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>

src/testdir/test_vim9_class.vim

@@ -10349,4 +10349,75 @@ def Test_Ref_Class_Within_Same_Class()
   v9.CheckScriptFailure(lines, 'E1347: Not a valid interface: A', 3)
 enddef
 
+" Test for using a compound operator from a lambda function in an object method
+def Test_compound_op_in_objmethod_lambda()
+  # Test using the "+=" operator
+  var lines =<< trim END
+    vim9script
+    class A
+      var n: number = 10
+      def Foo()
+        var Fn = () => {
+          this.n += 1
+        }
+        Fn()
+      enddef
+    endclass
+
+    var a = A.new()
+    a.Foo()
+    assert_equal(11, a.n)
+  END
+  v9.CheckScriptSuccess(lines)
+
+  # Test using the "..=" operator
+  lines =<< trim END
+    vim9script
+    class A
+      var s: string = "a"
+      def Foo()
+        var Fn = () => {
+          this.s ..= "a"
+        }
+        Fn()
+      enddef
+    endclass
+
+    var a = A.new()
+    a.Foo()
+    a.Foo()
+    assert_equal("aaa", a.s)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+" call a lambda function in one object from another object
+def Test_lambda_invocation_across_classes()
+  var lines =<< trim END
+    vim9script
+    class A
+      var s: string = "foo"
+      def GetFn(): func
+        var Fn = (): string => {
+          return this.s
+        }
+        return Fn
+      enddef
+    endclass
+
+    class B
+      var s: string = "bar"
+      def GetFn(): func
+        var a = A.new()
+        return a.GetFn()
+      enddef
+    endclass
+
+    var b = B.new()
+    var Fn = b.GetFn()
+    assert_equal("foo", Fn())
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
 " vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker

src/testdir/test_vim9_disassemble.vim

@@ -3436,4 +3436,36 @@ def Test_disassemble_object_len()
   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

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    198,
 /**/
     197,
 /**/

src/vim9compile.c

@@ -2285,7 +2285,17 @@ compile_load_lhs_with_index(lhs_T *lhs, char_u *var_start, cctx_T *cctx)
 	if (dot - var_start == 4 && STRNCMP(var_start, "this", 4) == 0)
 	{
 	    // load "this"
-	    if (generate_LOAD(cctx, ISN_LOAD, 0, NULL, lhs->lhs_type) == FAIL)
+	    lvar_T  *lvar = lhs->lhs_lvar;
+	    int	    rc;
+
+	    if (lvar->lv_from_outer > 0)
+		rc = generate_LOADOUTER(cctx, lvar->lv_idx,
+			lvar->lv_from_outer, lvar->lv_loop_depth,
+			lvar->lv_loop_idx, type);
+	    else
+		rc = generate_LOAD(cctx, ISN_LOAD, lvar->lv_idx, NULL, type);
+
+	    if (rc == FAIL)
 		return FAIL;
 	}
 	else