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

39 files changed, 220 insertions, 226 deletions

diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c
index ed16f93acc..9a0bcf6698 100644
--- a/src/backend/access/brin/brin_minmax_multi.c
+++ b/src/backend/access/brin/brin_minmax_multi.c
@@ -3059,16 +3059,16 @@ brin_minmax_multi_summary_out(PG_FUNCTION_ARGS)
 		char	   *a,
 				   *b;
 		text	   *c;
-		StringInfoData str;
+		StringInfoData buf;
 
-		initStringInfo(&str);
+		initStringInfo(&buf);
 
 		a = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]);
 		b = OutputFunctionCall(&fmgrinfo, ranges_deserialized->values[idx++]);
 
-		appendStringInfo(&str, "%s ... %s", a, b);
+		appendStringInfo(&buf, "%s ... %s", a, b);
 
-		c = cstring_to_text_with_len(str.data, str.len);
+		c = cstring_to_text_with_len(buf.data, buf.len);
 
 		astate_values = accumArrayResult(astate_values,
 										 PointerGetDatum(c),
diff --git a/src/backend/access/gin/ginget.c b/src/backend/access/gin/ginget.c
index fc85ba99ac..553500cec0 100644
--- a/src/backend/access/gin/ginget.c
+++ b/src/backend/access/gin/ginget.c
@@ -397,7 +397,7 @@ restartScanEntry:
 		{
 			BlockNumber rootPostingTree = GinGetPostingTree(itup);
 			GinBtreeStack *stack;
-			Page		page;
+			Page		entrypage;
 			ItemPointerData minItem;
 
 			/*
@@ -428,13 +428,13 @@ restartScanEntry:
 			 */
 			IncrBufferRefCount(entry->buffer);
 
-			page = BufferGetPage(entry->buffer);
+			entrypage = BufferGetPage(entry->buffer);
 
 			/*
 			 * Load the first page into memory.
 			 */
 			ItemPointerSetMin(&minItem);
-			entry->list = GinDataLeafPageGetItems(page, &entry->nlist, minItem);
+			entry->list = GinDataLeafPageGetItems(entrypage, &entry->nlist, minItem);
 
 			entry->predictNumberResult = stack->predictNumber * entry->nlist;
 
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 75b214824d..bd4d85041d 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6283,14 +6283,14 @@ FreezeMultiXactId(MultiXactId multi, uint16 t_infomask,
 		 */
 		if (ISUPDATE_from_mxstatus(members[i].status))
 		{
-			TransactionId xid = members[i].xid;
+			TransactionId txid = members[i].xid;
 
-			Assert(TransactionIdIsValid(xid));
-			if (TransactionIdPrecedes(xid, relfrozenxid))
+			Assert(TransactionIdIsValid(txid));
+			if (TransactionIdPrecedes(txid, relfrozenxid))
 				ereport(ERROR,
 						(errcode(ERRCODE_DATA_CORRUPTED),
 						 errmsg_internal("found update xid %u from before relfrozenxid %u",
-										 xid, relfrozenxid)));
+										 txid, relfrozenxid)));
 
 			/*
 			 * It's an update; should we keep it?  If the transaction is known
@@ -6304,13 +6304,13 @@ FreezeMultiXactId(MultiXactId multi, uint16 t_infomask,
 			 * because of race conditions explained in detail in
 			 * heapam_visibility.c.
 			 */
-			if (TransactionIdIsCurrentTransactionId(xid) ||
-				TransactionIdIsInProgress(xid))
+			if (TransactionIdIsCurrentTransactionId(txid) ||
+				TransactionIdIsInProgress(txid))
 			{
 				Assert(!TransactionIdIsValid(update_xid));
-				update_xid = xid;
+				update_xid = txid;
 			}
-			else if (TransactionIdDidCommit(xid))
+			else if (TransactionIdDidCommit(txid))
 			{
 				/*
 				 * The transaction committed, so we can tell caller to set
@@ -6319,7 +6319,7 @@ FreezeMultiXactId(MultiXactId multi, uint16 t_infomask,
 				 */
 				Assert(!TransactionIdIsValid(update_xid));
 				update_committed = true;
-				update_xid = xid;
+				update_xid = txid;
 			}
 			else
 			{
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 3d9088a704..a7dfcfb4da 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -516,23 +516,23 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 	/* Walk the list and update the status of all XIDs. */
 	while (nextidx != INVALID_PGPROCNO)
 	{
-		PGPROC	   *proc = &ProcGlobal->allProcs[nextidx];
+		PGPROC	   *nextproc = &ProcGlobal->allProcs[nextidx];
 
 		/*
 		 * Transactions with more than THRESHOLD_SUBTRANS_CLOG_OPT sub-XIDs
 		 * should not use group XID status update mechanism.
 		 */
-		Assert(proc->subxidStatus.count <= THRESHOLD_SUBTRANS_CLOG_OPT);
+		Assert(nextproc->subxidStatus.count <= THRESHOLD_SUBTRANS_CLOG_OPT);
 
-		TransactionIdSetPageStatusInternal(proc->clogGroupMemberXid,
-										   proc->subxidStatus.count,
-										   proc->subxids.xids,
-										   proc->clogGroupMemberXidStatus,
-										   proc->clogGroupMemberLsn,
-										   proc->clogGroupMemberPage);
+		TransactionIdSetPageStatusInternal(nextproc->clogGroupMemberXid,
+										   nextproc->subxidStatus.count,
+										   nextproc->subxids.xids,
+										   nextproc->clogGroupMemberXidStatus,
+										   nextproc->clogGroupMemberLsn,
+										   nextproc->clogGroupMemberPage);
 
 		/* Move to next proc in list. */
-		nextidx = pg_atomic_read_u32(&proc->clogGroupNext);
+		nextidx = pg_atomic_read_u32(&nextproc->clogGroupNext);
 	}
 
