTTP proxy and custom root CA errors when downloading PHPStan Pro
  • Use plain old Guzzle and system CA (phpstan/phpstan-src@a3af1cd), Pro-User behind a http-proxy #12486, [Pro] Allow installation on corporate networks (HTTP Proxy) #11244
• Report invalid printf placeholder (#4478), Warning: printf(): Too few arguments #1889, Missing sprintf error #8547, thanks @VincentLanglet!
• Respect rule level in ParameterCastableToNumberRule (#4873), thanks @VincentLanglet!
• Report non existent offset on non empty array (#4399), Union of optional keyed arrays doesn't mean both keys exists at same time #7143, thanks @VincentLanglet!
• TableErrorFormatter - always show identifier, even if non-ignorable (phpstan/phpstan-src@d64ce37)
• Show instructions to coding agent about how to handle errors (phpstan/phpstan-src@bb42c9f)
• Tip about adding @phpstan-impure where applicable (#5031), Error tip for @phpstan-impure #14183
• Report error when trying to instantiate a trait with new (#5182)

Bugfixes 🐛

• Fix createConditionalExpressions (phpstan/phpstan-src@3993c52), incorrect type narrowing with combination of two dependent variables #14191
• Differentiate signaturePrototype and inheritancePrototype (#4945), Method Child::__construct() overrides method Parent::__construct() but misses parameter #X #11067, Incorrect non-ignorable "parameter is not contravariant" errors for constructors in subclasses where __construct() is in an interface #12830, Should this 'Parameter of method SubClass::__construct() is not contravariant with parameter of method ParentClass::__construct()' error be unignorable? #12272, thanks @VincentLanglet!
• Avoid false error on is_subclass_of (#4472), PHPStan incorrectly narrows type of object after an instanceof check #13713, thanks @VincentLanglet!
• Fix execution branch confusion (#5058), Execution branch confusion #5051, Says string is mixed after checked and exception thrown #9647, thanks @staabm and @VincentLanglet!
• Fix spurious error in specific combination of namespace blocks and function declaration with phpdoc type annotation (#5077), spurious error in specific combination of namespace blocks and function declaration with phpdoc type annotation #13831, thanks @VincentLanglet!
• Fix SimplXmlElement and GMP casts (#5020), SimpleXmlElement is valid in intval #14136, thanks @VincentLanglet!
• Fix: False match.unhandled on array with multiple booleans (#5107), False match.unhandled on array with multiple booleans #13029, thanks @VincentLanglet and @staabm!
• Fix seemingly same type reports as invalid/incompatible. (#5094), Seemingly same type reports as invalid/incompatible. #13440, Template declaration with a default type sometimes gives assign.propertyType #12688, thanks @VincentLanglet!
• Fix: $this(Type~Subtracted) does not work on conditional return type as Type~Subtracted (#5104), $this(Type~Subtracted) does not work on conditional return type as Type~Subtracted #12244, thanks @staabm and @VincentLanglet!
• Fix: False positive with array_key_exists and union types (#5114), False positive with array_key_exists and union types #13526, thanks @staabm!
• Fix: Nonexistent offset detection on lists if ($index < count($array)) (#5090), Nonexistent offset detection on lists (if ($index < count($array))) #13770, thanks @VincentLanglet and @staabm!
• Fix: Defining Array Constants in PHP Traits Causes Errors When Using Class Constants as Keys or Values (#5115), Defining Array Constants in PHP Traits Causes Errors When Using Class Constants as Keys or Values #11351, Constant in trait analysis incorrect #11088, thanks @VincentLanglet!
• Fix: Generator suspension points should be treated as infinite loop break points (#5057), Generator suspension points should be treated as infinite loop break points #6189, Generator::send in infinite loop #10054, thanks @VincentLanglet and @staabm!
• Fix: BenevolentUnionType with generics produce confusing errors (#5070), BenevolentUnionType with generics produce confusing errors #9732, thanks @staabm and @VincentLanglet!
• Fix while-true-if-break: Variable might not be defined (#5118), while-true-if-break: Variable might not be defined #11545, while-true-try: Variable might not be defined #10245, Always taken exit path in loop is not detected #11984, False positive - variable might not be define when while(true) and try-catch is involved #5477, Only one possible (always entered) loop exit path is not detected #5919, False positive undefined variable when break-ing out of infinite loop. #9023, thanks @VincentLanglet!
• Fix: False positive staticMethod.impossibleType (#5121), False positive staticMethod.impossibleType #13566, Conditional type in @param - Call to method Xxx::xxx() with true will always evaluate to true. #10337, thanks @staabm and @VincentLanglet!
• Fix: Variable $ in empty() always exists and is not falsy. (#5124), Variable $ in empty() always exists and is not falsy. #14223, thanks @VincentLanglet and @staabm!
• Fix: Incorrect 'Variable $value might not be defined.' (#5125), Incorrect 'Variable $value might not be defined.' #14117, Wrong error message when use variable from other code blocks #8430, False positive "variable might not be defined" inside for loop #10657, thanks @VincentLanglet and @staabm!
• Fix: Assignment inside match statement no longer recognized (#5120), Assignment inside match statement no longer recognized #13981, thanks @staabm!
• Fix: Incorrect: Class referenced with incorrect case, (#5064), Incorrect: Class referenced with incorrect case, #14205, thanks @staabm and @VincentLanglet!
