Add -Wimplicit-fallthrough.

Clang doesn't enable this warning by default, so we pass it explicitly.
GCC pre-GCC 7 doesn't recognize the flag, so we can't pass it for GCC.
GCC 7 enables it by default as part of -Wextra.

Makefile.simple

@@ -82,22 +82,22 @@ endif
 ifeq (${TOOLCHAIN},clang)
   CXXFLAGS_STD = -std=c++11
   CXXFLAGS_EARLY += -march=native
-  CXXFLAGS_EARLY += -W -Wall -Wextra -Werror -pedantic
-  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized -Wno-unknown-warning-option
+  CXXFLAGS_EARLY += -W -Wall -Wextra -Wimplicit-fallthrough -Werror -pedantic
+  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-maybe-uninitialized -Wno-unknown-warning-option
 endif
 
 ifeq (${TOOLCHAIN},gcc)
   CXXFLAGS_STD = -std=c++11
   CXXFLAGS_EARLY += -march=native
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror -pedantic
-  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized
+  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-maybe-uninitialized
 endif
 
 ifeq (${TOOLCHAIN},mingw)
   CXXFLAGS_STD = -std=c++11
   CXXFLAGS_EARLY += -march=native
   CXXFLAGS_EARLY += -W -Wall -Wextra -Werror
-  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-implicit-fallthrough -Wno-maybe-uninitialized
+  CXXFLAGS_EARLY += -Wno-unused-parameter -Wno-maybe-uninitialized
 endif
 
 

binary-tiling.cpp

@@ -486,6 +486,8 @@ EX namespace bt {
             add(-2 * t0 + shift1);
             }
           }
+          // WARNING! UNINTENTIONAL FALLTHROUGH??
+          goto fallthru; fallthru:
         case gHoroRec: {
           ld r2 = sqrt(2);
           for(int y=-1; y<=1; y++) for(int x=-1; x<=1; x+=2) for(int z=-1; z<=1; z++)

celldrawer.cpp

@@ -532,14 +532,14 @@ void celldrawer::setcolors() {
         wcol = fcol;  
       break;
 
-    case waMineUnknown: case waMineMine: 
-      if(mine::marked_safe(c))
-        fcol = wcol = gradient(wcol, 0x40FF40, 0, 0.2, 1);
+    case waMineUnknown: case waMineMine: case waMineOpen:
+      if(c->wall == waMineOpen)
+        ;
+      else if(mine::marked_safe(c))
+        wcol = gradient(wcol, 0x40FF40, 0, 0.2, 1);
       else if(mine::marked_mine(c))
-        fcol = wcol = gradient(wcol, 0xFF4040, -1, sintick(100), 1);
-      // fallthrough
+        wcol = gradient(wcol, 0xFF4040, -1, sintick(100), 1);
 
-    case waMineOpen:
       if(wmblack || wmascii) {
         wcol &= 0xFEFEFE;
         wcol >>= 1;
@@ -554,6 +554,7 @@ void celldrawer::setcolors() {
     case waEditStatue:
       if(c->land == laCanvas) wcol = c->landparam;
       else wcol = (0x125628 * c->wparam) & 0xFFFFFF;
+      break;
 
     default:
       break;    
@@ -1345,11 +1346,8 @@ void celldrawer::draw_features() {
       break;
       }
 
-    case waTrapdoor:
-      if(c->land == laZebra) break;
-      /* fallthrough */
-
-    case waClosePlate: case waOpenPlate: {
+    case waTrapdoor: case waClosePlate: case waOpenPlate: {
+      if (c->wall == waTrapdoor && c->land == laZebra) break;
       transmatrix V2 = V;
       if(wmescher && geosupport_football() == 2 && pseudohept(c) && c->land == laPalace) V2 = V * spin(M_PI / c->type);
       if(GDIM == 3) {

expansion.cpp

@@ -513,6 +513,7 @@ void celldrawer::do_viewdist() {
         celldistance(c, distance_from == dfPlayer ? cwt.at : currentmap->gamestart());
       dc = (d != cd) ? 0xFF0000 : 0x00FF00;
       label = its(d);
+      break;
       }
     case ncNone: ;
     }
@@ -927,4 +928,4 @@ EX int hyperbolic_celldistance(cell *c1, cell *c2) {
     }
   }
 
-}
+}

hypgraph.cpp

@@ -901,6 +901,7 @@ EX void applymodel(hyperpoint H, hyperpoint& ret) {
         if(pconf.skiprope) 
           ret = mobius(ret, pconf.skiprope, 1);
         }
+      break;
       }
 
     case mdGUARD: case mdManual: break;
@@ -1650,7 +1651,10 @@ EX void draw_model_elements() {
         }
 
       queuereset(pmodel, PPR::CIRCLE);
-      /* fallthrough */
+      ld a = -pconf.model_orientation * degree;
+      queuestr(xspinpush0(a, +pconf.twopoint_param), vid.xres / 100, "X", ringcolor >> 8);
+      queuestr(xspinpush0(a, -pconf.twopoint_param), vid.xres / 100, "X", ringcolor >> 8);
+      return;
       }
 
     case mdTwoPoint: case mdSimulatedPerspective: {

mymake.cpp

@@ -26,7 +26,7 @@ string preprocessor =
   "g++ -E";
 
 string compiler = 
-  "g++ -Wall -Wextra -Wno-maybe-uninitialized -Wno-unused-parameter -Wno-implicit-fallthrough -rdynamic -fdiagnostics-color=always -c";
+  "g++ -Wall -Wextra -Wno-maybe-uninitialized -Wno-unused-parameter -rdynamic -fdiagnostics-color=always -c";
 
 string linker = 
   "g++ -rdynamic -o hyper";

pattern2.cpp

@@ -1685,6 +1685,7 @@ EX namespace patterns {
         if(arcm::in()) return colortables['A'][arcm::current.tilegroup[arcm::id_of(c->master)]];
         #endif
         if(arb::in()) return colortables['A'][c->master->zebraval + c->master->emeraldval * isize(arb::current.shapes)];
+        return colortables['B'][c->type & 15];
       case 'B':
         return colortables['B'][c->type & 15];
       #if CAP_FIELD