 	/* We're done with the lock now. */
@@ -545,18 +545,18 @@ TransactionGroupUpdateXidStatus(TransactionId xid, XidStatus status,
 	 */
 	while (wakeidx != INVALID_PGPROCNO)
 	{
-		PGPROC	   *proc = &ProcGlobal->allProcs[wakeidx];
+		PGPROC	   *wakeproc = &ProcGlobal->allProcs[wakeidx];
 
-		wakeidx = pg_atomic_read_u32(&proc->clogGroupNext);
-		pg_atomic_write_u32(&proc->clogGroupNext, INVALID_PGPROCNO);
+		wakeidx = pg_atomic_read_u32(&wakeproc->clogGroupNext);
+		pg_atomic_write_u32(&wakeproc->clogGroupNext, INVALID_PGPROCNO);
 
 		/* ensure all previous writes are visible before follower continues. */
 		pg_write_barrier();
 
-		proc->clogGroupMember = false;
+		wakeproc->clogGroupMember = false;
 
-		if (proc != MyProc)
-			PGSemaphoreUnlock(proc->sem);
+		if (wakeproc != MyProc)
+			PGSemaphoreUnlock(wakeproc->sem);
 	}
 
 	return true;
diff --git a/src/backend/backup/basebackup.c b/src/backend/backup/basebackup.c
index e252ad7421..74fb529380 100644
--- a/src/backend/backup/basebackup.c
+++ b/src/backend/backup/basebackup.c
@@ -275,12 +275,12 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
 	PG_ENSURE_ERROR_CLEANUP(do_pg_abort_backup, BoolGetDatum(false));
 	{
 		ListCell   *lc;
-		tablespaceinfo *ti;
+		tablespaceinfo *newti;
 
 		/* Add a node for the base directory at the end */
-		ti = palloc0(sizeof(tablespaceinfo));
-		ti->size = -1;
-		state.tablespaces = lappend(state.tablespaces, ti);
+		newti = palloc0(sizeof(tablespaceinfo));
+		newti->size = -1;
+		state.tablespaces = lappend(state.tablespaces, newti);
 
 		/*
 		 * Calculate the total backup size by summing up the size of each
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 9a80ccdccd..5b49cc5a09 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -1818,19 +1818,19 @@ heap_drop_with_catalog(Oid relid)
 	 */
 	if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
 	{
-		Relation	rel;
-		HeapTuple	tuple;
+		Relation	ftrel;
+		HeapTuple	fttuple;
 
-		rel = table_open(ForeignTableRelationId, RowExclusiveLock);
+		ftrel = table_open(ForeignTableRelationId, RowExclusiveLock);
 
-		tuple = SearchSysCache1(FOREIGNTABLEREL, ObjectIdGetDatum(relid));
-		if (!HeapTupleIsValid(tuple))
+		fttuple = SearchSysCache1(FOREIGNTABLEREL, ObjectIdGetDatum(relid));
+		if (!HeapTupleIsValid(fttuple))
 			elog(ERROR, "cache lookup failed for foreign table %u", relid);
 
-		CatalogTupleDelete(rel, &tuple->t_self);
+		CatalogTupleDelete(ftrel, &fttuple->t_self);
 
-		ReleaseSysCache(tuple);
-		table_close(rel, RowExclusiveLock);
+		ReleaseSysCache(fttuple);
+		table_close(ftrel, RowExclusiveLock);
 	}
 
 	/*
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index a7022824d8..92aed2ff8b 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -1151,10 +1151,8 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 		if (argnumbers)
 		{
 			/* Re-order the argument types into call's logical order */
-			int			i;
-
-			for (i = 0; i < pronargs; i++)
-				newResult->args[i] = proargtypes[argnumbers[i]];
+			for (int j = 0; j < pronargs; j++)
+				newResult->args[j] = proargtypes[argnumbers[j]];
 		}
 		else
 		{
@@ -1163,12 +1161,10 @@ FuncnameGetCandidates(List *names, int nargs, List *argnames,
 		}
 		if (variadic)
 		{
-			int			i;
-
 			newResult->nvargs = effective_nargs - pronargs + 1;
 			/* Expand variadic argument into N copies of element type */
-			for (i = pronargs - 1; i < effective_nargs; i++)
-				newResult->args[i] = va_elem_type;
+			for (int j = pronargs - 1; j < effective_nargs; j++)
+				newResult->args[j] = va_elem_type;
 		}
 		else
 			newResult->nvargs = 0;
diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index 8514ebfe91..a8b75eb1be 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -107,7 +107,7 @@ parse_publication_options(ParseState *pstate,
 		{
 			char	   *publish;
 			List	   *publish_list;
-			ListCell   *lc;
+			ListCell   *lc2;
 
 			if (*publish_given)
 				errorConflictingDefElem(defel, pstate);
@@ -131,9 +131,9 @@ parse_publication_options(ParseState *pstate,
 								"publish")));
 
 			/* Process the option list. */
-			foreach(lc, publish_list)
+			foreach(lc2, publish_list)
 			{
-				char	   *publish_opt = (char *) lfirst(lc);
+				char	   *publish_opt = (char *) lfirst(lc2);
 
 				if (strcmp(publish_opt, "insert") == 0)
 					pubactions->pubinsert = true;
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7d8a75d23c..1f774ac065 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -10223,7 +10223,7 @@ CloneFkReferencing(List **wqueue, Relation parentRel, Relation partRel)
 		Oid			constrOid;
 		ObjectAddress address,
 					referenced;
-		ListCell   *cell;
+		ListCell   *lc;
 		Oid			insertTriggerOid,
 					updateTriggerOid;
 
