diff --git a/coverage/files.py b/coverage/files.py
index 2c520b8ab..56400e9fd 100644
--- a/coverage/files.py
+++ b/coverage/files.py
@@ -3,7 +3,6 @@
 
 """File wrangling."""
 
-import fnmatch
 import hashlib
 import ntpath
 import os
@@ -282,7 +281,35 @@ def sep(s):
     return the_sep
 
 
+PATHEX_SUBS = [(re.compile(rx), sub) for rx, sub in [
+    (r"^\*+[/\\]", r"^(.*[/\\\\])?"),
+    (r"[/\\]\*+$", r".*"),
+    (r"\*\*+[/\\]?", r".*"),
+    (r"[/\\]", r"[/\\\\]"),
+    (r"\*", r"[^/\\\\]*"),
+    (r"\?", r"[^/\\\\]"),
+    (r"\[.*?\]", r"\g<0>"),
+    (r"[a-zA-Z0-9_-]+", r"\g<0>"),
+    (r".", r"\\\g<0>"),
+]]
+
+def pathex(pattern):
+    """Convert a file-path pattern into a regex."""
+    if not re.search(r"[/\\]", pattern):
+        pattern = "**/" + pattern
+    path_rx = ""
+    pos = 0
+    while pos < len(pattern):
+        for rx, sub in PATHEX_SUBS:
+            m = rx.match(pattern, pos=pos)
+            if m:
+                path_rx += m.expand(sub)
+                pos = m.end()
+                break
+    return path_rx
+
 def fnmatches_to_regex(patterns, case_insensitive=False, partial=False):
+    1 # todo: fix this docstring
     """Convert fnmatch patterns to a compiled regex that matches any of them.
 
     Slashes are always converted to match either slash or backslash, for
@@ -295,24 +322,13 @@ def fnmatches_to_regex(patterns, case_insensitive=False, partial=False):
     strings.
 
     """
-    regexes = (fnmatch.translate(pattern) for pattern in patterns)
-    # */ at the start should also match nothing.
-    regexes = (re.sub(r"^\(\?s:\.\*(\\\\|/)", r"(?s:^(.*\1)?", regex) for regex in regexes)
-    # Be agnostic: / can mean backslash or slash.
-    regexes = (re.sub(r"/", r"[\\\\/]", regex) for regex in regexes)
-
-    if partial:
-        # fnmatch always adds a \Z to match the whole string, which we don't
-        # want, so we remove the \Z.  While removing it, we only replace \Z if
-        # followed by paren (introducing flags), or at end, to keep from
-        # destroying a literal \Z in the pattern.
-        regexes = (re.sub(r'\\Z(\(\?|$)', r'\1', regex) for regex in regexes)
-
     flags = 0
     if case_insensitive:
         flags |= re.IGNORECASE
-    compiled = re.compile(join_regex(regexes), flags=flags)
-
+    rx = join_regex(map(pathex, patterns))
+    if not partial:
+        rx = rf"(?:{rx})\Z"
+    compiled = re.compile(rx, flags=flags)
     return compiled
 
 
diff --git a/tests/test_api.py b/tests/test_api.py
index 375edcec1..07bd07f33 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -71,7 +71,6 @@ def test_unexecuted_file(self):
         assert missing == [1]
 
     def test_filenames(self):
-
         self.make_file("mymain.py", """\
             import mymod
             a = 1
diff --git a/tests/test_files.py b/tests/test_files.py
index 8fea61d07..38208cf0e 100644
--- a/tests/test_files.py
+++ b/tests/test_files.py
@@ -3,6 +3,7 @@
 
 """Tests for files.py"""
 
+import itertools
 import os
 import os.path
 from unittest import mock
@@ -104,59 +105,99 @@ def test_flat_rootname(original, flat):
     assert flat_rootname(original) == flat
 
