diff --git a/common/struct_reflection.h b/common/struct_reflection.h
index 560cb5bb1574..2583e24a0681 100644
--- a/common/struct_reflection.h
+++ b/common/struct_reflection.h
@@ -36,8 +36,11 @@ namespace Internal {
 template <typename T>
 struct AnyField {
   template <typename FieldT>
+  // NOLINTNEXTLINE(google-explicit-constructor)
   operator FieldT&() const;
+
   template <typename FieldT>
+  // NOLINTNEXTLINE(google-explicit-constructor)
   operator FieldT&&() const;
 
   // Don't allow conversion to T itself. This ensures we don't match against a
@@ -52,11 +55,11 @@ struct AnyField {
 
 // Detector for whether we can list-initialize T from the given list of fields.
 template <typename T, typename... Fields>
-constexpr bool CanListInitialize(decltype(T{Fields()...})*) {
+constexpr auto CanListInitialize(decltype(T{Fields()...})* /*unused*/) -> bool {
   return true;
 }
 template <typename T, typename... Fields>
-constexpr bool CanListInitialize(...) {
+constexpr auto CanListInitialize(...) -> bool {
   return false;
 }
 
diff --git a/common/struct_reflection_test.cpp b/common/struct_reflection_test.cpp
index ec53639a61f0..619cb231e9bf 100644
--- a/common/struct_reflection_test.cpp
+++ b/common/struct_reflection_test.cpp
@@ -25,7 +25,7 @@ struct ReferenceField {
 };
 
 struct NoDefaultConstructor {
-  NoDefaultConstructor(int n) : v(n) {}
+  explicit NoDefaultConstructor(int n) : v(n) {}
   int v;
 };
 
@@ -42,8 +42,8 @@ TEST(StructReflectionTest, CanListInitialize) {
   {
     using Type = OneField;
     using Field = Internal::AnyField<Type>;
-    static_assert(Internal::CanListInitialize<Type>(0));
-    static_assert(Internal::CanListInitialize<Type, Field>(0));
+    static_assert(Internal::CanListInitialize<Type>(nullptr));
+    static_assert(Internal::CanListInitialize<Type, Field>(nullptr));
     static_assert(!Internal::CanListInitialize<Type, Field, Field>(0));
   }
 
@@ -51,7 +51,7 @@ TEST(StructReflectionTest, CanListInitialize) {
     using Type = OneFieldNoDefaultConstructor;
     using Field = Internal::AnyField<Type>;
     static_assert(!Internal::CanListInitialize<Type>(0));
-    static_assert(Internal::CanListInitialize<Type, Field>(0));
+    static_assert(Internal::CanListInitialize<Type, Field>(nullptr));
     static_assert(!Internal::CanListInitialize<Type, Field, Field>(0));
   }
 }
@@ -82,7 +82,8 @@ TEST(StructReflectionTest, TwoField) {
 
 TEST(StructReflectionTest, NoDefaultConstructor) {
   std::tuple<NoDefaultConstructor, NoDefaultConstructor> fields =
-      AsTuple(TwoFieldsNoDefaultConstructor{.x = 1, .y = 2});
+      AsTuple(TwoFieldsNoDefaultConstructor{.x = NoDefaultConstructor(1),
+                                            .y = NoDefaultConstructor(2)});
   EXPECT_EQ(std::get<0>(fields).v, 1);
   EXPECT_EQ(std::get<1>(fields).v, 2);
 }
diff --git a/testing/file_test/line.h b/testing/file_test/line.h
index e0783fed3c4f..6ceb45c25b80 100644
--- a/testing/file_test/line.h
+++ b/testing/file_test/line.h
@@ -15,7 +15,7 @@ class FileTestLineBase : public Printable<FileTestLineBase> {
  public:
   explicit FileTestLineBase(int file_number, int line_number)
       : file_number_(file_number), line_number_(line_number) {}
-  virtual ~FileTestLineBase() {}
+  virtual ~FileTestLineBase() = default;
 
   // Prints the autoupdated line.
   virtual auto Print(llvm::raw_ostream& out) const -> void = 0;