patch 8.2.2855: white space after "->" does not give E274

Problem:    White space after "->" does not give E274.
Solution:   Do not skip white space in legacy script. (closes #8212)
diff --git a/src/eval.c b/src/eval.c
index 0d4f5fe..97c5f78 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5916,10 +5916,18 @@
 	}
 	else if (p[0] == '-' && p[1] == '>')
 	{
-	    *arg = skipwhite(p + 2);
+	    if (in_vim9script())
+		*arg = skipwhite(p + 2);
+	    else
+		*arg = p + 2;
 	    if (ret == OK)
 	    {
-		if ((**arg == '{' && !in_vim9script()) || **arg == '(')
+		if (VIM_ISWHITE(**arg))
+		{
+		    emsg(_(e_nowhitespace));
+		    ret = FAIL;
+		}
+		else if ((**arg == '{' && !in_vim9script()) || **arg == '(')
 		    // expr->{lambda}() or expr->(lambda)()
 		    ret = eval_lambda(arg, rettv, evalarg, verbose);
 		else