diff --git a/.gitignore b/.gitignore
index 0d77ea5894..910b1d2d2f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -124,7 +124,6 @@
 /git-rebase--am
 /git-rebase--common
 /git-rebase--interactive
-/git-rebase--merge
 /git-rebase--preserve-merges
 /git-receive-pack
 /git-reflog
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index dff17b3178..8bfa36a185 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -504,15 +504,7 @@ See also INCOMPATIBLE OPTIONS below.
 INCOMPATIBLE OPTIONS
 --------------------
 
-git-rebase has many flags that are incompatible with each other,
-predominantly due to the fact that it has three different underlying
-implementations:
-
- * one based on linkgit:git-am[1] (the default)
- * one based on git-merge-recursive (merge backend)
- * one based on linkgit:git-cherry-pick[1] (interactive backend)
-
-Flags only understood by the am backend:
+The following options:
 
  * --committer-date-is-author-date
  * --ignore-date
@@ -520,15 +512,12 @@ Flags only understood by the am backend:
  * --ignore-whitespace
  * -C
 
-Flags understood by both merge and interactive backends:
+are incompatible with the following options:
 
  * --merge
  * --strategy
  * --strategy-option
  * --allow-empty-message
-
-Flags only understood by the interactive backend:
-
  * --[no-]autosquash
  * --rebase-merges
  * --preserve-merges
@@ -539,7 +528,7 @@ Flags only understood by the interactive backend:
  * --edit-todo
  * --root when used in combination with --onto
 
-Other incompatible flag pairs:
+In addition, the following pairs of options are incompatible:
 
  * --preserve-merges and --interactive
  * --preserve-merges and --signoff
diff --git a/Makefile b/Makefile
index 1a44c811aa..82e1eb1a4a 100644
--- a/Makefile
+++ b/Makefile
@@ -628,7 +628,6 @@ SCRIPT_LIB += git-parse-remote
 SCRIPT_LIB += git-rebase--am
 SCRIPT_LIB += git-rebase--common
 SCRIPT_LIB += git-rebase--preserve-merges
-SCRIPT_LIB += git-rebase--merge
 SCRIPT_LIB += git-sh-setup
 SCRIPT_LIB += git-sh-i18n
 
diff --git a/builtin/rebase.c b/builtin/rebase.c
index ec2e5fbf23..d95843a8d4 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -122,7 +122,7 @@ static void imply_interactive(struct rebase_options *opts, const char *option)
 	case REBASE_PRESERVE_MERGES:
 		break;
 	case REBASE_MERGE:
-		/* we silently *upgrade* --merge to --interactive if needed */
+		/* we now implement --merge via --interactive */
 	default:
 		opts->type = REBASE_INTERACTIVE; /* implied */
 		break;
@@ -481,10 +481,6 @@ static int run_specific_rebase(struct rebase_options *opts)
 		backend = "git-rebase--am";
 		backend_func = "git_rebase__am";
 		break;
-	case REBASE_MERGE:
-		backend = "git-rebase--merge";
-		backend_func = "git_rebase__merge";
-		break;
 	case REBASE_PRESERVE_MERGES:
 		backend = "git-rebase--preserve-merges";
 		backend_func = "git_rebase__preserve_merges";
@@ -1191,6 +1187,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (options.type == REBASE_MERGE)
+		imply_interactive(&options, "--merge");
+
 	if (options.root && !options.onto_name)
 		imply_interactive(&options, "--root without --onto");
 
@@ -1220,10 +1219,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 				break;
 
 		if (is_interactive(&options) && i >= 0)
-			die(_("cannot combine am options "
-			      "with interactive options"));
-		if (options.type == REBASE_MERGE && i >= 0)
-			die(_("cannot combine am options with merge options "));
+			die(_("cannot combine am options with either "
+			      "interactive or merge options"));
 	}
 
 	if (options.signoff) {
diff --git a/git-legacy-rebase.sh b/git-legacy-rebase.sh
index 6baf10192d..0c9c19bc60 100755
--- a/git-legacy-rebase.sh
+++ b/git-legacy-rebase.sh
@@ -218,6 +218,7 @@ then
 	state_dir="$apply_dir"
 elif test -d "$merge_dir"
 then
+	type=interactive
 	if test -d "$merge_dir"/rewritten
 	then
 		type=preserve-merges
@@ -225,10 +226,7 @@ then
 		preserve_merges=t
 	elif test -f "$merge_dir"/interactive
 	then
-		type=interactive
 		interactive_rebase=explicit
-	else
-		type=merge
 	fi
 	state_dir="$merge_dir"
 fi
@@ -477,6 +475,7 @@ then
 	test -z "$interactive_rebase" && interactive_rebase=implied
 fi
 
