Properly union HasOffsetValueType in huge intersections describing the same offsets

Author: ondrejmirtes

phpstan-baseline.neon

@@ -1716,7 +1716,7 @@ parameters:
 		-
 			rawMessage: Doing instanceof PHPStan\Type\IntersectionType is error-prone and deprecated.
 			identifier: phpstanApi.instanceofType
-			count: 3
+			count: 5
 			path: src/Type/TypeCombinator.php
 
 		-

src/Type/TypeCombinator.php

@@ -26,6 +26,7 @@
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateTypeFactory;
 use PHPStan\Type\Generic\TemplateUnionType;
+use function array_fill;
 use function array_key_exists;
 use function array_key_first;
 use function array_merge;
@@ -463,6 +464,12 @@ private static function compareTypesInUnion(Type $a, Type $b): ?array
 				return [new HasOffsetValueType($a->getOffsetType(), self::union($a->getValueType(), $b->getValueType())), null];
 			}
 		}
+		if ($a instanceof IntersectionType && $b instanceof IntersectionType) {
+			$merged = self::mergeIntersectionsForUnion($a, $b);
+			if ($merged !== null) {
+				return [$merged, null];
+			}
+		}
 		if ($a->isConstantArray()->yes() && $b->isConstantArray()->yes()) {
 			return null;
 		}
@@ -1516,6 +1523,66 @@ public static function intersect(Type ...$types): Type
 		return new IntersectionType($types);
 	}
 
+	/**
+	 * Merge two IntersectionTypes that have the same structure but differ
+	 * in HasOffsetValueType value types (matched by offset key).
+	 *
+	 * E.g. (A & hasOV('k', X)) | (A & hasOV('k', Y)) → (A & hasOV('k', X|Y))
+	 */
+	private static function mergeIntersectionsForUnion(IntersectionType $a, IntersectionType $b): ?Type
+	{
+		$aTypes = $a->getTypes();
+		$bTypes = $b->getTypes();
+
+		if (count($aTypes) !== count($bTypes)) {
+			return null;
+		}
+
+		$mergedTypes = [];
+		$hasDifference = false;
+		$bUsed = array_fill(0, count($bTypes), false);
+
+		foreach ($aTypes as $aType) {
+			$matched = false;
+			foreach ($bTypes as $bIdx => $bType) {
+				if ($bUsed[$bIdx]) {
+					continue;
+				}
+
+				if ($aType->equals($bType)) {
+					$mergedTypes[] = $aType;
+					$bUsed[$bIdx] = true;
+					$matched = true;
+					break;
+				}
+
+				// HasOffsetValueType: merge value types when offset keys match
+				if ($aType instanceof HasOffsetValueType && $bType instanceof HasOffsetValueType
+					&& $aType->getOffsetType()->equals($bType->getOffsetType())) {
+					$mergedTypes[] = new HasOffsetValueType(
+						$aType->getOffsetType(),
+						self::union($aType->getValueType(), $bType->getValueType()),
+					);
+					$hasDifference = true;
+					$bUsed[$bIdx] = true;
+					$matched = true;
+					break;
+				}
+
+				// HasOffsetType, HasMethodType, HasPropertyType: only equal values match (no merging possible)
+			}
+			if (!$matched) {
+				return null;
+			}
+		}
+
+		if (!$hasDifference) {
+			return null;
+		}
+
+		return self::intersect(...$mergedTypes);
+	}
+
 	public static function removeFalsey(Type $type): Type
 	{
 		return self::remove($type, StaticTypeFactory::falsey());

tests/PHPStan/Analyser/nsrt/bug-14319.php

@@ -43,7 +43,7 @@ protected function edit(int|string|null $IdNum = null): void
 			if ($rows['rap_roz3']) {
 				$raport .= 'Roz: '.$rows['rap_roz3'].", \n";
 			}
-			assertType("(non-empty-array&hasOffsetValue('rap_br', mixed)&hasOffsetValue('rap_ks', mixed)&hasOffsetValue('rap_tr', mixed))|(ArrayAccess&hasOffsetValue('rap_br', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_ks', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_tr', 0|0.0|''|'0'|array{}|false|null))|(ArrayAccess&hasOffsetValue('rap_br', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_ks', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_tr', mixed~(0|0.0|''|'0'|array{}|false|null)))|(ArrayAccess&hasOffsetValue('rap_br', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_ks', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_tr', 0|0.0|''|'0'|array{}|false|null))|(ArrayAccess&hasOffsetValue('rap_br', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_ks', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_tr', mixed~(0|0.0|''|'0'|array{}|false|null)))|(ArrayAccess&hasOffsetValue('rap_br', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_ks', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_tr', 0|0.0|''|'0'|array{}|false|null))|(ArrayAccess&hasOffsetValue('rap_br', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_ks', 0|0.0|''|'0'|array{}|false|null)&hasOffsetValue('rap_tr', mixed~(0|0.0|''|'0'|array{}|false|null)))|(ArrayAccess&hasOffsetValue('rap_br', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_ks', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_tr', 0|0.0|''|'0'|array{}|false|null))|(ArrayAccess&hasOffsetValue('rap_br', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_ks', mixed~(0|0.0|''|'0'|array{}|false|null))&hasOffsetValue('rap_tr', mixed~(0|0.0|''|'0'|array{}|false|null)))", $rows);
+			assertType("(non-empty-array&hasOffsetValue('rap_br', mixed)&hasOffsetValue('rap_cz', mixed)&hasOffsetValue('rap_fil', mixed)&hasOffsetValue('rap_ks', mixed)&hasOffsetValue('rap_roz', mixed)&hasOffsetValue('rap_roz2', mixed)&hasOffsetValue('rap_roz3', mixed)&hasOffsetValue('rap_tr', mixed))|(ArrayAccess&hasOffsetValue('rap_br', mixed)&hasOffsetValue('rap_cz', mixed)&hasOffsetValue('rap_fil', mixed)&hasOffsetValue('rap_ks', mixed)&hasOffsetValue('rap_roz', mixed)&hasOffsetValue('rap_roz2', mixed)&hasOffsetValue('rap_roz3', mixed)&hasOffsetValue('rap_tr', mixed))", $rows);
 		}
 	}
 }