Merge pull request #21850 from zeertzjq/vim-8.2.4463

vim-patch:8.2.{4463,4465,4475,4477,4478,4479,4608}: fuzzy cmdline builtin completion

12 files changed, 943 insertions, 139 deletions

diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 3dc21c0d73..bdbd026a09 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -3000,6 +3000,10 @@ getcompletion({pat}, {type} [, {filtered}])		*getcompletion()*
 		is applied to filter the results.  Otherwise all the matches
 		are returned. The 'wildignorecase' option always applies.
 
+		If the 'wildoptions' option contains "fuzzy", then fuzzy
+		matching is used to get the completion matches. Otherwise
+		regular expression matching is used.
+
 		If {type} is "cmdline", then the |cmdline-completion| result is
 		returned.  For example, to complete the possible values after
 		a ":call" command: >
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index efeeba983e..0683bb0602 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -7126,6 +7126,14 @@ A jump table for the options with a short description can be found at |Q_op|.
 			global
 	A list of words that change how |cmdline-completion| is done.
 	The following values are supported:
+	  fuzzy		Use fuzzy matching to find completion matches. When
+			this value is specified, wildcard expansion will not
+			be used for completion.  The matches will be sorted by
+			the "best match" rather than alphabetically sorted.
+			This will find more matches than the wildcard
+			expansion. Currently fuzzy matching based completion
+			is not supported for file and directory names and
+			instead wildcard expansion is used.
 	  pum		Display the completion matches using the popup menu
 			in the same style as the |ins-completion-menu|.
 	  tagfile	When using CTRL-D to list matching tags, the kind of
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index cd1059eb0d..32e0cf5acf 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -88,6 +88,7 @@
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
 #include "nvim/screen.h"
+#include "nvim/search.h"
 #include "nvim/sign.h"
 #include "nvim/spell.h"
 #include "nvim/statusline.h"
@@ -2337,7 +2338,6 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
   int round;
   char *p;
   int attempt;
-  char *patc;
   bufmatch_T *matches = NULL;
 
   *num_file = 0;                    // return values in case of FAIL
@@ -2347,31 +2347,40 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
     return FAIL;
   }
 
-  // Make a copy of "pat" and change "^" to "\(^\|[\/]\)".
-  if (*pat == '^') {
-    patc = xmalloc(strlen(pat) + 11);
-    STRCPY(patc, "\\(^\\|[\\/]\\)");
-    STRCPY(patc + 11, pat + 1);
-  } else {
-    patc = pat;
+  const bool fuzzy = cmdline_fuzzy_complete(pat);
+
+  char *patc = NULL;
+  // Make a copy of "pat" and change "^" to "\(^\|[\/]\)" (if doing regular
+  // expression matching)
+  if (!fuzzy) {
+    if (*pat == '^') {
+      patc = xmalloc(strlen(pat) + 11);
+      STRCPY(patc, "\\(^\\|[\\/]\\)");
+      STRCPY(patc + 11, pat + 1);
+    } else {
+      patc = pat;
+    }
   }
 
+  fuzmatch_str_T *fuzmatch = NULL;
   // attempt == 0: try match with    '\<', match at start of word
   // attempt == 1: try match without '\<', match anywhere
-  for (attempt = 0; attempt <= 1; attempt++) {
-    if (attempt > 0 && patc == pat) {
-      break;            // there was no anchor, no need to try again
-    }
-
+  for (attempt = 0; attempt <= (fuzzy ? 0 : 1); attempt++) {
     regmatch_T regmatch;
-    regmatch.regprog = vim_regcomp(patc + attempt * 11, RE_MAGIC);
-    if (regmatch.regprog == NULL) {
-      if (patc != pat) {
-        xfree(patc);
+    if (!fuzzy) {
+      if (attempt > 0 && patc == pat) {
+        break;            // there was no anchor, no need to try again
+      }
+      regmatch.regprog = vim_regcomp(patc + attempt * 11, RE_MAGIC);
+      if (regmatch.regprog == NULL) {
+        if (patc != pat) {
+          xfree(patc);
+        }
+        return FAIL;
       }
-      return FAIL;
     }
 
+    int score = 0;
     // round == 1: Count the matches.
     // round == 2: Build the array to keep the matches.
     for (round = 1; round <= 2; round++) {
@@ -2387,7 +2396,23 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
             continue;
           }
         }
-        p = buflist_match(&regmatch, buf, p_wic);
+
+        if (!fuzzy) {
+          p = buflist_match(&regmatch, buf, p_wic);
+        } else {
+          p = NULL;
+          // first try matching with the short file name
+          if ((score = fuzzy_match_str(buf->b_sfname, pat)) != 0) {
+            p = buf->b_sfname;
+          }
+          if (p == NULL) {
+            // next try matching with the full path file name
+            if ((score = fuzzy_match_str(buf->b_ffname, pat)) != 0) {
+              p = buf->b_ffname;
+            }
+          }
+        }
+
         if (p != NULL) {
           if (round == 1) {
             count++;
@@ -2397,12 +2422,20 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
             } else {
               p = xstrdup(p);
             }
-            if (matches != NULL) {
-              matches[count].buf = buf;
-              matches[count].match = p;
-              count++;
+
+            if (!fuzzy) {
+              if (matches != NULL) {
+                matches[count].buf = buf;
+                matches[count].match = p;
+                count++;
+              } else {
+                (*file)[count++] = p;
+              }
             } else {
-              (*file)[count++] = p;
+              fuzmatch[count].idx = count;
+              fuzmatch[count].str = p;
+              fuzmatch[count].score = score;
+              count++;
             }
           }
         }
@@ -2411,40 +2444,50 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
         break;
       }
       if (round == 1) {
-        *file = xmalloc((size_t)count * sizeof(**file));
-
-        if (options & WILD_BUFLASTUSED) {
-          matches = xmalloc((size_t)count * sizeof(*matches));
+        if (!fuzzy) {
+          *file = xmalloc((size_t)count * sizeof(**file));
+          if (options & WILD_BUFLASTUSED) {
+            matches = xmalloc((size_t)count * sizeof(*matches));
+          }
+        } else {
+          fuzmatch = xmalloc((size_t)count * sizeof(fuzmatch_str_T));
         }
       }
     }
-    vim_regfree(regmatch.regprog);
-    if (count) {                // match(es) found, break here
-      break;
+
+    if (!fuzzy) {
+      vim_regfree(regmatch.regprog);
+      if (count) {                // match(es) found, break here
+        break;
+      }
     }
   }
 
-  if (patc != pat) {
+  if (!fuzzy && patc != pat) {
     xfree(patc);
   }
 
-  if (matches != NULL) {
-    if (count > 1) {
-      qsort(matches, (size_t)count, sizeof(bufmatch_T), buf_time_compare);
-    }
-
-    // if the current buffer is first in the list, place it at the end
-    if (matches[0].buf == curbuf) {
-      for (int i = 1; i < count; i++) {
-        (*file)[i - 1] = matches[i].match;
+  if (!fuzzy) {
+    if (matches != NULL) {
+      if (count > 1) {
+        qsort(matches, (size_t)count, sizeof(bufmatch_T), buf_time_compare);
       }
-      (*file)[count - 1] = matches[0].match;
-    } else {
-      for (int i = 0; i < count; i++) {
-        (*file)[i] = matches[i].match;
+
+      // if the current buffer is first in the list, place it at the end
+      if (matches[0].buf == curbuf) {
+        for (int i = 1; i < count; i++) {
+          (*file)[i - 1] = matches[i].match;
+        }
+        (*file)[count - 1] = matches[0].match;
+      } else {
+        for (int i = 0; i < count; i++) {
+          (*file)[i] = matches[i].match;
+        }
       }
+      xfree(matches);
     }
-    xfree(matches);
+  } else {
+    fuzzymatches_to_strmatches(fuzmatch, file, count, false);
   }
 
