diff --git a/src/eval.c b/src/eval.c
index f23d721..199dc9c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2769,10 +2769,11 @@
 	int	    vim9script = in_vim9script();
 
 	// "." is only string concatenation when scriptversion is 1
+	// "+=" and "-=" are assignment
 	p = eval_next_non_blank(*arg, evalarg, &getnext);
 	op = *p;
 	concat = op == '.' && (*(p + 1) == '.' || current_sctx.sc_version < 2);
-	if (op != '+' && op != '-' && !concat)
+	if ((op != '+' && op != '-' && !concat) || p[1] == '=')
 	    break;
 
 	evaluate = evalarg == NULL ? 0 : (evalarg->eval_flags & EVAL_EVALUATE);
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index a06e8a8..d530c08 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -3332,9 +3332,13 @@
 
 		// When followed by "=" or "+=" then it is an assignment.
 		++emsg_silent;
-		if (skip_expr(&after, NULL) == OK
-				  && (*after == '='
-				      || (*after != NUL && after[1] == '=')))
+		if (skip_expr(&after, NULL) == OK)
+		    after = skipwhite(after);
+		else
+		    after = (char_u *)"";
+		if (*after == '=' || (*after != NUL && after[1] == '=')
+					 || (after[0] == '.' && after[1] == '.'
+							   && after[2] == '='))
 		    eap->cmdidx = CMD_var;
 		else
 		    eap->cmdidx = CMD_eval;
diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index fe9fc44..2e08e8b 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -866,18 +866,17 @@
   END
   CheckScriptSuccess(lines)
 
-  # doesn't work yet
-  #lines =<< trim END
-  #    vim9script
-  #    var mylist = [[]]
-  #    mylist[0] += [#{one: 'one'}]
-  #    def Func()
-  #      var dd = mylist[0][0]
-  #      assert_equal('one', dd.one)
-  #    enddef
-  #    Func()
-  #END
-  #CheckScriptSuccess(lines)
+  lines =<< trim END
+      vim9script
+      var mylist = [[]]
+      mylist[0] += [#{one: 'one'}]
+      def Func()
+        var dd = mylist[0][0]
+        assert_equal('one', dd.one)
+      enddef
+      Func()
+  END
+  CheckScriptSuccess(lines)
 enddef
 
 def Test_assign_lambda()
diff --git a/src/version.c b/src/version.c
index dac3d5c..b94f0df 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2066,
+/**/
     2065,
 /**/
     2064,