@@ -10276,9 +10276,9 @@ CloneFkReferencing(List **wqueue, Relation parentRel, Relation partRel)
 		 * don't need to recurse to partitions for this constraint.
 		 */
 		attached = false;
-		foreach(cell, partFKs)
+		foreach(lc, partFKs)
 		{
-			ForeignKeyCacheInfo *fk = lfirst_node(ForeignKeyCacheInfo, cell);
+			ForeignKeyCacheInfo *fk = lfirst_node(ForeignKeyCacheInfo, lc);
 
 			if (tryAttachPartitionForeignKey(fk,
 											 RelationGetRelid(partRel),
@@ -10877,7 +10877,7 @@ ATExecAlterConstrRecurse(Constraint *cmdcon, Relation conrel, Relation tgrel,
 		{
 			Form_pg_trigger tgform = (Form_pg_trigger) GETSTRUCT(tgtuple);
 			Form_pg_trigger copy_tg;
-			HeapTuple	copyTuple;
+			HeapTuple	tgCopyTuple;
 
 			/*
 			 * Remember OIDs of other relation(s) involved in FK constraint.
@@ -10901,16 +10901,16 @@ ATExecAlterConstrRecurse(Constraint *cmdcon, Relation conrel, Relation tgrel,
 				tgform->tgfoid != F_RI_FKEY_CHECK_UPD)
 				continue;
 
-			copyTuple = heap_copytuple(tgtuple);
-			copy_tg = (Form_pg_trigger) GETSTRUCT(copyTuple);
+			tgCopyTuple = heap_copytuple(tgtuple);
+			copy_tg = (Form_pg_trigger) GETSTRUCT(tgCopyTuple);
 
 			copy_tg->tgdeferrable = cmdcon->deferrable;
 			copy_tg->tginitdeferred = cmdcon->initdeferred;
-			CatalogTupleUpdate(tgrel, &copyTuple->t_self, copyTuple);
+			CatalogTupleUpdate(tgrel, &tgCopyTuple->t_self, tgCopyTuple);
 
 			InvokeObjectPostAlterHook(TriggerRelationId, tgform->oid, 0);
 
-			heap_freetuple(copyTuple);
+			heap_freetuple(tgCopyTuple);
 		}
 
 		systable_endscan(tgscan);
@@ -18083,14 +18083,14 @@ AttachPartitionEnsureIndexes(Relation rel, Relation attachrel)
 		if (!found)
 		{
 			IndexStmt  *stmt;
-			Oid			constraintOid;
+			Oid			conOid;
 
 			stmt = generateClonedIndexStmt(NULL,
 										   idxRel, attmap,
-										   &constraintOid);
+										   &conOid);
 			DefineIndex(RelationGetRelid(attachrel), stmt, InvalidOid,
 						RelationGetRelid(idxRel),
-						constraintOid,
+						conOid,
 						true, false, false, false, false);
 		}
 
diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index 0fcf090f22..182e6161e0 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -1694,9 +1694,9 @@ renametrig_partition(Relation tgrel, Oid partitionId, Oid parentTriggerOid,
 
 			for (int i = 0; i < partdesc->nparts; i++)
 			{
-				Oid			partitionId = partdesc->oids[i];
+				Oid			partoid = partdesc->oids[i];
 
-				renametrig_partition(tgrel, partitionId, tgform->oid, newname,
+				renametrig_partition(tgrel, partoid, tgform->oid, newname,
 									 NameStr(tgform->tgname));
 			}
 		}
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index fe74e49814..373bcf6188 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -3483,8 +3483,6 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 			 */
 			if (aggnode->aggstrategy == AGG_SORTED)
 			{
-				int			i = 0;
-
 				Assert(aggnode->numCols > 0);
 
 				/*
@@ -3495,9 +3493,9 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 					(ExprState **) palloc0(aggnode->numCols * sizeof(ExprState *));
 
 				/* for each grouping set */
-				for (i = 0; i < phasedata->numsets; i++)
+				for (int k = 0; k < phasedata->numsets; k++)
 				{
-					int			length = phasedata->gset_lengths[i];
+					int			length = phasedata->gset_lengths[k];
 
 					if (phasedata->eqfunctions[length - 1] != NULL)
 						continue;
@@ -3576,7 +3574,6 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 	{
 		Plan	   *outerplan = outerPlan(node);
 		uint64		totalGroups = 0;
-		int			i;
 
 		aggstate->hash_metacxt = AllocSetContextCreate(aggstate->ss.ps.state->es_query_cxt,
 													   "HashAgg meta context",
@@ -3599,8 +3596,8 @@ ExecInitAgg(Agg *node, EState *estate, int eflags)
 		 * when there is more than one grouping set, but should still be
 		 * reasonable.
 		 */
-		for (i = 0; i < aggstate->num_hashes; i++)
-			totalGroups += aggstate->perhash[i].aggnode->numGroups;
+		for (int k = 0; k < aggstate->num_hashes; k++)
+			totalGroups += aggstate->perhash[k].aggnode->numGroups;
 
 		hash_agg_set_limits(aggstate->hashentrysize, totalGroups, 0,
 							&aggstate->hash_mem_limit,
diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 29bc26669b..fd5796f1b9 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -2484,35 +2484,35 @@ _SPI_execute_plan(SPIPlanPtr plan, const SPIExecuteOptions *options,
 		{
 			RawStmt    *parsetree = plansource->raw_parse_tree;
 			const char *src = plansource->query_string;
-			List	   *stmt_list;
+			List	   *querytree_list;
 
 			/*
 			 * Parameter datatypes are driven by parserSetup hook if provided,
 			 * otherwise we use the fixed parameter list.
 			 */
 			if (parsetree == NULL)
-				stmt_list = NIL;
+				querytree_list = NIL;
 			else if (plan->parserSetup != NULL)
 			{
 				Assert(plan->nargs == 0);
-				stmt_list = pg_analyze_and_rewrite_withcb(parsetree,
-														  src,
-														  plan->parserSetup,
-														  plan->parserSetupArg,
-														  _SPI_current->queryEnv);
+				querytree_list = pg_analyze_and_rewrite_withcb(parsetree,
+															   src,
+															   plan->parserSetup,
+															   plan->parserSetupArg,
+															   _SPI_current->queryEnv);
 			}
 			else
 			{
-				stmt_list = pg_analyze_and_rewrite_fixedparams(parsetree,
-															   src,
-															   plan->argtypes,
-															   plan->nargs,
-															   _SPI_current->queryEnv);
+				querytree_list = pg_analyze_and_rewrite_fixedparams(parsetree,
+																	src,
+																	plan->argtypes,
+																	plan->nargs,
+																	_SPI_current->queryEnv);
 			}
 
