strtr returns non-empty-string

Author: staabm

src/Type/Php/ReplaceFunctionsDynamicReturnTypeExtension.php

@@ -30,6 +30,7 @@ class ReplaceFunctionsDynamicReturnTypeExtension implements DynamicFunctionRetur
 		'str_replace' => 2,
 		'str_ireplace' => 2,
 		'substr_replace' => 0,
+		'strtr' => 0,
 	];
 
 	/** @var array<string, int> */
@@ -38,6 +39,7 @@ class ReplaceFunctionsDynamicReturnTypeExtension implements DynamicFunctionRetur
 		'str_replace' => 1,
 		'str_ireplace' => 1,
 		'substr_replace' => 1,
+		'strtr' => 2,
 	];
 
 	public function isFunctionSupported(FunctionReflection $functionReflection): bool
@@ -53,7 +55,11 @@ public function getTypeFromFunctionCall(
 	{
 		$type = $this->getPreliminarilyResolvedTypeFromFunctionCall($functionReflection, $functionCall, $scope);
 
-		$possibleTypes = ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
+		$possibleTypes = ParametersAcceptorSelector::selectFromArgs(
+			$scope,
+			$functionCall->getArgs(),
+			$functionReflection->getVariants(),
+		)->getReturnType();
 		// resolve conditional return types
 		$possibleTypes = TypeUtils::resolveLateResolvableTypes($possibleTypes);
 
@@ -71,12 +77,17 @@ private function getPreliminarilyResolvedTypeFromFunctionCall(
 	): Type
 	{
 		$argumentPosition = $this->functionsSubjectPosition[$functionReflection->getName()];
+		$defaultReturnType = ParametersAcceptorSelector::selectFromArgs(
+			$scope,
+			$functionCall->getArgs(),
+			$functionReflection->getVariants(),
+		)->getReturnType();
+
 		if (count($functionCall->getArgs()) <= $argumentPosition) {
-			return ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
+			return $defaultReturnType;
 		}
 
 		$subjectArgumentType = $scope->getType($functionCall->getArgs()[$argumentPosition]->value);
-		$defaultReturnType = ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
 		if ($subjectArgumentType instanceof MixedType) {
 			return TypeUtils::toBenevolentUnion($defaultReturnType);
 		}

tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php

@@ -9060,7 +9060,7 @@ public function dataGeneralizeScope(): array
 	{
 		return [
 			[
-				'array<non-empty-array<int|string, array{saveCount: int<0, max>, removeCount: int<0, max>, loadCount: int<0, max>, hitCount: int<0, max>}>>',
+				'array<string, non-empty-array<int|string, array{saveCount: int<0, max>, removeCount: int<0, max>, loadCount: int<0, max>, hitCount: int<0, max>}>>',
 				'$statistics',
 			],
 		];

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1122,6 +1122,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7913.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Functions/data/bug-8280.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8272.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/strtr.php');
 	}
 
 	/**

tests/PHPStan/Analyser/data/strtr.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Strtr;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @param non-empty-string $nonEmptyString
+ * @param non-falsy-string $nonFalseyString
+ */
+function doFoo(string $s, $nonEmptyString, $nonFalseyString) {
+	assertType('string', strtr($s, 'f', 'b'));
+	assertType('string', strtr($s, ['f' => 'b']));
+	assertType('string', strtr($s, ['f' => 'b', 'o' => 'a']));
+
+	assertType('string', strtr($s, $s, $nonEmptyString));
+	assertType('string', strtr($s, $nonEmptyString, $nonEmptyString));
+	assertType('string', strtr($s, $nonFalseyString, $nonFalseyString));
+
+	assertType('non-empty-string', strtr($nonEmptyString, $s, $nonEmptyString));
+	assertType('non-empty-string', strtr($nonEmptyString, $nonEmptyString, $nonEmptyString));
+	assertType('non-empty-string', strtr($nonEmptyString, $nonFalseyString, $nonFalseyString));
+
+	assertType('non-empty-string', strtr($nonFalseyString, $s, $nonEmptyString));
+	assertType('non-falsy-string', strtr($nonFalseyString, $nonEmptyString, $nonFalseyString));
+	assertType('non-falsy-string', strtr($nonFalseyString, $nonFalseyString, $nonFalseyString));
+}