--- a/Source/WebCore/crypto/CryptoKey.cpp	
+++ a/Source/WebCore/crypto/CryptoKey.cpp	
@@ -67,6 +67,8 @@ auto CryptoKey::algorithm() const -> AlgorithmVariant
     case KeyAlgorithmClass::Raw:
         return downcast<RawKeyAlgorithm>(*algorithm).dictionary();
     }
+
+    RELEASE_ASSERT_NOT_REACHED();
 }
 
 auto CryptoKey::usages() const -> Vector<CryptoKeyUsage>
--- a/Source/WebCore/crypto/SubtleCrypto.cpp	
+++ a/Source/WebCore/crypto/SubtleCrypto.cpp	
@@ -394,6 +394,8 @@ static CryptoKeyUsageBitmap toCryptoKeyUsageBitmap(CryptoKeyUsage usage)
     case CryptoKeyUsage::UnwrapKey:
         return CryptoKeyUsageUnwrapKey;
     }
+
+    RELEASE_ASSERT_NOT_REACHED();
 }
 
 static CryptoKeyUsageBitmap toCryptoKeyUsageBitmap(const Vector<CryptoKeyUsage>& usages)
@@ -476,6 +478,8 @@ static std::optional<KeyData> toKeyData(SubtleCrypto::KeyFormat format, SubtleCr
             }
         );
     }
+
+    RELEASE_ASSERT_NOT_REACHED();
 }
 
 static Vector<uint8_t> copyToVector(BufferSource&& data)