 
+def gen_params(patterns, case_insensitive=False, partial=False, matches=(), nomatches=()):
+    pat_id = "|".join(patterns)
+    for text in matches:
+        yield pytest.param(
+            patterns, case_insensitive, partial, text, True,
+            id=f"{pat_id}:ci{case_insensitive}:par{partial}:{text}:match",
+        )
+    for text in nomatches:
+        yield pytest.param(
+            patterns, case_insensitive, partial, text, False,
+            id=f"{pat_id}:ci{case_insensitive}:par{partial}:{text}:nomatch",
+        )
+
 @pytest.mark.parametrize(
-        "patterns, case_insensitive, partial," +
-            "matches," +
-            "nomatches",
-[
-    (
-        ["abc", "xyz"], False, False,
-            ["abc", "xyz"],
-            ["ABC", "xYz", "abcx", "xabc", "axyz", "xyza"],
+    "patterns, case_insensitive, partial, text, result",
+list(itertools.chain.from_iterable([
+    gen_params(
+        ["abc", "xyz"],
+        matches=["abc", "xyz", "sub/mod/abc"],
+        nomatches=["ABC", "xYz", "abcx", "xabc", "axyz", "xyza", "sub/mod/abcd", "sub/abc/more"],
     ),
-    (
-        ["abc", "xyz"], True, False,
-            ["abc", "xyz", "Abc", "XYZ", "AbC"],
-            ["abcx", "xabc", "axyz", "xyza"],
+    gen_params(
+        ["abc", "xyz"], case_insensitive=True,
+        matches=["abc", "xyz", "Abc", "XYZ", "AbC"],
+        nomatches=["abcx", "xabc", "axyz", "xyza"],
     ),
-    (
-        ["abc/hi.py"], True, False,
-            ["abc/hi.py", "ABC/hi.py", r"ABC\hi.py"],
-            ["abc_hi.py", "abc/hi.pyc"],
+    gen_params(
+        ["a?c", "x?z"],
+        matches=["abc", "xyz", "xYz", "azc", "xaz"],
+        nomatches=["ABC", "abcx", "xabc", "axyz", "xyza"],
     ),
-    (
-        [r"abc\hi.py"], True, False,
-            [r"abc\hi.py", r"ABC\hi.py"],
-            ["abc/hi.py", "ABC/hi.py", "abc_hi.py", "abc/hi.pyc"],
+    gen_params(
+        ["a??d"],
+        matches=["abcd", "azcd", "a12d"],
+        nomatches=["ABCD", "abcx", "axyz", "abcde"],
     ),
-    (
-        ["abc/*/hi.py"], True, False,
-            ["abc/foo/hi.py", "ABC/foo/bar/hi.py", r"ABC\foo/bar/hi.py"],
-            ["abc/hi.py", "abc/hi.pyc"],
+    gen_params(
+        ["abc/hi.py"], case_insensitive=True,
+        matches=["abc/hi.py", "ABC/hi.py", r"ABC\hi.py"],
+        nomatches=["abc_hi.py", "abc/hi.pyc"],
     ),
-    (
-        ["abc/[a-f]*/hi.py"], True, False,
-            ["abc/foo/hi.py", "ABC/foo/bar/hi.py", r"ABC\foo/bar/hi.py"],
-            ["abc/zoo/hi.py", "abc/hi.py", "abc/hi.pyc"],
+    gen_params(
+        [r"abc\hi.py"], case_insensitive=True,
+        matches=[r"abc\hi.py", r"ABC\hi.py", "abc/hi.py", "ABC/hi.py"],
+        nomatches=["abc_hi.py", "abc/hi.pyc"],
     ),
-    (
-        ["abc/"], True, True,
-            ["abc/foo/hi.py", "ABC/foo/bar/hi.py", r"ABC\foo/bar/hi.py"],
-            ["abcd/foo.py", "xabc/hi.py"],
+    gen_params(
+        ["abc/*/hi.py"], case_insensitive=True,
+        matches=["abc/foo/hi.py", r"ABC\foo/hi.py"],
+        nomatches=["abc/hi.py", "abc/hi.pyc", "ABC/foo/bar/hi.py", r"ABC\foo/bar/hi.py"],
     ),
-    (
-        ["*/foo"], False, True,
-            ["abc/foo/hi.py", "foo/hi.py"],
-            ["abc/xfoo/hi.py"],
+    gen_params(
+        ["abc/**/hi.py"], case_insensitive=True,
+        matches=[
+            "abc/foo/hi.py", r"ABC\foo/hi.py", "abc/hi.py", "ABC/foo/bar/hi.py",
+            r"ABC\foo/bar/hi.py",
+        ],
+        nomatches=["abc/hi.pyc"],
     ),
-
-])
-def test_fnmatches_to_regex(patterns, case_insensitive, partial, matches, nomatches):
+    gen_params(
+        ["abc/[a-f]*/hi.py"], case_insensitive=True,
+        matches=["abc/foo/hi.py", r"ABC\boo/hi.py"],
+        nomatches=[
+            "abc/zoo/hi.py", "abc/hi.py", "abc/hi.pyc", "abc/foo/bar/hi.py", r"abc\foo/bar/hi.py",
+        ],
+    ),
+    gen_params(
+        ["abc/[a-f]/hi.py"], case_insensitive=True,
+        matches=["abc/f/hi.py", r"ABC\b/hi.py"],
+        nomatches=[
+            "abc/foo/hi.py", "abc/zoo/hi.py", "abc/hi.py", "abc/hi.pyc", "abc/foo/bar/hi.py",
+            r"abc\foo/bar/hi.py",
+        ],
+    ),
+    gen_params(
+        ["abc/"], case_insensitive=True, partial=True,
+        matches=["abc/foo/hi.py", "ABC/foo/bar/hi.py", r"ABC\foo/bar/hi.py"],
+        nomatches=["abcd/foo.py", "xabc/hi.py"],
+    ),
+    gen_params(
+        ["*/foo"], case_insensitive=False, partial=True,
+        matches=["abc/foo/hi.py", "foo/hi.py"],
+        nomatches=["abc/xfoo/hi.py"],
+    ),
+    gen_params(
+        ["**/foo"],
+        matches=["foo", "hello/foo", "hi/there/foo"],
+        nomatches=["foob", "hello/foob", "hello/Foo"],
+    ),
+])))
+def test_fnmatches_to_regex(patterns, case_insensitive, partial, text, result):
     regex = fnmatches_to_regex(patterns, case_insensitive=case_insensitive, partial=partial)
-    for s in matches:
-        assert regex.match(s)
-    for s in nomatches:
-        assert not regex.match(s)
+    assert bool(regex.match(text)) == result
 
