fix

Author: staabm

src/Analyser/TypeSpecifier.php

@@ -715,8 +715,9 @@ public function specifyTypesInCondition(
 continue;
 }
 
+$hasOffsetType = $type->hasOffsetValueType($dimType);
 $offsetType = $type->getOffsetValueType($dimType);
-if (!TypeCombinator::containsNull($offsetType)) {
+if ($hasOffsetType->yes() && !TypeCombinator::containsNull($offsetType)) {
 $specifiedTypes = $specifiedTypes->unionWith($this->create(
 new NotIssetExpr($var),
 new ErrorType(),

tests/PHPStan/Analyser/data/falsy-isset.php

@@ -61,7 +61,7 @@ public function optionalOffsetNonNull($a): void
 }
 
 assertVariableCertainty(TrinaryLogic::createYes(), $a);
-assertType("array{bar?: null}|array{bar: 1}", $a);
+assertType("array{}|array{bar: 1}", $a);
 }
 
 public function maybeCertainNull(): void