Remove dim expression coercion, fix HasOffsetValueType key coercion instead

Instead of coercing array key expressions (e.g. String_('2') → Int_(2))
when constructing intertwined ref dim expressions, use the original key
expression directly and fix HasOffsetValueType to apply toArrayKey()
coercion when matching offset types.

This properly handles PHP's array key coercion ('2' → 2) in the type
system rather than in expression construction, which works correctly
for union types as well.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Analyser/ExprHandler/AssignHandler.php

@@ -948,9 +948,9 @@ private function processArrayByRefItems(MutatingScope $scope, string $rootVarNam
 		foreach ($arrayExpr->items as $arrayItem) {
 			if ($arrayItem->key !== null) {
 				$keyType = $scope->getType($arrayItem->key)->toArrayKey();
-				$keyValues = $keyType->getConstantScalarValues();
 
 				if ($implicitIndex !== null) {
+					$keyValues = $keyType->getConstantScalarValues();
 					if (count($keyValues) === 1) {
 						$keyValue = $keyValues[0];
 						if (is_int($keyValue) && $keyValue >= $implicitIndex) {
@@ -963,20 +963,7 @@ private function processArrayByRefItems(MutatingScope $scope, string $rootVarNam
 					}
 				}
 
-				// Use the coerced key value for the dim expression so that
-				// e.g. '2' => &$b creates ArrayDimFetch with Int_(2), matching $array[2] access
-				if (count($keyValues) === 1) {
-					$coercedKey = $keyValues[0];
-					if (is_int($coercedKey)) {
-						$dimExpr = new Node\Scalar\Int_($coercedKey);
-					} elseif (is_string($coercedKey)) {
-						$dimExpr = new Node\Scalar\String_($coercedKey);
-					} else {
-						$dimExpr = $arrayItem->key;
-					}
-				} else {
-					$dimExpr = $arrayItem->key;
-				}
+				$dimExpr = $arrayItem->key;
 			} elseif ($implicitIndex !== null) {
 				$dimExpr = new Node\Scalar\Int_($implicitIndex);
 				$implicitIndex++;

src/Type/Accessory/HasOffsetValueType.php

@@ -156,7 +156,7 @@ public function isOffsetAccessLegal(): TrinaryLogic
 
 	public function hasOffsetValueType(Type $offsetType): TrinaryLogic
 	{
-		if ($offsetType->isConstantScalarValue()->yes() && $offsetType->equals($this->offsetType)) {
+		if ($offsetType->isConstantScalarValue()->yes() && $offsetType->toArrayKey()->equals($this->offsetType)) {
 			return TrinaryLogic::createYes();
 		}
 
@@ -165,7 +165,7 @@ public function hasOffsetValueType(Type $offsetType): TrinaryLogic
 
 	public function getOffsetValueType(Type $offsetType): Type
 	{
-		if ($offsetType->isConstantScalarValue()->yes() && $offsetType->equals($this->offsetType)) {
+		if ($offsetType->isConstantScalarValue()->yes() && $offsetType->toArrayKey()->equals($this->offsetType)) {
 			return $this->valueType;
 		}