   *num_file = count;
diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index ca19d6de95..4559e83e20 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -91,6 +91,38 @@ static int compl_selected;
 
 #define SHOW_MATCH(m) (showtail ? showmatches_gettail(matches[m], false) : matches[m])
 
+/// Returns true if fuzzy completion is supported for a given cmdline completion
+/// context.
+static bool cmdline_fuzzy_completion_supported(const expand_T *const xp)
+  FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  return (wop_flags & WOP_FUZZY)
+         && xp->xp_context != EXPAND_BOOL_SETTINGS
+         && xp->xp_context != EXPAND_COLORS
+         && xp->xp_context != EXPAND_COMPILER
+         && xp->xp_context != EXPAND_DIRECTORIES
+         && xp->xp_context != EXPAND_FILES
+         && xp->xp_context != EXPAND_FILES_IN_PATH
+         && xp->xp_context != EXPAND_FILETYPE
+         && xp->xp_context != EXPAND_HELP
+         && xp->xp_context != EXPAND_OLD_SETTING
+         && xp->xp_context != EXPAND_OWNSYNTAX
+         && xp->xp_context != EXPAND_PACKADD
+         && xp->xp_context != EXPAND_SHELLCMD
+         && xp->xp_context != EXPAND_TAGS
+         && xp->xp_context != EXPAND_TAGS_LISTFILES
+         && xp->xp_context != EXPAND_USER_DEFINED
+         && xp->xp_context != EXPAND_USER_LIST;
+}
+
+/// Returns true if fuzzy completion for cmdline completion is enabled and
+/// "fuzzystr" is not empty.
+bool cmdline_fuzzy_complete(const char *const fuzzystr)
+  FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  return (wop_flags & WOP_FUZZY) && *fuzzystr != NUL;
+}
+
 /// Sort function for the completion matches.
 /// <SNR> functions should be sorted to the end.
 static int sort_func_compare(const void *s1, const void *s2)
@@ -223,8 +255,13 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
     // Get next/previous match for a previous expanded pattern.
     p2 = ExpandOne(xp, NULL, NULL, 0, type);
   } else {
+    if (cmdline_fuzzy_completion_supported(xp)) {
+      // If fuzzy matching, don't modify the search string
+      p1 = xstrdup(xp->xp_pattern);
+    } else {
+      p1 = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
+    }
     // Translate string into pattern and expand it.
-    p1 = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
     const int use_options = (options
                              | WILD_HOME_REPLACE
                              | WILD_ADD_SLASH
@@ -1335,13 +1372,16 @@ static const char *set_cmd_index(const char *cmd, exarg_T *eap, expand_T *xp, in
 {
   const char *p = NULL;
   size_t len = 0;
+  const bool fuzzy = cmdline_fuzzy_complete(cmd);
 
   // Isolate the command and search for it in the command table.
   // Exceptions:
-  // - the 'k' command can directly be followed by any character, but
-  //   do accept "keepmarks", "keepalt" and "keepjumps".
+  // - the 'k' command can directly be followed by any character, but do
+  // accept "keepmarks", "keepalt" and "keepjumps". As fuzzy matching can
+  // find matches anywhere in the command name, do this only for command
+  // expansion based on regular expression and not for fuzzy matching.
   // - the 's' command can be followed directly by 'c', 'g', 'i', 'I' or 'r'
-  if (*cmd == 'k' && cmd[1] != 'e') {
+  if (!fuzzy && (*cmd == 'k' && cmd[1] != 'e')) {
     eap->cmdidx = CMD_k;
     p = cmd + 1;
   } else {
@@ -1375,7 +1415,9 @@ static const char *set_cmd_index(const char *cmd, exarg_T *eap, expand_T *xp, in
 
     eap->cmdidx = excmd_get_cmdidx(cmd, len);
 
-    if (cmd[0] >= 'A' && cmd[0] <= 'Z') {
+    // User defined commands support alphanumeric characters.
+    // Also when doing fuzzy expansion, support alphanumeric characters.
+    if ((cmd[0] >= 'A' && cmd[0] <= 'Z') || (fuzzy && *p != NUL)) {
       while (ASCII_ISALNUM(*p) || *p == '*') {  // Allow * wild card
         p++;
       }
@@ -2330,7 +2372,12 @@ int expand_cmdline(expand_T *xp, const char *str, int col, int *matchcount, char
   // add star to file name, or convert to regexp if not exp. files.
   assert((str + col) - xp->xp_pattern >= 0);
   xp->xp_pattern_len = (size_t)((str + col) - xp->xp_pattern);
-  file_str = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
+  if (cmdline_fuzzy_completion_supported(xp)) {
+    // If fuzzy matching, don't modify the search string
+    file_str = xstrdup(xp->xp_pattern);
+  } else {
+    file_str = addstar(xp->xp_pattern, xp->xp_pattern_len, xp->xp_context);
+  }
 
   if (p_wic) {
     options += WILD_ICASE;
@@ -2490,7 +2537,7 @@ static char *get_healthcheck_names(expand_T *xp FUNC_ATTR_UNUSED, int idx)
 }
 
 /// Do the expansion based on xp->xp_context and "rmp".
-static int ExpandOther(expand_T *xp, regmatch_T *rmp, char ***matches, int *numMatches)
+static int ExpandOther(char *pat, expand_T *xp, regmatch_T *rmp, char ***matches, int *numMatches)
 {
   typedef CompleteListItemGetter ExpandFunc;
   static struct expgen {
@@ -2538,10 +2585,16 @@ static int ExpandOther(expand_T *xp, regmatch_T *rmp, char ***matches, int *numM
   // right function to do the expansion.
   for (int i = 0; i < (int)ARRAY_SIZE(tab); i++) {
     if (xp->xp_context == tab[i].context) {
+      // Use fuzzy matching if 'wildoptions' has "fuzzy".
+      // If no search pattern is supplied, then don't use fuzzy
+      // matching and return all the found items.
+      const bool fuzzy = cmdline_fuzzy_complete(pat);
+
       if (tab[i].ic) {
         rmp->rm_ic = true;
       }
-      ExpandGeneric(xp, rmp, matches, numMatches, tab[i].func, tab[i].escaped);
+      ExpandGeneric(xp, rmp, matches, numMatches, tab[i].func, tab[i].escaped,
+                    fuzzy ? pat : NULL);
       ret = OK;
       break;
     }
@@ -2581,9 +2634,11 @@ static int map_wildopts_to_ewflags(int options)
 /// @param options  WILD_ flags
 static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numMatches, int options)
 {
-  regmatch_T regmatch;
+  regmatch_T regmatch = { .rm_ic = false };
   int ret;
   int flags = map_wildopts_to_ewflags(options);
+  const bool fuzzy = cmdline_fuzzy_complete(pat)
+                     && cmdline_fuzzy_completion_supported(xp);
 
   if (xp->xp_context == EXPAND_FILES
       || xp->xp_context == EXPAND_DIRECTORIES
@@ -2664,26 +2719,30 @@ static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numM
     return nlua_expand_pat(xp, pat, numMatches, matches);
   }
 
