Improve trim on numeric string

src/Type/Php/LtrimFunctionReturnTypeExtension.php

@@ -7,6 +7,7 @@
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\Accessory\AccessoryLowercaseStringType;
+use PHPStan\Type\Accessory\AccessoryNumericStringType;
 use PHPStan\Type\Accessory\AccessoryUppercaseStringType;
 use PHPStan\Type\ClassStringType;
 use PHPStan\Type\Constant\ConstantStringType;
@@ -17,6 +18,7 @@
 use PHPStan\Type\TypeCombinator;
 use function count;
 use function ltrim;
+use function preg_match;
 
 #[AutowiredService]
 final class LtrimFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
@@ -69,6 +71,8 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 					}
 				} elseif ($trimConstantString->getValue() === '\\' && $string->isClassString()->yes()) {
 					$result[] = new ClassStringType();
+				} elseif (preg_match('/\d/', $trimConstantString->getValue()) === 0 && $string->isNumericString()->yes()) {
+					$result[] = new AccessoryNumericStringType();
 				} else {
 					return $defaultType;
 				}

src/Type/Php/TrimFunctionDynamicReturnTypeExtension.php

@@ -7,6 +7,7 @@
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\Accessory\AccessoryLowercaseStringType;
+use PHPStan\Type\Accessory\AccessoryNumericStringType;
 use PHPStan\Type\Accessory\AccessoryUppercaseStringType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
@@ -16,6 +17,7 @@
 use PHPStan\Type\TypeCombinator;
 use function count;
 use function in_array;
+use function preg_match;
 use function rtrim;
 use function trim;
 
@@ -66,18 +68,20 @@ public function getTypeFromFunctionCall(
 			$functionName = $functionReflection->getName();
 
 			foreach ($trimConstantStrings as $trimConstantString) {
-				if (count($stringConstantStrings) === 0) {
+				if (count($stringConstantStrings) > 0) {
+					foreach ($stringConstantStrings as $stringConstantString) {
+						$result[] = new ConstantStringType(
+							$functionName === 'rtrim'
+								? rtrim($stringConstantString->getValue(), $trimConstantString->getValue())
+								: trim($stringConstantString->getValue(), $trimConstantString->getValue()),
+							true,
+						);
+					}
+				} elseif (preg_match('/\d/', $trimConstantString->getValue()) === 0 && $stringType->isNumericString()->yes()) {
+					$result[] = new AccessoryNumericStringType();
+				} else {
 					return $defaultType;
 				}
-
-				foreach ($stringConstantStrings as $stringConstantString) {
-					$result[] = new ConstantStringType(
-						$functionName === 'rtrim'
-							? rtrim($stringConstantString->getValue(), $trimConstantString->getValue())
-							: trim($stringConstantString->getValue(), $trimConstantString->getValue()),
-						true,
-					);
-				}
 			}
 
 			return TypeCombinator::union(...$result);

tests/PHPStan/Analyser/nsrt/numeric-string-trim.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace NumericStringTrim;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+
+	/**
+	 * @param numeric-string $numericString
+	 * @param string $string
+	 */
+	public function doTrim(string $numericString, string $string): void
+	{
+		assertType('string', trim($numericString, $string));
+		assertType('string', ltrim($numericString, $string));
+		assertType('string', rtrim($numericString, $string));
+
+		assertType('numeric-string', trim($numericString, '-'));
+		assertType('numeric-string', ltrim($numericString, '-'));
+		assertType('numeric-string', rtrim($numericString, '-'));
+
+		assertType('string', trim($numericString, '0'));
+		assertType('string', ltrim($numericString, '0'));
+		assertType('string', rtrim($numericString, '0'));
+
+		assertType('string', trim($numericString, '-0'));
+		assertType('string', ltrim($numericString, '-0'));
+		assertType('string', rtrim($numericString, '-0'));
+	}
+
+}