From 9beb60c71370182fb6004a7019c550fd919498d3 Mon Sep 17 00:00:00 2001
From: Jiancheng Chen <2742581175@qq.com>
Date: Thu, 18 Aug 2022 11:22:36 +0800
Subject: [PATCH] improve error messages in
 change_box,create_box,domain,input,lattice and neighbor.cpp

---
 src/change_box.cpp | 35 ++++++++++++++---------------
 src/create_box.cpp | 22 +++++++++---------
 src/domain.cpp     |  6 ++---
 src/input.cpp      |  8 +++----
 src/lattice.cpp    | 56 +++++++++++++++++++++++++---------------------
 src/neighbor.cpp   |  6 ++---
 6 files changed, 69 insertions(+), 64 deletions(-)

diff --git a/src/change_box.cpp b/src/change_box.cpp
index 08af5f11c9..b26d7803ed 100644
--- a/src/change_box.cpp
+++ b/src/change_box.cpp
@@ -46,14 +46,14 @@ void ChangeBox::command(int narg, char **arg)
 
   if (domain->box_exist == 0)
     error->all(FLERR,"Change_box command before simulation box is defined");
-  if (narg < 2) error->all(FLERR,"Illegal change_box command");
+  if (narg < 2) utils::missing_cmd_args(FLERR, "change_box", error);
 
   if (comm->me == 0) utils::logmesg(lmp,"Changing box ...\n");
 
   // group
 
   int igroup = group->find(arg[0]);
-  if (igroup == -1) error->all(FLERR,"Could not find change_box group ID");
+  if (igroup == -1) error->all(FLERR,"Could not find change_box group ID {}", arg[0]);
   int groupbit = group->bitmask[igroup];
 
   // parse operation arguments
@@ -70,7 +70,7 @@ void ChangeBox::command(int narg, char **arg)
   while (iarg < narg) {
     if (strcmp(arg[iarg],"x") == 0 || strcmp(arg[iarg],"y") == 0 ||
         strcmp(arg[iarg],"z") == 0) {
-      if (iarg+2 > narg) error->all(FLERR,"Illegal change_box command");
+      if (iarg+2 > narg) error->all(FLERR, "Illegal change_box {} command: missing argument(s)", arg[iarg]);
       ops[nops].style = XYZ;
       if (strcmp(arg[iarg],"x") == 0) ops[nops].dim = X;
       else if (strcmp(arg[iarg],"y") == 0) ops[nops].dim = Y;
@@ -80,7 +80,7 @@ void ChangeBox::command(int narg, char **arg)
         error->all(FLERR,"Cannot change_box in z dimension for 2d simulation");
 
       if (strcmp(arg[iarg+1],"final") == 0) {
-        if (iarg+4 > narg) error->all(FLERR,"Illegal change_box command");
+        if (iarg+4 > narg) error->all(FLERR, "Illegal change_box {} final command: missing argument(s)", arg[iarg]);
         ops[nops].flavor = FINAL;
         ops[nops].flo = utils::numeric(FLERR,arg[iarg+2],false,lmp);
         ops[nops].fhi = utils::numeric(FLERR,arg[iarg+3],false,lmp);
@@ -88,7 +88,7 @@ void ChangeBox::command(int narg, char **arg)
         nops++;
         iarg += 4;
       } else if (strcmp(arg[iarg+1],"delta") == 0) {
-        if (iarg+4 > narg) error->all(FLERR,"Illegal change_box command");
+        if (iarg+4 > narg) error->all(FLERR, "Illegal change_box {} delta command: missing argument(s)", arg[iarg]);
         ops[nops].flavor = DELTA;
         ops[nops].dlo = utils::numeric(FLERR,arg[iarg+2],false,lmp);
         ops[nops].dhi = utils::numeric(FLERR,arg[iarg+3],false,lmp);
@@ -96,7 +96,7 @@ void ChangeBox::command(int narg, char **arg)
         nops++;
         iarg += 4;
       } else if (strcmp(arg[iarg+1],"scale") == 0) {
-        if (iarg+3 > narg) error->all(FLERR,"Illegal change_box command");
+        if (iarg+3 > narg) error->all(FLERR, "Illegal change_box {} scale command: missing argument(s)", arg[iarg]);
         ops[nops].flavor = SCALE;
         ops[nops].scale = utils::numeric(FLERR,arg[iarg+2],false,lmp);
         ops[nops].vdim1 = ops[nops].vdim2 = -1;
@@ -112,11 +112,11 @@ void ChangeBox::command(int narg, char **arg)
         else ops[nops-1].vdim1 = ops[nops].dim;
         iarg += 2;
 
-      } else error->all(FLERR,"Illegal change_box command");
+      } else error->all(FLERR, "Unknown change_box {} argument: {}", arg[iarg], arg[iarg+1]);
 
     } else if (strcmp(arg[iarg],"xy") == 0 || strcmp(arg[iarg],"xz") == 0 ||
         strcmp(arg[iarg],"yz") == 0) {
-      if (iarg+2 > narg) error->all(FLERR,"Illegal change_box command");
+      if (iarg+2 > narg) error->all(FLERR, "Illegal change_box {} command: missing argument(s)", arg[iarg]);
       ops[nops].style = TILT;
       if (strcmp(arg[iarg],"xy") == 0) ops[nops].dim = XY;
       else if (strcmp(arg[iarg],"xz") == 0) ops[nops].dim = XZ;
@@ -126,21 +126,21 @@ void ChangeBox::command(int narg, char **arg)
         error->all(FLERR,"Cannot change_box in xz or yz for 2d simulation");
 
       if (strcmp(arg[iarg+1],"final") == 0) {
-        if (iarg+3 > narg) error->all(FLERR,"Illegal change_box command");
+        if (iarg+3 > narg) error->all(FLERR, "Illegal change_box {} final command: missing argument(s)", arg[iarg]);
         ops[nops].flavor = FINAL;
         ops[nops].ftilt = utils::numeric(FLERR,arg[iarg+2],false,lmp);
         nops++;
         iarg += 3;
       } else if (strcmp(arg[iarg+1],"delta") == 0) {
-        if (iarg+3 > narg) error->all(FLERR,"Illegal change_box command");
+        if (iarg+3 > narg) error->all(FLERR, "Illegal change_box {} delta command: missing argument(s)", arg[iarg]);
         ops[nops].flavor = DELTA;
         ops[nops].dtilt = utils::numeric(FLERR,arg[iarg+2],false,lmp);
         nops++;
         iarg += 3;
-      } else error->all(FLERR,"Illegal change_box command");
+      } else error->all(FLERR, "Unknown change_box {} argument: {}", arg[iarg], arg[iarg+1]);
 
     } else if (strcmp(arg[iarg],"boundary") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal change_box command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "change_box boundary", error);
       ops[nops].style = BOUNDARY;
       ops[nops].boundindex = iarg+1;
       nops++;
@@ -157,7 +157,6 @@ void ChangeBox::command(int narg, char **arg)
       iarg += 1;
 
     } else if (strcmp(arg[iarg],"set") == 0) {
-      if (iarg+1 > narg) error->all(FLERR,"Illegal change_box command");
       ops[nops].style = SET;
       nops++;
       iarg += 1;
@@ -170,7 +169,7 @@ void ChangeBox::command(int narg, char **arg)
     } else break;
   }
 
-  if (nops == 0) error->all(FLERR,"Illegal change_box command");
+  if (nops == 0) error->all(FLERR, "Unknown change_box keyword: {}", arg[iarg]);
 
   // move_atoms = 1 if need to move atoms to new procs after box changes
   // anything other than ORTHO or TRICLINIC may cause atom movement
@@ -393,19 +392,19 @@ void ChangeBox::command(int narg, char **arg)
 
 void ChangeBox::options(int narg, char **arg)
 {
-  if (narg < 0) error->all(FLERR,"Illegal change_box command");
+  if (narg < 0) utils::missing_cmd_args(FLERR, "change_box", error);
 
   scaleflag = 1;
 
   int iarg = 0;
   while (iarg < narg) {
     if (strcmp(arg[iarg],"units") == 0) {
-      if (iarg+2 > narg) error->all(FLERR,"Illegal change_box command");
+      if (iarg+2 > narg) utils::missing_cmd_args(FLERR, "change_box units", error);
       if (strcmp(arg[iarg+1],"box") == 0) scaleflag = 0;
       else if (strcmp(arg[iarg+1],"lattice") == 0) scaleflag = 1;
-      else error->all(FLERR,"Illegal change_box command");
+      else error->all(FLERR, "Invalid change_box units argument: {}", arg[iarg+1]);
       iarg += 2;
-    } else error->all(FLERR,"Illegal change_box command");
+    } else error->all(FLERR,"Unknown change_box keyword: {}", arg[iarg]);
   }
 }
 
diff --git a/src/create_box.cpp b/src/create_box.cpp
index cd6a63ca44..b05bfe0825 100644
--- a/src/create_box.cpp
+++ b/src/create_box.cpp
@@ -35,7 +35,7 @@ CreateBox::CreateBox(LAMMPS *lmp) : Command(lmp) {}
 
 void CreateBox::command(int narg, char **arg)
 {
-  if (narg < 2) error->all(FLERR, "Illegal create_box command");
+  if (narg < 2) utils::missing_cmd_args(FLERR, "create_box", error);
 
   if (domain->box_exist) error->all(FLERR, "Cannot create_box after simulation box is defined");
   if (domain->dimension == 2 && domain->zperiodic == 0)
@@ -107,56 +107,56 @@ void CreateBox::command(int narg, char **arg)
   int iarg = 2;
   while (iarg < narg) {
     if (strcmp(arg[iarg], "bond/types") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box bond/type", error);
       if (!atom->avec->bonds_allow) error->all(FLERR, "No bonds allowed with this atom style");
       atom->nbondtypes = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "angle/types") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box angle/types", error);
       if (!atom->avec->angles_allow) error->all(FLERR, "No angles allowed with this atom style");
       atom->nangletypes = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "dihedral/types") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box dihedral/types", error);
       if (!atom->avec->dihedrals_allow)
         error->all(FLERR, "No dihedrals allowed with this atom style");
       atom->ndihedraltypes = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "improper/types") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box improper/types", error);
       if (!atom->avec->impropers_allow)
         error->all(FLERR, "No impropers allowed with this atom style");
       atom->nimpropertypes = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "extra/bond/per/atom") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box extra/bond/per/atom", error);
       if (!atom->avec->bonds_allow) error->all(FLERR, "No bonds allowed with this atom style");
       atom->bond_per_atom = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "extra/angle/per/atom") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box extra/angle/per/atom", error);
       if (!atom->avec->angles_allow) error->all(FLERR, "No angles allowed with this atom style");
       atom->angle_per_atom = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "extra/dihedral/per/atom") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box extra/dihedral/per/atom", error);
       if (!atom->avec->dihedrals_allow)
         error->all(FLERR, "No dihedrals allowed with this atom style");
       atom->dihedral_per_atom = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "extra/improper/per/atom") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box extra/improper/per/atom", error);
       if (!atom->avec->impropers_allow)
         error->all(FLERR, "No impropers allowed with this atom style");
       atom->improper_per_atom = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "extra/special/per/atom") == 0) {
-      if (iarg + 2 > narg) error->all(FLERR, "Illegal create_box command");
+      if (iarg + 2 > narg) utils::missing_cmd_args(FLERR, "create_box extra/special/per/atom", error);
       force->special_extra = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
       atom->maxspecial += force->special_extra;
       iarg += 2;
     } else
-      error->all(FLERR, "Illegal create_box command");
+      error->all(FLERR, "Unknown create_box keyword: {}", arg[iarg]);
   }
 
