Revert "Useful PhpMethodReflection native type refactoring from #3966"

src/Reflection/Php/PhpMethodReflection.php

@@ -302,9 +302,30 @@ public function isPublic(): bool
 	private function getReturnType(): Type
 	{
 		if ($this->returnType === null) {
-			$this->returnType = TypehintHelper::decideType(
-				$this->getNativeReturnType(),
+			$name = strtolower($this->getName());
+			$returnType = $this->reflection->getReturnType();
+			if ($returnType === null) {
+				if (in_array($name, ['__construct', '__destruct', '__unset', '__wakeup', '__clone'], true)) {
+					return $this->returnType = TypehintHelper::decideType(new VoidType(), $this->phpDocReturnType);
+				}
+				if ($name === '__tostring') {
+					return $this->returnType = TypehintHelper::decideType(new StringType(), $this->phpDocReturnType);
+				}
+				if ($name === '__isset') {
+					return $this->returnType = TypehintHelper::decideType(new BooleanType(), $this->phpDocReturnType);
+				}
+				if ($name === '__sleep') {
+					return $this->returnType = TypehintHelper::decideType(new ArrayType(new IntegerType(), new StringType()), $this->phpDocReturnType);
+				}
+				if ($name === '__set_state') {
+					return $this->returnType = TypehintHelper::decideType(new ObjectWithoutClassType(), $this->phpDocReturnType);
+				}
+			}
+
+			$this->returnType = TypehintHelper::decideTypeFromReflection(
+				$returnType,
 				$this->phpDocReturnType,
+				$this->declaringClass,
 			);
 		}
 
@@ -323,28 +344,8 @@ private function getPhpDocReturnType(): Type
 	private function getNativeReturnType(): Type
 	{
 		if ($this->nativeReturnType === null) {
-			$returnType = $this->reflection->getReturnType();
-			if ($returnType === null) {
-				$name = strtolower($this->getName());
-				if (in_array($this->getName(), ['__construct', '__destruct', '__unset', '__wakeup', '__clone'], true)) {
-					return $this->nativeReturnType = new VoidType();
-				}
-				if ($name === '__tostring') {
-					return $this->nativeReturnType = new StringType();
-				}
-				if ($name === '__isset') {
-					return $this->nativeReturnType = new BooleanType();
-				}
-				if ($name === '__sleep') {
-					return $this->nativeReturnType = new ArrayType(new IntegerType(), new StringType());
-				}
-				if ($name === '__set_state') {
-					return $this->nativeReturnType = new ObjectWithoutClassType();
-				}
-			}
-
 			$this->nativeReturnType = TypehintHelper::decideTypeFromReflection(
-				$returnType,
+				$this->reflection->getReturnType(),
 				null,
 				$this->declaringClass,
 			);

src/Type/TypehintHelper.php

@@ -68,6 +68,8 @@ public static function decideTypeFromReflection(
 		$type = ParserNodeTypeToPHPStanType::resolve($typeNode, $selfClass);
 		if ($reflectionType->allowsNull()) {
 			$type = TypeCombinator::addNull($type);
+		} elseif ($phpDocType !== null) {
+			$phpDocType = TypeCombinator::removeNull($phpDocType);
 		}
 
 		return self::decideType($type, $phpDocType);
@@ -78,9 +80,6 @@ public static function decideType(
 		?Type $phpDocType,
 	): Type
 	{
-		if ($phpDocType !== null && $type->isNull()->no()) {
-			$phpDocType = TypeCombinator::removeNull($phpDocType);
-		}
 		if ($type instanceof BenevolentUnionType) {
 			return $type;
 		}

tests/PHPStan/Analyser/nsrt/bug-to-string-type.php

@@ -0,0 +1,36 @@
+<?php
+
+namespace BugToStringType;
+
+use function PHPStan\Testing\assertNativeType;
+use function PHPStan\Testing\assertType;
+
+class ParentClassWithToStringMixedReturn
+{
+    public function __toString()
+    {
+        return 'a';
+    }
+}
+
+class WithParentMixedReturn extends ParentClassWithToStringMixedReturn
+{
+    public function __toString()
+    {
+        return 'value';
+    }
+}
+
+class Consumer extends WithParentMixedReturn
+{
+    public function __toString()
+    {
+        return 'value';
+    }
+}
+
+function test(Consumer $test): void
+{
+	assertType('string', $test->__toString());
+	assertNativeType('mixed', $test->__toString());
+}