3 files changed, 13 insertions, 3 deletions
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 62e006fd57..465d76de69 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -2277,10 +2277,15 @@ int eval0(char *arg, typval_T *rettv, char **nextcmd, int evaluate)
   char *p;
   const int did_emsg_before = did_emsg;
   const int called_emsg_before = called_emsg;
+  bool end_error = false;
 
   p = skipwhite(arg);
   ret = eval1(&p, rettv, evaluate);
-  if (ret == FAIL || !ends_excmd(*p)) {
+
+  if (ret != FAIL) {
+    end_error = !ends_excmd(*p);
+  }
+  if (ret == FAIL || end_error) {
     if (ret != FAIL) {
       tv_clear(rettv);
     }
@@ -2290,7 +2295,11 @@ int eval0(char *arg, typval_T *rettv, char **nextcmd, int evaluate)
     // Also check called_emsg for when using assert_fails().
     if (!aborting() && did_emsg == did_emsg_before
         && called_emsg == called_emsg_before) {
-      semsg(_(e_invexpr2), arg);
+      if (end_error) {
+        semsg(_(e_trailing_arg), p);
+      } else {
+        semsg(_(e_invexpr2), arg);
+      }
     }
     ret = FAIL;
   }
diff --git a/src/nvim/testdir/test_let.vim b/src/nvim/testdir/test_let.vim
index 3ef3d961a7..48c5699093 100644
--- a/src/nvim/testdir/test_let.vim
+++ b/src/nvim/testdir/test_let.vim
@@ -297,6 +297,7 @@ func Test_let_errors()
     let ch = test_null_channel()
     call assert_fails('let ch += 1', 'E734:')
   endif
+  call assert_fails('let name = "a" .. "b",', 'E488: Trailing characters: ,')
 
   " This test works only when the language is English
   if v:lang == "C" || v:lang =~ '^[Ee]n'
diff --git a/src/nvim/testdir/test_vimscript.vim b/src/nvim/testdir/test_vimscript.vim
index 8faa9135e5..44904af160 100644
--- a/src/nvim/testdir/test_vimscript.vim
+++ b/src/nvim/testdir/test_vimscript.vim
@@ -5569,7 +5569,7 @@ func Test_expr_eval_error_msg()
     call T(19, '{(1} + CONT(19)',	'E110',	"Missing ')'")
     call T(20, '("abc"[1) + CONT(20)',	'E111',	"Missing ']'")
     call T(21, '(1 +) + CONT(21)',	'E15',	"Invalid expression")
-    call T(22, '1 2 + CONT(22)',	'E15',	"Invalid expression")
+    call T(22, '1 2 + CONT(22)',	'E488',	"Trailing characters: 2 +")
     call T(23, '(1 ? 2) + CONT(23)',	'E109',	"Missing ':' after '?'")
     call T(24, '("abc) + CONT(24)',	'E114',	"Missing quote")
     call T(25, "('abc) + CONT(25)",	'E115',	"Missing quote")