 			/* Finish filling in the CachedPlanSource */
 			CompleteCachedPlan(plansource,
-							   stmt_list,
+							   querytree_list,
 							   NULL,
 							   plan->argtypes,
 							   plan->nargs,
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index 5ef29eea69..4c6b1d1f55 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/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)
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 63a8eef45c..c31fcc917d 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/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,
diff --git a/src/backend/optimizer/path/tidpath.c b/src/backend/optimizer/path/tidpath.c
index 279ca1f5b4..c4e035b049 100644
--- a/src/backend/optimizer/path/tidpath.c
+++ b/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);
 				}
 
 				/*
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index 9c5836683c..5d0fd6e072 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/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,
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index 71052c841d..f6046768fb 100644
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/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);
 
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index bf3a7cae60..7fb32a0710 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/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
diff --git a/src/backend/optimizer/util/paramassign.c b/src/backend/optimizer/util/paramassign.c
index 8e2d4bf515..933460989b 100644
--- a/src/backend/optimizer/util/paramassign.c
+++ b/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);
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 202a38f813..c2b5474f5f 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -539,11 +539,11 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r)
 				!fc->func_variadic &&
 				coldeflist == NIL)
 			{
-				ListCell   *lc;
+				ListCell   *lc2;
 
-				foreach(lc, fc->args)
+				foreach(lc2, fc->args)
 				{
-					Node	   *arg = (Node *) lfirst(lc);
+					Node	   *arg = (Node *) lfirst(lc2);
 					FuncCall   *newfc;
 
 					last_srf = pstate->p_last_srf;
diff --git a/src/backend/partitioning/partbounds.c b/src/backend/partitioning/partbounds.c
index 7f74ed212f..a49e97a225 100644
--- a/src/backend/partitioning/partbounds.c
+++ b/src/backend/partitioning/partbounds.c
@@ -4321,11 +4321,11 @@ get_qual_for_range(Relation parent, PartitionBoundSpec *spec,
 		PartitionDesc pdesc = RelationGetPartitionDesc(parent, false);
 		Oid		   *inhoids = pdesc->oids;
 		int			nparts = pdesc->nparts,
-					i;
+					k;
 
-		for (i = 0; i < nparts; i++)
+		for (k = 0; k < nparts; k++)
 		{
-			Oid			inhrelid = inhoids[i];
+			Oid			inhrelid = inhoids[k];
 			HeapTuple	tuple;
 			Datum		datum;
 			bool		isnull;
diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index 5ab4612367..6188bf69cb 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -2289,11 +2289,10 @@ match_clause_to_partition_key(GeneratePruningStepsContext *context,
 		elem_clauses = NIL;
 		foreach(lc1, elem_exprs)
 		{
-			Expr	   *rightop = (Expr *) lfirst(lc1),
-					   *elem_clause;
+			Expr	   *elem_clause;
 
 			elem_clause = make_opclause(saop_op, BOOLOID, false,
-										leftop, rightop,
+										leftop, lfirst(lc1),
 										InvalidOid, saop_coll);
 			elem_clauses = lappend(elem_clauses, elem_clause);
 		}
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index 03d9c9c86a..6dff9915a5 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -2320,17 +2320,17 @@ ReorderBufferProcessTXN(ReorderBuffer *rb, ReorderBufferTXN *txn,
 						for (i = 0; i < nrelids; i++)
 						{
 							Oid			relid = change->data.truncate.relids[i];
-							Relation	relation;
+							Relation	rel;
 
-							relation = RelationIdGetRelation(relid);
+							rel = RelationIdGetRelation(relid);
 
-							if (!RelationIsValid(relation))
+							if (!RelationIsValid(rel))
 								elog(ERROR, "could not open relation with OID %u", relid);
 
-							if (!RelationIsLogicallyLogged(relation))
+							if (!RelationIsLogicallyLogged(rel))
 								continue;
 
-							relations[nrelations++] = relation;
+							relations[nrelations++] = rel;
 						}
 
 						/* Apply the truncate. */
diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c
index 3767466ef3..6cbb67c92a 100644
--- a/src/backend/replication/walreceiver.c
+++ b/src/backend/replication/walreceiver.c
@@ -180,7 +180,7 @@ WalReceiverMain(void)
 	bool		first_stream;
 	WalRcvData *walrcv = WalRcv;
 	TimestampTz last_recv_timestamp;
-	TimestampTz now;
+	TimestampTz starttime;
 	bool		ping_sent;
 	char	   *err;
 	char	   *sender_host = NULL;
@@ -192,7 +192,7 @@ WalReceiverMain(void)
 	 */
 	Assert(walrcv != NULL);
 
-	now = GetCurrentTimestamp();
+	starttime = GetCurrentTimestamp();
 
 	/*
 	 * Mark walreceiver as running in shared memory.
@@ -248,7 +248,7 @@ WalReceiverMain(void)
 
 	/* Initialise to a sanish value */
 	walrcv->lastMsgSendTime =
-		walrcv->lastMsgReceiptTime = walrcv->latestWalEndTime = now;
+		walrcv->lastMsgReceiptTime = walrcv->latestWalEndTime = starttime;
 
 	/* Report the latch to use to awaken this process */
 	walrcv->latch = &MyProc->procLatch;
diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index bf698c1fc3..744bc512b6 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -1692,7 +1692,6 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
 				{
 					int			idx;
 					Node	   *expr;
-					int			k;
 					AttrNumber	unique_attnum = InvalidAttrNumber;
 					AttrNumber	attnum;
 