   // problem setup using info from header
diff --git a/src/domain.cpp b/src/domain.cpp
index ebc468faed..7d60c20a24 100644
--- a/src/domain.cpp
+++ b/src/domain.cpp
@@ -1856,7 +1856,7 @@ const std::vector<Region *> Domain::get_region_list()
 
 void Domain::set_boundary(int narg, char **arg, int flag)
 {
-  if (narg != 3) error->all(FLERR,"Illegal boundary command");
+  if (narg != 3) error->all(FLERR,"Illegal boundary command: expected 3 argument but found {}", narg);
 
   char c;
   for (int idim = 0; idim < 3; idim++)
@@ -1870,8 +1870,8 @@ void Domain::set_boundary(int narg, char **arg, int flag)
       else if (c == 's') boundary[idim][iside] = 2;
       else if (c == 'm') boundary[idim][iside] = 3;
       else {
-        if (flag == 0) error->all(FLERR,"Illegal boundary command");
-        if (flag == 1) error->all(FLERR,"Illegal change_box command");
+        if (flag == 0) error->all(FLERR,"Unknown boundary keyword: {}", c);
+        if (flag == 1) error->all(FLERR,"Unknown change_box keyword: {}", c);
       }
     }
 
diff --git a/src/input.cpp b/src/input.cpp
index 2979503d30..bb84a86e2c 100644
--- a/src/input.cpp
+++ b/src/input.cpp
@@ -1351,7 +1351,7 @@ void Input::atom_modify()
 
 void Input::atom_style()
 {
-  if (narg < 1) error->all(FLERR,"Illegal atom_style command");
+  if (narg < 1) utils::missing_cmd_args(FLERR, "atom_style", error);
   if (domain->box_exist)
     error->all(FLERR,"Atom_style command after simulation box is defined");
   atom->create_avec(arg[0],narg-1,&arg[1],1);
@@ -1488,12 +1488,12 @@ void Input::dihedral_style()
 
 void Input::dimension()
 {
-  if (narg != 1) error->all(FLERR,"Illegal dimension command");
+  if (narg != 1) error->all(FLERR,"Illegal dimension command: expected 1 argument but found {}", narg);
   if (domain->box_exist)
     error->all(FLERR,"Dimension command after simulation box is defined");
   domain->dimension = utils::inumeric(FLERR,arg[0],false,lmp);
   if (domain->dimension != 2 && domain->dimension != 3)
-    error->all(FLERR,"Illegal dimension command");
+    error->all(FLERR, "Invalid dimension argument: {}", arg[0]);
 
   // must reset default extra_dof of all computes
   // since some were created before dimension command is encountered
@@ -1948,7 +1948,7 @@ void Input::unfix()
 
 void Input::units()
 {
-  if (narg != 1) error->all(FLERR,"Illegal units command");
+  if (narg != 1) error->all(FLERR,"Illegal units command: expected 1 argument but found {}", narg);
   if (domain->box_exist)
     error->all(FLERR,"Units command after simulation box is defined");
   update->set_units(arg[0]);
diff --git a/src/lattice.cpp b/src/lattice.cpp
index be69fc1821..f88a55a4d5 100644
--- a/src/lattice.cpp
+++ b/src/lattice.cpp
@@ -36,7 +36,7 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
 
   // parse style arg
 
-  if (narg < 1) error->all(FLERR,"Illegal lattice command");
+  if (narg < 1) utils::missing_cmd_args(FLERR, "lattice", error);
 
   if (strcmp(arg[0],"none") == 0) style = NONE;
   else if (strcmp(arg[0],"sc") == 0) style = SC;
@@ -48,10 +48,10 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
   else if (strcmp(arg[0],"sq2") == 0) style = SQ2;
   else if (strcmp(arg[0],"hex") == 0) style = HEX;
   else if (strcmp(arg[0],"custom") == 0) style = CUSTOM;
-  else error->all(FLERR,"Illegal lattice command");
+  else error->all(FLERR,"Unknown lattice keyword: {}", arg[0]);
 
   if (style == NONE) {
-    if (narg != 2) error->all(FLERR,"Illegal lattice command");
+    if (narg != 2) error->all(FLERR,"Illegal lattice command: expected 2 argument but found {}", narg);
 
