Preserve array type through dependent offset assignment with template keys#5625
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Preserve array type through dependent offset assignment with template keys#5625phpstan-bot wants to merge 1 commit intophpstan:2.1.xfrom
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… keys When assigning `$arr[$key] = $val` where `$key` is a template key-of<T> and `$val` is T[$key] (an OffsetAccessType), the assignment is type- preserving by definition. Previously PHPStan would eagerly resolve the OffsetAccessType, losing the dependent relationship between key and value, then widen all value types to the union of all possible values. Detect this pattern in AssignHandler by examining the raw (unresolved) expression type: if the assigned value's raw type is an OffsetAccessType whose offset matches the dim's template parameter and whose accessed type is a supertype of the array being assigned to, skip the widening step and preserve the original array type. Also compare template parameters by identity (name + scope) rather than strict equals, since the same template K may appear as TemplateKeyOfType in the OffsetAccessType but as TemplateStringType in the resolved dim. Closes phpstan/phpstan#7380
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Summary
Fixes false positives when assigning to an array with a dependent template key and value type, such as
$attr[$key] = $valwhere$key: K of key-of<Attrs>and$val: Attrs[K].Previously, PHPStan eagerly resolved
Attrs[K](anOffsetAccessType) into the union of all possible value types (string|5|6|7|bool), then widened each key's value type with this union, producingnon-empty-array<'bar'|'baz'|'foo'|K, 5|6|7|bool|string>instead of preserving the originalarray{foo?: string, bar?: 5|6|7, baz?: bool}. This caused a false positive on the subsequent$this->setAttributes($attr)call.Changes
src/Analyser/ExprHandler/AssignHandler.php: Before callingproduceArrayDimFetchAssignValueToWrite(), detect when the assignment follows a dependent offset access pattern by inspecting the raw (unresolved) expression type from the scope. When the raw value type is anOffsetAccessTypewhose offset matches the dim's template parameter and whose accessed type is a supertype of the target array, skip the widening and preserve the original array type. Uses template identity comparison (name + scope) rather than strictequals()to handle cases where the same templateKappears asTemplateKeyOfTypevsTemplateStringType.src/Type/OffsetAccessType.php: AddedgetAccessedType()andgetAccessedOffset()public getters to enable inspecting the components of anOffsetAccessType.tests/PHPStan/Analyser/nsrt/bug-7380.php: New regression test covering both the concrete type alias case (@phpstan-type Attrs) and the generic class case (@template T).tests/PHPStan/Analyser/AnalyserIntegrationTest.php: UpdatedtestBug7094()to remove the false positive assertion at line 29 (previously expected 6 errors, now correctly expects 5).Closes phpstan/phpstan#7380