@@ -1740,15 +1739,15 @@ dependencies_clauselist_selectivity(PlannerInfo *root,
 					expr = (Node *) list_nth(stat->exprs, idx);
 
 					/* try to find the expression in the unique list */
-					for (k = 0; k < unique_exprs_cnt; k++)
+					for (int m = 0; m < unique_exprs_cnt; m++)
 					{
 						/*
 						 * found a matching unique expression, use the attnum
 						 * (derived from index of the unique expression)
 						 */
-						if (equal(unique_exprs[k], expr))
+						if (equal(unique_exprs[m], expr))
 						{
-							unique_attnum = -(k + 1) + attnum_offset;
+							unique_attnum = -(m + 1) + attnum_offset;
 							break;
 						}
 					}
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 5f5803f681..3d1049cf75 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -3922,7 +3922,7 @@ GetSingleProcBlockerStatusData(PGPROC *blocked_proc, BlockedProcsData *data)
 	SHM_QUEUE  *procLocks;
 	PROCLOCK   *proclock;
 	PROC_QUEUE *waitQueue;
-	PGPROC	   *proc;
+	PGPROC	   *queued_proc;
 	int			queue_size;
 	int			i;
 
@@ -3989,13 +3989,13 @@ GetSingleProcBlockerStatusData(PGPROC *blocked_proc, BlockedProcsData *data)
 	}
 
 	/* Collect PIDs from the lock's wait queue, stopping at blocked_proc */
-	proc = (PGPROC *) waitQueue->links.next;
+	queued_proc = (PGPROC *) waitQueue->links.next;
 	for (i = 0; i < queue_size; i++)
 	{
-		if (proc == blocked_proc)
+		if (queued_proc == blocked_proc)
 			break;
-		data->waiter_pids[data->npids++] = proc->pid;
-		proc = (PGPROC *) proc->links.next;
+		data->waiter_pids[data->npids++] = queued_proc->pid;
+		queued_proc = (PGPROC *) queued_proc->links.next;
 	}
 
 	bproc->num_locks = data->nlocks - bproc->first_lock;
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 37aaab1338..13fa07b0ff 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1450,7 +1450,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 			int			usecs;
 			long		msecs;
 			SHM_QUEUE  *procLocks;
-			PROCLOCK   *proclock;
+			PROCLOCK   *curproclock;
 			bool		first_holder = true,
 						first_waiter = true;
 			int			lockHoldersNum = 0;
@@ -1480,44 +1480,45 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
 			LWLockAcquire(partitionLock, LW_SHARED);
 
 			procLocks = &(lock->procLocks);
-			proclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
-												 offsetof(PROCLOCK, lockLink));
+			curproclock = (PROCLOCK *) SHMQueueNext(procLocks, procLocks,
+													offsetof(PROCLOCK, lockLink));
 
-			while (proclock)
+			while (curproclock)
 			{
 				/*
-				 * we are a waiter if myProc->waitProcLock == proclock; we are
-				 * a holder if it is NULL or something different
+				 * we are a waiter if myProc->waitProcLock == curproclock; we
+				 * are a holder if it is NULL or something different
 				 */
-				if (proclock->tag.myProc->waitProcLock == proclock)
+				if (curproclock->tag.myProc->waitProcLock == curproclock)
 				{
 					if (first_waiter)
 					{
 						appendStringInfo(&lock_waiters_sbuf, "%d",
-										 proclock->tag.myProc->pid);
+										 curproclock->tag.myProc->pid);
 						first_waiter = false;
 					}
 					else
 						appendStringInfo(&lock_waiters_sbuf, ", %d",
-										 proclock->tag.myProc->pid);
+										 curproclock->tag.myProc->pid);
 				}
 				else
 				{
 					if (first_holder)
 					{
 						appendStringInfo(&lock_holders_sbuf, "%d",
-										 proclock->tag.myProc->pid);
+										 curproclock->tag.myProc->pid);
 						first_holder = false;
 					}
 					else
 						appendStringInfo(&lock_holders_sbuf, ", %d",
-										 proclock->tag.myProc->pid);
+										 curproclock->tag.myProc->pid);
 
 					lockHoldersNum++;
 				}
 
-				proclock = (PROCLOCK *) SHMQueueNext(procLocks, &proclock->lockLink,
-													 offsetof(PROCLOCK, lockLink));
+				curproclock = (PROCLOCK *) SHMQueueNext(procLocks,
+														&curproclock->lockLink,
+														offsetof(PROCLOCK, lockLink));
 			}
 
 			LWLockRelease(partitionLock);
diff --git a/src/backend/tsearch/ts_typanalyze.c b/src/backend/tsearch/ts_typanalyze.c
index e2d2ec18c9..187d9f16b1 100644
--- a/src/backend/tsearch/ts_typanalyze.c
+++ b/src/backend/tsearch/ts_typanalyze.c
@@ -405,12 +405,12 @@ compute_tsvector_stats(VacAttrStats *stats,
 			 */
 			for (i = 0; i < num_mcelem; i++)
 			{
-				TrackItem  *item = sort_table[i];
+				TrackItem  *titem = sort_table[i];
 
 				mcelem_values[i] =
-					PointerGetDatum(cstring_to_text_with_len(item->key.lexeme,
-															 item->key.length));
-				mcelem_freqs[i] = (double) item->frequency / (double) nonnull_cnt;
+					PointerGetDatum(cstring_to_text_with_len(titem->key.lexeme,
+															 titem->key.length));
+				mcelem_freqs[i] = (double) titem->frequency / (double) nonnull_cnt;
 			}
 			mcelem_freqs[i++] = (double) minfreq / (double) nonnull_cnt;
 			mcelem_freqs[i] = (double) maxfreq / (double) nonnull_cnt;
diff --git a/src/backend/utils/adt/array_typanalyze.c b/src/backend/utils/adt/array_typanalyze.c
index 2360c680ac..68f845bdee 100644
--- a/src/backend/utils/adt/array_typanalyze.c
+++ b/src/backend/utils/adt/array_typanalyze.c
@@ -541,12 +541,12 @@ compute_array_stats(VacAttrStats *stats, AnalyzeAttrFetchFunc fetchfunc,
 			 */
 			for (i = 0; i < num_mcelem; i++)
 			{
-				TrackItem  *item = sort_table[i];
+				TrackItem  *titem = sort_table[i];
 