• Fix offset might not exist false-positives (#5137), Iterating over all except the last element of a list<T> reports that the offset might not exist #14234, Nonexistent offset detection on lists with count() -1 #14215, thanks @VincentLanglet!
• Consider ArrayAccess side effects for dead catch analysis (#5117), Wrong "dead catch" error, side effects of ArrayAccess not considered #11427, thanks @VincentLanglet!
• Fix: false positive on in_array(...) check with impure second argument (#5141), false positive on in_array(...) check with impure second argument #13799, thanks @VincentLanglet and @staabm!
• Fix: Spreading an associative array into a generic function/method call may restrict optional arguments to their default values. (#5079), Spreading an associative array into a generic function/method call may restrict optional arguments to their default values. #12363, Cannot infer type when unpacking array as args into a function with conditional generics #8257, Conditional return type not working as expected when method passed arguments from spread #7369, thanks @VincentLanglet and @staabm!
• Fix: array_splice resets int keys of the input array (#5139), array_splice resets int keys of the input array #14037, thanks @staabm and @VincentLanglet!
• Fix: iterable is equal to array|Traversable (#5144), iterable is equal to array|Traversable #13247, thanks @staabm and @VincentLanglet!
• Fix: Reassignment of $this is not an error (#5146), Reassignment of $this is not an error #3585, thanks @staabm!
• Fix spurious error nullCoalesce.offset (#5145), spurious error nullCoalesce.offset #13921, thanks @staabm!
• Support chop() function as an alias of rtrim() (#5157), thanks @zonuexe!
• Fix: Assignment in a key of array destructuring is ignored (#5164), Assignment in a key of array destructuring is ignored #14019, thanks @staabm and @VincentLanglet!
• Support sizeof() alias in addition to count() (#5179), thanks @staabm!
• TableErrorFormatter: Limit number of errors (#5136), thanks @staabm!
• Fix: list lost after overwriting last element (#5169), list lost after overwriting last element #14245, thanks @VincentLanglet and @staabm!
• Improve intersection of ConstantArray and AccessoryIsList (#5067), thanks @VincentLanglet!
• Fix list description with offset required (#5212), thanks @VincentLanglet!
• Fix: crash on first class callable as conditional do while (#5194), crash on first class callable as conditional do while #12246, thanks @staabm and @VincentLanglet!
• Fix maybe-undefined variable regression in loops with unrelated assignments (#5208), Regression: maybe undefined variable #14269, Interesting effect of (I suppose) dependent variables #4284
• Fix regression: regex matches after checking non-empty array (#5209), Regression: regex matches after checking non-empty array #14270, preg_match param-out is a list, and phpstan kind of agrees, but not enough #12397, thanks @staabm!
• Propagate @phpstan-assert-* annotations to First-class callables (Closures) and string callables (#5201), Propagate @phpstan-assert-* annotations to First-class callables (Closures) and string callables #14249, thanks @staabm!
• Fix: non-negative-int evaluated to int (#5176), non-negative-int evaluated to int #12163, thanks @staabm and @VincentLanglet!
• Fix: Error „should return static(Test) but returns Test“ (#5190), Error „should return static(Test) but returns Test“ #4860, thanks @VincentLanglet!
• Fix: PHPDoc types from overridden function are not included in trait typeinfo when aliased (#5204), PHPDoc types from overridden function are not included in trait typeinfo when aliased #9733, thanks @VincentLanglet!
• Fix: Index for loop inference should only work in lists (#5215), Index for loop inference should only work in lists #13773, thanks @VincentLanglet!
• Fix: Return in finally does not always overwrite return in try-catch (#5163), Return in finally does not always overwrite return in try-catch #6670, Exit points must behave consistently #12215, False positive in OverwrittenExitPointByFinallyRule for caught/handled exceptions #11906, False positive about overwritten throw/return when a finally conditionally exits #7665 thanks @VincentLanglet and @staabm!
• Fix: "Variable might not be defined" false positive (#5216), "Variable might not be defined" false positive #14274, thanks @staabm!
• Fix: should return array{a: string, b: int, c: int} but returns non-empty-array<'a'|'b'|'c', int|string> (#5193), should return array{a: string, b: int, c: int} but returns non-empty-array<'a'|'b'|'c', int|string> #12665, PHPStan thinks my array keys might be overwritten? #14080, Incorrect "Call to sprintf contains ... placeholders, ... value given." when format string is read from array which had its keys dynamically assigned #8774, Array shape is oversimplified when defined with a variable key #9907, array shape is not honored when combined with string literals #11006, thanks @VincentLanglet!
• Avoid duplicated InternalThrowPoint when simulating ArrayAccess calls (#5222), thanks @VincentLanglet!
• Fix: type narrowing on non-empty-list array shape (#5227), Regression: type narrowing on non-empty-list array shape #14297
• Fix: false positive “Match expression does not handle remaining value: int<...>” for match (count(...)) { ...} (#5228), false positive “Match expression does not handle remaining value: int<...>” for match (count(...)) { ...} #12790
• Fix count()-based type narrowing on unions of constant array shapes (#5229), Unioned array shapes are no longer disjunctive #14301, Wrongly assumed undefined variable since 1.11.10 #11488

