patch 8.2.3126: Vim9: for loop error reports wrong line number

Problem:    Vim9: for loop error reports wrong line number.
Solution:   Save and restore the line number when evaluating the expression.
            (closes #8514)

src/ex_eval.c

@@ -1225,9 +1225,14 @@ ex_while(exarg_T *eap)
 	    }
 	    else
 	    {
+		long save_lnum = SOURCING_LNUM;
+
 		// Evaluate the argument and get the info in a structure.
 		fi = eval_for_line(eap->arg, &error, eap, &evalarg);
 		cstack->cs_forinfo[cstack->cs_idx] = fi;
+
+		// Errors should use the first line number.
+		SOURCING_LNUM = save_lnum;
 	    }
 
 	    // use the element at the start of the list and advance

src/testdir/test_vim9_script.vim

@@ -2545,6 +2545,7 @@ def Test_for_loop_fails()
   CheckDefAndScriptFailure(['for # in range(5)'], 'E690:')
   CheckDefAndScriptFailure(['for i In range(5)'], 'E690:')
   CheckDefAndScriptFailure2(['var x = 5', 'for x in range(5)', 'endfor'], 'E1017:', 'E1041:')
+  CheckScriptFailure(['vim9script', 'var x = 5', 'for x in range(5)', '# comment', 'endfor'], 'E1041:', 3)
   CheckScriptFailure(['def Func(arg: any)', 'for arg in range(5)', 'enddef', 'defcompile'], 'E1006:')
   delfunc! g:Func
   CheckDefFailure(['for i in xxx'], 'E1001:')

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3126,
 /**/
     3125,
 /**/