-				mcelem_values[i] = datumCopy(item->key,
+				mcelem_values[i] = datumCopy(titem->key,
 											 extra_data->typbyval,
 											 extra_data->typlen);
-				mcelem_freqs[i] = (double) item->frequency /
+				mcelem_freqs[i] = (double) titem->frequency /
 					(double) nonnull_cnt;
 			}
 			mcelem_freqs[i++] = (double) minfreq / (double) nonnull_cnt;
diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 350039cc86..904ac2353c 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -1019,17 +1019,17 @@ DecodeDateTime(char **field, int *ftype, int nf,
 				if (ptype == DTK_JULIAN)
 				{
 					char	   *cp;
-					int			val;
+					int			jday;
 
 					if (tzp == NULL)
 						return DTERR_BAD_FORMAT;
 
 					errno = 0;
-					val = strtoint(field[i], &cp, 10);
-					if (errno == ERANGE || val < 0)
+					jday = strtoint(field[i], &cp, 10);
+					if (errno == ERANGE || jday < 0)
 						return DTERR_FIELD_OVERFLOW;
 
-					j2date(val, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+					j2date(jday, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 					isjulian = true;
 
 					/* Get the time zone from the end of the string */
@@ -1181,10 +1181,10 @@ DecodeDateTime(char **field, int *ftype, int nf,
 				if (ptype != 0)
 				{
 					char	   *cp;
-					int			val;
+					int			value;
 
 					errno = 0;
-					val = strtoint(field[i], &cp, 10);
+					value = strtoint(field[i], &cp, 10);
 					if (errno == ERANGE)
 						return DTERR_FIELD_OVERFLOW;
 
@@ -1209,7 +1209,7 @@ DecodeDateTime(char **field, int *ftype, int nf,
 					switch (ptype)
 					{
 						case DTK_YEAR:
-							tm->tm_year = val;
+							tm->tm_year = value;
 							tmask = DTK_M(YEAR);
 							break;
 
@@ -1222,33 +1222,33 @@ DecodeDateTime(char **field, int *ftype, int nf,
 							if ((fmask & DTK_M(MONTH)) != 0 &&
 								(fmask & DTK_M(HOUR)) != 0)
 							{
-								tm->tm_min = val;
+								tm->tm_min = value;
 								tmask = DTK_M(MINUTE);
 							}
 							else
 							{
-								tm->tm_mon = val;
+								tm->tm_mon = value;
 								tmask = DTK_M(MONTH);
 							}
 							break;
 
 						case DTK_DAY:
-							tm->tm_mday = val;
+							tm->tm_mday = value;
 							tmask = DTK_M(DAY);
 							break;
 
 						case DTK_HOUR:
-							tm->tm_hour = val;
+							tm->tm_hour = value;
 							tmask = DTK_M(HOUR);
 							break;
 
 						case DTK_MINUTE:
-							tm->tm_min = val;
+							tm->tm_min = value;
 							tmask = DTK_M(MINUTE);
 							break;
 
 						case DTK_SECOND:
-							tm->tm_sec = val;
+							tm->tm_sec = value;
 							tmask = DTK_M(SECOND);
 							if (*cp == '.')
 							{
@@ -1268,10 +1268,10 @@ DecodeDateTime(char **field, int *ftype, int nf,
 
 						case DTK_JULIAN:
 							/* previous field was a label for "julian date" */
-							if (val < 0)
+							if (value < 0)
 								return DTERR_FIELD_OVERFLOW;
 							tmask = DTK_DATE_M;
-							j2date(val, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+							j2date(value, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 							isjulian = true;
 
 							/* fractional Julian Day? */
@@ -2066,7 +2066,7 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 				if (ptype != 0)
 				{
 					char	   *cp;
-					int			val;
+					int			value;
 
 					/* Only accept a date under limited circumstances */
 					switch (ptype)
@@ -2082,7 +2082,7 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 					}
 
 					errno = 0;
-					val = strtoint(field[i], &cp, 10);
+					value = strtoint(field[i], &cp, 10);
 					if (errno == ERANGE)
 						return DTERR_FIELD_OVERFLOW;
 
@@ -2107,7 +2107,7 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 					switch (ptype)
 					{
 						case DTK_YEAR:
-							tm->tm_year = val;
+							tm->tm_year = value;
 							tmask = DTK_M(YEAR);
 							break;
 
@@ -2120,33 +2120,33 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 							if ((fmask & DTK_M(MONTH)) != 0 &&
 								(fmask & DTK_M(HOUR)) != 0)
 							{
-								tm->tm_min = val;
+								tm->tm_min = value;
 								tmask = DTK_M(MINUTE);
 							}
 							else
 							{
-								tm->tm_mon = val;
+								tm->tm_mon = value;
 								tmask = DTK_M(MONTH);
 							}
 							break;
 
 						case DTK_DAY:
-							tm->tm_mday = val;
+							tm->tm_mday = value;
 							tmask = DTK_M(DAY);
 							break;
 
 						case DTK_HOUR:
-							tm->tm_hour = val;
+							tm->tm_hour = value;
 							tmask = DTK_M(HOUR);
 							break;
 
 						case DTK_MINUTE:
-							tm->tm_min = val;
+							tm->tm_min = value;
 							tmask = DTK_M(MINUTE);
 							break;
 
