patch 8.2.3702: first key in dict is seen as curly expression and fails

Problem:    First key in dict is seen as curly expression and fails.
Solution:   Ignore failure of curly expression. (closes #9247)

Author: brammool

src/dict.c

@@ -891,7 +891,7 @@ eval_dict(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int literal)
     typval_T	tv;
     char_u	*key = NULL;
     dictitem_T	*item;
-    char_u	*start = skipwhite(*arg + 1);
+    char_u	*curly_expr = skipwhite(*arg + 1);
     char_u	buf[NUMBUFLEN];
     int		vim9script = in_vim9script();
     int		had_comma;
@@ -903,13 +903,11 @@ eval_dict(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int literal)
      * first item.
      * But {} is an empty Dictionary.
      */
-    if (!vim9script && *start != '}')
-    {
-	if (eval1(&start, &tv, NULL) == FAIL)	// recursive!
-	    return FAIL;
-	if (*skipwhite(start) == '}')
-	    return NOTDONE;
-    }
+    if (!vim9script
+	    && *curly_expr != '}'
+	    && eval1(&curly_expr, &tv, NULL) == OK
+	    && *skipwhite(curly_expr) == '}')
+	return NOTDONE;
 
     if (evaluate)
     {

src/testdir/test_listdict.vim

@@ -297,6 +297,9 @@ func Test_dict()
   call assert_fails('let d={[] : 10}', 'E730:')
   " undefined variable as value
   call assert_fails("let d={'k' : i}", 'E121:')
+
+  " allow key starting with number at the start, not a curly expression
+  call assert_equal({'1foo': 77}, #{1foo: 77})
 endfunc
 
 " This was allowed in legacy Vim script

src/typval.c

@@ -1822,7 +1822,8 @@ eval_number(
 		      : STR2NR_ALL, &n, NULL, 0, TRUE);
 	if (len == 0)
 	{
-	    semsg(_(e_invalid_expression_str), *arg);
+	    if (evaluate)
+		semsg(_(e_invalid_expression_str), *arg);
 	    return FAIL;
 	}
 	*arg += len;

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3702,
 /**/
     3701,
 /**/