5 files changed, 39 insertions, 13 deletions
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 600cf575fc..26dbbe8bb5 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -282,6 +282,27 @@ bool buf_valid(buf_T *buf)
   return false;
 }
 
+// Map used to quickly lookup a buffer by its number.
+static PMap(handle_T) *buf_map = NULL;
+
+static void buf_hashtab_add(buf_T *buf)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (pmap_has(handle_T)(buf_map, buf->handle)) {
+    EMSG(_("E931: Buffer cannot be registered"));
+  } else {
+    pmap_put(handle_T)(buf_map, buf->handle, buf);
+  }
+}
+
+static void buf_hashtab_remove(buf_T *buf)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (pmap_has(handle_T)(buf_map, buf->handle)) {
+    pmap_del(handle_T)(buf_map, buf->handle);
+  }
+}
+
 /// Close the link to a buffer.
 ///
 /// @param win    If not NULL, set b_last_cursor.
@@ -585,6 +606,7 @@ static void free_buffer(buf_T *buf)
   free_buffer_stuff(buf, TRUE);
   unref_var_dict(buf->b_vars);
   aubuflocal_remove(buf);
+  buf_hashtab_remove(buf);
   dict_unref(buf->additional_data);
   clear_fmark(&buf->b_last_cursor);
   clear_fmark(&buf->b_last_insert);
@@ -1369,7 +1391,10 @@ buf_T * buflist_new(char_u *ffname, char_u *sfname, linenr_T lnum, int flags)
 {
   buf_T       *buf;
 
-  fname_expand(curbuf, &ffname, &sfname);       /* will allocate ffname */
+  if (top_file_num == 1) {
+    buf_map = pmap_new(handle_T)();
+  }
+  fname_expand(curbuf, &ffname, &sfname);       // will allocate ffname
 
   /*
    * If file name already exists in the list, update the entry.
@@ -1493,6 +1518,7 @@ buf_T * buflist_new(char_u *ffname, char_u *sfname, linenr_T lnum, int flags)
       }
       top_file_num = 1;
     }
+    buf_hashtab_add(buf);
 
     /*
      * Always copy the options from the current buffer.
@@ -2002,19 +2028,15 @@ static char_u *fname_match(regmatch_T *rmp, char_u *name, bool ignore_case)
   return match;
 }
 
-/*
- * find file in buffer list by number
- */
+/// Find a file in the buffer list by buffer number.
 buf_T *buflist_findnr(int nr)
 {
   if (nr == 0) {
     nr = curwin->w_alt_fnum;
   }
 
-  FOR_ALL_BUFFERS(buf) {
-    if (buf->b_fnum == nr) {
-      return buf;
-    }
+  if (pmap_has(handle_T)(buf_map, (handle_T)nr)) {
+    return pmap_get(handle_T)(buf_map, (handle_T)nr);
   }
   return NULL;
 }
diff --git a/src/nvim/indent_c.c b/src/nvim/indent_c.c
index 6f03cf6037..7b758b4dac 100644
--- a/src/nvim/indent_c.c
+++ b/src/nvim/indent_c.c
@@ -173,9 +173,8 @@ static char_u *skip_string(char_u *p)
         char_u *delim = p + 2;
         char_u *paren = vim_strchr(delim, '(');
 
-        if (paren != NULL)
-        {
-            long delim_len = paren - delim;
+        if (paren != NULL) {
+            ptrdiff_t delim_len = paren - delim;
 
             for (p += 3; *p; ++p)
                 if (p[0] == ')' && STRNCMP(p + 1, delim, delim_len) == 0
diff --git a/src/nvim/mbyte.c b/src/nvim/mbyte.c
index ec4969d4f6..c855d68605 100644
--- a/src/nvim/mbyte.c
+++ b/src/nvim/mbyte.c
@@ -1484,6 +1484,9 @@ int utf8_to_utf16(const char *str, WCHAR **strw)
                               (WCHAR *)pos,
                               wchar_len);
   assert(r == wchar_len);
+  if (r != wchar_len) {
+    EMSG2("MultiByteToWideChar failed: %d", r);
+  }
   *strw = (WCHAR *)pos;
 
   return 0;
@@ -1519,6 +1522,9 @@ int utf16_to_utf8(const WCHAR *strw, char **str)
                               NULL,
                               NULL);
   assert(r == utf8_len);
+  if (r != utf8_len) {
+    EMSG2("WideCharToMultiByte failed: %d", r);
+  }
   *str = pos;
 
   return 0;
diff --git a/src/nvim/os/fs.c b/src/nvim/os/fs.c
index 4aa727733e..30e08ac129 100644
--- a/src/nvim/os/fs.c
+++ b/src/nvim/os/fs.c
@@ -939,7 +939,6 @@ char_u * os_resolve_shortcut(char_u *fname)
   OLECHAR wsz[MAX_PATH];
   char_u *rfname = NULL;
   int len;
-  int conversion_result;
   IShellLinkW *pslw = NULL;
   WIN32_FIND_DATAW ffdw;
 
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 3bf87da376..3d81788a7e 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -404,7 +404,7 @@ static int included_patches[] = {
   // 2039 NA
   // 2038 NA
   // 2037 NA
-  // 2036,
+  2036,
   // 2035 NA
   // 2034 NA
   2033,