patch 9.1.0198: Vim9: compound operators broken for lambdas in an object

Problem:  Vim9: compound operators broken for lambdas in an object
          (girishji)
Solution: When using an object from the outer scope, use the LOADOUTER
          instruction to load the object (Yegappan Lakshmanan).

fixes: #14236
closes: #14266

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index 645b04b..1daef22 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -3436,4 +3436,36 @@
   unlet g:instr
 enddef
 
+" Disassemble instructions for using a compound operator in a closure
+def Test_disassemble_compound_op_in_closure()
+  var lines =<< trim END
+    vim9script
+    class A
+      var foo: number = 1
+      def Foo(): func
+        var Fn = () => {
+          this.foo += 1
+        }
+        return Fn
+      enddef
+    endclass
+    var a = A.new()
+    var Lambda = a.Foo()
+    var num = matchstr(string(Lambda), '\d\+')
+    g:instr = execute($'disassemble <lambda>{num}')
+  END
+  v9.CheckScriptSuccess(lines)
+  assert_match('<lambda>\d\+\_s*' ..
+    'this.foo += 1\_s*' ..
+    '0 LOADOUTER level 0 $0\_s*' ..
+    '1 OBJ_MEMBER 0\_s*' ..
+    '2 PUSHNR 1\_s*' ..
+    '3 OPNR +\_s*' ..
+    '4 PUSHNR 0\_s*' ..
+    '5 LOADOUTER level 0 $0\_s*' ..
+    '6 STOREINDEX object\_s*' ..
+    '7 RETURN void', g:instr)
+  unlet g:instr
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker