fix

Author: staabm

src/Type/Php/StrlenTypeSpecifyingExtension.php

@@ -14,6 +14,7 @@
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\FunctionTypeSpecifyingExtension;
 use PHPStan\Type\IntegerRangeType;
+use PHPStan\Type\NeverType;
 use function count;
 use function in_array;
 use function strtolower;
@@ -49,6 +50,10 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 		}
 
 		$returnType = $context->getReturnType();
+		if ($returnType instanceof NeverType) {
+			return $this->typeSpecifier->create($args[0]->value, $returnType, $context->negate(), $scope);
+		}
+
 		if (
 			$context->true() && IntegerRangeType::createAllGreaterThanOrEqualTo(1)->isSuperTypeOf($returnType)->yes()
 			|| ($context->false() && (new ConstantIntegerType(0))->isSuperTypeOf($returnType)->yes())

tests/PHPStan/Analyser/nsrt/strlen-never.php

@@ -0,0 +1,50 @@
+<?php
+
+namespace StrlenNever;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param non-empty-string $nonES
+ * @param non-falsy-string $nonFalsy
+ * @param numeric-string $numericString
+ * @param lowercase-string $lower
+ * @param uppercase-string $upper
+ */
+function doFoo(string $s, $nonES, $nonFalsy, $numericString, $lower, $upper) {
+	if (strlen($s) <= 0) {
+		assertType("''", $s);
+	}
+	if (strlen($nonES) <= 0) {
+		assertType('*NEVER*', $nonES);
+	}
+	if (strlen($nonFalsy) <= 0) {
+		assertType('*NEVER*', $nonFalsy);
+	}
+	if (strlen($numericString) <= 0) {
+		assertType("*NEVER*", $numericString);
+	}
+	if (strlen($lower) <= 0) {
+		assertType("''", $lower);
+	}
+	if (strlen($upper) <= 0) {
+		assertType("''", $upper);
+	}
+
+	if (strlen($nonES) >= 0) {
+		assertType('non-empty-string', $nonES);
+	} else {
+		assertType('*NEVER*', $nonES);
+	}
+}
+
+
+function doBar(string $m): void
+{
+	if (strlen($m) >= 1) {
+		if (strlen($m) <= 0) {
+			assertType('*NEVER*', $m);
+		}
+	}
+}
+