+actually_interactive=
 if test -n "$interactive_rebase"
 then
 	if test -z "$preserve_merges"
@@ -485,11 +484,12 @@ then
 	else
 		type=preserve-merges
 	fi
-
+	actually_interactive=t
 	state_dir="$merge_dir"
 elif test -n "$do_merge"
 then
-	type=merge
+	interactive_rebase=implied
+	type=interactive
 	state_dir="$merge_dir"
 else
 	type=am
@@ -505,13 +505,9 @@ incompatible_opts=$(echo " $git_am_opt " | \
 		    sed -e 's/ -q / /g' -e 's/^ \(.*\) $/\1/')
 if test -n "$incompatible_opts"
 then
-	if test -n "$interactive_rebase"
+	if test -n "$actually_interactive" || test "$do_merge"
 	then
-		die "$(gettext "fatal: cannot combine am options with interactive options")"
-	fi
-	if test -n "$do_merge"
-	then
-		die "$(gettext "fatal: cannot combine am options with merge options")"
+		die "$(gettext "fatal: cannot combine am options with either interactive or merge options")"
 	fi
 fi
 
@@ -676,7 +672,7 @@ require_clean_work_tree "rebase" "$(gettext "Please commit or stash them.")"
 # but this should be done only when upstream and onto are the same
 # and if this is not an interactive rebase.
 mb=$(git merge-base "$onto" "$orig_head")
-if test -z "$interactive_rebase" && test "$upstream" = "$onto" &&
+if test -z "$actually_interactive" && test "$upstream" = "$onto" &&
 	test "$mb" = "$onto" && test -z "$restrict_revision" &&
 	# linear history?
 	! (git rev-list --parents "$onto".."$orig_head" | sane_grep " .* ") > /dev/null
@@ -726,6 +722,19 @@ then
 	GIT_PAGER='' git diff --stat --summary "$mb_tree" "$onto"
 fi
 
+if test -z "$actually_interactive" && test "$mb" = "$orig_head"
+then
+	say "$(eval_gettext "Fast-forwarded \$branch_name to \$onto_name.")"
+	GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $onto_name" \
+		git checkout -q "$onto^0" || die "could not detach HEAD"
+	# If the $onto is a proper descendant of the tip of the branch, then
+	# we just fast-forwarded.
+	git update-ref ORIG_HEAD $orig_head
+	move_to_original_branch
+	finish_rebase
+	exit 0
+fi
+
 test -n "$interactive_rebase" && run_specific_rebase
 
 # Detach HEAD and reset the tree
@@ -735,16 +744,6 @@ GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $onto_name" \
 	git checkout -q "$onto^0" || die "could not detach HEAD"
 git update-ref ORIG_HEAD $orig_head
 
