Fix phpstan/phpstan#14348: TemplateIntersectionType is lost inside TypeCombinator::intersect#5275
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staabm merged 4 commits intophpstan:2.1.xfrom Mar 23, 2026
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confirmed this fix, also fixes the problem we see in #4441 (comment) |
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Add a new test-case into the TypeCombinatorTest::testIntersect data-provider which reproduces the origin problem before the fix
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Add a regression test for
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- TemplateIntersectionType extends IntersectionType, so the flattening logic in TypeCombinator::intersect was unwrapping it into its inner types, losing the template context - Added a TemplateType check to skip flattening for template types - New regression test in tests/PHPStan/Analyser/nsrt/bug-14348.php Closes phpstan/phpstan#14348
…pe preservation Adds a test case that verifies intersecting a TemplateIntersectionType (T of A&B) with MixedType preserves the template wrapper instead of flattening it to a plain IntersectionType. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Both issues involve template intersection types being lost during type narrowing, which is fixed by the TemplateIntersectionType preservation in TypeCombinator::intersect. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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This was referenced Mar 23, 2026
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Summary
When accessing elements of
non-empty-array<T>whereT of A&B(template with intersection bound), the template type was lost and reduced to justA&B. This happened becauseTypeCombinator::intersectflattenedTemplateIntersectionTypeas if it were a plainIntersectionType.Changes
!$type instanceof TemplateTypeguard to theIntersectionTypeflattening logic insrc/Type/TypeCombinator.php:1215tests/PHPStan/Analyser/nsrt/bug-14348.phpRoot cause
TemplateIntersectionTypeextendsIntersectionType, so the code atTypeCombinator::intersectthat transformsA & (B & C)intoA & B & Cwas also unwrapping template intersection types. For example, whenIntersectionType::getOffsetValueTypecomputedTypeCombinator::intersect(T, MixedType)for a non-empty array access, the template typeTwas flattened into its inner types (A & B), losing the template wrapper. The fix skips flattening when theIntersectionTypeis actually aTemplateType.Test
Added
tests/PHPStan/Analyser/nsrt/bug-14348.phpwhich verifies that accessing$tgs[0]onnon-empty-array<T>whereT of PositionEntityInterface&TgEntityInterfacepreserves the full template type.Fixes phpstan/phpstan#14348
Closes phpstan/phpstan#9961
Closes phpstan/phpstan#13577