 						case DTK_SECOND:
-							tm->tm_sec = val;
+							tm->tm_sec = value;
 							tmask = DTK_M(SECOND);
 							if (*cp == '.')
 							{
@@ -2166,10 +2166,10 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 
 						case DTK_JULIAN:
 							/* previous field was a label for "julian date" */
-							if (val < 0)
+							if (value < 0)
 								return DTERR_FIELD_OVERFLOW;
 							tmask = DTK_DATE_M;
-							j2date(val, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+							j2date(value, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 							isjulian = true;
 
 							if (*cp == '.')
diff --git a/src/backend/utils/adt/numutils.c b/src/backend/utils/adt/numutils.c
index cc3f95d399..834ec0b588 100644
--- a/src/backend/utils/adt/numutils.c
+++ b/src/backend/utils/adt/numutils.c
@@ -448,10 +448,10 @@ pg_ulltoa_n(uint64 value, char *a)
 	while (value >= 100000000)
 	{
 		const uint64 q = value / 100000000;
-		uint32		value2 = (uint32) (value - 100000000 * q);
+		uint32		value3 = (uint32) (value - 100000000 * q);
 
-		const uint32 c = value2 % 10000;
-		const uint32 d = value2 / 10000;
+		const uint32 c = value3 % 10000;
+		const uint32 d = value3 / 10000;
 		const uint32 c0 = (c % 100) << 1;
 		const uint32 c1 = (c / 100) << 1;
 		const uint32 d0 = (d % 100) << 1;
diff --git a/src/backend/utils/adt/partitionfuncs.c b/src/backend/utils/adt/partitionfuncs.c
index 109dc8023e..96b5ae52d2 100644
--- a/src/backend/utils/adt/partitionfuncs.c
+++ b/src/backend/utils/adt/partitionfuncs.c
@@ -238,9 +238,9 @@ pg_partition_ancestors(PG_FUNCTION_ARGS)
 
 	if (funcctx->call_cntr < list_length(ancestors))
 	{
-		Oid			relid = list_nth_oid(ancestors, funcctx->call_cntr);
+		Oid			resultrel = list_nth_oid(ancestors, funcctx->call_cntr);
 
-		SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(relid));
+		SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(resultrel));
 	}
 
 	SRF_RETURN_DONE(funcctx);
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index c418403537..855d48372a 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -8099,9 +8099,9 @@ get_parameter(Param *param, deparse_context *context)
 				 */
 				foreach(lc, context->namespaces)
 				{
-					deparse_namespace *dpns = lfirst(lc);
+					deparse_namespace *depns = lfirst(lc);
 
-					if (dpns->rtable_names != NIL)
+					if (depns->rtable_names != NIL)
 					{
 						should_qualify = true;
 						break;
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index a141146e70..ab613dd49e 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -3552,27 +3552,27 @@ do_connect(enum trivalue reuse_previous_specification,
 			param_is_newly_set(PQhost(o_conn), PQhost(pset.db)) ||
 			param_is_newly_set(PQport(o_conn), PQport(pset.db)))
 		{
-			char	   *host = PQhost(pset.db);
+			char	   *connhost = PQhost(pset.db);
 			char	   *hostaddr = PQhostaddr(pset.db);
 
-			if (is_unixsock_path(host))
+			if (is_unixsock_path(connhost))
 			{
-				/* hostaddr overrides host */
+				/* hostaddr overrides connhost */
 				if (hostaddr && *hostaddr)
 					printf(_("You are now connected to database \"%s\" as user \"%s\" on address \"%s\" at port \"%s\".\n"),
 						   PQdb(pset.db), PQuser(pset.db), hostaddr, PQport(pset.db));
 				else
 					printf(_("You are now connected to database \"%s\" as user \"%s\" via socket in \"%s\" at port \"%s\".\n"),
-						   PQdb(pset.db), PQuser(pset.db), host, PQport(pset.db));
+						   PQdb(pset.db), PQuser(pset.db), connhost, PQport(pset.db));
 			}
 			else
 			{
-				if (hostaddr && *hostaddr && strcmp(host, hostaddr) != 0)
+				if (hostaddr && *hostaddr && strcmp(connhost, hostaddr) != 0)
 					printf(_("You are now connected to database \"%s\" as user \"%s\" on host \"%s\" (address \"%s\") at port \"%s\".\n"),
-						   PQdb(pset.db), PQuser(pset.db), host, hostaddr, PQport(pset.db));
+						   PQdb(pset.db), PQuser(pset.db), connhost, hostaddr, PQport(pset.db));
 				else
 					printf(_("You are now connected to database \"%s\" as user \"%s\" on host \"%s\" at port \"%s\".\n"),
-						   PQdb(pset.db), PQuser(pset.db), host, PQport(pset.db));
+						   PQdb(pset.db), PQuser(pset.db), connhost, PQport(pset.db));
 			}
 		}
 		else
diff --git a/src/include/lib/simplehash.h b/src/include/lib/simplehash.h
index 4a3d0ec2c5..329687c1a5 100644
--- a/src/include/lib/simplehash.h
+++ b/src/include/lib/simplehash.h
@@ -546,13 +546,13 @@ SH_GROW(SH_TYPE * tb, uint64 newsize)
 		if (oldentry->status == SH_STATUS_IN_USE)
 		{
 			uint32		hash;
-			uint32		startelem;
+			uint32		startelem2;
 			uint32		curelem;
 			SH_ELEMENT_TYPE *newentry;
 
 			hash = SH_ENTRY_HASH(tb, oldentry);
-			startelem = SH_INITIAL_BUCKET(tb, hash);
-			curelem = startelem;
+			startelem2 = SH_INITIAL_BUCKET(tb, hash);
+			curelem = startelem2;
 
 			/* find empty element to put data into */
 			while (true)
@@ -564,7 +564,7 @@ SH_GROW(SH_TYPE * tb, uint64 newsize)
 					break;
 				}
 
