Merge #20530: lint, refactor: Update cppcheck linter to c++17 and improve explicit usage

1e62350 refactor: Improve use of explicit keyword (Fabian Jahr)
c502a6d lint: Use c++17 std in cppcheck linter (Fabian Jahr)

Pull request description:

  I found the `extended-lint-cppcheck` linter still uses `std=c++11` when reviewing #20471. The only difference in the output after this change is one line is missing:

  ```
  src/script/descriptor.cpp:159:5: warning: Struct 'PubkeyProvider' has a constructor with 1 argument that is not explicit. [noExplicitConstructor]
  ```

  After some digging, I am still not sure why this one is ignored with c++17 when 40 other`noExplicitConstructor` warnings were still appearing.

  In the second commit, I fix these warnings, adding `explicit` where appropriate and adding fixes to ignore otherwise.

ACKs for top commit:
  practicalswift:
    cr ACK 1e62350: patch looks correct!
  MarcoFalke:
    review ACK 1e62350

Tree-SHA512: dff7b324429a57160e217cf38d9ddbb6e70c6cb3d3e3e0bd4013d88e07afc2292c3df94d0acf7122e9d486322821682ecf15c8f2724a78667764c05d47f89a12

Author: fanquake

src/net_processing.cpp

@@ -451,7 +451,7 @@ struct Peer {
     /** Work queue of items requested by this peer **/
     std::deque<CInv> m_getdata_requests GUARDED_BY(m_getdata_requests_mutex);
 
-    Peer(NodeId id) : m_id(id) {}
+    explicit Peer(NodeId id) : m_id(id) {}
 };
 
 using PeerRef = std::shared_ptr<Peer>;

src/node/interfaces.cpp

@@ -64,7 +64,7 @@ namespace {
 class NodeImpl : public Node
 {
 public:
-    NodeImpl(NodeContext* context) { setContext(context); }
+    explicit NodeImpl(NodeContext* context) { setContext(context); }
     void initLogging() override { InitLogging(*Assert(m_context->args)); }
     void initParameterInteraction() override { InitParameterInteraction(*Assert(m_context->args)); }
     bilingual_str getWarnings() override { return GetWarnings(true); }

src/pubkey.h

@@ -223,7 +223,7 @@ class XOnlyPubKey
 
 public:
     /** Construct an x-only pubkey from exactly 32 bytes. */
-    XOnlyPubKey(Span<const unsigned char> bytes);
+    explicit XOnlyPubKey(Span<const unsigned char> bytes);
 
     /** Verify a Schnorr signature against this public key.
      *

src/qt/test/addressbooktests.h

@@ -15,7 +15,7 @@ class Node;
 class AddressBookTests : public QObject
 {
 public:
-    AddressBookTests(interfaces::Node& node) : m_node(node) {}
+    explicit AddressBookTests(interfaces::Node& node) : m_node(node) {}
     interfaces::Node& m_node;
 
     Q_OBJECT

src/qt/test/rpcnestedtests.h

@@ -15,7 +15,7 @@ class Node;
 class RPCNestedTests : public QObject
 {
 public:
-    RPCNestedTests(interfaces::Node& node) : m_node(node) {}
+    explicit RPCNestedTests(interfaces::Node& node) : m_node(node) {}
     interfaces::Node& m_node;
 
     Q_OBJECT

src/qt/test/wallettests.h

@@ -15,7 +15,7 @@ class Node;
 class WalletTests : public QObject
 {
  public:
-    WalletTests(interfaces::Node& node) : m_node(node) {}
+    explicit WalletTests(interfaces::Node& node) : m_node(node) {}
     interfaces::Node& m_node;
 
     Q_OBJECT

src/rpc/request.h

@@ -40,7 +40,7 @@ class JSONRPCRequest
     std::string peerAddr;
     const util::Ref& context;
 
-    JSONRPCRequest(const util::Ref& context) : id(NullUniValue), params(NullUniValue), fHelp(false), context(context) {}
+    explicit JSONRPCRequest(const util::Ref& context) : id(NullUniValue), params(NullUniValue), fHelp(false), context(context) {}
 
     //! Initializes request information from another request object and the
     //! given context. The implementation should be updated if any members are

src/script/descriptor.cpp

@@ -156,7 +156,7 @@ struct PubkeyProvider
     uint32_t m_expr_index;
 
 public:
-    PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
+    explicit PubkeyProvider(uint32_t exp_index) : m_expr_index(exp_index) {}
 
     virtual ~PubkeyProvider() = default;
 

src/script/standard.h

@@ -28,7 +28,7 @@ class BaseHash
 
 public:
     BaseHash() : m_hash() {}
-    BaseHash(const HashType& in) : m_hash(in) {}
+    explicit BaseHash(const HashType& in) : m_hash(in) {}
 
     unsigned char* begin()
     {

src/test/fuzz/signature_checker.cpp

@@ -24,7 +24,7 @@ class FuzzedSignatureChecker : public BaseSignatureChecker
     FuzzedDataProvider& m_fuzzed_data_provider;
 
 public:
-    FuzzedSignatureChecker(FuzzedDataProvider& fuzzed_data_provider) : m_fuzzed_data_provider(fuzzed_data_provider)
+    explicit FuzzedSignatureChecker(FuzzedDataProvider& fuzzed_data_provider) : m_fuzzed_data_provider(fuzzed_data_provider)
     {
     }