From c7dac8534ee7f7a49e9d7a37330397c64455cdd7 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Wed, 17 Feb 2021 18:49:11 +0100
Subject: [PATCH] patch 8.2.2528: Vim9: crash when compiling lambda fails

Problem:    Vim9: crash when compiling lambda fails.
Solution:   Bail out after compilation fails. (closes #7862)
---
 src/eval.c                       | 8 ++++++--
 src/testdir/test_vim9_assign.vim | 5 +++++
 src/version.c                    | 2 ++
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/eval.c b/src/eval.c
index 785d8417a..444c0faf3 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3428,8 +3428,12 @@ eval7(
 			ufunc_T *ufunc = rettv->vval.v_partial->pt_func;
 
 			// compile it here to get the return type
-			compile_def_function(ufunc,
-						 TRUE, PROFILING(ufunc), NULL);
+			if (compile_def_function(ufunc,
+					 TRUE, PROFILING(ufunc), NULL) == FAIL)
+			{
+			    clear_tv(rettv);
+			    ret = FAIL;
+			}
 		    }
 		}
 		if (ret == NOTDONE)
diff --git a/src/testdir/test_vim9_assign.vim b/src/testdir/test_vim9_assign.vim
index 4c63217f2..392a091a1 100644
--- a/src/testdir/test_vim9_assign.vim
+++ b/src/testdir/test_vim9_assign.vim
@@ -1118,6 +1118,11 @@ def Test_assign_lambda()
       Ref = (j) => !j
   END
   CheckDefAndScriptFailure(lines, 'E1012: Type mismatch; expected func(number) but got func(any): bool')
+
+  lines =<< trim END
+      echo filter([1, 2, 3], (_, v: string) => v + 1) 
+  END
+  CheckDefAndScriptFailure(lines, 'E1051:')
 enddef
 
 def Test_heredoc()
diff --git a/src/version.c b/src/version.c
index 0fb889621..4c0fb5c1e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2528,
 /**/
     2527,
 /**/
-- 
2.50.1