diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 1ccaeb3..f3fc4c7 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -174,6 +174,20 @@
       Outer()
   END
   CheckScriptFailure(lines, "E122:")
+
+  lines =<< trim END
+      vim9script
+      def Func()
+        echo 'script'
+      enddef
+      def Outer()
+        def Func()
+          echo 'inner'
+        enddef
+      enddef
+      defcompile
+  END
+  CheckScriptFailure(lines, "E1073:")
 enddef
 
 def Test_global_local_function()
diff --git a/src/version.c b/src/version.c
index f032581..70d90c5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1352,
+/**/
     1351,
 /**/
     1350,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 61be54d..3c7e121 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -291,15 +291,21 @@
     int
 check_defined(char_u *p, size_t len, cctx_T *cctx)
 {
+    int c = p[len];
+
+    p[len] = NUL;
     if (lookup_script(p, len) == OK
 	    || (cctx != NULL
 		&& (lookup_local(p, len, cctx) != NULL
 		    || lookup_arg(p, len, NULL, NULL, NULL, cctx) == OK))
-	    || find_imported(p, len, cctx) != NULL)
+	    || find_imported(p, len, cctx) != NULL
+	    || find_func_even_dead(p, FALSE, cctx) != NULL)
     {
+	p[len] = c;
 	semsg(_(e_already_defined), p);
 	return FAIL;
     }
+    p[len] = c;
     return OK;
 }