Callable parameter types aren't correctly inferred

[nreynis]

Bug report

Types applied to callable doesn't seems to be correctly inferred.

Code snippet that reproduces the problem

https://phpstan.org/r/24105e02-8d5f-4fd9-a237-01ebec9938a9

Expected output

Both lines 29 and 34 should raise Else branch is unreachable because ternary operator condition is always true., only line 29 does.

Line 34 error reveals that the callable is inferred to callable(mixed): DateTimeImmutable generic should have been propagated to the callable and it should expect callable(T of DateTime): DateTimeImmutable

[nreynis]

Return types seems to have the same limitation:
https://phpstan.org/r/477de7ac-8952-4ab4-9aec-3c31e05027e5

[phpstan-bot]

@nreynis PHPStan now reports different result with your code snippet:

@@ @@
 ==========
 
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (2 errors)

Line	Error
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36

[phpstan-bot]

@nreynis After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
 ==========
 
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(T): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (2 errors)

Line	Error
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(T): DateTimeImmutable, Closure(mixed): DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36

[phpstan-bot]

@nreynis After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 7.4 – 8.0 (2 errors)
+PHP 7.4 – 8.0 (3 errors)
 ==========
 
+15: Property Test::$generator is never read, only written.
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (3 errors)

Line	Error
15	Property Test::$generator is never read, only written.
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36

[phpstan-bot]

@nreynis After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 7.4 – 8.0 (1 error)
+PHP 7.4 – 8.0 (2 errors)
 ==========
 
+16: Property Test::$generator is never read, only written.
 30: Else branch is unreachable because ternary operator condition is always true.
 
 PHP 7.1 – 7.3 (4 errors)

Full report

PHP 7.4 – 8.0 (2 errors)

Line	Error
16	Property Test::$generator is never read, only written.
30	Else branch is unreachable because ternary operator condition is always true.

PHP 7.1 – 7.3 (4 errors)

Line	Error
30	Syntax error, unexpected T_VARIABLE, expecting ')' on line 30
31	Syntax error, unexpected ')' on line 31
36	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 36
37	Syntax error, unexpected ')' on line 37

[phpstan-bot]

@nreynis After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 7.4 – 8.0 (2 errors)
+PHP 7.4 – 8.0 (3 errors)
 ==========
 
+15: Property Test::$generator is never read, only written.
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (3 errors)

Line	Error
15	Property Test::$generator is never read, only written.
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36

[phpstan-bot]

@nreynis After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 7.4 – 8.0 (1 error)
+PHP 7.4 – 8.0 (2 errors)
 ==========
 
+16: Property Test::$generator is never read, only written.
 30: Else branch is unreachable because ternary operator condition is always true.
 
 PHP 7.1 – 7.3 (4 errors)

Full report

PHP 7.4 – 8.0 (2 errors)

Line	Error
16	Property Test::$generator is never read, only written.
30	Else branch is unreachable because ternary operator condition is always true.

PHP 7.1 – 7.3 (4 errors)

Line	Error
30	Syntax error, unexpected T_VARIABLE, expecting ')' on line 30
31	Syntax error, unexpected ')' on line 31
36	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 36
37	Syntax error, unexpected ')' on line 37

[Einenlum]

Not sure if it's the exact same issue, but I found something that looks similar.

https://phpstan.org/r/525c36eb-c861-45bf-85ca-0315555e923f

Not sure how to fix this.

[phpstan-bot]

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

@@ @@
-PHP 7.4 – 8.0 (2 errors)
+PHP 7.4 – 8.0 (3 errors)
 ==========
 
+15: Property Test::$generator is never read, only written.
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): (DateTimeImmutable|null) given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (3 errors)

Line	Error
15	Property Test::$generator is never read, only written.
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): (DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36

[phpstan-bot]

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

@@ @@
-PHP 8.1 – 8.2 (1 error)
+PHP 8.1 – 8.2
 ==========
 
-17: Parameter #1 $a of callable (Closure(A): void)|(Closure(B): void) expects A, A|B given.
+No errors
 
-PHP 8.0 (3 errors)
+PHP 8.0 (2 errors)
 ==========
 
 15: First-class callables are supported only on PHP 8.1 and later.
 15: First-class callables are supported only on PHP 8.1 and later.
-17: Parameter #1 $a of callable (Closure(A): void)|(Closure(B): void) expects A, A|B given.
 
-PHP 7.2 – 7.4 (4 errors)
+PHP 7.2 – 7.4 (3 errors)
 ==========
 
 13: Method Foo::handle() uses native union types but they're supported only on PHP 8.0 and later.
 15: First-class callables are supported only on PHP 8.1 and later.
-15: First-class callables are supported only on PHP 8.1 and later.
-17: Parameter #1 $a of callable (Closure(A): void)|(Closure(B): void) expects A, A|B given.
+15: First-class callables are supported only on PHP 8.1 and later.

Full report

PHP 8.1 – 8.2

No errors

PHP 8.0 (2 errors)

Line	Error
15	First-class callables are supported only on PHP 8.1 and later.
15	First-class callables are supported only on PHP 8.1 and later.

PHP 7.2 – 7.4 (3 errors)

Line	Error
13	Method Foo::handle() uses native union types but they're supported only on PHP 8.0 and later.
15	First-class callables are supported only on PHP 8.1 and later.
15	First-class callables are supported only on PHP 8.1 and later.

[phpstan-bot]

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

@@ @@
-PHP 7.4 – 8.0 (2 errors)
+PHP 7.4 – 8.0 (3 errors)
 ==========
 
+15: Property Test::$generator is never read, only written.
 29: Else branch is unreachable because ternary operator condition is always true.
-34: Parameter #1 $immutableGenerator of class Test constructor expects callable(mixed): DateTimeImmutable, Closure(mixed): DateTimeImmutable|null given.
+35: Parameter #1 $immutableGenerator of class Test constructor expects callable(T): DateTimeImmutable, Closure(T): (DateTimeImmutable|null) given.
 
 PHP 7.1 – 7.3 (4 errors)
 ==========

Full report

PHP 7.4 – 8.0 (3 errors)

Line	Error
15	Property Test::$generator is never read, only written.
29	Else branch is unreachable because ternary operator condition is always true.
35	`Parameter #1 $immutableGenerator of class Test constructor expects callable(T): DateTimeImmutable, Closure(T): (DateTimeImmutable

PHP 7.1 – 7.3 (4 errors)

Line	Error
29	Syntax error, unexpected T_VARIABLE, expecting ')' on line 29
30	Syntax error, unexpected ')' on line 30
35	Syntax error, unexpected T_DOUBLE_ARROW, expecting ')' on line 35
36	Syntax error, unexpected ')' on line 36