Fix #12875: Possible type loss when binding variables with 'use' in anonymous functions

src/Analyser/MutatingScope.php

@@ -2653,7 +2653,7 @@ public function enterAnonymousFunction(
 			$scope->getNamespace(),
 			$scope->expressionTypes,
 			$scope->nativeExpressionTypes,
-			[],
+			$scope->conditionalExpressions,
 			$scope->inClosureBindScopeClasses,
 			$anonymousFunctionReflection,
 			true,
@@ -2703,12 +2703,14 @@ private function enterAnonymousFunctionWithoutReflection(
 		}
 
 		$nonRefVariableNames = [];
+		$useVariableNames = [];
 		foreach ($closure->uses as $use) {
 			if (!is_string($use->var->name)) {
 				throw new ShouldNotHappenException();
 			}
 			$variableName = $use->var->name;
 			$paramExprString = '$' . $use->var->name;
+			$useVariableNames[$paramExprString] = true;
 			if ($use->byRef) {
 				$holder = ExpressionTypeHolder::createYes($use->var, new MixedType());
 				$expressionTypes[$paramExprString] = $holder;
@@ -2774,14 +2776,33 @@ private function enterAnonymousFunctionWithoutReflection(
 			}
 		}
 
+		$filteredConditionalExpressions = [];
+		foreach ($this->conditionalExpressions as $conditionalExprString => $holders) {
+			if (!array_key_exists($conditionalExprString, $useVariableNames)) {
+				continue;
+			}
+			$filteredHolders = [];
+			foreach ($holders as $holder) {
+				foreach ($holder->getConditionExpressionTypeHolders() as $holderExprString => $conditionalTypeHolder) {
+					if (!array_key_exists($holderExprString, $useVariableNames)) {
+						continue 2;
+					}
+				}
+				$filteredHolders[] = $holder;
+			}
+			if ($filteredHolders !== []) {
+				$filteredConditionalExpressions[$conditionalExprString] = $filteredHolders;
+			}
+		}
+
 		return $this->scopeFactory->create(
 			$this->context,
 			$this->isDeclareStrictTypes(),
 			$this->getFunction(),
 			$this->getNamespace(),
 			array_merge($this->getConstantTypes(), $expressionTypes),
 			array_merge($this->getNativeConstantTypes(), $nativeTypes),
-			[],
+			$filteredConditionalExpressions,
 			$this->inClosureBindScopeClasses,
 			new ClosureType(),
 			true,

tests/PHPStan/Analyser/nsrt/bug-12875.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1); // lint >= 8.0
+
+namespace Bug12875;
+
+use function PHPStan\Testing\assertType;
+
+interface HasFoo
+{
+	public function foo(): int;
+}
+
+interface HasBar
+{
+	public function bar(): int;
+}
+
+class HelloWorld
+{
+	/**
+	 * @param "foo"|"bar" $method
+	 * @param ($method is "foo" ? HasFoo : HasBar) $a
+	 * @param ($method is "foo" ? HasFoo : HasBar) $b
+	 */
+	public function add(string $method, HasFoo|HasBar $a, HasFoo|HasBar $b): void
+	{
+		assertType('int', $a->{$method}());
+		assertType('int', $b->{$method}());
+
+		$addInArrow = fn () => assertType('int', $a->{$method}());
+
+		$addInAnonymous = function () use ($a, $b, $method): void {
+			assertType('int', $a->{$method}());
+			assertType('int', $b->{$method}());
+		};
+	}
+}

tests/PHPStan/Rules/Methods/CallMethodsRuleTest.php

@@ -3827,4 +3827,13 @@ public function testDiscussion14038(): void
 		$this->analyse([__DIR__ . '/data/discussion-14038.php'], []);
 	}
 
+	public function testBug12875(): void
+	{
+		$this->checkThisOnly = false;
+		$this->checkNullables = true;
+		$this->checkUnionTypes = true;
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-12875.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-12875.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types = 1); // lint >= 8.0
+
+namespace Bug12875;
+
+interface HasFoo
+{
+	public function foo(): int;
+}
+
+interface HasBar
+{
+	public function bar(): int;
+}
+
+class HelloWorld
+{
+	/**
+	 * @param "foo"|"bar" $method
+	 * @param ($method is "foo" ? HasFoo : HasBar) $a
+	 * @param ($method is "foo" ? HasFoo : HasBar) $b
+	 */
+	public function add(string $method, HasFoo|HasBar $a, HasFoo|HasBar $b): void
+	{
+		$add = $a->{$method}() + $b->{$method}();
+		$addInArrow = fn () => $a->{$method}() + $b->{$method}();
+		$addInAnonymous = function () use ($a, $b, $method): int {
+			return $a->{$method}() + $b->{$method}();
+		};
+	}
+}