diff --git a/gtsam/base/TestableAssertions.h b/gtsam/base/TestableAssertions.h
index b5068ad955..f0ea79a2eb 100644
--- a/gtsam/base/TestableAssertions.h
+++ b/gtsam/base/TestableAssertions.h
@@ -32,7 +32,8 @@ namespace gtsam {
 /**
  * Equals testing for basic types
  */
-inline bool assert_equal(const Key& expected, const Key& actual, double tol = 0.0) {
+inline bool assert_equal(const Key& expected, const Key& actual) {
+  // TODO - why isn't tol used?
   if(expected != actual) {
     std::cout << "Not equal:\nexpected: " << expected << "\nactual: " << actual << std::endl;
     return false;
diff --git a/gtsam/geometry/Line3.cpp b/gtsam/geometry/Line3.cpp
index f5cf344f51..5a4b22075e 100644
--- a/gtsam/geometry/Line3.cpp
+++ b/gtsam/geometry/Line3.cpp
@@ -97,7 +97,6 @@ Line3 transformTo(const Pose3 &wTc, const Line3 &wL,
   Rot3 cRw = wRc.inverse();
   Rot3 cRl = cRw * wL.R_;
 
-  Vector2 w_ab;
   Vector3 t = ((wL.R_).transpose() * wTc.translation());
   Vector2 c_ab(wL.a_ - t[0], wL.b_ - t[1]);
 
diff --git a/gtsam/geometry/Pose3.h b/gtsam/geometry/Pose3.h
index 54bdd7f4c4..e4896ae26f 100644
--- a/gtsam/geometry/Pose3.h
+++ b/gtsam/geometry/Pose3.h
@@ -56,9 +56,8 @@ class GTSAM_EXPORT Pose3: public LieGroup<Pose3, 6> {
 
   /** Copy constructor */
   Pose3(const Pose3& pose) = default;
-  //  :
-  //     R_(pose.R_), t_(pose.t_) {
-  // }
+
+  Pose3& operator=(const Pose3& other) = default;
 
   /** Construct from R,t */
   Pose3(const Rot3& R, const Point3& t) :
diff --git a/gtsam/geometry/Rot2.h b/gtsam/geometry/Rot2.h
index 7a6f25c4d0..faa0e79a28 100644
--- a/gtsam/geometry/Rot2.h
+++ b/gtsam/geometry/Rot2.h
@@ -53,7 +53,8 @@ namespace gtsam {
     
     /** copy constructor */
     Rot2(const Rot2& r) = default;
-    //  : Rot2(r.c_, r.s_) {}
+
+    Rot2& operator=(const Rot2& other) = default;
 
     /// Constructor from angle in radians == exponential map at identity
     Rot2(double theta) : c_(cos(theta)), s_(sin(theta)) {}
diff --git a/gtsam/geometry/SO4.cpp b/gtsam/geometry/SO4.cpp
index 1c4920af86..e2d6c2a69d 100644
--- a/gtsam/geometry/SO4.cpp
+++ b/gtsam/geometry/SO4.cpp
@@ -107,7 +107,6 @@ SO4 SO4::Expmap(const Vector6& xi, ChartJacobian H) {
   }
 
   // Build expX = exp(xi^)
-  Matrix4 expX;
   using std::cos;
   using std::sin;
   const auto X2 = X * X;
diff --git a/gtsam/geometry/Similarity3.cpp b/gtsam/geometry/Similarity3.cpp
index cf2360b083..e569755efe 100644
--- a/gtsam/geometry/Similarity3.cpp
+++ b/gtsam/geometry/Similarity3.cpp
@@ -45,7 +45,6 @@ static Point3Pairs subtractCentroids(const Point3Pairs &abPointPairs,
 static double calculateScale(const Point3Pairs &d_abPointPairs,
                              const Rot3 &aRb) {
   double x = 0, y = 0;
-  Point3 da, db;
   for (const auto& [da, db] : d_abPointPairs) {
     const Vector3 da_prime = aRb * db;
     y += da.transpose() * da_prime;
diff --git a/gtsam/hybrid/HybridGaussianProductFactor.cpp b/gtsam/hybrid/HybridGaussianProductFactor.cpp
index 280059f542..9a34ea1e95 100644
--- a/gtsam/hybrid/HybridGaussianProductFactor.cpp
+++ b/gtsam/hybrid/HybridGaussianProductFactor.cpp
@@ -33,7 +33,7 @@ static Y add(const Y& y1, const Y& y2) {
   GaussianFactorGraph result = y1.first;
   result.push_back(y2.first);
   return {result, y1.second + y2.second};
-};
+}
 
