STYLE: Prefer = default to explicitly trivial implementations

This check replaces default bodies of special member functions with
= default;. The explicitly defaulted function declarations enable more
opportunities in optimization, because the compiler might treat
explicitly defaulted functions as trivial.

Additionally, the C++11 use of = default more clearly expreses the
intent for the special member functions.

Author: hjmjohnson

include/itkArrivalFunctionToPathFilter.h

@@ -84,8 +84,8 @@ class ITK_TEMPLATE_EXPORT ArrivalFunctionToPathCommand : public itk::Command
   }
 
 protected:
-  ArrivalFunctionToPathCommand() {}
-  ~ArrivalFunctionToPathCommand() override {}
+  ArrivalFunctionToPathCommand() = default;
+  ~ArrivalFunctionToPathCommand() override = default;
 
 private:
   typename FilterType::Pointer m_Filter;

include/itkArrivalFunctionToPathFilter.hxx

@@ -34,8 +34,7 @@ ArrivalFunctionToPathFilter<TInputImage, TOutputPath>::ArrivalFunctionToPathFilt
 
 
 template <typename TInputImage, typename TOutputPath>
-ArrivalFunctionToPathFilter<TInputImage, TOutputPath>::~ArrivalFunctionToPathFilter()
-{}
+ArrivalFunctionToPathFilter<TInputImage, TOutputPath>::~ArrivalFunctionToPathFilter() = default;
 
 template <typename TInputImage, typename TOutputPath>
 void

include/itkIterateNeighborhoodOptimizer.h

@@ -122,7 +122,7 @@ class MinimalPathExtraction_EXPORT IterateNeighborhoodOptimizer : public SingleV
 
 protected:
   IterateNeighborhoodOptimizer();
-  ~IterateNeighborhoodOptimizer() override{};
+  ~IterateNeighborhoodOptimizer() override = default;
   void
   PrintSelf(std::ostream & os, Indent indent) const override;
 

include/itkPhysicalCentralDifferenceImageFunction.h

@@ -132,7 +132,7 @@ class ITK_TEMPLATE_EXPORT PhysicalCentralDifferenceImageFunction
 
 protected:
   PhysicalCentralDifferenceImageFunction();
-  ~PhysicalCentralDifferenceImageFunction() override{};
+  ~PhysicalCentralDifferenceImageFunction() override = default;
   void
   PrintSelf(std::ostream & os, Indent indent) const override;
 

include/itkSingleImageCostFunction.h

@@ -151,7 +151,7 @@ class ITK_TEMPLATE_EXPORT SingleImageCostFunction : public SingleValuedCostFunct
 
 protected:
   SingleImageCostFunction();
-  ~SingleImageCostFunction() override {}
+  ~SingleImageCostFunction() override = default;
   void
   PrintSelf(std::ostream & os, Indent indent) const override;
 

include/itkSpeedFunctionPathInformation.hxx

@@ -31,8 +31,7 @@ SpeedFunctionPathInformation<TPoint>::SpeedFunctionPathInformation()
 
 
 template <typename TPoint>
-SpeedFunctionPathInformation<TPoint>::~SpeedFunctionPathInformation()
-{}
+SpeedFunctionPathInformation<TPoint>::~SpeedFunctionPathInformation() = default;
 
 
 template <typename TPoint>

include/itkSpeedFunctionToPathFilter.hxx

@@ -33,8 +33,7 @@ SpeedFunctionToPathFilter<TInputImage, TOutputPath>::SpeedFunctionToPathFilter()
 
 
 template <typename TInputImage, typename TOutputPath>
-SpeedFunctionToPathFilter<TInputImage, TOutputPath>::~SpeedFunctionToPathFilter()
-{}
+SpeedFunctionToPathFilter<TInputImage, TOutputPath>::~SpeedFunctionToPathFilter() = default;
 
 
 template <typename TInputImage, typename TOutputPath>