Implement ReturnTypeFromStrictParamRector

[staabm]

<?php

namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromStrictParamRector\Fixture;

class Example {
-    public function doFoo(Example $param) {
+    public function doFoo(Example $param): Example {
        return $param;
    }
}

?>

[staabm]

@samsonasik hopefully I am right and this feature is not covered by a existing rule which I was not able to find ? :-)

[samsonasik]

Possible void return fixture should be added:

class SkipPossibleVoid
{
    public function run(int $p)
    {
           if (rand(0, 1)) {
                return $p;
           }
    }
}

You can check with root Return validation like in other rule:

$inferReturnType = $this->returnTypeInferer->inferFunctionLike($node);

and verify the inferred return type.

rector-src/rules/TypeDeclaration/Rector/ClassMethod/ReturnTypeFromStrictTypedCallRector.php

Lines 135 to 140 in a10ddea

	private function isUnionPossibleReturnsVoid(ClassMethod | Function_ | Closure $node): bool
	{
	$inferReturnType = $this->returnTypeInferer->inferFunctionLike($node);
	if ($inferReturnType instanceof UnionType) {
	foreach ($inferReturnType->getTypes() as $type) {
	if ($type->isVoid()->yes()) {

[staabm]

Possible void return fixture should be added:

great hint, thanks.

and verify the inferred return type.

I am not sure I would want to infer a union type at all (besides a simple nullable-object-type).
union return types are not good design in my opinion

[samsonasik]

Yes, but that possible void are exists in many legacy code :)

[staabm]

exists in many legacy code

could you give me an example? the one you posted above is already covered

[samsonasik]

not sure if I can find and show it here, but It seems you already covered it 👍

[staabm]

covers https://3v4l.org/E2XOE

[samsonasik]

this can be moved to shouldSkipNode() method so early cheap check is handled for abstract method.

[staabm]

👍

[staabm]

reverted, since its required to make phpstan happy

 ------ ------------------------------------------------------------------------------
  Line   rules\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromStrictParamRector.php
 ------ ------------------------------------------------------------------------------
  128    Parameter #1 $nodes of method
         Rector\Core\Rector\AbstractRector::traverseNodesWithCallable()
         expects array<PhpParser\Node>|PhpParser\Node,
         array<PhpParser\Node\Stmt>|null given.
  157    Parameter #1 $nodes of method
         Rector\Core\Rector\AbstractRector::traverseNodesWithCallable()
         expects array<PhpParser\Node>|PhpParser\Node,
         array<PhpParser\Node\Stmt>|null given.
 ------ ------------------------------------------------------------------------------

[samsonasik]

No worries, I will check after it get merged 👍

[samsonasik]

#4512

[staabm]

should be good to go

[staabm]

ping @TomasVotruba :)

[TomasVotruba]

Looks good, let's give it a try 👍