catch.alreadyCaught - Phpstan

Code example

php

<?php declare(strict_types = 1);

function doFoo(): void
{
	try {
		doSomething();
	} catch (\Throwable $e) {

	} catch (\TypeError $e) {

	}
}

Why is it reported?

PHP evaluates catch blocks in order from top to bottom and enters the first one whose type matches the thrown exception. In the example above, \Throwable is a supertype of \TypeError, so the first catch block will always match any TypeError before the second block is reached. The second catch block is dead code and will never execute.

How to fix it

Reorder the catch blocks so that more specific exception types come first:

diff-php

 <?php declare(strict_types = 1);

 function doFoo(): void
 {
 	try {
 		doSomething();
-	} catch (\Throwable $e) {
-
 	} catch (\TypeError $e) {
+		// Handle TypeError specifically
+	} catch (\Throwable $e) {
+		// Handle everything else
 	}
 }

Or remove the dead catch block if it is not needed:

diff-php

 <?php declare(strict_types = 1);

 function doFoo(): void
 {
 	try {
 		doSomething();
 	} catch (\Throwable $e) {

-	} catch (\TypeError $e) {
-
 	}
 }