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

1e62350ca20898189904a88dfef9ea11ddcd8626 refactor: Improve use of explicit keyword (Fabian Jahr)
c502a6dbfb854ca827a5a3925394f9e09d29b898 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 1e62350ca20898189904a88dfef9ea11ddcd8626: patch looks correct!
  MarcoFalke:
    review ACK 1e62350ca20898189904a88dfef9ea11ddcd8626

Tree-SHA512: dff7b324429a57160e217cf38d9ddbb6e70c6cb3d3e3e0bd4013d88e07afc2292c3df94d0acf7122e9d486322821682ecf15c8f2724a78667764c05d47f89a12

3 files changed, 3 insertions, 3 deletions

diff --git a/src/test/fuzz/signature_checker.cpp b/src/test/fuzz/signature_checker.cpp
index e121c89665..970452dbcc 100644
--- a/src/test/fuzz/signature_checker.cpp
+++ b/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)
     {
     }
 
diff --git a/src/test/util/logging.h b/src/test/util/logging.h
index 1fcf7ca305..a49f9a7292 100644
--- a/src/test/util/logging.h
+++ b/src/test/util/logging.h
@@ -32,7 +32,7 @@ class DebugLogHelper
     void check_found();
 
 public:
-    DebugLogHelper(std::string message, MatchFn match = [](const std::string*){ return true; });
+    explicit DebugLogHelper(std::string message, MatchFn match = [](const std::string*){ return true; });
     ~DebugLogHelper() { check_found(); }
 };
 
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 36fa1a0299..131508f5f8 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -231,7 +231,7 @@ public:
         Optional<std::vector<std::string>> list_value;
         const char* error = nullptr;
 
-        Expect(util::SettingsValue s) : setting(std::move(s)) {}
+        explicit Expect(util::SettingsValue s) : setting(std::move(s)) {}
         Expect& DefaultString() { default_string = true; return *this; }
         Expect& DefaultInt() { default_int = true; return *this; }
         Expect& DefaultBool() { default_bool = true; return *this; }