-# If the $onto is a proper descendant of the tip of the branch, then
-# we just fast-forwarded.
-if test "$mb" = "$orig_head"
-then
-	say "$(eval_gettext "Fast-forwarded \$branch_name to \$onto_name.")"
-	move_to_original_branch
-	finish_rebase
-	exit 0
-fi
-
 if test -n "$rebase_root"
 then
 	revisions="$onto..$orig_head"
diff --git a/git-rebase--merge.sh b/git-rebase--merge.sh
deleted file mode 100644
index ced38bb3a6..0000000000
--- a/git-rebase--merge.sh
+++ /dev/null
@@ -1,166 +0,0 @@
-# This shell script fragment is sourced by git-rebase to implement
-# its merge-based non-interactive mode that copes well with renamed
-# files.
-#
-# Copyright (c) 2010 Junio C Hamano.
-#
-
-prec=4
-
-read_state () {
-	onto_name=$(cat "$state_dir"/onto_name) &&
-	end=$(cat "$state_dir"/end) &&
-	msgnum=$(cat "$state_dir"/msgnum)
-}
-
-continue_merge () {
-	test -d "$state_dir" || die "$state_dir directory does not exist"
-
-	unmerged=$(git ls-files -u)
-	if test -n "$unmerged"
-	then
-		echo "You still have unmerged paths in your index"
-		echo "did you forget to use git add?"
-		die "$resolvemsg"
-	fi
-
-	cmt=$(cat "$state_dir/current")
-	if ! git diff-index --quiet --ignore-submodules HEAD --
-	then
-		if ! git commit ${gpg_sign_opt:+"$gpg_sign_opt"} $signoff $allow_empty_message \
-			--no-verify -C "$cmt"
-		then
-			echo "Commit failed, please do not call \"git commit\""
-			echo "directly, but instead do one of the following: "
-			die "$resolvemsg"
-		fi
-		if test -z "$GIT_QUIET"
-		then
-			printf "Committed: %0${prec}d " $msgnum
-		fi
-		echo "$cmt $(git rev-parse HEAD^0)" >> "$state_dir/rewritten"
-	else
-		if test -z "$GIT_QUIET"
-		then
-			printf "Already applied: %0${prec}d " $msgnum
-		fi
-	fi
-	test -z "$GIT_QUIET" &&
-	GIT_PAGER='' git log --format=%s -1 "$cmt"
-
-	# onto the next patch:
-	msgnum=$(($msgnum + 1))
-	echo "$msgnum" >"$state_dir/msgnum"
-}
-
-call_merge () {
-	msgnum="$1"
-	echo "$msgnum" >"$state_dir/msgnum"
-	cmt="$(cat "$state_dir/cmt.$msgnum")"
-	echo "$cmt" > "$state_dir/current"
-	git update-ref REBASE_HEAD "$cmt"
-	hd=$(git rev-parse --verify HEAD)
-	cmt_name=$(git symbolic-ref HEAD 2> /dev/null || echo HEAD)
-	eval GITHEAD_$cmt='"${cmt_name##refs/heads/}~$(($end - $msgnum))"'
-	eval GITHEAD_$hd='$onto_name'
-	export GITHEAD_$cmt GITHEAD_$hd
-	if test -n "$GIT_QUIET"
-	then
-		GIT_MERGE_VERBOSITY=1 && export GIT_MERGE_VERBOSITY
-	fi
-	test -z "$strategy" && strategy=recursive
-	# If cmt doesn't have a parent, don't include it as a base
-	base=$(git rev-parse --verify --quiet $cmt^)
-	eval 'git merge-$strategy' $strategy_opts $base ' -- "$hd" "$cmt"'
-	rv=$?
-	case "$rv" in
-	0)
-		unset GITHEAD_$cmt GITHEAD_$hd
-		return
-		;;
-	1)
-		git rerere $allow_rerere_autoupdate
-		die "$resolvemsg"
-		;;
-	2)
-		echo "Strategy: $strategy failed, try another" 1>&2
-		die "$resolvemsg"
-		;;
-	*)
-		die "Unknown exit code ($rv) from command:" \
-			"git merge-$strategy $cmt^ -- HEAD $cmt"
-		;;
-	esac
-}
-
-finish_rb_merge () {
-	move_to_original_branch
-	if test -s "$state_dir"/rewritten
-	then
-		git notes copy --for-rewrite=rebase <"$state_dir"/rewritten
-		hook="$(git rev-parse --git-path hooks/post-rewrite)"
-		test -x "$hook" && "$hook" rebase <"$state_dir"/rewritten
-	fi
-	say All done.
-}
-
-git_rebase__merge () {
-
-case "$action" in
-continue)
-	read_state
-	continue_merge
-	while test "$msgnum" -le "$end"
-	do
-		call_merge "$msgnum"
-		continue_merge
-	done
-	finish_rb_merge
-	return
-	;;
-skip)
-	read_state
-	git rerere clear
-	cmt="$(cat "$state_dir/cmt.$msgnum")"
-	echo "$cmt $(git rev-parse HEAD^0)" >> "$state_dir/rewritten"
-	msgnum=$(($msgnum + 1))
-	while test "$msgnum" -le "$end"
-	do
-		call_merge "$msgnum"
-		continue_merge
-	done
-	finish_rb_merge
-	return
-	;;
-show-current-patch)
-	exec git show REBASE_HEAD --
-	;;
-esac
-
-mkdir -p "$state_dir"
-echo "$onto_name" > "$state_dir/onto_name"
-write_basic_state
-rm -f "$(git rev-parse --git-path REBASE_HEAD)"
-
-msgnum=0
-for cmt in $(git rev-list --topo-order --reverse --no-merges "$revisions")
-do
-	msgnum=$(($msgnum + 1))
-	echo "$cmt" > "$state_dir/cmt.$msgnum"
-done
-
-echo 1 >"$state_dir/msgnum"
-echo $msgnum >"$state_dir/end"
-
-end=$msgnum
-msgnum=1
-
-while test "$msgnum" -le "$end"
-do
-	call_merge "$msgnum"
-	continue_merge
-done
-
-finish_rb_merge
-
-}
diff --git a/t/t3406-rebase-message.sh b/t/t3406-rebase-message.sh
index f64b130cb8..b393e1e9fe 100755
--- a/t/t3406-rebase-message.sh
+++ b/t/t3406-rebase-message.sh
@@ -17,14 +17,9 @@ test_expect_success 'setup' '
 	git tag start
 '
 
