diff --git a/src/eval.c b/src/eval.c
index cfa86ef..3c4e5bd 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2574,6 +2574,7 @@
 	int	    getnext;
 	char_u	    *p;
 	int	    op;
+	int	    oplen;
 	int	    concat;
 	typval_T    var2;
 
@@ -2584,11 +2585,19 @@
 	if (op != '+' && op != '-' && !concat)
 	    break;
 
+	evaluate = evalarg == NULL ? 0 : (evalarg->eval_flags & EVAL_EVALUATE);
 	if (getnext)
 	    *arg = eval_next_line(evalarg);
 	else
+	{
+	    if (evaluate && in_vim9script() && !VIM_ISWHITE(**arg))
+	    {
+		error_white_both(p, 1);
+		clear_tv(rettv);
+		return FAIL;
+	    }
 	    *arg = p;
-	evaluate = evalarg == NULL ? 0 : (evalarg->eval_flags & EVAL_EVALUATE);
+	}
 	if ((op != '+' || (rettv->v_type != VAR_LIST
 						 && rettv->v_type != VAR_BLOB))
 #ifdef FEAT_FLOAT
@@ -2613,9 +2622,14 @@
 	/*
 	 * Get the second variable.
 	 */
-	if (op == '.' && *(*arg + 1) == '.')  // .. string concatenation
-	    ++*arg;
-	*arg = skipwhite_and_linebreak(*arg + 1, evalarg);
+	oplen = (op == '.' && *(*arg + 1) == '.') ? 2 : 1;
+	if (evaluate && in_vim9script() && !IS_WHITE_OR_NUL((*arg)[oplen]))
+	{
+	    error_white_both(p, oplen);
+	    clear_tv(rettv);
+	    return FAIL;
+	}
+	*arg = skipwhite_and_linebreak(*arg + oplen, evalarg);
 	if (eval6(arg, &var2, evalarg, op == '.') == FAIL)
 	{
 	    clear_tv(rettv);
@@ -3358,6 +3372,7 @@
     }
     else
     {
+	*arg = skipwhite(*arg);
 	if (**arg != '(')
 	{
 	    if (verbose)
@@ -4841,7 +4856,7 @@
 
 /*
  * Get the length of the name of a function or internal variable.
- * "arg" is advanced to the first non-white character after the name.
+ * "arg" is advanced to after the name.
  * Return 0 if something is wrong.
  */
     int
@@ -4867,7 +4882,7 @@
 	return 0;
 
     len = (int)(p - *arg);
-    *arg = skipwhite(p);
+    *arg = p;
 
     return len;
 }