Static Function in Namespace Not Defined

Error

static function 'FString OS_MDC_Keys::ReplaceAll()' declared but not defined

namespace OS_MDC_Keys
{
  static FString ReplaceAll();
}

Cause

A function declared as static in a namespace needs to be defined in the header.

Fix

Either move the function definition to the header OR remove the static specifier. Global functions in namespaces do not need to be static.

namespace OS_MDC_Keys
{
  static FString ReplaceAll() {}
}

namespace OS_MDC_Keys
{
  FString ReplaceAll();
}