Fix callable array intersection type offset narrowing by phpstan-bot · Pull Request #5548 · phpstan/phpstan-src

phpstan-bot · 2026-04-26T19:15:02Z

Summary

When is_array() narrows a callable parameter, the resulting type is array<mixed, mixed>&callable(): mixed. Previously, accessing offsets on this intersection type returned mixed for all offsets, causing false positives when passing the value to functions expecting array{string|object, string} or array{class-string|object, string}.

This PR teaches IntersectionType that when an intersection is both callable and an array (i.e., a callable array), offsets 0 and 1 are guaranteed to exist with specific types:

Offset 0: class-string|object (the class or object the method belongs to)
Offset 1: string (the method name)

Changes

src/Type/IntersectionType.php: Enhanced hasOffsetValueType() to return Yes for offsets 0 and 1 on callable array intersections. Enhanced getOffsetValueType() to narrow the result type for those offsets.
Tests: Added regression tests for both type inference (NSRT) and rule-level acceptance checking.

Test plan

New NSRT test verifies $value[0] is class-string|object and $value[1] is string after is_array() narrowing on a callable
New NSRT test verifies the same for callable-array PHPDoc type
New rule test verifies no false positive when passing callable array to array{string|object, string} parameter
Full test suite passes (11927 tests)
PHPStan self-analysis passes
Coding standards check passes

…rsections When is_array() narrows a callable parameter, the resulting array&callable intersection type now correctly reports that offset 0 is class-string|object and offset 1 is string. This fixes false positives when passing the narrowed value to functions expecting array{string|object, string} or similar callable-array shapes.

VincentLanglet · 2026-04-26T20:09:04Z

+		if (!$result->yes() && $this->isCallable()->yes() && $this->isArray()->yes()) {
+			$arrayKeyOffsetType = $offsetType->toArrayKey();
+			if (
+				(new ConstantIntegerType(0))->isSuperTypeOf($arrayKeyOffsetType)->yes()


(new ConstantIntegerType(0))->isSuperTypeOf($arrayKeyOffsetType)->yes() || (new ConstantIntegerType(1))->isSuperTypeOf($arrayKeyOffsetType)->yes()

Should be rework into an UnionType->isSuperTypeOf check.

Cause we could look for the offset 0|1, which always exists.

Pushed. Here's a summary of the changes addressing the review:

hasOffsetValueType: Replaced the two separate ConstantIntegerType(0)->isSuperTypeOf(...) || ConstantIntegerType(1)->isSuperTypeOf(...) checks with a single UnionType([0, 1])->isSuperTypeOf(...) check. This correctly handles the case where the offset itself is 0|1.

getOffsetValueType: Instead of an if/elseif that only matched exact offsets, the code now:

Guards with the same UnionType([0, 1])->isSuperTypeOf(...) check

Checks which concrete offsets are possible within the offset type (using reversed isSuperTypeOf)

Unions the applicable narrowed types — so offset 0|1 correctly narrows to object|string

Test: Added a test case for 0|1 offset access asserting the result is object|string.

All 11927 tests pass and PHPStan self-analysis reports no errors.

VincentLanglet · 2026-04-26T20:11:17Z

+			if ((new ConstantIntegerType(0))->isSuperTypeOf($arrayKeyOffsetType)->yes()) {
+				$result = TypeCombinator::intersect($result, TypeCombinator::union(new ClassStringType(), new ObjectWithoutClassType()));
+			} elseif ((new ConstantIntegerType(1))->isSuperTypeOf($arrayKeyOffsetType)->yes()) {


What if I access to the offset 0|1 ?
This could be narrowed to object|string.

