Fix: destructing record field in pattern

src/analysis/destruct.ml

@@ -605,8 +605,14 @@ let rec node config source selected_node parents =
               (* If only one pattern is generated, then we're only refining the
                 current pattern, not generating new branches. *)
               let ppat = filter_pat_attr (Untypeast.untype_pattern more_precise) in
-              let str = Mreader.print_pretty
-                  config source (Pretty_pattern ppat) in
+              let str = Mreader.print_pretty config source (Pretty_pattern ppat) in
+              let str = (* { r<|> } should result in { r = <destructed value> } *)
+                match patt, parents with
+                | { pat_desc = Tpat_var (_, {txt; _ })},
+                    (Pattern { pat_desc = Typedtree.Tpat_record _; _ }) :: _ ->
+                  txt ^ " = " ^ str
+                | _ -> str
+              in
               patt.Typedtree.pat_loc, str
             | sub_patterns ->
               let rev_before, after, top_patt =

tests/test-dirs/destruct/record.t

@@ -99,3 +99,53 @@ Record fields in patterns should also be refinable:
     ],
     "notifications": []
   }
+
+Destructing a record field should leave the field name in place
+
+  $ $MERLIN single case-analysis -start 3:10 -end 3:10 -filename test.ml <<EOF
+  > type r = { x : int } 
+  > type r_out = { r : r ; y : string } 
+  > let f ({ r ; y } : r_out) = ()
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 3,
+          "col": 9
+        },
+        "end": {
+          "line": 3,
+          "col": 10
+        }
+      },
+      "r = { x }"
+    ],
+    "notifications": []
+  }
+
+Destructing a record field (variant)
+
+  $ $MERLIN single case-analysis -start 3:10 -end 3:10 -filename test.ml <<EOF
+  > type v = A | B of int 
+  > type r = { v : v ; y:string } 
+  > let f ({ v ; y } : r) = ()
+  > EOF
+  {
+    "class": "return",
+    "value": [
+      {
+        "start": {
+          "line": 3,
+          "col": 7
+        },
+        "end": {
+          "line": 3,
+          "col": 16
+        }
+      },
+      "({ v = A; y } : r) |({ v = B _; y } : r)"
+    ],
+    "notifications": []
+  }