diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 4af0904..a30e3eb 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -12,8 +12,10 @@
 'git checkout' [-q] [-f] [-m] --detach [<branch>]
 'git checkout' [-q] [-f] [-m] [--detach] <commit>
 'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new-branch>] [<start-point>]
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <pathspec>...
-'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] --pathspec-from-file=<file> [--pathspec-file-nul]
+'git checkout' [-f] <tree-ish> [--] <pathspec>...
+'git checkout' [-f] <tree-ish> --pathspec-from-file=<file> [--pathspec-file-nul]
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [--] <pathspec>...
+'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] --pathspec-from-file=<file> [--pathspec-file-nul]
 'git checkout' (-p|--patch) [<tree-ish>] [--] [<pathspec>...]
 
 DESCRIPTION
@@ -260,7 +262,8 @@
 should result in deletion of the path).
 +
 When checking out paths from the index, this option lets you recreate
-the conflicted merge in the specified paths.
+the conflicted merge in the specified paths.  This option cannot be
+used when checking out paths from a tree-ish.
 +
 When switching branches with `--merge`, staged changes may be lost.
 
diff --git a/Documentation/git-restore.txt b/Documentation/git-restore.txt
index 5964810..c704447 100644
--- a/Documentation/git-restore.txt
+++ b/Documentation/git-restore.txt
@@ -78,6 +78,8 @@
 --theirs::
 	When restoring files in the working tree from the index, use
 	stage #2 ('ours') or #3 ('theirs') for unmerged paths.
+	This option cannot be used when checking out paths from a
+	tree-ish (i.e. with the `--source` option).
 +
 Note that during `git rebase` and `git pull --rebase`, 'ours' and
 'theirs' may appear swapped. See the explanation of the same options
@@ -87,6 +89,8 @@
 --merge::
 	When restoring files on the working tree from the index,
 	recreate the conflicted merge in the unmerged paths.
+	This option cannot be used when checking out paths from a
+	tree-ish (i.e. with the `--source` option).
 
 --conflict=<style>::
 	The same as `--merge` option above, but changes the way the
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 715eeb5..b8dfba5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -520,6 +520,15 @@ static int checkout_paths(const struct checkout_opts *opts,
 			    "--merge", "--conflict", "--staged");
 	}
 
+	/*
+	 * recreating unmerged index entries and writing out data from
+	 * unmerged index entries would make no sense when checking out
+	 * of a tree-ish.
+	 */
+	if ((opts->merge || opts->writeout_stage) && opts->source_tree)
+		die(_("'%s', '%s', or '%s' cannot be used when checking out of a tree"),
+		    "--merge", "--ours", "--theirs");
+
 	if (opts->patch_mode) {
 		enum add_p_mode patch_mode;
 		const char *rev = new_branch_info->name;
diff --git a/t/t2070-restore.sh b/t/t2070-restore.sh
index c5d19dd..fd77580 100755
--- a/t/t2070-restore.sh
+++ b/t/t2070-restore.sh
@@ -137,11 +137,14 @@
 	test_must_fail git rev-parse HEAD:new1
 '
 
-test_expect_success 'restore with merge options rejects --staged' '
+test_expect_success 'restore with merge options are incompatible with certain options' '
 	for opts in \
 		"--staged --ours" \
 		"--staged --theirs" \
 		"--staged --merge" \
+		"--source=HEAD --ours" \
+		"--source=HEAD --theirs" \
+		"--source=HEAD --merge" \
 		"--staged --conflict=diff3" \
 		"--staged --worktree --ours" \
 		"--staged --worktree --theirs" \
@@ -149,7 +152,7 @@
 		"--staged --worktree --conflict=zdiff3"
 	do
 		test_must_fail git restore $opts . 2>err &&
-		grep "cannot be used with --staged" err || return
+		grep "cannot be used" err || return
 	done
 '
 
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 61ad47b..23d4dad 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -497,6 +497,11 @@
 	test ztheirside = "z$(cat file)"
 '
 
+test_expect_success 'checkout path with --merge from tree-ish is a no-no' '
+	setup_conflicting_index &&
+	test_must_fail git checkout -m HEAD -- file
+'
+
 test_expect_success 'checkout with --merge' '
 	setup_conflicting_index &&
 	echo "none of the above" >sample &&