-  regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
-  if (regmatch.regprog == NULL) {
-    return FAIL;
-  }
+  if (!fuzzy) {
+    regmatch.regprog = vim_regcomp(pat, magic_isset() ? RE_MAGIC : 0);
+    if (regmatch.regprog == NULL) {
+      return FAIL;
+    }
 
-  // set ignore-case according to p_ic, p_scs and pat
-  regmatch.rm_ic = ignorecase(pat);
+    // set ignore-case according to p_ic, p_scs and pat
+    regmatch.rm_ic = ignorecase(pat);
+  }
 
   if (xp->xp_context == EXPAND_SETTINGS
       || xp->xp_context == EXPAND_BOOL_SETTINGS) {
-    ret = ExpandSettings(xp, &regmatch, numMatches, matches);
+    ret = ExpandSettings(xp, &regmatch, pat, numMatches, matches);
   } else if (xp->xp_context == EXPAND_MAPPINGS) {
-    ret = ExpandMappings(&regmatch, numMatches, matches);
+    ret = ExpandMappings(pat, &regmatch, numMatches, matches);
   } else if (xp->xp_context == EXPAND_USER_DEFINED) {
     ret = ExpandUserDefined(xp, &regmatch, matches, numMatches);
   } else {
-    ret = ExpandOther(xp, &regmatch, matches, numMatches);
+    ret = ExpandOther(pat, xp, &regmatch, matches, numMatches);
   }
 
-  vim_regfree(regmatch.regprog);
+  if (!fuzzy) {
+    vim_regfree(regmatch.regprog);
+  }
   xfree(tofree);
 
   return ret;
@@ -2695,13 +2754,17 @@ static int ExpandFromContext(expand_T *xp, char *pat, char ***matches, int *numM
 /// obtain strings, one by one.  The strings are matched against a regexp
 /// program.  Matching strings are copied into an array, which is returned.
 ///
+/// If "fuzzystr" is not NULL, then fuzzy matching is used. Otherwise,
+/// regex matching is used.
+///
 /// @param func  returns a string from the list
 static void ExpandGeneric(expand_T *xp, regmatch_T *regmatch, char ***matches, int *numMatches,
-                          CompleteListItemGetter func, int escaped)
+                          CompleteListItemGetter func, int escaped, const char *const fuzzystr)
 {
   int i;
   size_t count = 0;
   char *str;
+  const bool fuzzy = fuzzystr != NULL;
 
   // count the number of matching names
   for (i = 0;; i++) {
@@ -2712,7 +2775,14 @@ static void ExpandGeneric(expand_T *xp, regmatch_T *regmatch, char ***matches, i
     if (*str == NUL) {  // skip empty strings
       continue;
     }
-    if (vim_regexec(regmatch, str, (colnr_T)0)) {
+
+    bool match;
+    if (!fuzzy) {
+      match = vim_regexec(regmatch, str, (colnr_T)0);
+    } else {
+      match = fuzzy_match_str(str, fuzzystr) != 0;
+    }
+    if (match) {
       count++;
     }
   }
@@ -2721,7 +2791,12 @@ static void ExpandGeneric(expand_T *xp, regmatch_T *regmatch, char ***matches, i
   }
   assert(count < INT_MAX);
   *numMatches = (int)count;
-  *matches = xmalloc(count * sizeof(char *));
+  fuzmatch_str_T *fuzmatch = NULL;
+  if (fuzzy) {
+    fuzmatch = xmalloc(count * sizeof(fuzmatch_str_T));
+  } else {
+    *matches = xmalloc(count * sizeof(char *));
+  }
 
   // copy the matching names into allocated memory
   count = 0;
@@ -2733,38 +2808,66 @@ static void ExpandGeneric(expand_T *xp, regmatch_T *regmatch, char ***matches, i
     if (*str == NUL) {  // Skip empty strings.
       continue;
     }
-    if (vim_regexec(regmatch, str, (colnr_T)0)) {
-      if (escaped) {
-        str = vim_strsave_escaped(str, " \t\\.");
-      } else {
-        str = xstrdup(str);
-      }
-      (*matches)[count++] = str;
-      if (func == get_menu_names) {
-        // Test for separator added by get_menu_names().
-        str += strlen(str) - 1;
-        if (*str == '\001') {
-          *str = '.';
-        }
+
+    bool match;
+    int score = 0;
+    if (!fuzzy) {
+      match = vim_regexec(regmatch, str, (colnr_T)0);
+    } else {
+      score = fuzzy_match_str(str, fuzzystr);
+      match = (score != 0);
+    }
+    if (!match) {
+      continue;
+    }
+
+    if (escaped) {
+      str = vim_strsave_escaped(str, " \t\\.");
+    } else {
+      str = xstrdup(str);
+    }
+    if (fuzzy) {
+      fuzmatch[count].idx = (int)count;
+      fuzmatch[count].str = str;
+      fuzmatch[count].score = score;
+    } else {
+      (*matches)[count] = str;
+    }
+    count++;
+    if (func == get_menu_names) {
+      // Test for separator added by get_menu_names().
+      str += strlen(str) - 1;
+      if (*str == '\001') {
+        *str = '.';
       }
     }
   }
 
   // Sort the results.  Keep menu's in the specified order.
+  bool funcsort = false;
   if (xp->xp_context != EXPAND_MENUNAMES && xp->xp_context != EXPAND_MENUS) {
     if (xp->xp_context == EXPAND_EXPRESSION
         || xp->xp_context == EXPAND_FUNCTIONS
         || xp->xp_context == EXPAND_USER_FUNC) {
       // <SNR> functions should be sorted to the end.
-      qsort((void *)(*matches), (size_t)(*numMatches), sizeof(char *), sort_func_compare);
+      funcsort = true;
+      if (!fuzzy) {
+        qsort(*matches, (size_t)(*numMatches), sizeof(char *), sort_func_compare);
+      }
     } else {
-      sort_strings(*matches, *numMatches);
+      if (!fuzzy) {
+        sort_strings(*matches, *numMatches);
+      }
     }
   }
 
   // Reset the variables used for special highlight names expansion, so that
   // they don't show up when getting normal highlight names by ID.
   reset_expand_highlight();
+
+  if (fuzzy) {
+    fuzzymatches_to_strmatches(fuzmatch, matches, (int)count, funcsort);
+  }
 }
 
 /// Expand shell command matches in one directory of $PATH.
@@ -3369,7 +3472,13 @@ void f_getcompletion(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 
 theend:
-  pat = addstar(xpc.xp_pattern, xpc.xp_pattern_len, xpc.xp_context);
+  if (cmdline_fuzzy_completion_supported(&xpc)) {
+    // when fuzzy matching, don't modify the search string
+    pat = xstrdup(xpc.xp_pattern);
+  } else {
+    pat = addstar(xpc.xp_pattern, xpc.xp_pattern_len, xpc.xp_context);
+  }
+
   ExpandOne(&xpc, pat, NULL, options, WILD_ALL_KEEP);
   tv_list_alloc_ret(rettv, xpc.xp_numfiles);
 
diff --git a/src/nvim/mapping.c b/src/nvim/mapping.c
index 2e1563760b..1785f41a37 100644
--- a/src/nvim/mapping.c
+++ b/src/nvim/mapping.c
@@ -18,6 +18,7 @@
 #include "nvim/ascii.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
+#include "nvim/cmdexpand.h"
 #include "nvim/eval.h"
 #include "nvim/eval/typval.h"
 #include "nvim/eval/typval_defs.h"
@@ -39,6 +40,7 @@
 #include "nvim/pos.h"
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
+#include "nvim/search.h"
 #include "nvim/strings.h"
 #include "nvim/vim.h"
 