-cat >expect <<\EOF
-Already applied: 0001 A
-Already applied: 0002 B
-Committed: 0003 Z
-EOF
-
 test_expect_success 'rebase -m' '
 	git rebase -m master >report &&
+	>expect &&
 	sed -n -e "/^Already applied: /p" \
 		-e "/^Committed: /p" report >actual &&
 	test_cmp expect actual
diff --git a/t/t3420-rebase-autostash.sh b/t/t3420-rebase-autostash.sh
index 4c7494cc8f..2d1094e483 100755
--- a/t/t3420-rebase-autostash.sh
+++ b/t/t3420-rebase-autostash.sh
@@ -53,41 +53,6 @@ create_expected_success_interactive () {
 	EOF
 }
 
-create_expected_success_merge () {
-	cat >expected <<-EOF
-	$(grep "^Created autostash: [0-9a-f][0-9a-f]*\$" actual)
-	HEAD is now at $(git rev-parse --short feature-branch) third commit
-	First, rewinding head to replay your work on top of it...
-	Merging unrelated-onto-branch with HEAD~1
-	Merging:
-	$(git rev-parse --short unrelated-onto-branch) unrelated commit
-	$(git rev-parse --short feature-branch^) second commit
-	found 1 common ancestor:
-	$(git rev-parse --short feature-branch~2) initial commit
-	[detached HEAD $(git rev-parse --short rebased-feature-branch~1)] second commit
-	 Author: A U Thor <author@example.com>
-	 Date: Thu Apr 7 15:14:13 2005 -0700
-	 2 files changed, 2 insertions(+)
-	 create mode 100644 file1
-	 create mode 100644 file2
-	Committed: 0001 second commit
-	Merging unrelated-onto-branch with HEAD~0
-	Merging:
-	$(git rev-parse --short rebased-feature-branch~1) second commit
-	$(git rev-parse --short feature-branch) third commit
-	found 1 common ancestor:
-	$(git rev-parse --short feature-branch~1) second commit
-	[detached HEAD $(git rev-parse --short rebased-feature-branch)] third commit
-	 Author: A U Thor <author@example.com>
-	 Date: Thu Apr 7 15:15:13 2005 -0700
-	 1 file changed, 1 insertion(+)
-	 create mode 100644 file3
-	Committed: 0002 third commit
-	All done.
-	Applied autostash.
-	EOF
-}
-
 create_expected_failure_am () {
 	cat >expected <<-EOF
 	$(grep "^Created autostash: [0-9a-f][0-9a-f]*\$" actual)
@@ -112,43 +77,6 @@ create_expected_failure_interactive () {
 	EOF
 }
 