     // Domain creates a default lattice of style "none"
     //   before Force class is instantiated, just use atof() in that case
@@ -61,7 +61,7 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
     else
       xlattice = ylattice = zlattice = atof(arg[1]);
 
-    if (xlattice <= 0.0) error->all(FLERR,"Illegal lattice command");
+    if (xlattice <= 0.0) error->all(FLERR, "Invalid lattice none argument: {}", arg[1]);
     return;
   }
 
@@ -81,9 +81,9 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
 
   // scale = conversion factor between lattice and box units
 
-  if (narg < 2) error->all(FLERR,"Illegal lattice command");
+  if (narg < 2) utils::missing_cmd_args(FLERR, "lattice", error);
   scale = utils::numeric(FLERR,arg[1],false,lmp);
-  if (scale <= 0.0) error->all(FLERR,"Illegal lattice command");
+  if (scale <= 0.0) error->all(FLERR, "Invalid lattice {} argument: {}", arg[0], arg[1]);
 
   // set basis atoms for each style
   // x,y,z = fractional coords within unit cell
@@ -148,23 +148,25 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
   int iarg = 2;
   while (iarg < narg) {
     if (strcmp(arg[iarg],"origin") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice origin", error);
       origin[0] = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       origin[1] = utils::numeric(FLERR,arg[iarg+2],false,lmp);
       origin[2] = utils::numeric(FLERR,arg[iarg+3],false,lmp);
-      if (origin[0] < 0.0 || origin[0] >= 1.0 ||
-          origin[1] < 0.0 || origin[1] >= 1.0 ||
-          origin[2] < 0.0 || origin[2] >= 1.0)
-        error->all(FLERR,"Illegal lattice command");
+      if (origin[0] < 0.0 || origin[0] >= 1.0)
+        error->all(FLERR, "Invalid lattice origin argument: {}", origin[0]);
+      if (origin[1] < 0.0 || origin[1] >= 1.0)
+        error->all(FLERR, "Invalid lattice origin argument: {}", origin[1]);
+      if (origin[2] < 0.0 || origin[2] >= 1.0)
+        error->all(FLERR, "Invalid lattice origin argument: {}", origin[2]);
       iarg += 4;
 
     } else if (strcmp(arg[iarg],"orient") == 0) {
-      if (iarg+5 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+5 > narg) utils::missing_cmd_args(FLERR, "lattice orient", error);
       int dim = -1;
       if (strcmp(arg[iarg+1],"x") == 0) dim = 0;
       else if (strcmp(arg[iarg+1],"y") == 0) dim = 1;
       else if (strcmp(arg[iarg+1],"z") == 0) dim = 2;
-      else error->all(FLERR,"Illegal lattice command");
+      else error->all(FLERR,"Unknown lattice orient argument: {}", arg[iarg+1]);
       int *orient = nullptr;
       if (dim == 0) orient = orientx;
       else if (dim == 1) orient = orienty;
@@ -175,7 +177,7 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
       iarg += 5;
 
     } else if (strcmp(arg[iarg],"spacing") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice spacing", error);
       spaceflag = 1;
       xlattice = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       ylattice = utils::numeric(FLERR,arg[iarg+2],false,lmp);
@@ -183,46 +185,50 @@ Lattice::Lattice(LAMMPS *lmp, int narg, char **arg) : Pointers(lmp)
       iarg += 4;
 