@@ -1268,7 +1270,7 @@ char_u *set_context_in_map_cmd(expand_T *xp, char *cmd, char *arg, bool forceit,
 /// Find all mapping/abbreviation names that match regexp "regmatch".
 /// For command line expansion of ":[un]map" and ":[un]abbrev" in all modes.
 /// @return OK if matches found, FAIL otherwise.
-int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
+int ExpandMappings(char *pat, regmatch_T *regmatch, int *numMatches, char ***matches)
 {
   mapblock_T *mp;
   int hash;
@@ -1277,14 +1279,18 @@ int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
   char *p;
   int i;
 
-  *num_file = 0;                    // return values in case of FAIL
-  *file = NULL;
+  fuzmatch_str_T *fuzmatch = NULL;
+  const bool fuzzy = cmdline_fuzzy_complete(pat);
+
+  *numMatches = 0;                    // return values in case of FAIL
+  *matches = NULL;
 
   // round == 1: Count the matches.
   // round == 2: Build the array to keep the matches.
   for (round = 1; round <= 2; round++) {
     count = 0;
 
+    // First search in map modifier arguments
     for (i = 0; i < 7; i++) {
       if (i == 0) {
         p = "<silent>";
@@ -1304,13 +1310,29 @@ int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
         continue;
       }
 
-      if (vim_regexec(regmatch, p, (colnr_T)0)) {
-        if (round == 1) {
-          count++;
+      bool match;
+      int score = 0;
+      if (!fuzzy) {
+        match = vim_regexec(regmatch, p, (colnr_T)0);
+      } else {
+        score = fuzzy_match_str(p, pat);
+        match = (score != 0);
+      }
+
+      if (!match) {
+        continue;
+      }
+
+      if (round == 2) {
+        if (fuzzy) {
+          fuzmatch[count].idx = count;
+          fuzmatch[count].str = xstrdup(p);
+          fuzmatch[count].score = score;
         } else {
-          (*file)[count++] = xstrdup(p);
+          (*matches)[count] = xstrdup(p);
         }
       }
+      count++;
     }
 
     for (hash = 0; hash < 256; hash++) {
@@ -1327,12 +1349,28 @@ int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
       for (; mp; mp = mp->m_next) {
         if (mp->m_mode & expand_mapmodes) {
           p = (char *)translate_mapping((char_u *)mp->m_keys, CPO_TO_CPO_FLAGS);
-          if (p != NULL && vim_regexec(regmatch, p, (colnr_T)0)) {
-            if (round == 1) {
-              count++;
+          if (p != NULL) {
+            bool match;
+            int score = 0;
+            if (!fuzzy) {
+              match = vim_regexec(regmatch, p, (colnr_T)0);
             } else {
-              (*file)[count++] = p;
-              p = NULL;
+              score = fuzzy_match_str(p, pat);
+              match = (score != 0);
+            }
+
+            if (match) {
+              if (round == 2) {
+                if (fuzzy) {
+                  fuzmatch[count].idx = count;
+                  fuzmatch[count].str = p;
+                  fuzmatch[count].score = score;
+                } else {
+                  (*matches)[count] = p;
+                }
+                p = NULL;
+              }
+              count++;
             }
           }
           xfree(p);
@@ -1345,16 +1383,27 @@ int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
     }
 
     if (round == 1) {
-      *file = xmalloc((size_t)count * sizeof(char *));
+      if (fuzzy) {
+        fuzmatch = xmalloc((size_t)count * sizeof(fuzmatch_str_T));
+      } else {
+        *matches = xmalloc((size_t)count * sizeof(char *));
+      }
     }
   }   // for (round)
 
+  if (fuzzy) {
+    fuzzymatches_to_strmatches(fuzmatch, matches, count, false);
+  }
+
   if (count > 1) {
     // Sort the matches
-    sort_strings(*file, count);
+    // Fuzzy matching already sorts the matches
+    if (!fuzzy) {
+      sort_strings(*matches, count);
+    }
 
     // Remove multiple entries
-    char **ptr1 = *file;
+    char **ptr1 = *matches;
     char **ptr2 = ptr1 + 1;
     char **ptr3 = ptr1 + count;
 
@@ -1368,7 +1417,7 @@ int ExpandMappings(regmatch_T *regmatch, int *num_file, char ***file)
     }
   }
 
-  *num_file = count;
+  *numMatches = count;
   return count == 0 ? FAIL : OK;
 }
 
diff --git a/src/nvim/option.c b/src/nvim/option.c
index 85725f36ea..aec91a4dc6 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -36,6 +36,7 @@
 #include "nvim/buffer.h"
 #include "nvim/change.h"
 #include "nvim/charset.h"
+#include "nvim/cmdexpand.h"
 #include "nvim/cursor_shape.h"
 #include "nvim/decoration_provider.h"
 #include "nvim/diff.h"
@@ -81,6 +82,7 @@
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
 #include "nvim/screen.h"
+#include "nvim/search.h"
 #include "nvim/sign_defs.h"
 #include "nvim/spell.h"
 #include "nvim/spellfile.h"
@@ -4698,13 +4700,56 @@ void set_context_in_set_cmd(expand_T *xp, char *arg, int opt_flags)
   }
 }
 
-int ExpandSettings(expand_T *xp, regmatch_T *regmatch, int *num_file, char ***file)
+/// Returns true if "str" either matches "regmatch" or fuzzy matches "pat".
+///
+/// If "test_only" is true and "fuzzy" is false and if "str" matches the regular
+/// expression "regmatch", then returns true.  Otherwise returns false.
+///
+/// If "test_only" is false and "fuzzy" is false and if "str" matches the
+/// regular expression "regmatch", then stores the match in matches[idx] and
+/// returns true.
+///
+/// If "test_only" is true and "fuzzy" is true and if "str" fuzzy matches
+/// "fuzzystr", then returns true. Otherwise returns false.
+///
+/// If "test_only" is false and "fuzzy" is true and if "str" fuzzy matches
+/// "fuzzystr", then stores the match details in fuzmatch[idx] and returns true.
+static bool match_str(char *const str, regmatch_T *const regmatch, char **const matches,
+                      const int idx, const bool test_only, const bool fuzzy,
+                      const char *const fuzzystr, fuzmatch_str_T *const fuzmatch)
+{
+  if (!fuzzy) {
+    if (vim_regexec(regmatch, str, (colnr_T)0)) {
+      if (!test_only) {
+        matches[idx] = xstrdup(str);
+      }
+      return true;
+    }
+  } else {
+    const int score = fuzzy_match_str(str, fuzzystr);
+    if (score != 0) {
+      if (!test_only) {
+        fuzmatch[idx].idx = idx;
+        fuzmatch[idx].str = xstrdup(str);
+        fuzmatch[idx].score = score;
+      }
+      return true;
+    }
+  }
+  return false;
+}
+
+int ExpandSettings(expand_T *xp, regmatch_T *regmatch, char *fuzzystr, int *numMatches,
+                   char ***matches)
 {
   int num_normal = 0;  // Nr of matching non-term-code settings
   int count = 0;
   static char *(names[]) = { "all" };
   int ic = regmatch->rm_ic;  // remember the ignore-case flag
 
