patch 8.2.1430: Vim9: error for missing comma instead of extra white space

Problem:    Vim9: error for missing comma instead of extra white space.
Solution:   Check if comma can be found after white space. (closes #6668)
            Also check for extra white space in literal dict. (closes #6670)

src/dict.c

@@ -781,7 +781,7 @@ get_literal_key(char_u **arg, typval_T *tv)
     tv->v_type = VAR_STRING;
     tv->vval.v_string = vim_strnsave(*arg, p - *arg);
 
-    *arg = skipwhite(p);
+    *arg = p;
     return OK;
 }
 
@@ -845,7 +845,12 @@ eval_dict(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int literal)
 	if (**arg != ':')
 	{
 	    if (evaluate)
+	    {
+		if (*skipwhite(*arg) == ':')
+		    semsg(_(e_no_white_before), ":");
+		else
 		    semsg(_(e_missing_dict_colon), *arg);
+	    }
 	    clear_tv(&tvkey);
 	    goto failret;
 	}

src/list.c

@@ -1219,7 +1219,12 @@ eval_list(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int do_error)
 	if (!had_comma)
 	{
 	    if (do_error)
+	    {
+		if (**arg == ',')
+		    semsg(_(e_no_white_before), ",");
+		else
 		    semsg(_("E696: Missing comma in List: %s"), *arg);
+	    }
 	    goto failret;
 	}
     }

src/testdir/test_vim9_expr.vim

@@ -1383,7 +1383,10 @@ def Test_expr7_list()
 
   call CheckDefExecFailure(["let x = g:anint[3]"], 'E714:')
   call CheckDefFailure(["let x = g:list_mixed[xxx]"], 'E1001:')
+
   call CheckDefFailure(["let x = [1,2,3]"], 'E1069:')
+  call CheckDefFailure(["let x = [1 ,2, 3]"], 'E1068:')
+
   call CheckDefExecFailure(["let x = g:list_mixed['xx']"], 'E1029:')
   call CheckDefFailure(["let x = g:list_mixed["], 'E1097:')
   call CheckDefFailure(["let x = g:list_mixed[0"], 'E1097:')
@@ -1422,6 +1425,12 @@ def Test_expr7_list_vim9script()
       let l = [11,22]
   END
   CheckScriptFailure(lines, 'E1069:')
+
+  lines =<< trim END
+      vim9script
+      let l = [11 , 22]
+  END
+  CheckScriptFailure(lines, 'E1068:')
 enddef
 
 def Test_expr7_lambda()
@@ -1556,6 +1565,18 @@ def Test_expr7_dict_vim9script()
       let d = #{one: 1,two: 2}
   END
   CheckScriptFailure(lines, 'E1069:')
+
+  lines =<< trim END
+      vim9script
+      let d = #{one : 1}
+  END
+  CheckScriptFailure(lines, 'E1068:')
+
+  lines =<< trim END
+      vim9script
+      let d = #{one:1}
+  END
+  CheckScriptFailure(lines, 'E1069:')
 enddef
 
 let g:oneString = 'one'

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1430,
 /**/
     1429,
 /**/

src/vim9compile.c

@@ -2394,6 +2394,11 @@ compile_list(char_u **arg, cctx_T *cctx)
 	    semsg(_(e_list_end), *arg);
 	    return FAIL;
 	}
+	if (*p == ',')
+	{
+	    semsg(_(e_no_white_before), ",");
+	    return FAIL;
+	}
 	if (*p == ']')
 	{
 	    ++p;