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41 lines
834 B
Markdown
41 lines
834 B
Markdown
# NoValue
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Emitted when Psalm invalidated all possible types for a given expression. It is often an indication that Psalm found dead code or that documented types were not exhaustive
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```php
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<?php
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/**
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* @return never
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*/
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function foo() : void {
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exit();
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}
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$a = foo(); // Psalm knows $a will never contain any type because foo() won't return
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```
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```php
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<?php
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function foo() : void {
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return throw new Exception(''); //Psalm detected the return expression is never used
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}
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```
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```php
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<?php
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function shutdown(): never {die('Application closed unexpectedly');}
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function foo(string $_a): void{}
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foo(shutdown()); // foo() will never be called
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```
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```php
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<?php
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$a = [];
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/** @psalm-suppress TypeDoesNotContainType */
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assert(!empty($a));
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count($a); // Assert above always fail. There is no possible type that $a can have here
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``` |