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67 lines
1.1 KiB
Markdown
67 lines
1.1 KiB
Markdown
# MixedMethodCall
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Emitted when calling a method on a value that Psalm cannot infer a type for
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```php
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<?php
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class A {
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public function foo() : void {}
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}
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function callFoo(array $arr) : void {
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array_pop($arr)->foo(); // MixedMethodCall emitted here
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}
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callFoo(
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[new A()]
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);
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```
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## Why this is bad
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If Psalm doesn’t know what `array_pop($arr)` is, it can't verify whether `array_pop($arr)->foo()` will work or not.
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## How to fix
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Make sure that to provide as much type information as possible to Psalm so that it can perform inference. For example, you could add a docblock to the `callFoo` function:
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```php
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<?php
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class A {
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public function foo() : void {}
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}
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/**
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* @param array<A> $arr
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*/
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function callFoo(array $arr) : void {
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array_pop($arr)->foo(); // MixedMethodCall emitted here
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}
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callFoo(
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[new A()]
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);
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```
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Alternatively you could add a runtime check:
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```php
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<?php
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class A {
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public function foo() : void {}
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}
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function callFoo(array $arr) : void {
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$a = array_pop($arr);
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assert($a instanceof A);
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$a->foo(); // MixedMethodCall emitted here
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}
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callFoo(
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[new A()]
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);
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```
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