Resolve method reflection for $var::method() static calls

- When $expr->class is an Expr (variable), resolve method reflection and
  parameters acceptor using getObjectTypeOrClassStringObjectType() so
  by-reference parameters and other argument analysis work correctly
- Guard $this invalidation and constructor property initialization blocks
  with $expr->class instanceof Name to prevent $other::__construct()
  from incorrectly affecting $this
- New regression test in tests/PHPStan/Analyser/nsrt/bug-5020.php

Author: ondrejmirtes

src/Analyser/NodeScopeResolver.php

@@ -3381,6 +3381,25 @@ function (MutatingScope $scope) use ($stmt, $expr, $nodeCallback, $context, $sto
 				foreach ($additionalThrowPoints as $throwPoint) {
 					$throwPoints[] = $throwPoint;
 				}
+
+				if ($expr->name instanceof Identifier && $methodReflection === null) {
+					$staticMethodCalledOnType = TypeCombinator::removeNull($scope->getType($expr->class))->getObjectTypeOrClassStringObjectType();
+					$methodName = $expr->name->name;
+					if ($staticMethodCalledOnType->hasMethod($methodName)->yes()) {
+						$methodReflection = $staticMethodCalledOnType->getMethod($methodName, $scope);
+						$parametersAcceptor = ParametersAcceptorSelector::selectFromArgs(
+							$scope,
+							$expr->getArgs(),
+							$methodReflection->getVariants(),
+							$methodReflection->getNamedArgumentsVariants(),
+						);
+
+						$methodThrowPoint = $this->getStaticMethodThrowPoint($methodReflection, $parametersAcceptor, $expr, $scope);
+						if ($methodThrowPoint !== null) {
+							$throwPoints[] = $methodThrowPoint;
+						}
+					}
+				}
 			}
 
 			if ($methodReflection !== null) {
@@ -3410,6 +3429,7 @@ function (MutatingScope $scope) use ($stmt, $expr, $nodeCallback, $context, $sto
 
 			if (
 				$methodReflection !== null
+				&& $expr->class instanceof Name
 				&& (
 					(
 						!$methodReflection->isStatic()
@@ -3425,6 +3445,7 @@ function (MutatingScope $scope) use ($stmt, $expr, $nodeCallback, $context, $sto
 
 			if (
 				$methodReflection !== null
+				&& $expr->class instanceof Name
 				&& !$methodReflection->isStatic()
 				&& $methodReflection->getName() === '__construct'
 				&& $scopeFunction instanceof MethodReflection

tests/PHPStan/Analyser/nsrt/bug-5020.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace Bug5020;
+
+use function PHPStan\Testing\assertType;
+
+interface ITransformer
+{
+	public static function Transform(string $theInput, bool &$theErrorEncountered): string;
+}
+
+class Transformer implements ITransformer
+{
+	public static function Transform(string $theInput, bool &$theErrorEncountered): string
+	{
+		if ($theInput === 'invalid') {
+			$theErrorEncountered = true;
+			return '';
+		}
+		return strtoupper(trim($theInput));
+	}
+}
+
+function testConstantStringStaticCall(): void
+{
+	$transformer = 'Bug5020\Transformer';
+	$input = ' asdasda asdasd ';
+	$error = false;
+	$output = $transformer::Transform($input, $error);
+	assertType('string', $output);
+	assertType('bool', $error);
+}
+
+function testDirectStaticCall(): void
+{
+	$input = ' asdasda asdasd ';
+	$error = false;
+	$output = Transformer::Transform($input, $error);
+	assertType('string', $output);
+	assertType('bool', $error);
+}
+
+function testClassStringStaticCall(): void
+{
+	/** @var class-string<ITransformer> $transformer */
+	$transformer = 'Bug5020\Transformer';
+	$input = ' asdasda asdasd ';
+	$error = false;
+	$output = $transformer::Transform($input, $error);
+	assertType('string', $output);
+	assertType('bool', $error);
+}