More precise microtime() return type

src/Type/Php/MicrotimeFunctionReturnTypeExtension.php

@@ -6,9 +6,11 @@
 use PHPStan\Analyser\Scope;
 use PHPStan\DependencyInjection\AutowiredService;
 use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
 use PHPStan\Type\BenevolentUnionType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\FloatType;
+use PHPStan\Type\IntersectionType;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\Type;
@@ -26,8 +28,10 @@ public function isFunctionSupported(FunctionReflection $functionReflection): boo
 
 	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): Type
 	{
+		$stringType = new IntersectionType([new StringType(), new AccessoryNonFalsyStringType()]);
+
 		if (count($functionCall->getArgs()) < 1) {
-			return new StringType();
+			return $stringType;
 		}
 
 		$argType = $scope->getType($functionCall->getArgs()[0]->value);
@@ -38,14 +42,14 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 			return new FloatType();
 		}
 		if ($compareTypes === $isFalseType) {
-			return new StringType();
+			return $stringType;
 		}
 
 		if ($argType instanceof MixedType) {
-			return new BenevolentUnionType([new StringType(), new FloatType()]);
+			return new BenevolentUnionType([$stringType, new FloatType()]);
 		}
 
-		return new UnionType([new StringType(), new FloatType()]);
+		return new UnionType([$stringType, new FloatType()]);
 	}
 
 }

tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php

@@ -5193,23 +5193,23 @@ public static function dataFunctions(): array
 	{
 		return [
 			[
-				'string',
+				'non-falsy-string',
 				'$microtimeStringWithoutArg',
 			],
 			[
-				'string',
+				'non-falsy-string',
 				'$microtimeString',
 			],
 			[
 				'float',
 				'$microtimeFloat',
 			],
 			[
-				'float|string',
+				'float|non-falsy-string',
 				'$microtimeDefault',
 			],
 			[
-				'(float|string)',
+				'(float|non-falsy-string)',
 				'$microtimeBenevolent',
 			],
 			[