Allow names marking unused variable ($_, $__ etc.)

Author: simPod

src/Cdn77/Sniffs/NamingConventions/ValidVariableNameSniff.php

@@ -26,7 +26,7 @@
 
 class ValidVariableNameSniff extends AbstractVariableSniff
 {
-    public string $pattern = '\b[a-zA-Z][a-zA-Z0-9]*?([A-Z][a-zA-Z0-9]*?)*?\b';
+    public string $pattern = '\b(([a-zA-Z][a-zA-Z0-9]*?([A-Z][a-zA-Z0-9]*?)*?)|_+)\b';
 
     /**
      * Processes this test, when one of its tokens is encountered.

tests/Sniffs/NamingConventions/ValidVariableNameSniffTest.php

@@ -61,6 +61,7 @@ public function testErrors(): void
             141 => self::CODE_NOT_CAMEL_CAPS,
             146 => self::CODE_MEMBER_NOT_CAMEL_CAPS,
             150 => [self::CODE_NOT_CAMEL_CAPS, self::CODE_NOT_CAMEL_CAPS],
+            152 => self::CODE_NOT_CAMEL_CAPS,
         ];
         $possibleLines = array_keys($errorTypesPerLine);
 
@@ -78,6 +79,6 @@ public function testErrors(): void
             }
         }
 
-        self::assertSame(37, $file->getErrorCount());
+        self::assertSame(38, $file->getErrorCount());
     }
 }

tests/Sniffs/NamingConventions/data/ValidVariableNameSniffTest.inc

@@ -148,3 +148,5 @@ echo $obj?->varname;
 echo $obj?->_varName;
 
 $var_name . $var_name;
+
+fn($_, $__, $_x) => true;