Fix phpstan/phpstan#14223: Variable $ in empty() always exists and is not falsy. (#5124)

Author: phpstan-bot

src/Type/Php/ArrayCountValuesDynamicReturnTypeExtension.php

@@ -44,6 +44,7 @@ public function getTypeFromFunctionCall(
 		$inputType = $scope->getType($args[0]->value);
 
 		$arrayTypes = $inputType->getArrays();
+		$isInputNonEmpty = $inputType->isIterableAtLeastOnce()->yes();
 
 		$outputTypes = [];
 		$allowedValues = new UnionType([new IntegerType(), new StringType()]);
@@ -54,10 +55,16 @@ public function getTypeFromFunctionCall(
 				continue;
 			}
 
-			$outputTypes[] = new IntersectionType([
-				new ArrayType($itemType->toArrayKey(), IntegerRangeType::fromInterval(1, null)),
-				new NonEmptyArrayType(),
-			]);
+			$resultArrayType = new ArrayType($itemType->toArrayKey(), IntegerRangeType::fromInterval(1, null));
+
+			if ($isInputNonEmpty) {
+				$outputTypes[] = new IntersectionType([
+					$resultArrayType,
+					new NonEmptyArrayType(),
+				]);
+			} else {
+				$outputTypes[] = $resultArrayType;
+			}
 		}
 
 		if (count($outputTypes) === 0) {

tests/PHPStan/Analyser/nsrt/array-count-values.php

@@ -25,7 +25,7 @@ function returnsStringOrObjectArray(): array
 }
 
 // Objects are ignored by array_count_values, with a warning emitted.
-assertType('non-empty-array<string, int<1, max>>', array_count_values(returnsStringOrObjectArray()));
+assertType('array<string, int<1, max>>', array_count_values(returnsStringOrObjectArray()));
 
 class StringableObject
 {

tests/PHPStan/Analyser/nsrt/bug-14223.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Bug14223;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param list<string> $a1
+ */
+function doFoo(array $a1): void
+{
+	$a2 = array_count_values($a1);
+	assertType('array<string, int<1, max>>', $a2);
+}
+
+/**
+ * @param non-empty-list<string> $a1
+ */
+function doBar(array $a1): void
+{
+	$a2 = array_count_values($a1);
+	assertType('non-empty-array<string, int<1, max>>', $a2);
+}