diff --git a/src/BPM/bond_bpm.cpp b/src/BPM/bond_bpm.cpp
index c35e5d4b9b..5a20059860 100644
--- a/src/BPM/bond_bpm.cpp
+++ b/src/BPM/bond_bpm.cpp
@@ -279,8 +279,7 @@ double BondBPM::equilibrium_distance(int /*i*/)
       }
     } else {
       int type, j;
-      double delx, dely, delz, r;
-      double **x = atom->x;
+      double r;
       for (int i = 0; i < atom->nlocal; i++) {
         for (int m = 0; m < atom->num_bond[i]; m++) {
           type = atom->bond_type[i][m];
diff --git a/src/MC/fix_gcmc.h b/src/MC/fix_gcmc.h
index 2bdd9eb461..685451aaa1 100644
--- a/src/MC/fix_gcmc.h
+++ b/src/MC/fix_gcmc.h
@@ -35,7 +35,7 @@ class FixGCMC : public Fix {
   double memory_usage() override;
   void write_restart(FILE *) override;
   void restart(char *) override;
-  void *extract(const char *, int &);
+  void *extract(const char *, int &) override;
 
  private:
   int molecule_group, molecule_group_bit;
diff --git a/src/fix_pair.cpp b/src/fix_pair.cpp
index 5f9363daaa..4ef42b2f8b 100644
--- a/src/fix_pair.cpp
+++ b/src/fix_pair.cpp
@@ -84,7 +84,7 @@ FixPair::FixPair(LAMMPS *lmp, int narg, char **arg) :
 
   for (int ifield = 0; ifield < nfield; ifield++) {
     int columns = 0;         // set in case fieldname not recognized by pstyle
-    void *pvoid = pstyle->extract_peratom(fieldname[ifield],columns);
+    pstyle->extract_peratom(fieldname[ifield],columns);
     if (columns) ncols += columns;
     else ncols++;
     if (trigger[ifield]) {
diff --git a/src/fix_update_special_bonds.cpp b/src/fix_update_special_bonds.cpp
index 2eb24ff726..4b06b39ad4 100644
--- a/src/fix_update_special_bonds.cpp
+++ b/src/fix_update_special_bonds.cpp
@@ -84,7 +84,7 @@ void FixUpdateSpecialBonds::setup(int /*vflag*/)
 
 void FixUpdateSpecialBonds::pre_exchange()
 {
-  int i, j, m, n1, n3;
+  int i, j, m, n1;
   tagint tagi, tagj;
   int nlocal = atom->nlocal;