Rename shadowed local variables

In a similar effort to f01592f91, here we mostly rename shadowed local
variables to remove the warnings produced when compiling with
-Wshadow=compatible-local.

This fixes 63 warnings and leaves just 5.

Author: Justin Pryzby, David Rowley
Reviewed-by: Justin Pryzby
Discussion https://postgr.es/m/20220817145434.GC26426%40telsasoft.com

src/backend/optimizer/path/costsize.c

@@ -2217,13 +2217,13 @@ cost_append(AppendPath *apath)
 
 		if (pathkeys == NIL)
 		{
-			Path	   *subpath = (Path *) linitial(apath->subpaths);
+			Path	   *firstsubpath = (Path *) linitial(apath->subpaths);
 
 			/*
 			 * For an unordered, non-parallel-aware Append we take the startup
 			 * cost as the startup cost of the first subpath.
 			 */
-			apath->path.startup_cost = subpath->startup_cost;
+			apath->path.startup_cost = firstsubpath->startup_cost;
 
 			/* Compute rows and costs as sums of subplan rows and costs. */
 			foreach(l, apath->subpaths)

src/backend/optimizer/path/indxpath.c

@@ -1303,11 +1303,11 @@ generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel,
 			}
 			else
 			{
-				RestrictInfo *rinfo = castNode(RestrictInfo, orarg);
+				RestrictInfo *ri = castNode(RestrictInfo, orarg);
 				List	   *orargs;
 
-				Assert(!restriction_is_or_clause(rinfo));
-				orargs = list_make1(rinfo);
+				Assert(!restriction_is_or_clause(ri));
+				orargs = list_make1(ri);
 
 				indlist = build_paths_for_OR(root, rel,
 											 orargs,

src/backend/optimizer/path/tidpath.c

@@ -305,10 +305,10 @@ TidQualFromRestrictInfoList(PlannerInfo *root, List *rlist, RelOptInfo *rel)
 				}
 				else
 				{
-					RestrictInfo *rinfo = castNode(RestrictInfo, orarg);
+					RestrictInfo *ri = castNode(RestrictInfo, orarg);
 
-					Assert(!restriction_is_or_clause(rinfo));
-					sublist = TidQualFromRestrictInfo(root, rinfo, rel);
+					Assert(!restriction_is_or_clause(ri));
+					sublist = TidQualFromRestrictInfo(root, ri, rel);
 				}
 
 				/*

src/backend/optimizer/plan/planner.c

@@ -3449,7 +3449,6 @@ get_number_of_groups(PlannerInfo *root,
 		{
 			/* Add up the estimates for each grouping set */
 			ListCell   *lc;
-			ListCell   *lc2;
 
 			Assert(gd);			/* keep Coverity happy */
 
@@ -3458,17 +3457,18 @@ get_number_of_groups(PlannerInfo *root,
 			foreach(lc, gd->rollups)
 			{
 				RollupData *rollup = lfirst_node(RollupData, lc);
-				ListCell   *lc;
+				ListCell   *lc2;
+				ListCell   *lc3;
 
 				groupExprs = get_sortgrouplist_exprs(rollup->groupClause,
 													 target_list);
 
 				rollup->numGroups = 0.0;
 
-				forboth(lc, rollup->gsets, lc2, rollup->gsets_data)
+				forboth(lc2, rollup->gsets, lc3, rollup->gsets_data)
 				{
-					List	   *gset = (List *) lfirst(lc);
-					GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
+					List	   *gset = (List *) lfirst(lc2);
+					GroupingSetData *gs = lfirst_node(GroupingSetData, lc3);
 					double		numGroups = estimate_num_groups(root,
 																groupExprs,
 																path_rows,
@@ -3484,6 +3484,8 @@ get_number_of_groups(PlannerInfo *root,
 
 			if (gd->hash_sets_idx)
 			{
+				ListCell   *lc2;
+
 				gd->dNumHashGroups = 0;
 
 				groupExprs = get_sortgrouplist_exprs(parse->groupClause,

src/backend/optimizer/prep/prepunion.c

@@ -658,9 +658,10 @@ generate_union_paths(SetOperationStmt *op, PlannerInfo *root,
 		/* Find the highest number of workers requested for any subpath. */
 		foreach(lc, partial_pathlist)
 		{
-			Path	   *path = lfirst(lc);
+			Path	   *subpath = lfirst(lc);
 
-			parallel_workers = Max(parallel_workers, path->parallel_workers);
+			parallel_workers = Max(parallel_workers,
+								   subpath->parallel_workers);
 		}
 		Assert(parallel_workers > 0);
 

src/backend/optimizer/util/clauses.c

@@ -4463,16 +4463,16 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
 	if (!isNull)
 	{
 		Node	   *n;
-		List	   *querytree_list;
+		List	   *query_list;
 
 		n = stringToNode(TextDatumGetCString(tmp));
 		if (IsA(n, List))
-			querytree_list = linitial_node(List, castNode(List, n));
+			query_list = linitial_node(List, castNode(List, n));
 		else
-			querytree_list = list_make1(n);
-		if (list_length(querytree_list) != 1)
+			query_list = list_make1(n);
+		if (list_length(query_list) != 1)
 			goto fail;
-		querytree = linitial(querytree_list);
+		querytree = linitial(query_list);
 
 		/*
 		 * Because we'll insist below that the querytree have an empty rtable

src/backend/optimizer/util/paramassign.c

@@ -437,16 +437,16 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 		{
 			Var		   *var = (Var *) pitem->item;
 			NestLoopParam *nlp;
-			ListCell   *lc;
+			ListCell   *lc2;
 
 			/* If not from a nestloop outer rel, complain */
 			if (!bms_is_member(var->varno, root->curOuterRels))
 				elog(ERROR, "non-LATERAL parameter required by subquery");
 
 			/* Is this param already listed in root->curOuterParams? */
-			foreach(lc, root->curOuterParams)
+			foreach(lc2, root->curOuterParams)
 			{
-				nlp = (NestLoopParam *) lfirst(lc);
+				nlp = (NestLoopParam *) lfirst(lc2);
 				if (nlp->paramno == pitem->paramId)
 				{
 					Assert(equal(var, nlp->paramval));
@@ -454,7 +454,7 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 					break;
 				}
 			}
-			if (lc == NULL)
+			if (lc2 == NULL)
 			{
 				/* No, so add it */
 				nlp = makeNode(NestLoopParam);
@@ -467,7 +467,7 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 		{
 			PlaceHolderVar *phv = (PlaceHolderVar *) pitem->item;
 			NestLoopParam *nlp;
-			ListCell   *lc;
+			ListCell   *lc2;
 
 			/* If not from a nestloop outer rel, complain */
 			if (!bms_is_subset(find_placeholder_info(root, phv)->ph_eval_at,
@@ -475,9 +475,9 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 				elog(ERROR, "non-LATERAL parameter required by subquery");
 
 			/* Is this param already listed in root->curOuterParams? */
-			foreach(lc, root->curOuterParams)
+			foreach(lc2, root->curOuterParams)
 			{
-				nlp = (NestLoopParam *) lfirst(lc);
+				nlp = (NestLoopParam *) lfirst(lc2);
 				if (nlp->paramno == pitem->paramId)
 				{
 					Assert(equal(phv, nlp->paramval));
@@ -485,7 +485,7 @@ process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
 					break;
 				}
 			}
-			if (lc == NULL)
+			if (lc2 == NULL)
 			{
 				/* No, so add it */
 				nlp = makeNode(NestLoopParam);