+  fuzmatch_str_T *fuzmatch = NULL;
+  const bool fuzzy = cmdline_fuzzy_complete(fuzzystr);
+
   // do this loop twice:
   // loop == 0: count the number of matching options
   // loop == 1: copy the matching options into allocated memory
@@ -4714,11 +4759,12 @@ int ExpandSettings(expand_T *xp, regmatch_T *regmatch, int *num_file, char ***fi
     if (xp->xp_context != EXPAND_BOOL_SETTINGS) {
       for (match = 0; match < (int)ARRAY_SIZE(names);
            match++) {
-        if (vim_regexec(regmatch, names[match], (colnr_T)0)) {
+        if (match_str(names[match], regmatch, *matches,
+                      count, (loop == 0), fuzzy, fuzzystr, fuzmatch)) {
           if (loop == 0) {
             num_normal++;
           } else {
-            (*file)[count++] = xstrdup(names[match]);
+            count++;
           }
         }
       }
@@ -4733,33 +4779,45 @@ int ExpandSettings(expand_T *xp, regmatch_T *regmatch, int *num_file, char ***fi
           && !(options[opt_idx].flags & P_BOOL)) {
         continue;
       }
-      match = false;
-      if (vim_regexec(regmatch, str, (colnr_T)0)
-          || (options[opt_idx].shortname != NULL
-              && vim_regexec(regmatch,
-                             options[opt_idx].shortname,
-                             (colnr_T)0))) {
-        match = true;
-      }
 
-      if (match) {
+      if (match_str(str, regmatch, *matches, count, (loop == 0),
+                    fuzzy, fuzzystr, fuzmatch)) {
         if (loop == 0) {
           num_normal++;
         } else {
-          (*file)[count++] = xstrdup(str);
+          count++;
+        }
+      } else if (!fuzzy && options[opt_idx].shortname != NULL
+                 && vim_regexec(regmatch, options[opt_idx].shortname, (colnr_T)0)) {
+        // Compare against the abbreviated option name (for regular
+        // expression match). Fuzzy matching (previous if) already
+        // matches against both the expanded and abbreviated names.
+        if (loop == 0) {
+          num_normal++;
+        } else {
+          (*matches)[count++] = xstrdup(str);
         }
       }
     }
 
     if (loop == 0) {
       if (num_normal > 0) {
-        *num_file = num_normal;
+        *numMatches = num_normal;
       } else {
         return OK;
       }
-      *file = xmalloc((size_t)(*num_file) * sizeof(char *));
+      if (!fuzzy) {
+        *matches = xmalloc((size_t)(*numMatches) * sizeof(char *));
+      } else {
+        fuzmatch = xmalloc((size_t)(*numMatches) * sizeof(fuzmatch_str_T));
+      }
     }
   }
+
+  if (fuzzy) {
+    fuzzymatches_to_strmatches(fuzmatch, matches, count, false);
+  }
+
   return OK;
 }
 
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index 3ffab71f22..6385d968dd 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -795,6 +795,7 @@ EXTERN char *p_wop;             // 'wildoptions'
 EXTERN unsigned wop_flags;
 #define WOP_TAGFILE             0x01
 #define WOP_PUM                 0x02
+#define WOP_FUZZY               0x04
 EXTERN long p_window;           // 'window'
 EXTERN char *p_wak;             // 'winaltkeys'
 EXTERN char *p_wig;             // 'wildignore'
diff --git a/src/nvim/optionstr.c b/src/nvim/optionstr.c
index 86fd5c9404..a1a5cadd8d 100644
--- a/src/nvim/optionstr.c
+++ b/src/nvim/optionstr.c
@@ -91,7 +91,7 @@ static char *(p_swb_values[]) = { "useopen", "usetab", "split", "newtab", "vspli
 static char *(p_spk_values[]) = { "cursor", "screen", "topline", NULL };
 static char *(p_tc_values[]) = { "followic", "ignore", "match", "followscs", "smart", NULL };
 static char *(p_ve_values[]) = { "block", "insert", "all", "onemore", "none", "NONE", NULL };
-static char *(p_wop_values[]) = { "tagfile", "pum", NULL };
+static char *(p_wop_values[]) = { "tagfile", "pum", "fuzzy", NULL };
 static char *(p_wak_values[]) = { "yes", "menu", "no", NULL };
 static char *(p_mousem_values[]) = { "extend", "popup", "popup_setpos", "mac", NULL };
 static char *(p_sel_values[]) = { "inclusive", "exclusive", "old", NULL };
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index c895ac16f1..3d09fa1030 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -5230,8 +5230,7 @@ static bool vgr_match_buflines(qf_list_T *qfl, char *fname, buf_T *buf, char *sp
       const size_t sz = sizeof(matches) / sizeof(matches[0]);
 
       // Fuzzy string match
-      while (fuzzy_match((char_u *)str + col, (char_u *)spat, false, &score, matches,
-                         (int)sz) > 0) {
+      while (fuzzy_match(str + col, spat, false, &score, matches, (int)sz) > 0) {
         // Pass the buffer number so that it gets used even for a
         // dummy buffer, unless duplicate_name is set, then the
         // buffer will be wiped out below.
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 871d2f9a0a..205eec8b35 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -2942,7 +2942,7 @@ typedef struct {
 #define FUZZY_MATCH_RECURSION_LIMIT 10
 
 /// Compute a score for a fuzzy matched string. The matching character locations
-/// are in 'matches'.
+/// are in "matches".
 static int fuzzy_match_compute_score(const char *const str, const int strSz,
                                      const uint32_t *const matches, const int numMatches)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
@@ -3007,7 +3007,7 @@ static int fuzzy_match_compute_score(const char *const str, const int strSz,
   return score;
 }
 
-/// Perform a recursive search for fuzzy matching 'fuzpat' in 'str'.
+/// Perform a recursive search for fuzzy matching "fuzpat" in "str".
 /// @return the number of matching characters.
 static int fuzzy_match_recursive(const char *fuzpat, const char *str, uint32_t strIdx,
                                  int *const outScore, const char *const strBegin, const int strLen,
@@ -3107,23 +3107,23 @@ static int fuzzy_match_recursive(const char *fuzpat, const char *str, uint32_t s
 /// Uses char_u for match indices. Therefore patterns are limited to
 /// MAX_FUZZY_MATCHES characters.
 ///
-/// @return true if 'pat_arg' matches 'str'. Also returns the match score in
-/// 'outScore' and the matching character positions in 'matches'.
-bool fuzzy_match(char_u *const str, const char_u *const pat_arg, const bool matchseq,
+/// @return true if "pat_arg" matches "str". Also returns the match score in
+/// "outScore" and the matching character positions in "matches".
+bool fuzzy_match(char *const str, const char *const pat_arg, const bool matchseq,
                  int *const outScore, uint32_t *const matches, const int maxMatches)
-  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
+  FUNC_ATTR_NONNULL_ALL
 {
-  const int len = mb_charlen((char *)str);
+  const int len = mb_charlen(str);
   bool complete = false;
   int numMatches = 0;
 
   *outScore = 0;
 
-  char *const save_pat = xstrdup((char *)pat_arg);
+  char *const save_pat = xstrdup(pat_arg);
   char *pat = save_pat;
   char *p = pat;
 
