Narrow to non-empty-string/non-falsey-string after mb_strlen()

src/Analyser/TypeSpecifier.php

@@ -210,11 +210,11 @@ public function specifyTypesInCondition(
 				$expr->left instanceof FuncCall
 				&& count($expr->left->getArgs()) === 1
 				&& $expr->left->name instanceof Name
-				&& in_array(strtolower((string) $expr->left->name), ['count', 'sizeof', 'strlen'], true)
+				&& in_array(strtolower((string) $expr->left->name), ['count', 'sizeof', 'strlen', 'mb_strlen'], true)
 				&& (
 					!$expr->right instanceof FuncCall
 					|| !$expr->right->name instanceof Name
-					|| !in_array(strtolower((string) $expr->right->name), ['count', 'sizeof', 'strlen'], true)
+					|| !in_array(strtolower((string) $expr->right->name), ['count', 'sizeof', 'strlen', 'mb_strlen'], true)
 				)
 			) {
 				$inverseOperator = $expr instanceof Node\Expr\BinaryOp\Smaller
@@ -265,7 +265,7 @@ public function specifyTypesInCondition(
 				&& $expr->right instanceof FuncCall
 				&& count($expr->right->getArgs()) === 1
 				&& $expr->right->name instanceof Name
-				&& strtolower((string) $expr->right->name) === 'strlen'
+				&& in_array(strtolower((string) $expr->right->name), ['strlen', 'mb_strlen'], true)
 				&& $leftType->isInteger()->yes()
 			) {
 				if (
@@ -977,7 +977,7 @@ private function specifyTypesForConstantBinaryExpression(
 			&& $exprNode instanceof FuncCall
 			&& count($exprNode->getArgs()) === 1
 			&& $exprNode->name instanceof Name
-			&& strtolower((string) $exprNode->name) === 'strlen'
+			&& in_array(strtolower((string) $exprNode->name), ['strlen', 'mb_strlen'], true)
 			&& $constantType instanceof ConstantIntegerType
 		) {
 			if ($context->truthy() || $constantType->getValue() === 0) {

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1476,6 +1476,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10187.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10834.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10952.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10952b.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-10893.php');
 	}
 

tests/PHPStan/Analyser/data/bug-10952b.php

@@ -0,0 +1,41 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10952b;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	public function getString(): string
+	{
+		return 'hallo';
+	}
+
+	public function test(): void
+	{
+		$string = $this->getString();
+
+		if (1 < mb_strlen($string)) {
+			assertType('non-empty-string', $string);
+		} else {
+			assertType("string", $string);
+		}
+
+		if (mb_strlen($string) > 1) {
+			assertType('non-empty-string', $string);
+		} else {
+			assertType("string", $string);
+		}
+
+		if (2 < mb_strlen($string)) {
+			assertType('non-falsy-string', $string);
+		} else {
+			assertType("string", $string);
+		}
+
+		match (true) {
+			mb_strlen($string) > 0 => assertType('non-empty-string', $string),
+			default => assertType("''", $string),
+		};
+	}
+}