Add NoDiscard attribute on mutation free methods

psalm.xml

@@ -14,4 +14,7 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
+    <issueHandlers>
+        <UndefinedAttributeClass errorLevel="suppress" />
+    </issueHandlers>
 </psalm>

src/LineParser.php

@@ -13,5 +13,6 @@ interface LineParser
     /**
      * @return Maybe<Log>
      */
+    #[\NoDiscard]
     public function __invoke(Str $line): Maybe;
 }

src/Log.php

@@ -41,11 +41,13 @@ public static function of(PointInTime $time, Str $raw, Set $attributes): self
         return new self($time, $raw, $attributes);
     }
 
+    #[\NoDiscard]
     public function time(): PointInTime
     {
         return $this->time;
     }
 
+    #[\NoDiscard]
     public function raw(): Str
     {
         return $this->raw;
@@ -54,6 +56,7 @@ public function raw(): Str
     /**
      * @return Set<Attribute>
      */
+    #[\NoDiscard]
     public function attributes(): Set
     {
         return $this->attributes;
@@ -62,16 +65,19 @@ public function attributes(): Set
     /**
      * @return Maybe<Attribute>
      */
+    #[\NoDiscard]
     public function attribute(string $key): Maybe
     {
         return $this->attributes->find(static fn($attribute) => $attribute->key() === $key);
     }
 
+    #[\NoDiscard]
     public function equals(self $log): bool
     {
         return $this->raw->equals($log->raw());
     }
 
+    #[\NoDiscard]
     public function toString(): string
     {
         return $this->raw->toString();

src/Log/Attribute.php

@@ -8,6 +8,8 @@
  */
 interface Attribute
 {
+    #[\NoDiscard]
     public function key(): string;
+    #[\NoDiscard]
     public function value(): mixed;
 }

src/Reader.php

@@ -18,6 +18,7 @@ private function __construct(LineParser $parser)
         $this->parse = $parser;
     }
 
+    #[\NoDiscard]
     public function __invoke(Content $file): Sequence
     {
         /**