-				curelem = SH_NEXT(tb, curelem, startelem);
+				curelem = SH_NEXT(tb, curelem, startelem2);
 			}
 
 			/* copy entry to new slot */
diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c
index bd94bd4e6c..641851983d 100644
--- a/src/interfaces/ecpg/ecpglib/execute.c
+++ b/src/interfaces/ecpg/ecpglib/execute.c
@@ -367,10 +367,10 @@ ecpg_store_result(const PGresult *results, int act_field,
 						/* check strlen for each tuple */
 						for (act_tuple = 0; act_tuple < ntuples; act_tuple++)
 						{
-							int			len = strlen(PQgetvalue(results, act_tuple, act_field)) + 1;
+							int			slen = strlen(PQgetvalue(results, act_tuple, act_field)) + 1;
 
-							if (len > var->varcharsize)
-								var->varcharsize = len;
+							if (slen > var->varcharsize)
+								var->varcharsize = slen;
 						}
 						var->offset *= var->varcharsize;
 						len = var->offset * ntuples;
diff --git a/src/interfaces/ecpg/ecpglib/misc.c b/src/interfaces/ecpg/ecpglib/misc.c
index 1eef1ec044..7f75e18733 100644
--- a/src/interfaces/ecpg/ecpglib/misc.c
+++ b/src/interfaces/ecpg/ecpglib/misc.c
@@ -558,7 +558,7 @@ ECPGset_var(int number, void *pointer, int lineno)
 	ptr = (struct var_list *) calloc(1L, sizeof(struct var_list));
 	if (!ptr)
 	{
-		struct sqlca_t *sqlca = ECPGget_sqlca();
+		sqlca = ECPGget_sqlca();
 
 		if (sqlca == NULL)
 		{
diff --git a/src/interfaces/ecpg/pgtypeslib/dt_common.c b/src/interfaces/ecpg/pgtypeslib/dt_common.c
index e0fae3d5f1..99bdc94d6d 100644
--- a/src/interfaces/ecpg/pgtypeslib/dt_common.c
+++ b/src/interfaces/ecpg/pgtypeslib/dt_common.c
@@ -1820,16 +1820,16 @@ DecodeDateTime(char **field, int *ftype, int nf,
 				if (ptype == DTK_JULIAN)
 				{
 					char	   *cp;
-					int			val;
+					int			jday;
 
 					if (tzp == NULL)
 						return -1;
 
-					val = strtoint(field[i], &cp, 10);
+					jday = strtoint(field[i], &cp, 10);
 					if (*cp != '-')
 						return -1;
 
-					j2date(val, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+					j2date(jday, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 					/* Get the time zone from the end of the string */
 					if (DecodeTimezone(cp, tzp) != 0)
 						return -1;
@@ -1958,9 +1958,9 @@ DecodeDateTime(char **field, int *ftype, int nf,
 				if (ptype != 0)
 				{
 					char	   *cp;
-					int			val;
+					int			value;
 
-					val = strtoint(field[i], &cp, 10);
+					value = strtoint(field[i], &cp, 10);
 
 					/*
 					 * only a few kinds are allowed to have an embedded
@@ -1983,7 +1983,7 @@ DecodeDateTime(char **field, int *ftype, int nf,
 					switch (ptype)
 					{
 						case DTK_YEAR:
-							tm->tm_year = val;
+							tm->tm_year = value;
 							tmask = DTK_M(YEAR);
 							break;
 
@@ -1996,33 +1996,33 @@ DecodeDateTime(char **field, int *ftype, int nf,
 							if ((fmask & DTK_M(MONTH)) != 0 &&
 								(fmask & DTK_M(HOUR)) != 0)
 							{
-								tm->tm_min = val;
+								tm->tm_min = value;
 								tmask = DTK_M(MINUTE);
 							}
 							else
 							{
-								tm->tm_mon = val;
+								tm->tm_mon = value;
 								tmask = DTK_M(MONTH);
 							}
 							break;
 
 						case DTK_DAY:
-							tm->tm_mday = val;
+							tm->tm_mday = value;
 							tmask = DTK_M(DAY);
 							break;
 
 						case DTK_HOUR:
-							tm->tm_hour = val;
+							tm->tm_hour = value;
 							tmask = DTK_M(HOUR);
 							break;
 
 						case DTK_MINUTE:
-							tm->tm_min = val;
+							tm->tm_min = value;
 							tmask = DTK_M(MINUTE);
 							break;
 
 						case DTK_SECOND:
-							tm->tm_sec = val;
+							tm->tm_sec = value;
 							tmask = DTK_M(SECOND);
 							if (*cp == '.')
 							{
@@ -2046,7 +2046,7 @@ DecodeDateTime(char **field, int *ftype, int nf,
 							 * previous field was a label for "julian date"?
 							 ***/
 							tmask = DTK_DATE_M;
-							j2date(val, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
+							j2date(value, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 							/* fractional Julian Day? */
 							if (*cp == '.')
 							{
diff --git a/src/pl/plpgsql/src/pl_funcs.c b/src/pl/plpgsql/src/pl_funcs.c
index 93d9cef06b..8d7b6b58c0 100644
--- a/src/pl/plpgsql/src/pl_funcs.c
+++ b/src/pl/plpgsql/src/pl_funcs.c
@@ -1647,13 +1647,12 @@ plpgsql_dumptree(PLpgSQL_function *func)
 			case PLPGSQL_DTYPE_ROW:
 				{
 					PLpgSQL_row *row = (PLpgSQL_row *) d;
-					int			i;
 
 					printf("ROW %-16s fields", row->refname);
-					for (i = 0; i < row->nfields; i++)
+					for (int j = 0; j < row->nfields; j++)
 					{
-						printf(" %s=var %d", row->fieldnames[i],
-							   row->varnos[i]);
+						printf(" %s=var %d", row->fieldnames[j],
+							   row->varnos[j]);
 					}
 					printf("\n");
 				}