 
 class MatcherTest(CoverageTest):
@@ -235,6 +276,8 @@ def test_fnmatch_matcher_overload(self):
         self.assertMatches(fnm, "x007foo.txt", True)
         self.assertMatches(fnm, "x123foo.txt", True)
         self.assertMatches(fnm, "x798bar.txt", False)
+        self.assertMatches(fnm, "x499.txt", True)
+        self.assertMatches(fnm, "x500.txt", False)
 
     def test_fnmatch_windows_paths(self):
         # We should be able to match Windows paths even if we are running on
@@ -309,9 +352,9 @@ def test_multiple_patterns(self, rel_yn):
             assert msgs == [
                 "Aliases (relative=True):",
                 " Rule: '/home/*/src' -> './mysrc/' using regex " +
-                    "'(?s:[\\\\\\\\/]home[\\\\\\\\/].*[\\\\\\\\/]src[\\\\\\\\/])'",
+                    "'[/\\\\\\\\]home[/\\\\\\\\][^/\\\\\\\\]*[/\\\\\\\\]src[/\\\\\\\\]'",
                 " Rule: '/lib/*/libsrc' -> './mylib/' using regex " +
-                    "'(?s:[\\\\\\\\/]lib[\\\\\\\\/].*[\\\\\\\\/]libsrc[\\\\\\\\/])'",
+                    "'[/\\\\\\\\]lib[/\\\\\\\\][^/\\\\\\\\]*[/\\\\\\\\]libsrc[/\\\\\\\\]'",
                 "Matched path '/home/foo/src/a.py' to rule '/home/*/src' -> './mysrc/', " +
                     "producing './mysrc/a.py'",
                 "Matched path '/lib/foo/libsrc/a.py' to rule '/lib/*/libsrc' -> './mylib/', " +
@@ -321,9 +364,9 @@ def test_multiple_patterns(self, rel_yn):
             assert msgs == [
                 "Aliases (relative=False):",
                 " Rule: '/home/*/src' -> './mysrc/' using regex " +
-                    "'(?s:[\\\\\\\\/]home[\\\\\\\\/].*[\\\\\\\\/]src[\\\\\\\\/])'",
+                    "'[/\\\\\\\\]home[/\\\\\\\\][^/\\\\\\\\]*[/\\\\\\\\]src[/\\\\\\\\]'",
                 " Rule: '/lib/*/libsrc' -> './mylib/' using regex " +
-                    "'(?s:[\\\\\\\\/]lib[\\\\\\\\/].*[\\\\\\\\/]libsrc[\\\\\\\\/])'",
+                    "'[/\\\\\\\\]lib[/\\\\\\\\][^/\\\\\\\\]*[/\\\\\\\\]libsrc[/\\\\\\\\]'",
                 "Matched path '/home/foo/src/a.py' to rule '/home/*/src' -> './mysrc/', " +
                     f"producing {files.canonical_filename('./mysrc/a.py')!r}",
                 "Matched path '/lib/foo/libsrc/a.py' to rule '/lib/*/libsrc' -> './mylib/', " +