covariant return type error not detected

[staabm]

Bug report

phpstan can detect covariant return types in situations like https://phpstan.org/r/892b3d92-db4c-4fd3-9d5f-b47fb5bf3355.
detecting these is important, because they turn into fatal errors at runtime https://3v4l.org/jdXiU

Code snippet that reproduces the problem

It turns out though, that phpstan does only compare the method in question with the top-most baseclass.
when more layers of inheritance are involved the covariant type is not detected and the runtime fatal error keeps hidden

https://phpstan.org/r/2c6d3ee9-55cb-4ad9-9afd-c6e293f1b3f2
https://3v4l.org/OPasV

Expected output

A non-ignorable error on line 28

Return type mixed of method extended::renderForUser() is not covariant with return type string of method middle::renderForUser().

[ondrejmirtes]

Why is this a problem? You already have the error for middle.

[staabm]

in our case extended was on the phpstan analyze path and middle and base both were defined in a vendor/ package which we did not scan with phpstan - because its just a dependency

[ondrejmirtes]

Yeah, but middle is already wrong which should be fixed first and foremost. If the problem wasn't in the dependency then PHPStan wouldn't have anything to report.

[staabm]

ok, let me be more precise about the layers involved :-).

the base-package contains middle and base:
https://phpstan.org/r/d645ea74-7b18-4145-8488-e5bba9864797
which is from the base-package point of view all green.

the project which consumes the base-package via composer declares only the extended class, which analyzed on its own, without analyzing middle and base does not report the non-ignorable problem either.
https://phpstan.org/r/00ca30ad-0420-459a-a25a-658b9c7f7f67

only when all 3 classes are on the analyzed path, I get the error

[ondrejmirtes]

Oh right, didn't realize that https://phpstan.org/r/d645ea74-7b18-4145-8488-e5bba9864797 is valid.

[ondrejmirtes]

Another example https://phpstan.org/r/6671900f-0059-4169-a188-9437907e2c47

[phpstan-bot]

@staabm After the latest push in 1.11.x, PHPStan now reports different result with your code snippet:

@@ @@
+PHP 7.4 – 8.2 (4 errors)
+==========
+
  7: Method base::renderForUser() has no return type specified.
 17: Method middle::renderForUser() should return string but return statement is missing.
-28: Method extended::renderForUser() has no return type specified.
+28: Method extended::renderForUser() has no return type specified.
+28: Return type mixed of method extended::renderForUser() is not covariant with return type string of method middle::renderForUser().
+
+PHP 7.2 – 7.3 (4 errors)
+==========
+
+ 7: Method base::renderForUser() has no return type specified.
+17: Method middle::renderForUser() should return string but return statement is missing.
+28: Method extended::renderForUser() has no return type specified.
+28: Return type mixed of method extended::renderForUser() is not compatible with return type string of method middle::renderForUser().

Full report

PHP 7.4 – 8.2 (4 errors)

Line	Error
7	Method base::renderForUser() has no return type specified.
17	Method middle::renderForUser() should return string but return statement is missing.
28	Method extended::renderForUser() has no return type specified.
28	Return type mixed of method extended::renderForUser() is not covariant with return type string of method middle::renderForUser().

PHP 7.2 – 7.3 (4 errors)

Line	Error
7	Method base::renderForUser() has no return type specified.
17	Method middle::renderForUser() should return string but return statement is missing.
28	Method extended::renderForUser() has no return type specified.
28	Return type mixed of method extended::renderForUser() is not compatible with return type string of method middle::renderForUser().

[phpstan-bot]

@staabm After the latest push in 1.11.x, PHPStan now reports different result with your code snippet:

@@ @@
+PHP 7.4 – 8.2 (4 errors)
+==========
+
  7: Method base::renderForUser() has no return type specified.
 15: Method middle::renderForUser() should return string but return statement is missing.
-26: Method extended::renderForUser() has no return type specified.
+26: Method extended::renderForUser() has no return type specified.
+26: Return type mixed of method extended::renderForUser() is not covariant with return type string of method middle::renderForUser().
+
+PHP 7.2 – 7.3 (4 errors)
+==========
+
+ 7: Method base::renderForUser() has no return type specified.
+15: Method middle::renderForUser() should return string but return statement is missing.
+26: Method extended::renderForUser() has no return type specified.
+26: Return type mixed of method extended::renderForUser() is not compatible with return type string of method middle::renderForUser().

Full report

PHP 7.4 – 8.2 (4 errors)

Line	Error
7	Method base::renderForUser() has no return type specified.
15	Method middle::renderForUser() should return string but return statement is missing.
26	Method extended::renderForUser() has no return type specified.
26	Return type mixed of method extended::renderForUser() is not covariant with return type string of method middle::renderForUser().

PHP 7.2 – 7.3 (4 errors)

Line	Error
7	Method base::renderForUser() has no return type specified.
15	Method middle::renderForUser() should return string but return statement is missing.
26	Method extended::renderForUser() has no return type specified.
26	Return type mixed of method extended::renderForUser() is not compatible with return type string of method middle::renderForUser().

[phpstan-bot]

@ondrejmirtes After the latest push in 1.11.x, PHPStan now reports different result with your code snippet:

@@ @@
-No errors
+15: Method Bar::test() overrides method Foo::test() but misses parameter #2 $test.

Full report

Line	Error
15	Method Bar::test() overrides method Foo::test() but misses parameter #2 $test.

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.