Support tagged unions in array_merge

Author: herndlm

Diff for: phpstan-baseline.neon

@@ -1312,11 +1312,6 @@ parameters:
 			count: 1
 			path: src/Type/Php/ArrayKeyExistsFunctionTypeSpecifyingExtension.php
 
-		-
-			message: "#^Doing instanceof PHPStan\\\\Type\\\\Constant\\\\ConstantArrayType is error\\-prone and deprecated\\. Use Type\\:\\:getConstantArrays\\(\\) instead\\.$#"
-			count: 4
-			path: src/Type/Php/ArrayMergeFunctionDynamicReturnTypeExtension.php
-
 		-
 			message: "#^Doing instanceof PHPStan\\\\Type\\\\ConstantScalarType is error\\-prone and deprecated\\. Use Type\\:\\:isConstantScalarValue\\(\\) or Type\\:\\:getConstantScalarTypes\\(\\) or Type\\:\\:getConstantScalarValues\\(\\) instead\\.$#"
 			count: 16

Diff for: src/Type/Php/ArrayMergeFunctionDynamicReturnTypeExtension.php

@@ -5,13 +5,14 @@
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
-use PHPStan\ShouldNotHappenException;
+use PHPStan\TrinaryLogic;
 use PHPStan\Type\Accessory\AccessoryArrayListType;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
 use PHPStan\Type\Constant\ConstantIntegerType;
+use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\NeverType;
@@ -39,58 +40,53 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 
 		$argTypes = [];
 		$optionalArgTypes = [];
-		$allConstant = true;
 		foreach ($args as $arg) {
 			$argType = $scope->getType($arg->value);
 
 			if ($arg->unpack) {
-				if ($argType instanceof ConstantArrayType) {
-					$argTypesFound = $argType->getValueTypes();
-				} else {
-					$argTypesFound = [$argType->getIterableValueType()];
-				}
-
-				foreach ($argTypesFound as $argTypeFound) {
-					$argTypes[] = $argTypeFound;
-					if ($argTypeFound instanceof ConstantArrayType) {
-						continue;
+				if ($argType->isConstantArray()->yes()) {
+					foreach ($argType->getConstantArrays() as $constantArray) {
+						foreach ($constantArray->getValueTypes() as $valueType) {
+							$argTypes[] = $valueType;
+						}
 					}
-					$allConstant = false;
+				} else {
+					$argTypes[] = $argType->getIterableValueType();
 				}
 
 				if (!$argType->isIterableAtLeastOnce()->yes()) {
 					// unpacked params can be empty, making them optional
 					$optionalArgTypesOffset = count($argTypes) - 1;
-					foreach (array_keys($argTypesFound) as $key) {
+					foreach (array_keys($argTypes) as $key) {
 						$optionalArgTypes[] = $optionalArgTypesOffset + $key;
 					}
 				}
 			} else {
 				$argTypes[] = $argType;
-				if (!$argType instanceof ConstantArrayType) {
-					$allConstant = false;
-				}
 			}
 		}
 
-		if ($allConstant) {
+		$allConstant = TrinaryLogic::createYes()->lazyAnd(
+			$argTypes,
+			static fn (Type $argType) => $argType->isConstantArray(),
+		);
+
+		if ($allConstant->yes()) {
 			$newArrayBuilder = ConstantArrayTypeBuilder::createEmpty();
 			foreach ($argTypes as $argType) {
-				if (!$argType instanceof ConstantArrayType) {
-					throw new ShouldNotHappenException();
+				/** @var array<int|string, ConstantIntegerType|ConstantStringType> $keyTypes */
+				$keyTypes = [];
+				foreach ($argType->getConstantArrays() as $constantArray) {
+					foreach ($constantArray->getKeyTypes() as $keyType) {
+						$keyTypes[$keyType->getValue()] = $keyType;
+					}
 				}
 
-				$keyTypes = $argType->getKeyTypes();
-				$valueTypes = $argType->getValueTypes();
-				$optionalKeys = $argType->getOptionalKeys();
-
-				foreach ($keyTypes as $k => $keyType) {
-					$isOptional = in_array($k, $optionalKeys, true);
-
+				foreach ($keyTypes as $keyType) {
 					$newArrayBuilder->setOffsetValueType(
 						$keyType instanceof ConstantIntegerType ? null : $keyType,
-						$valueTypes[$k],
-						$isOptional,
+						$argType->getOffsetValueType($keyType),
+						!$argType->hasOffsetValueType($keyType)->yes(),
 					);
 				}
 			}