-create_expected_failure_merge () {
-	cat >expected <<-EOF
-	$(grep "^Created autostash: [0-9a-f][0-9a-f]*\$" actual)
-	HEAD is now at $(git rev-parse --short feature-branch) third commit
-	First, rewinding head to replay your work on top of it...
-	Merging unrelated-onto-branch with HEAD~1
-	Merging:
-	$(git rev-parse --short unrelated-onto-branch) unrelated commit
-	$(git rev-parse --short feature-branch^) second commit
-	found 1 common ancestor:
-	$(git rev-parse --short feature-branch~2) initial commit
-	[detached HEAD $(git rev-parse --short rebased-feature-branch~1)] second commit
-	 Author: A U Thor <author@example.com>
-	 Date: Thu Apr 7 15:14:13 2005 -0700
-	 2 files changed, 2 insertions(+)
-	 create mode 100644 file1
-	 create mode 100644 file2
-	Committed: 0001 second commit
-	Merging unrelated-onto-branch with HEAD~0
-	Merging:
-	$(git rev-parse --short rebased-feature-branch~1) second commit
-	$(git rev-parse --short feature-branch) third commit
-	found 1 common ancestor:
-	$(git rev-parse --short feature-branch~1) second commit
-	[detached HEAD $(git rev-parse --short rebased-feature-branch)] third commit
-	 Author: A U Thor <author@example.com>
-	 Date: Thu Apr 7 15:15:13 2005 -0700
-	 1 file changed, 1 insertion(+)
-	 create mode 100644 file3
-	Committed: 0002 third commit
-	All done.
-	Applying autostash resulted in conflicts.
-	Your changes are safe in the stash.
-	You can run "git stash pop" or "git stash drop" at any time.
-	EOF
-}
-
 testrebase () {
 	type=$1
 	dotest=$2
@@ -177,6 +105,9 @@ testrebase () {
 	test_expect_success "rebase$type --autostash: check output" '
 		test_when_finished git branch -D rebased-feature-branch &&
 		suffix=${type#\ --} && suffix=${suffix:-am} &&
+		if test ${suffix} = "merge"; then
+			suffix=interactive
+		fi &&
 		create_expected_success_$suffix &&
 		test_i18ncmp expected actual
 	'
@@ -274,6 +205,9 @@ testrebase () {
 	test_expect_success "rebase$type: check output with conflicting stash" '
 		test_when_finished git branch -D rebased-feature-branch &&
 		suffix=${type#\ --} && suffix=${suffix:-am} &&
+		if test ${suffix} = "merge"; then
+			suffix=interactive
+		fi &&
 		create_expected_failure_$suffix &&
 		test_i18ncmp expected actual
 	'
diff --git a/t/t3421-rebase-topology-linear.sh b/t/t3421-rebase-topology-linear.sh
index 23ad4cff35..7274dca40b 100755
--- a/t/t3421-rebase-topology-linear.sh
+++ b/t/t3421-rebase-topology-linear.sh
@@ -111,7 +111,7 @@ test_run_rebase () {
 	"
 }
 test_run_rebase success ''
-test_run_rebase failure -m
+test_run_rebase success -m
 test_run_rebase success -i
 test_have_prereq !REBASE_P || test_run_rebase success -p
 
@@ -126,7 +126,7 @@ test_run_rebase () {
 	"
 }
 test_run_rebase success ''
-test_run_rebase failure -m
+test_run_rebase success -m
 test_run_rebase success -i
 test_have_prereq !REBASE_P || test_run_rebase success -p
 
@@ -141,7 +141,7 @@ test_run_rebase () {
 	"
 }
 test_run_rebase success ''
-test_run_rebase failure -m
+test_run_rebase success -m
 test_run_rebase success -i
 test_have_prereq !REBASE_P || test_run_rebase success -p
 
@@ -284,7 +284,7 @@ test_run_rebase () {
 	"
 }
 test_run_rebase success ''
-test_run_rebase failure -m
+test_run_rebase success -m
 test_run_rebase success -i
 test_have_prereq !REBASE_P || test_run_rebase success -p
 
@@ -315,7 +315,7 @@ test_run_rebase () {
 	"
 }
 test_run_rebase success ''
-test_run_rebase failure -m
+test_run_rebase success -m
 test_run_rebase success -i
 test_have_prereq !REBASE_P || test_run_rebase failure -p
 
diff --git a/t/t9903-bash-prompt.sh b/t/t9903-bash-prompt.sh
index 81a5179e28..5cadedb2a9 100755
--- a/t/t9903-bash-prompt.sh
+++ b/t/t9903-bash-prompt.sh
@@ -180,7 +180,7 @@ test_expect_success 'prompt - interactive rebase' '
 '
 
 test_expect_success 'prompt - rebase merge' '
-	printf " (b2|REBASE-m 1/3)" >expected &&
+	printf " (b2|REBASE-i 1/3)" >expected &&
 	git checkout b2 &&
 	test_when_finished "git checkout master" &&
 	test_must_fail git rebase --merge b1 b2 &&