From ae5f911f76dedd93903e2a3b4322bba444a2dae0 Mon Sep 17 00:00:00 2001
From: xvw <xaviervdw@gmail.com>
Date: Fri, 23 Feb 2024 12:06:42 +0100
Subject: [PATCH 1/2] destruct: Removal of residual patterns

---
 src/analysis/destruct.ml             |   5 +-
 tests/test-dirs/destruct/issue1560.t | 162 +++++++++++++++++++++++++++
 2 files changed, 163 insertions(+), 4 deletions(-)
 create mode 100644 tests/test-dirs/destruct/issue1560.t

diff --git a/src/analysis/destruct.ml b/src/analysis/destruct.ml
index e30f456384..e1941ceae2 100644
--- a/src/analysis/destruct.ml
+++ b/src/analysis/destruct.ml
@@ -584,10 +584,7 @@ let rec node config source selected_node parents =
                   subst_patt patt ~by top_patt
                 )
               in
-              let patterns =
-                List.rev_append rev_before
-                  (List.append new_branches after)
-              in
+              let patterns = after @ rev_before @ new_branches in
               let unused = Parmatch.return_unused patterns in
               let new_branches =
                 List.fold_left unused ~init:new_branches ~f:(fun branches u ->
diff --git a/tests/test-dirs/destruct/issue1560.t b/tests/test-dirs/destruct/issue1560.t
new file mode 100644
index 0000000000..e328d8012b
--- /dev/null
+++ b/tests/test-dirs/destruct/issue1560.t
@@ -0,0 +1,162 @@
+  $ $MERLIN single case-analysis -start 2:29 -end 2:29 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C
+  > let f = function A x -> x | _ -> 1
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 28
+        },
+        "end": {
+          "line": 2,
+          "col": 29
+        }
+      },
+      "B | C"
+    ],
+    "notifications": []
+  }
+
+  $ $MERLIN single case-analysis -start 2:18 -end 2:18 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C
+  > let f = function A x -> x
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 25
+        },
+        "end": {
+          "line": 2,
+          "col": 25
+        }
+      },
+      "
+  | B | C -> _"
+    ],
+    "notifications": []
+  }
+
+
+  $ $MERLIN single case-analysis -start 2:29 -end 2:29 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C
+  > let f = function A 0 -> 0 | _ -> 1
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 28
+        },
+        "end": {
+          "line": 2,
+          "col": 29
+        }
+      },
+      "A _ | B | C"
+    ],
+    "notifications": []
+  }
+
+  $ $MERLIN single case-analysis -start 2:29 -end 2:29 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C
+  > let f = function A x -> x | _ -> 1 | C -> 2
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 28
+        },
+        "end": {
+          "line": 2,
+          "col": 29
+        }
+      },
+      "B"
+    ],
+    "notifications": []
+  }
+
+  $ $MERLIN single case-analysis -start 2:38 -end 2:38 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C
+  > let f = function A x -> x | C -> 2 | _ -> 1
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 37
+        },
+        "end": {
+          "line": 2,
+          "col": 38
+        }
+      },
+      "B"
+    ],
+    "notifications": []
+  }
+
+  $ $MERLIN single case-analysis -start 2:47 -end 2:47 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C | D
+  > let f = function A x -> x | B -> 2 | D -> 1 | _ -> 3
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 46
+        },
+        "end": {
+          "line": 2,
+          "col": 47
+        }
+      },
+      "C"
+    ],
+    "notifications": []
+  }
+
+  $ $MERLIN single case-analysis -start 2:47 -end 2:47 \
+  > -filename main.ml <<EOF
+  > type t = A of int | B | C | D
+  > let f = function A 2 -> 2 | B -> 2 | D -> 1 | _ -> 3
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 2,
+          "col": 46
+        },
+        "end": {
+          "line": 2,
+          "col": 47
+        }
+      },
+      "A _ | C"
+    ],
+    "notifications": []
+  }

From af62e1262e23b951cc1a62e72738ec617b89ecfb Mon Sep 17 00:00:00 2001
From: xvw <xaviervdw@gmail.com>
Date: Fri, 23 Feb 2024 12:22:51 +0100
Subject: [PATCH 2/2] Add CHANGES entry

---
 CHANGES.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index bb4de3cb2a..bcb9912894 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,9 @@
+merlin NEXT_VERSION
+==================
+
+  + merlin binary
+    - destruct: Removal of residual patterns (#1737, fixes #1560)
+
 merlin 4.14
 ===========
 Thu Feb 22 14:00:42 CET 2024