Diff for: tests/PHPStan/Analyser/nsrt/array-merge2.php

@@ -21,6 +21,10 @@ public function arrayMergeArrayShapes($array1, $array2): void
 		assertType("array{foo: '1', bar: '2', lall2: '3', 0: '4', 1: '6', lall: '3', 2: '2', 3: '3'}", array_merge($array2, $array1));
 		assertType("array{foo: 3, bar: '2', lall2: '3', 0: '4', 1: '6', lall: '3', 2: '2', 3: '3'}", array_merge($array2, $array1, ['foo' => 3]));
 		assertType("array{foo: 3, bar: '2', lall2: '3', 0: '4', 1: '6', lall: '3', 2: '2', 3: '3'}", array_merge($array2, $array1, ...[['foo' => 3]]));
+		assertType("array{foo: '1', bar: '2'|'4', lall?: '3', 0: '2'|'4', 1: '3'|'6', lall2?: '3'}", array_merge(rand(0, 1) ? $array1 : $array2, []));
+		assertType("array{foo?: 3, bar?: 3}", array_merge([], ...[rand(0, 1) ? ['foo' => 3] : ['bar' => 3]]));
+		assertType("array{foo: '1', bar: '2'|'4', lall?: '3', 0: '2'|'4', 1: '3'|'6', lall2?: '3'}", array_merge([], ...[rand(0, 1) ? $array1 : $array2]));
+		assertType("array{foo: 1, bar: 2, 0: 2, 1: 3}", array_merge(['foo' => 4, 'bar' => 5], ...[['foo' => 1, 'bar' => 2], [2, 3]]));
 	}
 
 	/**

Diff for: tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php

@@ -1598,6 +1598,15 @@ public function testBug9399(): void
 		$this->analyse([__DIR__ . '/data/bug-9399.php'], []);
 	}
 
+	public function testBug9559(): void
+	{
+		if (PHP_VERSION_ID < 80000) {
+			$this->markTestSkipped('Test requires PHP 8.0');
+		}
+
+		$this->analyse([__DIR__ . '/data/bug-9559.php'], []);
+	}
+
 	public function testBug9923(): void
 	{
 		if (PHP_VERSION_ID < 80000) {

Diff for: tests/PHPStan/Rules/Functions/data/bug-9559.php

@@ -0,0 +1,12 @@
+<?php declare(strict_types = 1);
+
+namespace Bug9559;
+
+class ZZ {};
+function foo(?ZZ $z = null, ?int $a = 0, ?string $b = "x"): string { return "bah"; }
+
+function doit(int $x): void {
+	$call = [];
+	if ($x) $call['a'] = 45;
+	foo(...array_merge($call, [ "b" => "3" ]));
+}

Diff for: tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -846,6 +846,16 @@ public function testBug8573(): void
 		$this->analyse([__DIR__ . '/data/bug-8573.php'], []);
 	}
 
+	public function testBug8632(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-8632.php'], []);
+	}
+
+	public function testBug7857(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-7857.php'], []);
+	}
+
 	public function testBug8879(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-8879.php'], []);

Diff for: tests/PHPStan/Rules/Methods/data/bug-7857.php

@@ -0,0 +1,17 @@
+<?php declare(strict_types = 1);
+
+namespace Bug7857;
+
+class Paginator
+{
+	/**
+	 * @return array{page: int, perPage?: int}
+	 */
+	public function toArray(int $page, ?int $perPage): array
+	{
+		return array_merge(
+			['page' => $page],
+			$perPage !== null ? ['perPage' => $perPage] : []
+		);
+	}
+}

Diff for: tests/PHPStan/Rules/Methods/data/bug-8632.php

@@ -0,0 +1,26 @@
+<?php declare(strict_types = 1);
+
+namespace Bug8632;
+
+class HelloWorld
+{
+	/**
+	 * @return array{
+	 *     id?: int,
+	 *     categories?: string[],
+	 * }
+	 */
+	public function test(bool $foo): array
+	{
+		if ($foo) {
+			$arr = [
+				'id'         => 1,
+				'categories' => ['news'],
+			];
+		} else {
+			$arr = [];
+		}
+
+		return array_merge($arr, []);
+	}
+}