--- a/mercurial/commands.py	Wed Apr 17 01:12:21 2019 +0200
+++ b/mercurial/commands.py	Wed Apr 17 01:11:09 2019 +0200
@@ -63,6 +63,7 @@
     tags as tagsmod,
     ui as uimod,
     util,
+    verify as verifymod,
     wireprotoserver,
 )
 from .utils import (
@@ -6147,8 +6148,10 @@
                 ui.warn("(%s)\n" % obsfatemsg)
         return ret
 
-@command('verify', [], helpcategory=command.CATEGORY_MAINTENANCE)
-def verify(ui, repo):
+@command('verify',
+         [('', 'full', False, 'perform more checks (EXPERIMENTAL)')],
+         helpcategory=command.CATEGORY_MAINTENANCE)
+def verify(ui, repo, **opts):
     """verify the integrity of the repository
 
     Verify the integrity of the current repository.
@@ -6164,7 +6167,10 @@
 
     Returns 0 on success, 1 if errors are encountered.
     """
-    return hg.verify(repo)
+    level = None
+    if opts['full']:
+        level = verifymod.VERIFY_FULL
+    return hg.verify(repo, level)
 
 @command(
     'version', [] + formatteropts, helpcategory=command.CATEGORY_HELP,

--- a/mercurial/verify.py	Wed Apr 17 01:12:21 2019 +0200
+++ b/mercurial/verify.py	Wed Apr 17 01:11:09 2019 +0200
@@ -23,6 +23,7 @@
 )
 
 VERIFY_DEFAULT = 0
+VERIFY_FULL = 1
 
 def verify(repo, level=None):
     with repo.lock():

--- a/tests/test-completion.t	Wed Apr 17 01:12:21 2019 +0200
+++ b/tests/test-completion.t	Wed Apr 17 01:11:09 2019 +0200
@@ -347,7 +347,7 @@
   tip: patch, git, style, template
   unbundle: update
   update: clean, check, merge, date, rev, tool
-  verify: 
+  verify: full
   version: template
 
   $ hg init a

--- a/tests/test-help.t	Wed Apr 17 01:12:21 2019 +0200
+++ b/tests/test-help.t	Wed Apr 17 01:11:09 2019 +0200
@@ -615,6 +615,8 @@
   
       Returns 0 on success, 1 if errors are encountered.
   
+  options:
+  
   (some details hidden, use --verbose to show complete help)
 
   $ hg help diff