Fix warnings produced by -Wshadow=compatible-local

FDW-627, Suraj Kharage, reviewed by Vaibhav Dalvi.

Author: jeevanchalke

mysql_fdw.c

@@ -1401,8 +1401,6 @@ mysqlGetForeignPlan(PlannerInfo *root, RelOptInfo *foreignrel,
 
 		if (outer_plan)
 		{
-			ListCell   *lc;
-
 			/*
 			 * Right now, we only consider grouping and aggregation beyond
 			 * joins.  Queries involving aggregates or grouping do not require
@@ -2584,8 +2582,6 @@ bind_stmt_params_and_exec(ForeignScanState *node)
 	 */
 	if (numParams > 0)
 	{
-		MemoryContext oldcontext;
-
 		oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
 
 		mysql_bind_buffer = (MYSQL_BIND *) palloc0(sizeof(MYSQL_BIND) * numParams);
@@ -3641,10 +3637,10 @@ mysql_foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel,
 				 */
 				foreach(l, aggvars)
 				{
-					Expr	   *expr = (Expr *) lfirst(l);
+					Expr	   *aggref = (Expr *) lfirst(l);
 
-					if (IsA(expr, Aggref))
-						tlist = add_to_flat_tlist(tlist, list_make1(expr));
+					if (IsA(aggref, Aggref))
+						tlist = add_to_flat_tlist(tlist, list_make1(aggref));
 				}
 			}
 		}
@@ -3658,8 +3654,6 @@ mysql_foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel,
 	 */
 	if (havingQual)
 	{
-		ListCell   *lc;
-
 		foreach(lc, (List *) havingQual)
 		{
 			Expr	   *expr = (Expr *) lfirst(lc);
@@ -3716,7 +3710,6 @@ mysql_foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel,
 	if (fpinfo->local_conds)
 	{
 		List	   *aggvars = NIL;
-		ListCell   *lc;
 
 		foreach(lc, fpinfo->local_conds)
 		{