AK: Simplify constructors and conversions from nullptr_t

Problem:
- Many constructors are defined as `{}` rather than using the ` =
  default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
  instead of requiring the caller to default construct. This violates
  the C++ Core Guidelines suggestion to declare single-argument
  constructors explicit
  (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).

Solution:
- Change default constructors to use the compiler-provided default
  constructor.
- Remove implicit conversion operators from `nullptr_t` and change
  usage to enforce type consistency without conversion.

1 files changed, 1 insertions, 1 deletions

diff --git a/AK/Weakable.h b/AK/Weakable.h
index 4db6e1344d..867877f4e3 100644
--- a/AK/Weakable.h
+++ b/AK/Weakable.h
@@ -130,7 +130,7 @@ public:
     WeakPtr<U> make_weak_ptr() const;
 
 protected:
-    Weakable() { }
+    Weakable() = default;
 
     ~Weakable()
     {