Fixed assigning nested arrays

src/Analyser/NodeScopeResolver.php

@@ -2298,10 +2298,12 @@ private function processAssignVar(
 					$offsetValueTypeStack[] = $offsetValueType;
 				}
 
-				foreach (array_reverse($offsetTypes) as $offsetType) {
+				foreach (array_reverse($offsetTypes) as $i => $offsetType) {
 					/** @var Type $offsetValueType */
 					$offsetValueType = array_pop($offsetValueTypeStack);
-					$valueToWrite = $offsetValueType->setOffsetValueType($offsetType, $valueToWrite);
+
+					/** @phpstan-ignore-next-line */
+					$valueToWrite = $offsetValueType->setOffsetValueType($offsetType, $valueToWrite, $i === 0);
 				}
 
 				if ($var instanceof Variable && is_string($var->name)) {

src/Type/ArrayType.php

@@ -216,15 +216,15 @@ public function getOffsetValueType(Type $offsetType): Type
 		return $type;
 	}
 
-	public function setOffsetValueType(?Type $offsetType, Type $valueType): Type
+	public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $unionValues = true): Type
 	{
 		if ($offsetType === null) {
 			$offsetType = new IntegerType();
 		}
 
 		return new self(
 			TypeCombinator::union($this->keyType, self::castToArrayKeyType($offsetType)),
-			TypeCombinator::union($this->itemType, $valueType)
+			$unionValues ? TypeCombinator::union($this->itemType, $valueType) : $valueType
 		);
 	}
 

src/Type/Constant/ConstantArrayType.php

@@ -431,7 +431,7 @@ public function getOffsetValueType(Type $offsetType): Type
 		return new ErrorType(); // undefined offset
 	}
 
-	public function setOffsetValueType(?Type $offsetType, Type $valueType): Type
+	public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $unionValues = false): Type
 	{
 		$builder = ConstantArrayTypeBuilder::createFromConstantArray($this);
 		$builder->setOffsetValueType($offsetType, $valueType);

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -9889,6 +9889,11 @@ public function dataBug3269(): array
 		return $this->gatherAssertTypes(__DIR__ . '/data/bug-3269.php');
 	}
 
+	public function dataAssignNestedArray(): array
+	{
+		return $this->gatherAssertTypes(__DIR__ . '/data/assign-nested-arrays.php');
+	}
+
 	/**
 	 * @dataProvider dataBug2574
 	 * @dataProvider dataBug2577
@@ -9935,6 +9940,7 @@ public function dataBug3269(): array
 	 * @dataProvider dataInheritPhpDocMerging
 	 * @dataProvider dataBug3266
 	 * @dataProvider dataBug3269
+	 * @dataProvider dataAssignNestedArray
 	 * @param ConstantStringType $expectedType
 	 * @param Type $actualType
 	 */

tests/PHPStan/Analyser/data/assign-nested-arrays.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace AssignNestedArrays;
+
+use function PHPStan\Analyser\assertType;
+
+class Foo
+{
+
+	public function doFoo(int $i)
+	{
+		$array = [];
+
+		$array[$i]['bar'] = 1;
+		$array[$i]['baz'] = 2;
+
+		assertType('array<int, array(\'bar\' => 1, \'baz\' => 2)>', $array);
+	}
+
+	public function doBar(int $i, int $j)
+	{
+		$array = [];
+
+		$array[$i][$j]['bar'] = 1;
+		$array[$i][$j]['baz'] = 2;
+
+		echo $array[$i][$j]['bar'];
+		echo $array[$i][$j]['baz'];
+
+		assertType('array<int, array<int, array(\'bar\' => 1, \'baz\' => 2)>>', $array);
+	}
+
+}

tests/PHPStan/Rules/Arrays/data/nonexistent-offset.php

@@ -358,15 +358,15 @@ public function arrayWithMultipleKeysAfterForeaches(int $i, int $j)
 		$array[$i]['baz'] = 2;
 
 		echo $array[$i]['bar'];
-		//echo $array[$i]['baz'];
+		echo $array[$i]['baz'];
 
 		$array = [];
 
 		$array[$i][$j]['bar'] = 1;
 		$array[$i][$j]['baz'] = 2;
 
 		echo $array[$i][$j]['bar'];
-		//echo $array[$i][$j]['baz'];
+		echo $array[$i][$j]['baz'];
 	}
 }