-  // Try matching each word in 'pat_arg' in 'str'
+  // Try matching each word in "pat_arg" in "str"
   while (true) {
     if (matchseq) {
       complete = true;
@@ -3146,7 +3146,7 @@ bool fuzzy_match(char_u *const str, const char_u *const pat_arg, const bool matc
     int score = 0;
     int recursionCount = 0;
     const int matchCount
-      = fuzzy_match_recursive(pat, (char *)str, 0, &score, (char *)str, len, NULL,
+      = fuzzy_match_recursive(pat, str, 0, &score, str, len, NULL,
                               matches + numMatches,
                               maxMatches - numMatches, 0, &recursionCount);
     if (matchCount == 0) {
@@ -3183,14 +3183,14 @@ static int fuzzy_match_item_compare(const void *const s1, const void *const s2)
   return v1 == v2 ? (idx1 - idx2) : v1 > v2 ? -1 : 1;
 }
 
-/// Fuzzy search the string 'str' in a list of 'items' and return the matching
-/// strings in 'fmatchlist'.
-/// If 'matchseq' is true, then for multi-word search strings, match all the
+/// Fuzzy search the string "str" in a list of "items" and return the matching
+/// strings in "fmatchlist".
+/// If "matchseq" is true, then for multi-word search strings, match all the
 /// words in sequence.
-/// If 'items' is a list of strings, then search for 'str' in the list.
-/// If 'items' is a list of dicts, then either use 'key' to lookup the string
-/// for each item or use 'item_cb' Funcref function to get the string.
-/// If 'retmatchpos' is true, then return a list of positions where 'str'
+/// If "items" is a list of strings, then search for "str" in the list.
+/// If "items" is a list of dicts, then either use "key" to lookup the string
+/// for each item or use "item_cb" Funcref function to get the string.
+/// If "retmatchpos" is true, then return a list of positions where "str"
 /// matches for each item.
 static void fuzzy_match_in_list(list_T *const l, char *const str, const bool matchseq,
                                 const char *const key, Callback *const item_cb,
@@ -3245,14 +3245,14 @@ static void fuzzy_match_in_list(list_T *const l, char *const str, const bool mat
     }
 
     int score;
-    if (itemstr != NULL && fuzzy_match((char_u *)itemstr, (char_u *)str, matchseq, &score, matches,
+    if (itemstr != NULL && fuzzy_match(itemstr, str, matchseq, &score, matches,
                                        MAX_FUZZY_MATCHES)) {
       items[match_count].idx = (int)match_count;
       items[match_count].item = li;
       items[match_count].score = score;
 
       // Copy the list of matching positions in itemstr to a list, if
-      // 'retmatchpos' is set.
+      // "retmatchpos" is set.
       if (retmatchpos) {
         items[match_count].lmatchpos = tv_list_alloc(kListLenMayKnow);
         int j = 0;
@@ -3326,8 +3326,8 @@ static void fuzzy_match_in_list(list_T *const l, char *const str, const bool mat
   xfree(items);
 }
 
-/// Do fuzzy matching. Returns the list of matched strings in 'rettv'.
-/// If 'retmatchpos' is true, also returns the matching character positions.
+/// Do fuzzy matching. Returns the list of matched strings in "rettv".
+/// If "retmatchpos" is true, also returns the matching character positions.
 static void do_fuzzymatch(const typval_T *const argvars, typval_T *const rettv,
                           const bool retmatchpos)
   FUNC_ATTR_NONNULL_ALL
@@ -3411,6 +3411,109 @@ void f_matchfuzzypos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   do_fuzzymatch(argvars, rettv, true);
 }
 
+/// Same as fuzzy_match_item_compare() except for use with a string match
+static int fuzzy_match_str_compare(const void *const s1, const void *const s2)
+  FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  const int v1 = ((fuzmatch_str_T *)s1)->score;
+  const int v2 = ((fuzmatch_str_T *)s2)->score;
+  const int idx1 = ((fuzmatch_str_T *)s1)->idx;
+  const int idx2 = ((fuzmatch_str_T *)s2)->idx;
+
+  return v1 == v2 ? (idx1 - idx2) : v1 > v2 ? -1 : 1;
+}
+
+/// Sort fuzzy matches by score
+static void fuzzy_match_str_sort(fuzmatch_str_T *const fm, const int sz)
+  FUNC_ATTR_NONNULL_ALL
+{
+  // Sort the list by the descending order of the match score
+  qsort(fm, (size_t)sz, sizeof(fuzmatch_str_T), fuzzy_match_str_compare);
+}
+
+/// Same as fuzzy_match_item_compare() except for use with a function name
+/// string match. <SNR> functions should be sorted to the end.
+static int fuzzy_match_func_compare(const void *const s1, const void *const s2)
+  FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL FUNC_ATTR_PURE
+{
+  const int v1 = ((fuzmatch_str_T *)s1)->score;
+  const int v2 = ((fuzmatch_str_T *)s2)->score;
+  const int idx1 = ((fuzmatch_str_T *)s1)->idx;
+  const int idx2 = ((fuzmatch_str_T *)s2)->idx;
+  const char *const str1 = ((fuzmatch_str_T *)s1)->str;
+  const char *const str2 = ((fuzmatch_str_T *)s2)->str;
+
+  if (*str1 != '<' && *str2 == '<') {
+    return -1;
+  }
+  if (*str1 == '<' && *str2 != '<') {
+    return 1;
+  }
+  return v1 == v2 ? (idx1 - idx2) : v1 > v2 ? -1 : 1;
+}
+
+/// Sort fuzzy matches of function names by score.
+/// <SNR> functions should be sorted to the end.
+static void fuzzy_match_func_sort(fuzmatch_str_T *const fm, const int sz)
+  FUNC_ATTR_NONNULL_ALL
+{
+  // Sort the list by the descending order of the match score
+  qsort(fm, (size_t)sz, sizeof(fuzmatch_str_T), fuzzy_match_func_compare);
+}
+
+/// Fuzzy match "pat" in "str".
+/// @returns 0 if there is no match. Otherwise, returns the match score.
+int fuzzy_match_str(char *const str, const char *const pat)
+  FUNC_ATTR_WARN_UNUSED_RESULT
+{
+  if (str == NULL || pat == NULL) {
+    return 0;
+  }
+
+  int score = 0;
+  uint32_t matchpos[MAX_FUZZY_MATCHES];
+  fuzzy_match(str, pat, true, &score, matchpos, sizeof(matchpos) / sizeof(matchpos[0]));
+
+  return score;
+}
+
+/// Copy a list of fuzzy matches into a string list after sorting the matches by
+/// the fuzzy score. Frees the memory allocated for "fuzmatch".
+void fuzzymatches_to_strmatches(fuzmatch_str_T *const fuzmatch, char ***const matches,
+                                const int count, const bool funcsort)
+  FUNC_ATTR_NONNULL_ARG(2)
+{
+  if (count <= 0) {
+    return;
+  }
+
+  *matches = xmalloc((size_t)count * sizeof(char *));
+
+  // Sort the list by the descending order of the match score
+  if (funcsort) {
+    fuzzy_match_func_sort(fuzmatch, count);
+  } else {
+    fuzzy_match_str_sort(fuzmatch, count);
+  }
+
+  for (int i = 0; i < count; i++) {
+    (*matches)[i] = fuzmatch[i].str;
+  }
+  xfree(fuzmatch);
+}
+
+/// Free a list of fuzzy string matches.
+void fuzmatch_str_free(fuzmatch_str_T *const fuzmatch, int count)
+{
+  if (count <= 0 || fuzmatch == NULL) {
+    return;
+  }
+  while (count--) {
+    xfree(fuzmatch[count].str);
+  }
+  xfree(fuzmatch);
+}
+
 /// Get line "lnum" and copy it into "buf[LSIZE]".
 /// The copy is made because the regexp may make the line invalid when using a
 /// mark.
diff --git a/src/nvim/search.h b/src/nvim/search.h
index 092098d5fd..2f140ba840 100644
--- a/src/nvim/search.h
+++ b/src/nvim/search.h
@@ -99,6 +99,14 @@ typedef struct searchstat {
   int last_maxcount;  // the max count of the last search
 } searchstat_T;
 