     } else if (strcmp(arg[iarg],"a1") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice a1", error);
       if (style != CUSTOM)
         error->all(FLERR,
-                   "Invalid option in lattice command for non-custom style");
+                   "Invalid a1 in lattice command for non-custom style");
       a1[0] = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       a1[1] = utils::numeric(FLERR,arg[iarg+2],false,lmp);
       a1[2] = utils::numeric(FLERR,arg[iarg+3],false,lmp);
       iarg += 4;
     } else if (strcmp(arg[iarg],"a2") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice a2", error);
       if (style != CUSTOM)
         error->all(FLERR,
-                   "Invalid option in lattice command for non-custom style");
+                   "Invalid a2 option in lattice command for non-custom style");
       a2[0] = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       a2[1] = utils::numeric(FLERR,arg[iarg+2],false,lmp);
       a2[2] = utils::numeric(FLERR,arg[iarg+3],false,lmp);
       iarg += 4;
     } else if (strcmp(arg[iarg],"a3") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice a3", error);
       if (style != CUSTOM)
         error->all(FLERR,
-                   "Invalid option in lattice command for non-custom style");
+                   "Invalid a3 option in lattice command for non-custom style");
       a3[0] = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       a3[1] = utils::numeric(FLERR,arg[iarg+2],false,lmp);
       a3[2] = utils::numeric(FLERR,arg[iarg+3],false,lmp);
       iarg += 4;
 
     } else if (strcmp(arg[iarg],"basis") == 0) {
-      if (iarg+4 > narg) error->all(FLERR,"Illegal lattice command");
+      if (iarg+4 > narg) utils::missing_cmd_args(FLERR, "lattice basis", error);
       if (style != CUSTOM)
         error->all(FLERR,
-                   "Invalid option in lattice command for non-custom style");
+                   "Invalid basis option in lattice command for non-custom style");
       double x = utils::numeric(FLERR,arg[iarg+1],false,lmp);
       double y = utils::numeric(FLERR,arg[iarg+2],false,lmp);
       double z = utils::numeric(FLERR,arg[iarg+3],false,lmp);
-      if (x < 0.0 || x >= 1.0 || y < 0.0 || y >= 1.0 || z < 0.0 || z >= 1.0)
-        error->all(FLERR,"Illegal lattice command");
+      if (x < 0.0 || x >= 1.0)
+        error->all(FLERR, "Invalid lattice basis argument: {}", x);
+      if (y < 0.0 || y >= 1.0)
+        error->all(FLERR, "Invalid lattice basis argument: {}", y);
+      if (z < 0.0 || z >= 1.0)
+        error->all(FLERR, "Invalid lattice basis argument: {}", z);
       add_basis(x,y,z);
       iarg += 4;
-    } else error->all(FLERR,"Illegal lattice command");
+    } else error->all(FLERR,"Unknown lattice keyword: {}", arg[iarg]);
   }
 
   // check settings for errors
diff --git a/src/neighbor.cpp b/src/neighbor.cpp
index 9e74ad3809..ab77e15a4b 100644
--- a/src/neighbor.cpp
+++ b/src/neighbor.cpp
@@ -2533,10 +2533,10 @@ void Neighbor::build_one(class NeighList *mylist, int preflag)
 
 void Neighbor::set(int narg, char **arg)
 {
-  if (narg != 2) error->all(FLERR,"Illegal neighbor command");
+  if (narg != 2) error->all(FLERR,"Illegal neighbor command: expected 2 argument but found {}", narg);
 
   skin = utils::numeric(FLERR,arg[0],false,lmp);
-  if (skin < 0.0) error->all(FLERR,"Illegal neighbor command");
+  if (skin < 0.0) error->all(FLERR, "Invalid neighbor argument: {}", arg[0]);
 
   if (strcmp(arg[1],"nsq") == 0) style = Neighbor::NSQ;
   else if (strcmp(arg[1],"bin") == 0) style = Neighbor::BIN;
@@ -2544,7 +2544,7 @@ void Neighbor::set(int narg, char **arg)
     style = Neighbor::MULTI;
     ncollections = atom->ntypes;
   } else if (strcmp(arg[1],"multi/old") == 0) style = Neighbor::MULTI_OLD;
-  else error->all(FLERR,"Illegal neighbor command");
+  else error->all(FLERR,"Unknown neighbor {} argument: {}", arg[0], arg[1]);
 
   if (style == Neighbor::MULTI_OLD && lmp->citeme) lmp->citeme->add(cite_neigh_multi_old);
   if (style == Neighbor::MULTI && lmp->citeme) lmp->citeme->add(cite_neigh_multi);