# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1609418704 -3600
# Node ID 681f042ae5ac94f999f28a24f8090f082b17f375
# Parent  4dfa0cd43a513a01b80840098987bfc4ad2fe629
patch 8.2.2252: Vim9: crash when using lambda without return type in dict

Commit: https://github.com/vim/vim/commit/6b55377303968e1624339cd95053201d5acdcaa2
Author: Bram Moolenaar <Bram@vim.org>
Date:   Thu Dec 31 13:31:23 2020 +0100

    patch 8.2.2252: Vim9: crash when using lambda without return type in dict

    Problem:    Vim9: crash when using lambda without return type in dict.
    Solution:   Without a return type use t_unknown. (closes https://github.com/vim/vim/issues/7587)

diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -2077,6 +2077,10 @@ def Test_expr7_dict()
       assert_equal(g:test_hash_dict, {one: 1, two: 2})
 
       assert_equal({['a a']: 1, ['b/c']: 2}, {'a a': 1, "b/c": 2})
+
+      var d = {a: () => 3, b: () => 7}
+      assert_equal(3, d.a())
+      assert_equal(7, d.b())
   END
   CheckDefAndScriptSuccess(lines)
  
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2252,
+/**/
     2251,
 /**/
     2250,
diff --git a/src/vim9compile.c b/src/vim9compile.c
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -4837,7 +4837,8 @@ compile_return(char_u *arg, int check_re
 	if (cctx->ctx_skip != SKIP_YES)
 	{
 	    stack_type = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-	    if (check_return_type && cctx->ctx_ufunc->uf_ret_type == NULL)
+	    if (check_return_type && (cctx->ctx_ufunc->uf_ret_type == NULL
+				|| cctx->ctx_ufunc->uf_ret_type == &t_unknown))
 	    {
 		cctx->ctx_ufunc->uf_ret_type = stack_type;
 	    }
diff --git a/src/vim9type.c b/src/vim9type.c
--- a/src/vim9type.c
+++ b/src/vim9type.c
@@ -480,7 +480,10 @@ check_type(type_T *expected, type_T *act
 	}
 	else if (expected->tt_type == VAR_FUNC)
 	{
-	    if (expected->tt_member != &t_unknown)
+	    // If the return type is unknown it can be anything, including
+	    // nothing, thus there is no point in checking.
+	    if (expected->tt_member != &t_unknown
+					    && actual->tt_member != &t_unknown)
 		ret = check_type(expected->tt_member, actual->tt_member,
 								     FALSE, 0);
 	    if (ret == OK && expected->tt_argcount != -1