+/// Fuzzy matched string list item. Used for fuzzy match completion. Items are
+/// usually sorted by "score". The "idx" member is used for stable-sort.
+typedef struct {
+  int idx;
+  char *str;
+  int score;
+} fuzmatch_str_T;
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "search.h.generated.h"
 #endif
diff --git a/src/nvim/testdir/test_cmdline.vim b/src/nvim/testdir/test_cmdline.vim
index a074263359..f5c84e0729 100644
--- a/src/nvim/testdir/test_cmdline.vim
+++ b/src/nvim/testdir/test_cmdline.vim
@@ -650,6 +650,22 @@ func Test_getcompletion()
   call assert_fails('call getcompletion("abc", [])', 'E475:')
 endfunc
 
+" Test for getcompletion() with "fuzzy" in 'wildoptions'
+func Test_getcompletion_wildoptions()
+  let save_wildoptions = &wildoptions
+  set wildoptions&
+  let l = getcompletion('space', 'option')
+  call assert_equal([], l)
+  let l = getcompletion('ier', 'command')
+  call assert_equal([], l)
+  set wildoptions=fuzzy
+  let l = getcompletion('space', 'option')
+  call assert_true(index(l, 'backspace') >= 0)
+  let l = getcompletion('ier', 'command')
+  call assert_true(index(l, 'compiler') >= 0)
+  let &wildoptions = save_wildoptions
+endfunc
+
 func Test_fullcommand()
   let tests = {
         \ '':           '',
@@ -2654,6 +2670,412 @@ func Test_cmdline_complete_dlist()
   call assert_equal("\"dlist 10 /pat/ | chistory", @:)
 endfunc
 
+" Test for 'fuzzy' in 'wildoptions' (fuzzy completion)
+func Test_wildoptions_fuzzy()
+  " argument list (only for :argdel)
+  argadd change.py count.py charge.py
+  set wildoptions&
+  call feedkeys(":argdel cge\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"argdel cge', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":argdel cge\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"argdel change.py charge.py', @:)
+  %argdelete
+
+  " autocmd group name fuzzy completion
+  set wildoptions&
+  augroup MyFuzzyGroup
+  augroup END
+  call feedkeys(":augroup mfg\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"augroup mfg', @:)
+  call feedkeys(":augroup My*p\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"augroup MyFuzzyGroup', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":augroup mfg\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"augroup MyFuzzyGroup', @:)
+  call feedkeys(":augroup My*p\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"augroup My*p', @:)
+  augroup! MyFuzzyGroup
+
+  " buffer name fuzzy completion
+  set wildoptions&
+  edit SomeFile.txt
+  enew
+  call feedkeys(":b SF\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"b SF', @:)
+  call feedkeys(":b S*File.txt\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"b SomeFile.txt', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":b SF\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"b SomeFile.txt', @:)
+  call feedkeys(":b S*File.txt\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"b S*File.txt', @:)
+  %bw!
+
+  " buffer name (full path) fuzzy completion
+  if has('unix')
+    set wildoptions&
+    call mkdir('Xcmd/Xstate/Xfile.js', 'p')
+    edit Xcmd/Xstate/Xfile.js
+    cd Xcmd/Xstate
+    enew
+    call feedkeys(":b CmdStateFile\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"b CmdStateFile', @:)
+    set wildoptions=fuzzy
+    call feedkeys(":b CmdStateFile\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_match('Xcmd/Xstate/Xfile.js$', @:)
+    cd -
+    call delete('Xcmd', 'rf')
+  endif
+
+  " :behave suboptions fuzzy completion
+  set wildoptions&
+  call feedkeys(":behave xm\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"behave xm', @:)
+  call feedkeys(":behave xt*m\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"behave xterm', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":behave xm\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"behave xterm', @:)
+  call feedkeys(":behave xt*m\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"behave xt*m', @:)
+  let g:Sline = ''
+  call feedkeys(":behave win\<C-D>\<F4>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('mswin', g:Sline)
+  call assert_equal('"behave win', @:)
+
+  " colorscheme name fuzzy completion - NOT supported
+
+  " built-in command name fuzzy completion
+  set wildoptions&
+  call feedkeys(":sbwin\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sbwin', @:)
+  call feedkeys(":sbr*d\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sbrewind', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":sbwin\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sbrewind', @:)
+  call feedkeys(":sbr*d\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sbr*d', @:)
+
+  " compiler name fuzzy completion - NOT supported
+
+  " :cscope suboptions fuzzy completion
+  if has('cscope')
+    set wildoptions&
+    call feedkeys(":cscope ret\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"cscope ret', @:)
+    call feedkeys(":cscope re*t\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"cscope reset', @:)
+    set wildoptions=fuzzy
+    call feedkeys(":cscope ret\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"cscope reset', @:)
+    call feedkeys(":cscope re*t\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"cscope re*t', @:)
+  endif
+
+  " :diffget/:diffput buffer name fuzzy completion
+  new SomeBuffer
+  diffthis
+  new OtherBuffer
+  diffthis
+  set wildoptions&
+  call feedkeys(":diffget sbuf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"diffget sbuf', @:)
+  call feedkeys(":diffput sbuf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"diffput sbuf', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":diffget sbuf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"diffget SomeBuffer', @:)
+  call feedkeys(":diffput sbuf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"diffput SomeBuffer', @:)
+  %bw!
+
+  " directory name fuzzy completion - NOT supported
+
+  " environment variable name fuzzy completion
+  set wildoptions&
+  call feedkeys(":echo $VUT\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"echo $VUT', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":echo $VUT\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"echo $VIMRUNTIME', @:)
+
+  " autocmd event fuzzy completion
+  set wildoptions&
+  call feedkeys(":autocmd BWout\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"autocmd BWout', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":autocmd BWout\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"autocmd BufWipeout', @:)
+
+  " vim expression fuzzy completion
+  let g:PerPlaceCount = 10
+  set wildoptions&
+  call feedkeys(":let c = ppc\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"let c = ppc', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":let c = ppc\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"let c = PerPlaceCount', @:)
+
+  " file name fuzzy completion - NOT supported
+
+  " files in path fuzzy completion - NOT supported
+
+  " filetype name fuzzy completion - NOT supported
+
+  " user defined function name completion
+  set wildoptions&
+  call feedkeys(":call Test_w_fuz\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"call Test_w_fuz', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":call Test_w_fuz\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"call Test_wildoptions_fuzzy()', @:)
+
+  " user defined command name completion
+  set wildoptions&
+  call feedkeys(":MsFeat\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"MsFeat', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":MsFeat\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"MissingFeature', @:)
+
+  " :help tag fuzzy completion - NOT supported
+
+  " highlight group name fuzzy completion
+  set wildoptions&
+  call feedkeys(":highlight SKey\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"highlight SKey', @:)
+  call feedkeys(":highlight Sp*Key\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"highlight SpecialKey', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":highlight SKey\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"highlight SpecialKey', @:)
+  call feedkeys(":highlight Sp*Key\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"highlight Sp*Key', @:)
+
+  " :history suboptions fuzzy completion
+  set wildoptions&
+  call feedkeys(":history dg\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"history dg', @:)
+  call feedkeys(":history se*h\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"history search', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":history dg\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"history debug', @:)
+  call feedkeys(":history se*h\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"history se*h', @:)
+
+  " :language locale name fuzzy completion
+  if has('unix')
+    set wildoptions&
+    call feedkeys(":lang psx\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"lang psx', @:)
+    set wildoptions=fuzzy
+    call feedkeys(":lang psx\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"lang POSIX', @:)
+  endif
+
+  " :mapclear buffer argument fuzzy completion
+  set wildoptions&
+  call feedkeys(":mapclear buf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"mapclear buf', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":mapclear buf\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"mapclear <buffer>', @:)
+
+  " map name fuzzy completion
+  " test regex completion works
+  set wildoptions=fuzzy
+  call feedkeys(":cnoremap <ex\<Tab> <esc> \<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"cnoremap <expr> <esc> \<Tab>", @:)
+  nmap <plug>MyLongMap :p<CR>
+  call feedkeys(":nmap MLM\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap <Plug>MyLongMap", @:)
+  call feedkeys(":nmap MLM \<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap MLM \t", @:)
+  call feedkeys(":nmap <F2> one two \<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap <F2> one two \t", @:)
+  " duplicate entries should be removed
+  vmap <plug>MyLongMap :<C-U>#<CR>
+  call feedkeys(":nmap MLM\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap <Plug>MyLongMap", @:)
+  nunmap <plug>MyLongMap
+  vunmap <plug>MyLongMap
+  call feedkeys(":nmap ABC\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap ABC\t", @:)
+  " results should be sorted by best match
+  nmap <Plug>format :
+  nmap <Plug>goformat :
+  nmap <Plug>TestFOrmat :
+  nmap <Plug>fendoff :
+  nmap <Plug>state :
+  nmap <Plug>FendingOff :
+  call feedkeys(":nmap <Plug>fo\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"nmap <Plug>format <Plug>TestFOrmat <Plug>FendingOff <Plug>goformat <Plug>fendoff", @:)
+  nunmap <Plug>format
+  nunmap <Plug>goformat
+  nunmap <Plug>TestFOrmat
+  nunmap <Plug>fendoff
+  nunmap <Plug>state
+  nunmap <Plug>FendingOff
+
+  " abbreviation fuzzy completion
+  set wildoptions=fuzzy
+  call feedkeys(":iabbr wait\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"iabbr <nowait>", @:)
+  iabbr WaitForCompletion WFC
+  call feedkeys(":iabbr fcl\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"iabbr WaitForCompletion", @:)
+  call feedkeys(":iabbr a1z\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"iabbr a1z\t", @:)
+  iunabbrev WaitForCompletion
+
+  " menu name fuzzy completion
+  if has('gui_running')
+    set wildoptions&
+    call feedkeys(":menu pup\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"menu pup', @:)
+    set wildoptions=fuzzy
+    call feedkeys(":menu pup\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"menu PopUp.', @:)
+  endif
+
+  " :messages suboptions fuzzy completion
+  set wildoptions&
+  call feedkeys(":messages clr\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"messages clr', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":messages clr\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"messages clear', @:)
+
+  " :set option name fuzzy completion
+  set wildoptions&
+  call feedkeys(":set brkopt\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"set brkopt', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":set brkopt\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"set breakindentopt', @:)
+  set wildoptions&
+  call feedkeys(":set fixeol\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"set fixendofline', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":set fixeol\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"set fixendofline', @:)
+
+  " :set <term_option>
+  " Nvim does not support term options
+  " set wildoptions&
+  " call feedkeys(":set t_E\<Tab>\<C-B>\"\<CR>", 'tx')
+  " call assert_equal('"set t_EC', @:)
+  " call feedkeys(":set <t_E\<Tab>\<C-B>\"\<CR>", 'tx')
+  " call assert_equal('"set <t_EC>', @:)
+  " set wildoptions=fuzzy
+  " call feedkeys(":set t_E\<Tab>\<C-B>\"\<CR>", 'tx')
+  " call assert_equal('"set t_EC', @:)
+  " call feedkeys(":set <t_E\<Tab>\<C-B>\"\<CR>", 'tx')
+  " call assert_equal('"set <t_EC>', @:)
+
+  " :packadd directory name fuzzy completion - NOT supported
+
+  " shell command name fuzzy completion - NOT supported
+
+  " :sign suboptions fuzzy completion
+  set wildoptions&
+  call feedkeys(":sign ufe\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sign ufe', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":sign ufe\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"sign undefine', @:)
+
+  " :syntax suboptions fuzzy completion
+  set wildoptions&
+  call feedkeys(":syntax kwd\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"syntax kwd', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":syntax kwd\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"syntax keyword', @:)
+
+  " syntax group name fuzzy completion
+  set wildoptions&
+  call feedkeys(":syntax list mpar\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"syntax list mpar', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":syntax list mpar\<Tab>\<C-B>\"\<CR>", 'tx')
+  " Fuzzy match favours NvimParenthesis over MatchParen
+  " call assert_equal('"syntax list MatchParen', @:)
+  call assert_equal('"syntax list NvimParenthesis', @:)
+
+  " :syntime suboptions fuzzy completion
+  if has('profile')
+    set wildoptions&
+    call feedkeys(":syntime clr\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"syntime clr', @:)
+    set wildoptions=fuzzy
+    call feedkeys(":syntime clr\<Tab>\<C-B>\"\<CR>", 'tx')
+    call assert_equal('"syntime clear', @:)
+  endif
+
+  " tag name fuzzy completion - NOT supported
+
+  " tag name and file fuzzy completion - NOT supported
+
+  " user names fuzzy completion - how to test this functionality?
+
+  " user defined variable name fuzzy completion
+  let g:SomeVariable=10
+  set wildoptions&
+  call feedkeys(":let SVar\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"let SVar', @:)
+  set wildoptions=fuzzy
+  call feedkeys(":let SVar\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"let SomeVariable', @:)
+
+  " Test for sorting the results by the best match
+  %bw!
+  command T123format :
+  command T123goformat :
+  command T123TestFOrmat :
+  command T123fendoff :
+  command T123state :
+  command T123FendingOff :
+  set wildoptions=fuzzy
+  call feedkeys(":T123fo\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"T123format T123TestFOrmat T123FendingOff T123goformat T123fendoff', @:)
+  delcommand T123format
+  delcommand T123goformat
+  delcommand T123TestFOrmat
+  delcommand T123fendoff
+  delcommand T123state
+  delcommand T123FendingOff
+  %bw
+
+  " Test for fuzzy completion of a command with lower case letters and a
+  " number
+  command Foo2Bar :
+  set wildoptions=fuzzy
+  call feedkeys(":foo2\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  call feedkeys(":foo\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  call feedkeys(":bar\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"Foo2Bar', @:)
+  delcommand Foo2Bar
+
+  " Test for command completion for a command starting with 'k'
+  command KillKillKill :
+  set wildoptions&
+  call feedkeys(":killkill\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"killkill\<Tab>", @:)
+  set wildoptions=fuzzy
+  call feedkeys(":killkill\<Tab>\<C-B>\"\<CR>", 'tx')
+  call assert_equal('"KillKillKill', @:)
+  delcom KillKillKill
+
+  set wildoptions&
+  %bw!
+endfunc
+
 " Test for :breakadd argument completion
 func Test_cmdline_complete_breakadd()
   call feedkeys(":breakadd \<C-A>\<C-B>\"\<CR>", 'tx')