diff --git a/gtsam/base/timing.cpp b/gtsam/base/timing.cpp
index b33f06045..4b41ea937 100644
--- a/gtsam/base/timing.cpp
+++ b/gtsam/base/timing.cpp
@@ -89,7 +89,7 @@ void TimingOutline::print(const std::string& outline) const {
     childOrder[child.second->myOrder_] = child.second;
   }
   // Print children
-  for(const ChildOrder::value_type order_child: childOrder) {
+  for(const ChildOrder::value_type& order_child: childOrder) {
     std::string childOutline(outline);
     childOutline += "|   ";
     order_child.second->print(childOutline);
diff --git a/gtsam/discrete/DecisionTreeFactor.cpp b/gtsam/discrete/DecisionTreeFactor.cpp
index f83349436..b7b9d7034 100644
--- a/gtsam/discrete/DecisionTreeFactor.cpp
+++ b/gtsam/discrete/DecisionTreeFactor.cpp
@@ -69,7 +69,7 @@ namespace gtsam {
     for(Key j: f.keys()) cs[j] = f.cardinality(j);
     // Convert map into keys
     DiscreteKeys keys;
-    for(const DiscreteKey& key: cs)
+    for(const std::pair<const Key,size_t>& key: cs)
       keys.push_back(key);
     // apply operand
     ADT result = ADT::apply(f, op);
diff --git a/gtsam/discrete/Potentials.cpp b/gtsam/discrete/Potentials.cpp
index fe99ea975..331a76c13 100644
--- a/gtsam/discrete/Potentials.cpp
+++ b/gtsam/discrete/Potentials.cpp
@@ -56,7 +56,7 @@ bool Potentials::equals(const Potentials& other, double tol) const {
 /* ************************************************************************* */
 void Potentials::print(const string& s, const KeyFormatter& formatter) const {
   cout << s << "\n  Cardinalities: {";
-  for (const DiscreteKey& key : cardinalities_)
+  for (const std::pair<const Key,size_t>& key : cardinalities_)
     cout << formatter(key.first) << ":" << key.second << ", ";
   cout << "}" << endl;
   ADT::print(" ");
diff --git a/gtsam/linear/Preconditioner.cpp b/gtsam/linear/Preconditioner.cpp
index 1c602a963..24a42afb8 100644
--- a/gtsam/linear/Preconditioner.cpp
+++ b/gtsam/linear/Preconditioner.cpp
@@ -145,7 +145,7 @@ void BlockJacobiPreconditioner::build(
 
   /* getting the block diagonals over the factors */
   std::map<Key, Matrix> hessianMap =gfg.hessianBlockDiagonal();
-  for ( const Matrix hessian: hessianMap | boost::adaptors::map_values)
+  for (const Matrix& hessian: hessianMap | boost::adaptors::map_values)
     blocks.push_back(hessian);
 
   /* if necessary, allocating the memory for cacheing the factorization results */
diff --git a/gtsam/linear/VectorValues.cpp b/gtsam/linear/VectorValues.cpp
index 0a25617e4..9b5868744 100644
--- a/gtsam/linear/VectorValues.cpp
+++ b/gtsam/linear/VectorValues.cpp
@@ -45,7 +45,7 @@ namespace gtsam {
 
   /* ************************************************************************* */
   VectorValues::VectorValues(const Vector& x, const Dims& dims) {
-    typedef pair<Key, size_t> Pair;
+    using Pair = pair<const Key, size_t>;
     size_t j = 0;
     for (const Pair& v : dims) {
       Key key;
diff --git a/gtsam/slam/dataset.cpp b/gtsam/slam/dataset.cpp
index 4a95b4297..3a2d04127 100644
--- a/gtsam/slam/dataset.cpp
+++ b/gtsam/slam/dataset.cpp
@@ -73,8 +73,8 @@ string findExampleDataFile(const string& name) {
   namesToSearch.push_back(name + ".xml");
 
   // Find first name that exists
-  for(const fs::path& root: rootsToSearch) {
-    for(const fs::path& name: namesToSearch) {
+  for(const fs::path root: rootsToSearch) {
+    for(const fs::path name: namesToSearch) {
       if (fs::is_regular_file(root / name))
         return (root / name).string();
     }
diff --git a/wrap/Module.cpp b/wrap/Module.cpp
index ec02dc412..780c6f8da 100644
--- a/wrap/Module.cpp
+++ b/wrap/Module.cpp
@@ -248,7 +248,7 @@ void Module::parseMarkup(const std::string& data) {
   // Create type attributes table and check validity
   typeAttributes.addClasses(expandedClasses);
   typeAttributes.addForwardDeclarations(forward_declarations);
-  for (const TypedefPair p: typedefs)
+  for (const TypedefPair& p: typedefs)
     typeAttributes.addType(p.newType);
   // add Eigen types as template arguments are also checked ?
   vector<ForwardDeclaration> eigen;