build: enable MSVC level 3 warnings (#21934)

MSVC has 4 different warning levels: 1 (severe), 2 (significant), 3
(production quality) and 4 (informational). Enabling level 3 warnings
mostly revealed conversion problems, similar to GCC/clang -Wconversion
flag.

3 files changed, 17 insertions, 17 deletions

diff --git a/src/nvim/lua/stdlib.c b/src/nvim/lua/stdlib.c
index 6ebca6d97e..73246f81b7 100644
--- a/src/nvim/lua/stdlib.c
+++ b/src/nvim/lua/stdlib.c
@@ -78,20 +78,20 @@ static int regex_match_line(lua_State *lstate)
     return luaL_error(lstate, "not enough args");
   }
 
-  long bufnr = luaL_checkinteger(lstate, 2);
+  handle_T bufnr = (handle_T)luaL_checkinteger(lstate, 2);
   linenr_T rownr = (linenr_T)luaL_checkinteger(lstate, 3);
-  long start = 0, end = -1;
+  int start = 0, end = -1;
   if (narg >= 4) {
-    start = luaL_checkinteger(lstate, 4);
+    start = (int)luaL_checkinteger(lstate, 4);
   }
   if (narg >= 5) {
-    end = luaL_checkinteger(lstate, 5);
+    end = (int)luaL_checkinteger(lstate, 5);
     if (end < 0) {
       return luaL_error(lstate, "invalid end");
     }
   }
 
-  buf_T *buf = bufnr ? handle_get_buffer((int)bufnr) : curbuf;
+  buf_T *buf = bufnr ? handle_get_buffer(bufnr) : curbuf;
   if (!buf || buf->b_ml.ml_mfp == NULL) {
     return luaL_error(lstate, "invalid buffer");
   }
@@ -218,7 +218,7 @@ static int nlua_str_utf_start(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 {
   size_t s1_len;
   const char *s1 = luaL_checklstring(lstate, 1, &s1_len);
-  long offset = luaL_checkinteger(lstate, 2);
+  ptrdiff_t offset = luaL_checkinteger(lstate, 2);
   if (offset < 0 || offset > (intptr_t)s1_len) {
     return luaL_error(lstate, "index out of range");
   }
@@ -238,7 +238,7 @@ static int nlua_str_utf_end(lua_State *const lstate) FUNC_ATTR_NONNULL_ALL
 {
   size_t s1_len;
   const char *s1 = luaL_checklstring(lstate, 1, &s1_len);
-  long offset = luaL_checkinteger(lstate, 2);
+  ptrdiff_t offset = luaL_checkinteger(lstate, 2);
   if (offset < 0 || offset > (intptr_t)s1_len) {
     return luaL_error(lstate, "index out of range");
   }
diff --git a/src/nvim/lua/treesitter.c b/src/nvim/lua/treesitter.c
index 56f4daed1a..5248ebed14 100644
--- a/src/nvim/lua/treesitter.c
+++ b/src/nvim/lua/treesitter.c
@@ -393,7 +393,7 @@ static int parser_parse(lua_State *L)
   TSTree *new_tree = NULL;
   size_t len;
   const char *str;
-  long bufnr;
+  handle_T bufnr;
   buf_T *buf;
   TSInput input;
 
@@ -406,13 +406,13 @@ static int parser_parse(lua_State *L)
     break;
 
   case LUA_TNUMBER:
-    bufnr = lua_tointeger(L, 3);
-    buf = handle_get_buffer((handle_T)bufnr);
+    bufnr = (handle_T)lua_tointeger(L, 3);
+    buf = handle_get_buffer(bufnr);
 
     if (!buf) {
 #define BUFSIZE 256
       char ebuf[BUFSIZE] = { 0 };
-      vim_snprintf(ebuf, BUFSIZE, "invalid buffer handle: %ld", bufnr);
+      vim_snprintf(ebuf, BUFSIZE, "invalid buffer handle: %d", bufnr);
       return luaL_argerror(L, 3, ebuf);
 #undef BUFSIZE
     }
@@ -898,8 +898,8 @@ static int node_child(lua_State *L)
   if (!node_check(L, 1, &node)) {
     return 0;
   }
-  long num = lua_tointeger(L, 2);
-  TSNode child = ts_node_child(node, (uint32_t)num);
+  uint32_t num = (uint32_t)lua_tointeger(L, 2);
+  TSNode child = ts_node_child(node, num);
 
   push_node(L, child, 1);
   return 1;
@@ -911,8 +911,8 @@ static int node_named_child(lua_State *L)
   if (!node_check(L, 1, &node)) {
     return 0;
   }
-  long num = lua_tointeger(L, 2);
-  TSNode child = ts_node_named_child(node, (uint32_t)num);
+  uint32_t num = (uint32_t)lua_tointeger(L, 2);
+  TSNode child = ts_node_named_child(node, num);
 
   push_node(L, child, 1);
   return 1;
diff --git a/src/nvim/lua/xdiff.c b/src/nvim/lua/xdiff.c
index 857b159af5..9a7ae5c146 100644
--- a/src/nvim/lua/xdiff.c
+++ b/src/nvim/lua/xdiff.c
@@ -257,13 +257,13 @@ static NluaXdiffMode process_xdl_diff_opts(lua_State *lstate, xdemitconf_t *cfg,
       if (check_xdiff_opt(v->type, kObjectTypeInteger, "ctxlen", err)) {
         goto exit_1;
       }
-      cfg->ctxlen = v->data.integer;
+      cfg->ctxlen = (long)v->data.integer;
     } else if (strequal("interhunkctxlen", k.data)) {
       if (check_xdiff_opt(v->type, kObjectTypeInteger, "interhunkctxlen",
                           err)) {
         goto exit_1;
       }
-      cfg->interhunkctxlen = v->data.integer;
+      cfg->interhunkctxlen = (long)v->data.integer;
     } else if (strequal("linematch", k.data)) {
       *linematch = api_object_to_bool(*v, "linematch", false, err);
       if (ERROR_SET(err)) {