Use abort() instead of assert(false) for things that should never happen

assert() is compiled out for release builds, but we don't want to
continue running in these impossible situations.

This also resolves the "implicit fallthrough" warnings for the asserts
in switch cases.

Author: jamessan

src/nvim/buffer.c

@@ -3270,7 +3270,7 @@ void maketitle(void)
         case 6: buf_p = strappend(buf_p, " -"); break;
         case 5:
         case 7: buf_p = strappend(buf_p, " -+"); break;
-        default: assert(false);
+        default: abort();
       }
 
       if (curbuf->b_fname != NULL) {

src/nvim/charset.c

@@ -1747,7 +1747,7 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
         goto vim_str2nr_dec;
       }
       default: {
-        assert(false);
+        abort();
       }
     }
   } else if ((what & (STR2NR_HEX|STR2NR_OCT|STR2NR_BIN))
@@ -1788,7 +1788,7 @@ void vim_str2nr(const char_u *const start, int *const prep, int *const len,
   }
 
   // Do the string-to-numeric conversion "manually" to avoid sscanf quirks.
-  assert(false);  // Should’ve used goto earlier.
+  abort();  // Should’ve used goto earlier.
 #define PARSE_NUMBER(base, cond, conv) \
   do { \
     while (!STRING_ENDED(ptr) && (cond)) { \

src/nvim/eval.c

@@ -365,7 +365,7 @@ void eval_init(void)
     eval_msgpack_type_lists[i] = type_list;
     if (tv_dict_add(msgpack_types_dict, di) == FAIL) {
       // There must not be duplicate items in this dictionary by definition.
-      assert(false);
+      abort();
     }
   }
   msgpack_types_dict->dv_lock = VAR_FIXED;

src/nvim/eval/decode.c

@@ -147,7 +147,7 @@ static inline int json_decoder_pop(ValuesStackItem obj,
       tv_clear(&key.val);
       if (tv_dict_add(last_container.container.vval.v_dict, obj_di)
           == FAIL) {
-        assert(false);
+        abort();
       }
       obj_di->di_tv = obj.val;
     } else {
@@ -480,7 +480,7 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
           break;
         }
         default: {
-          assert(false);
+          abort();
         }
       }
     } else {

src/nvim/eval/encode.c

@@ -174,7 +174,7 @@ static int conv_error(const char *const msg, const MPConvStack *const mpstack,
       case kMPConvPartial: {
         switch (v.data.p.stage) {
           case kMPConvPartialArgs: {
-            assert(false);
+            abort();
             break;
           }
           case kMPConvPartialSelf: {
@@ -237,7 +237,7 @@ bool encode_vim_list_to_buf(const list_T *const list, size_t *const ret_len,
   char *const buf = xmalloc(len);
   size_t read_bytes;
   if (encode_read_from_list(&lrstate, buf, len, &read_bytes) != OK) {
-    assert(false);
+    abort();
   }
   assert(len == read_bytes);
   *ret_buf = buf;

src/nvim/eval/executor.c

@@ -118,7 +118,7 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2,
         return OK;
       }
       case VAR_UNKNOWN: {
-        assert(false);
+        abort();
       }
     }
   }

src/nvim/eval/funcs.c

@@ -3307,7 +3307,7 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
       }
       break;
     case kCdScopeInvalid:     // We should never get here
-      assert(false);
+      abort();
   }
 
   if (from) {
@@ -4360,7 +4360,7 @@ static void f_haslocaldir(typval_T *argvars, typval_T *rettv, FunPtr fptr)
       break;
     case kCdScopeInvalid:
       // We should never get here
-      assert(false);
+      abort();
   }
 }
 

src/nvim/eval/typval.c

@@ -2521,7 +2521,7 @@ void tv_item_lock(typval_T *const tv, const int deep, const bool lock)
       break;
     }
     case VAR_UNKNOWN: {
-      assert(false);
+      abort();
     }
   }
 #undef CHANGE_LOCK
@@ -2693,7 +2693,7 @@ bool tv_equal(typval_T *const tv1, typval_T *const tv2, const bool ic,
     }
   }
 
-  assert(false);
+  abort();
   return false;
 }
 
@@ -2746,7 +2746,7 @@ bool tv_check_str_or_nr(const typval_T *const tv)
       return false;
     }
   }
-  assert(false);
+  abort();
   return false;
 }
 
@@ -2791,7 +2791,7 @@ bool tv_check_num(const typval_T *const tv)
       return false;
     }
   }
-  assert(false);
+  abort();
   return false;
 }
 
@@ -2836,7 +2836,7 @@ bool tv_check_str(const typval_T *const tv)
       return false;
     }
   }
-  assert(false);
+  abort();
   return false;
 }
 

src/nvim/ex_docmd.c

@@ -7591,7 +7591,7 @@ void post_chdir(CdScope scope, bool trigger_dirchanged)
     curwin->w_localdir = (char_u *)xstrdup(cwd);
     break;
   case kCdScopeInvalid:
-    assert(false);
+    abort();
   }
 
   shorten_fnames(true);

src/nvim/ex_getln.c

@@ -6383,7 +6383,7 @@ int hist_type2char(int type)
       return '>';
     }
     default: {
-      assert(false);
+      abort();
     }
   }
   return NUL;