Address review feedback: use a single UnionType(0|1)->isSuperTypeOf check instead of separate ConstantIntegerType checks, and handle the case where the offset is itself a union (e.g. 0|1) by narrowing to the union of both offset types (object|string). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

VincentLanglet · 2026-04-27T16:21:42Z

+			if ($callableArrayOffsetType->isSuperTypeOf($arrayKeyOffsetType)->yes()) {
+				$narrowedTypes = [];
+				if (!$arrayKeyOffsetType->isSuperTypeOf(new ConstantIntegerType(0))->no()) {
+					$narrowedTypes[] = TypeCombinator::union(new ClassStringType(), new ObjectWithoutClassType());


new UnionType can be used here

Done. Replaced TypeCombinator::union(new ClassStringType(), new ObjectWithoutClassType()) with new UnionType([new ClassStringType(), new ObjectWithoutClassType()]) as the reviewer suggested — since these types are known and won't simplify, using UnionType directly avoids unnecessary normalization overhead. All tests pass and PHPStan self-analysis is clean.

VincentLanglet · 2026-04-27T16:24:29Z

+					$narrowedTypes[] = new StringType();
+				}
+				if ($narrowedTypes !== []) {
+					$result = TypeCombinator::intersect($result, TypeCombinator::union(...$narrowedTypes));


We could save the TypeCombinator::union

if (0 is superType) we narrow new Union (new ClassStringType(), new ObjectWithoutClassType())

elseif (1 is superType) we narrow String

else we narrow new Union (new StringType(), new ObjectWithoutClassType())

Pushed. The change simplifies getOffsetValueType() by replacing the array-building + TypeCombinator::union pattern with a direct if/elseif/else that handles each case:

Offset 0 → class-string|object

Offset 1 → string

Offset 0|1 → object|string

All 11927 tests pass, PHPStan self-analysis and coding standards are clean.

…ngType|ObjectWithoutClassType Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Use direct UnionType construction instead of building an array and calling TypeCombinator::union, as suggested in review. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

VincentLanglet · 2026-04-27T16:35:00Z

@@ -0,0 +1,29 @@
+<?php declare(strict_types = 1);
+
+namespace Bug3842;


Merge the nsrt and data file in a single one which is loaded for both nsrt and rule tests.

Done. The change merges the two test files into a single shared one:

Deleted tests/PHPStan/Rules/Functions/data/bug-3842.php (duplicate data file)

Updated CallToFunctionParametersRuleTest::testBug3842() to reference tests/PHPStan/Analyser/nsrt/bug-3842.php instead

The nsrt file already contained all the test scenarios (including check() and checkClassString() calls), so no content changes were needed

All 11927 tests pass and PHPStan self-analysis is clean.

The rule test now references the nsrt test file directly instead of maintaining a separate duplicate data file. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

VincentLanglet reviewed Apr 26, 2026

View reviewed changes

Hanmac mentioned this pull request Apr 27, 2026

rector: ArrayToFirstClassCallableRector OpenMage/magento-lts#5434

Merged

VincentLanglet reviewed Apr 27, 2026

View reviewed changes

phpstan-bot and others added 2 commits April 27, 2026 16:27

Use UnionType directly instead of TypeCombinator::union for ClassStri…

d2a90f6

…ngType|ObjectWithoutClassType Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Simplify callable array offset type narrowing with if/elseif/else

9770799

Use direct UnionType construction instead of building an array and calling TypeCombinator::union, as suggested in review. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

VincentLanglet approved these changes Apr 27, 2026

View reviewed changes

VincentLanglet reviewed Apr 27, 2026

View reviewed changes

Merge bug-3842 test data into single shared nsrt file

f7f94c6

The rule test now references the nsrt test file directly instead of maintaining a separate duplicate data file. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

VincentLanglet approved these changes Apr 27, 2026

View reviewed changes

VincentLanglet requested a review from staabm April 27, 2026 17:27

sreichel mentioned this pull request Apr 27, 2026

phpstan: use callable-array ? OpenMage/magento-lts#5543

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Fix callable array intersection type offset narrowing#5548

Fix callable array intersection type offset narrowing#5548
phpstan-bot wants to merge 5 commits intophpstan:2.1.xfrom
phpstan-bot:create-pull-request/patch-ty6mco0

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		@@ -0,0 +1,29 @@
		<?php declare(strict_types = 1);

		namespace Bug3842;

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phpstan-bot commented Apr 26, 2026

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