Function signature fixes 🤖

• Update PDOStatement stub (#5132), Incorrect @var PDOStatement<int,string> contains unresolvable type #14206, PDOStatement can return objects but phpstan thinks its an array #9120, thanks @VincentLanglet!
• Add get_headers stub (#5140), Refine get_headers return type #13835, thanks @VincentLanglet!

Performance 🏎️

• Faster MutatingScope->getNodeKey() (#5014), thanks @staabm!
• Faster IsSuperTypeOfResult creation (#5042), thanks @staabm!
• Faster LazyInternalScopeFactory->create() (#5043), thanks @staabm!
• Faster TrinaryLogic::maxMin(), TrinaryLogic::lazyMaxMin() (#5045), thanks @staabm!
• Prevent TypeCombinator::intersect() calls in MutatingScope-> specifyExpressionType() (#5048), thanks @staabm!
• Prevent unnecessary $scope->getType() calls (#5051), thanks @staabm!
• Prevent unnecessary work in UnionType->describe() (#5062), thanks @staabm!
• Fix slow analysis on return with large OR condition chains (#5076), slow analysis on return with a big OR condition (wordpress) #14207
• Fix slow analysis on large AND condition chains (phpstan/phpstan-src@5b6cb3a), coalesce is slow with lots of variables #14214
• Prevent unnecessary work in IntersectionType (#5054), thanks @staabm!
• AcceptsResult: cache Yes/No/Maybe (#5095), thanks @VincentLanglet!
• TemplateTypeTrait: Prevent unnecessary work (#5122), thanks @staabm!
• MutatingScope->createConditionalExpressions(): cheap checks first (#5126), thanks @staabm!
• MemoizingContainer - memoize getServicesByTag (phpstan/phpstan-src@6a7d9e0)

Internals 🔍

• Add AnalysisResult::withFileSpecificErrors() to public API (#5034), thanks @janedbal!
• Add non regression test (#5035), thanks @VincentLanglet!
• Lint workflows (#5041)
• Added regression tests (#5050), Explicit mixed array becomes implicit in if statement #10559, Missing type check on array if another item is the correct type #11534, thanks @staabm!
• Regression tests (#5076)
• Added regression test (#5088), thanks @staabm!
• Add non regression tests (#5110), thanks @VincentLanglet!
• Add non regression test (#5109), thanks @VincentLanglet!
• TypeSpecifier refactor (#5123), thanks @staabm!
• Fix 'restricted open_basedir' e2e test (#5138), thanks @staabm!
• Rework LegacyNodeScopeResolverTest (phpstan/phpstan-src@b0019e9)
  • Slim down LegacyNodeScopeResolverTest (phpstan/phpstan-src@7b5e618)
  • More slimming down (phpstan/phpstan-src@bd783aa)
  • Slim down tests that used replaceClass=true (phpstan/phpstan-src@27d2abd)
  • Final LegacyNodeScopeResolverTest cleanup (phpstan/phpstan-src@456275f)
• Refactor: NonNullabilityHelper (#5154), thanks @staabm!
• Simplify NonNullabilityHelper (#5158), thanks @staabm!
• Fix typo (#5180), thanks @staabm!
• Trivial code style fixes (#5159), thanks @zonuexe!
• Start using phpbench (Introduce PHPBench and move performance tests from AnalyserIntegrationTest to RegressionBench phpstan-src#5200)
• Added missing namespace to test (#5214), thanks @staabm!
• Remove default handling of truthy/falsey callback because it's not applicable in these expressions (phpstan/phpstan-src@be0124d)
• Some handlers only need to reference truthy/falsey scope of the processed expression (phpstan/phpstan-src@bee17d3)