diff --git a/src/Reflection/ParametersAcceptorSelector.php b/src/Reflection/ParametersAcceptorSelector.php
index 20317a14053..427c5bee51c 100644
--- a/src/Reflection/ParametersAcceptorSelector.php
+++ b/src/Reflection/ParametersAcceptorSelector.php
@@ -516,7 +516,27 @@ public static function selectFromArgs(
 			}
 			if ($originalArg->unpack) {
 				$unpack = true;
-				$types[$index] = $type->getIterableValueType();
+				$constantArrays = $type->getConstantArrays();
+				if (count($constantArrays) > 0) {
+					foreach ($constantArrays as $constantArray) {
+						$values = $constantArray->getValueTypes();
+						foreach ($constantArray->getKeyTypes() as $j => $keyType) {
+							$valueType = $values[$j];
+							$valueIndex = $keyType->getValue();
+							if (is_string($valueIndex)) {
+								$hasName = true;
+							} else {
+								$valueIndex = $i + $j;
+							}
+
+							$types[$valueIndex] = isset($types[$valueIndex])
+								? TypeCombinator::union($types[$valueIndex], $valueType)
+								: $valueType;
+						}
+					}
+				} else {
+					$types[$index] = $type->getIterableValueType();
+				}
 			} else {
 				$types[$index] = $type;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-8257.php b/tests/PHPStan/Analyser/nsrt/bug-8257.php
new file mode 100644
index 00000000000..c674e66ad23
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-8257.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace Bug8257;
+
+use function PHPStan\Testing\assertType;
+
+interface TreeMapper
+{
+	/**
+	 * @template T of object
+	 *
+	 * @param string|class-string<T> $signature
+	 * @param mixed $source
+	 * @return (
+	 *     $signature is class-string<T>
+	 *         ? T
+	 *         : mixed
+	 * )
+	 */
+	public function map(string $signature, $source);
+}
+
+/** @var TreeMapper $tm */
+$tm;
+
+class A {}
+
+assertType('Bug8257\A', $tm->map(...[A::class, []]));
diff --git a/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php b/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
index a1db3f755a2..f8499b9c742 100644
--- a/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
+++ b/tests/PHPStan/Rules/Classes/InstantiationRuleTest.php
@@ -579,6 +579,12 @@ public function testBug13440(): void
 		$this->analyse([__DIR__ . '/data/bug-13440.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug12363(): void
+	{
+		$this->analyse([__DIR__ . '/../Methods/data/bug-12363.php'], []);
+	}
+
 	public function testNewStaticWithConsistentConstructor(): void
 	{
 		$this->analyse([__DIR__ . '/data/instantiation-new-static-consistent-constructor.php'], [
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 77ef9843bfe..d06950ad68f 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2735,4 +2735,10 @@ public function testBug10559(): void
 		$this->analyse([__DIR__ . '/data/bug-10559.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug12363(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-12363.php'], []);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Functions/data/bug-12363.php b/tests/PHPStan/Rules/Functions/data/bug-12363.php
new file mode 100644
index 00000000000..cf4c801e75c
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/bug-12363.php
@@ -0,0 +1,26 @@
+<?php // lint >= 8.0
+
+declare(strict_types = 1);
+
+namespace Bug12363;
+
+/**
+ * @template Y of 'a'|'b'
+ * @param Y $y
+ */
+function f(int $x, string $y = 'a'): void {}
+
+// Spreading associative array with required + optional template param
+f(...['x' => 5, 'y' => 'b']);
+
+// Without spread - should also work
+f(5, 'b');
+
+/**
+ * @template Y of 'a'|'b'
+ * @param Y $y
+ */
+function g(string $y = 'a'): void {}
+
+// Without preceding required arg - already works
+g(...['y' => 'b']);
diff --git a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
index 3460563a480..99480a40611 100644
--- a/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
+++ b/tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php
@@ -3908,6 +3908,19 @@ public function testBug1501(): void
 		$this->analyse([__DIR__ . '/data/bug-1501.php'], []);
 	}
 
+	public function testBug7369(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->analyse([__DIR__ . '/data/bug-7369.php'], [
+			[
+				'Cannot call method isAllowed() on bool.',
+				40,
+			],
+		]);
+	}
+
 	public function testBug11463(): void
 	{
 		$this->checkThisOnly = false;
diff --git a/tests/PHPStan/Rules/Methods/data/bug-12363.php b/tests/PHPStan/Rules/Methods/data/bug-12363.php
new file mode 100644
index 00000000000..68156b9669a
--- /dev/null
+++ b/tests/PHPStan/Rules/Methods/data/bug-12363.php
@@ -0,0 +1,52 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug12363Methods;
+
+/**
+ * @template Y of 'a'|'b'
+ */
+class A
+{
+	/**
+	 * @param Y $y
+	 */
+	public function __construct(
+		public readonly int $x,
+		public readonly string $y = 'a',
+	) {
+	}
+}
+
+$a = new A(...['x' => 5, 'y' => 'b']);
+
+$aa = new A(...[5, 'y' => 'b']);
+
+$aaa = new A(...[5, 'b']);
+
+$aaaa = new A(...[1 => 5, 2 => 'b']);
+
+/**
+ * @template Y of 'a'|'b'
+ */
+class B
+{
+	/**
+	 * @param Y $y
+	 */
+	public function __construct(
+		public readonly int $init,
+		public readonly int $x,
+		public readonly string $y = 'a',
+	) {
+	}
+}
+
+$a = new B(1, ...['x' => 5, 'y' => 'b']);
+
+$aa = new B(1, ...[5, 'y' => 'b']);
+
+$aaa = new B(1, ...[5, 'b']);
+
+$aaaa = new B(1, ...[1 => 5, 2 => 'b']);
diff --git a/tests/PHPStan/Rules/Methods/data/bug-7369.php b/tests/PHPStan/Rules/Methods/data/bug-7369.php
new file mode 100644
index 00000000000..224a2493fa7
--- /dev/null
+++ b/tests/PHPStan/Rules/Methods/data/bug-7369.php
@@ -0,0 +1,43 @@
+<?php declare(strict_types=1);
+
+namespace Bug7369;
+
+interface AccountInterface {}
+
+interface AccessResultInterface {
+	public function isAllowed(): bool;
+}
+
+interface AccessibleInterface {
+
+	/**
+	 * @return ($return_as_object is true ? AccessResultInterface : bool)
+	 */
+	public function access(string $operation, AccountInterface $account = NULL, bool $return_as_object = FALSE);
+}
+
+$class = new class() implements AccessibleInterface {
+	/**
+	 * {@inheritDoc}
+	 */
+	public function access(
+		string $operation,
+		AccountInterface $account = null,
+		bool $return_as_object = false
+	) {
+		if ($return_as_object) {
+			return new class () implements AccessResultInterface {
+				public function isAllowed(): bool {
+					return true;
+				}
+			};
+		}
+		return false;
+	}
+};
+
+$class->access('view', null, true)->isAllowed();
+$class->access('view', null, false)->isAllowed();
+
+$params = ['view', null, true];
+$class->access(...$params)->isAllowed();