[multi-radio] fix clang-tidy warnings (#6821)

- enable TREL in clang-tidy check
- add explicit keyword to constructors
- fix inconsistent parameter names
- remove redundant initializer
- use nullptr

script/make-pretty

@@ -115,6 +115,7 @@ readonly OT_CLANG_TIDY_BUILD_OPTS=(
     '-DOT_SNTP_CLIENT=ON'
     '-DOT_SRP_CLIENT=ON'
     '-DOT_THREAD_VERSION=1.2'
+    '-DOT_TREL=ON'
     '-DOT_COVERAGE=ON'
     '-DOT_LOG_LEVEL_DYNAMIC=ON'
     '-DOT_COMPILE_WARNING_AS_ERROR=ON'

src/core/api/multi_radio_api.cpp

@@ -47,7 +47,7 @@ using namespace ot;
 
 otError otMultiRadioGetNeighborInfo(otInstance *              aInstance,
                                     const otExtAddress *      aExtAddress,
-                                    otMultiRadioNeighborInfo *aInfo)
+                                    otMultiRadioNeighborInfo *aNeighborInfo)
 {
     Error     error    = kErrorNone;
     Instance &instance = *static_cast<Instance *>(aInstance);
@@ -55,9 +55,9 @@ otError otMultiRadioGetNeighborInfo(otInstance *              aInstance,
 
     neighbor = instance.Get<NeighborTable>().FindNeighbor(*static_cast<const Mac::ExtAddress *>(aExtAddress),
                                                           Neighbor::kInStateAnyExceptInvalid);
-    VerifyOrExit(neighbor != NULL, error = kErrorNotFound);
+    VerifyOrExit(neighbor != nullptr, error = kErrorNotFound);
 
-    neighbor->PopulateMultiRadioInfo(*aInfo);
+    neighbor->PopulateMultiRadioInfo(*aNeighborInfo);
 
 exit:
     return error;

src/core/mac/mac_links.cpp

@@ -51,9 +51,6 @@ TxFrames::TxFrames(Instance &aInstance)
 #if OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE
     , mTxFrameTrel(aInstance.Get<Trel::Link>().GetTransmitFrame())
 #endif
-#if OPENTHREAD_CONFIG_MULTI_RADIO
-    , mSelectedRadioTypes()
-#endif
 {
 }
 

src/core/mac/mac_types.hpp

@@ -671,7 +671,7 @@ public:
      * @param[in] aMask   A bit-mask representing the radio types (the first bit corresponds to radio type 0, and so on)
      *
      */
-    RadioTypes(uint8_t aMask)
+    explicit RadioTypes(uint8_t aMask)
         : mBitMask(aMask)
     {
     }

src/core/radio/trel_packet.cpp

@@ -116,14 +116,14 @@ void Packet::Init(uint8_t *aBuffer, uint16_t aLength)
     mLength = aLength;
 }
 
-void Packet::Init(Header::Type aType, uint8_t *mPayload, uint16_t mPayloadLength)
+void Packet::Init(Header::Type aType, uint8_t *aPayload, uint16_t aPayloadLength)
 {
     uint16_t headerSize = Header::GetSize(aType);
 
     // The payload buffer should reserve enough bytes for
     // header (depending on type) before the payload.
 
-    Init(mPayload - headerSize, mPayloadLength + headerSize);
+    Init(aPayload - headerSize, aPayloadLength + headerSize);
     GetHeader().Init(aType);
 }
 

src/core/radio/trel_packet.hpp

@@ -284,7 +284,6 @@ public:
      * @param[in] aPayloadLength The length (number of bytes) in the payload only (not including the header).
      *
      */
-
     void Init(Header::Type aType, uint8_t *aPayload, uint16_t aPayloadLength);
 
     /**

src/core/thread/mesh_forwarder.hpp

@@ -314,11 +314,11 @@ public:
      * on the radio link.
      *
      * @param[in] aNeighbor  The neighbor for which the deferred ack status is being reported.
-     * @param[in] aTxError   The deferred ack error status: `kErrorNone` to indicate a deferred ack was received,
+     * @param[in] aError     The deferred ack error status: `kErrorNone` to indicate a deferred ack was received,
      *                       `kErrorNoAck` to indicate an ack timeout.
      *
      */
-    void HandleDeferredAck(Neighbor &aNeighbor, Error aTxError);
+    void HandleDeferredAck(Neighbor &aNeighbor, Error aError);
 #endif
 
 private:

src/core/thread/radio_selector.hpp

@@ -114,7 +114,7 @@ public:
      * @param[in]  aInstance     A reference to the OpenThread instance.
      *
      */
-    RadioSelector(Instance &aInstance);
+    explicit RadioSelector(Instance &aInstance);
 
     /**
      * This method updates the neighbor info (for multi radio support) on a received frame event.
@@ -173,13 +173,13 @@ public:
      * The `aTxFrames` will also be updated to indicate which radio links are to be used.
      *
      * @param[inout] aMessage   The message to send.
-     * @param[in]    aDest      The MAC destination address.
+     * @param[in]    aMacDest   The MAC destination address.
      * @param[inout] aTxFrames  The set of TxFrames for all radio links.
      *
      * @returns  A reference to `mTxFrame` to use when preparing the frame for tx.
      *
      */
-    Mac::TxFrame &SelectRadio(Message &aMessage, const Mac::Address &aDest, Mac::TxFrames &aTxFrames);
+    Mac::TxFrame &SelectRadio(Message &aMessage, const Mac::Address &aMacDest, Mac::TxFrames &aTxFrames);
 
 private:
     enum