 /* *******************************************************************************/
 HybridGaussianProductFactor operator+(const HybridGaussianProductFactor& a,
diff --git a/gtsam/linear/VectorValues.h b/gtsam/linear/VectorValues.h
index 4728706c50..35a3817457 100644
--- a/gtsam/linear/VectorValues.h
+++ b/gtsam/linear/VectorValues.h
@@ -106,7 +106,7 @@ namespace gtsam {
     template<class CONTAINER>
     explicit VectorValues(const CONTAINER& c) : values_(c.begin(), c.end()) {}
 
-    /** Implicit copy constructor to specialize the explicit constructor from any container. */
+    /** Copy constructor to specialize the explicit constructor from any container. */
     VectorValues(const VectorValues& c) : values_(c.values_) {}
 
     /** Create from a pair of iterators over pair<Key,Vector>. */
@@ -119,6 +119,7 @@ namespace gtsam {
     /// Constructor from Vector, with Scatter
     VectorValues(const Vector& c, const Scatter& scatter);
 
+    // We override the copy constructor; expicitly declare operator=
     VectorValues& operator=(const VectorValues& other) = default;
 
     /** Create a VectorValues with the same structure as \c other, but filled with zeros. */
diff --git a/gtsam_unstable/base/Dummy.h b/gtsam_unstable/base/Dummy.h
index 548bce3445..f26585ac1e 100644
--- a/gtsam_unstable/base/Dummy.h
+++ b/gtsam_unstable/base/Dummy.h
@@ -29,6 +29,8 @@ namespace gtsam {
     size_t id;
     Dummy();
     ~Dummy();
+    Dummy(const Dummy& other) = default;
+    Dummy& operator=(const Dummy& other) = default;
     void print(const std::string& s="") const ;
     unsigned char dummyTwoVar(unsigned char a) const ;
   };
diff --git a/gtsam_unstable/base/FixedVector.h b/gtsam_unstable/base/FixedVector.h
index b1fff90ef5..ad6e4322d1 100644
--- a/gtsam_unstable/base/FixedVector.h
+++ b/gtsam_unstable/base/FixedVector.h
@@ -37,6 +37,8 @@ class FixedVector : public Eigen::Matrix<double, N, 1> {
   /** copy constructors */
   FixedVector(const FixedVector& v) : Base(v) {}
 
+  FixedVector& operator=(const FixedVector& other) = default;
+
   /** Convert from a variable-size vector to a fixed size vector */
   FixedVector(const Vector& v) : Base(v) {}
 
diff --git a/gtsam_unstable/slam/Mechanization_bRn2.h b/gtsam_unstable/slam/Mechanization_bRn2.h
index 3d91f6b0ea..b23a4c3eec 100644
--- a/gtsam_unstable/slam/Mechanization_bRn2.h
+++ b/gtsam_unstable/slam/Mechanization_bRn2.h
@@ -37,6 +37,8 @@ class GTSAM_UNSTABLE_EXPORT Mechanization_bRn2 {
   /// Copy constructor
   Mechanization_bRn2(const Mechanization_bRn2& other) = default;
 
+  Mechanization_bRn2& operator=(const Mechanization_bRn2& other) = default;
+
   /// gravity in the body frame
   Vector3 b_g(double g_e) const {
     Vector3 n_g(0, 0, g_e);