Further reduce warnings with -Wshadow=compatible-local

In a similar effort to f01592f91, here we're targetting fixing the
warnings that -Wshadow=compatible-local produces that we can fix by moving
a variable to an inner scope to stop that variable from being shadowed by
another variable declared somewhere later in the function.

All of the warnings being fixed here are changing the scope of variables
which are being used as an iterator for a "for" loop.  In each instance,
the fix happens to be changing the for loop to use the C99 type
initialization.  Much of this code likely pre-dates our use of C99.

Reducing the scope of the outer scoped variable seems like the safest way
to fix these.  Renaming seems more likely to risk patches using the wrong
variable.  Reducing the scope is more likely to result in a compilation
failure after applying some future patch rather than introducing bugs with
it.

By my count, this takes the warning count from 129 down to 114.

Author: Justin Pryzby
Discussion: https://postgr.es/m/CAApHDvrwLGBP%2BYw9vriayyf%3DXR4uPWP5jr6cQhP9au_kaDUhbA%40mail.gmail.com

src/backend/access/brin/brin.c

@@ -372,7 +372,6 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 			  **nullkeys;
 	int		   *nkeys,
 			   *nnullkeys;
-	int			keyno;
 	char	   *ptr;
 	Size		len;
 	char	   *tmp PG_USED_FOR_ASSERTS_ONLY;
@@ -454,7 +453,7 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	memset(nnullkeys, 0, sizeof(int) * bdesc->bd_tupdesc->natts);
 
 	/* Preprocess the scan keys - split them into per-attribute arrays. */
-	for (keyno = 0; keyno < scan->numberOfKeys; keyno++)
+	for (int keyno = 0; keyno < scan->numberOfKeys; keyno++)
 	{
 		ScanKey		key = &scan->keyData[keyno];
 		AttrNumber	keyattno = key->sk_attno;

src/backend/access/brin/brin_minmax_multi.c

@@ -582,7 +582,6 @@ brin_range_serialize(Ranges *range)
 	int			typlen;
 	bool		typbyval;
 
-	int			i;
 	char	   *ptr;
 
 	/* simple sanity checks */
@@ -662,7 +661,7 @@ brin_range_serialize(Ranges *range)
 	 */
 	ptr = serialized->data;		/* start of the serialized data */
 
-	for (i = 0; i < nvalues; i++)
+	for (int i = 0; i < nvalues; i++)
 	{
 		if (typbyval)			/* simple by-value data types */
 		{

src/backend/access/gist/gist.c

@@ -234,7 +234,6 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 	Page		page = BufferGetPage(buffer);
 	bool		is_leaf = (GistPageIsLeaf(page)) ? true : false;
 	XLogRecPtr	recptr;
-	int			i;
 	bool		is_split;
 
 	/*
@@ -420,7 +419,7 @@ gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
 		{
 			char	   *data = (char *) (ptr->list);
 
-			for (i = 0; i < ptr->block.num; i++)
+			for (int i = 0; i < ptr->block.num; i++)
 			{
 				IndexTuple	thistup = (IndexTuple) data;
 

src/backend/commands/copyfrom.c

@@ -1202,7 +1202,6 @@ BeginCopyFrom(ParseState *pstate,
 				num_defaults;
 	FmgrInfo   *in_functions;
 	Oid		   *typioparams;
-	int			attnum;
 	Oid			in_func_oid;
 	int		   *defmap;
 	ExprState **defexprs;
@@ -1401,7 +1400,7 @@ BeginCopyFrom(ParseState *pstate,
 	defmap = (int *) palloc(num_phys_attrs * sizeof(int));
 	defexprs = (ExprState **) palloc(num_phys_attrs * sizeof(ExprState *));
 
-	for (attnum = 1; attnum <= num_phys_attrs; attnum++)
+	for (int attnum = 1; attnum <= num_phys_attrs; attnum++)
 	{
 		Form_pg_attribute att = TupleDescAttr(tupDesc, attnum - 1);
 

src/backend/commands/indexcmds.c

@@ -565,7 +565,6 @@ DefineIndex(Oid relationId,
 	Oid			root_save_userid;
 	int			root_save_sec_context;
 	int			root_save_nestlevel;
-	int			i;
 
 	root_save_nestlevel = NewGUCNestLevel();
 
@@ -1047,7 +1046,7 @@ DefineIndex(Oid relationId,
 	 * We disallow indexes on system columns.  They would not necessarily get
 	 * updated correctly, and they don't seem useful anyway.
 	 */
-	for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
+	for (int i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
 	{
 		AttrNumber	attno = indexInfo->ii_IndexAttrNumbers[i];
 
@@ -1067,7 +1066,7 @@ DefineIndex(Oid relationId,
 		pull_varattnos((Node *) indexInfo->ii_Expressions, 1, &indexattrs);
 		pull_varattnos((Node *) indexInfo->ii_Predicate, 1, &indexattrs);
 
-		for (i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
+		for (int i = FirstLowInvalidHeapAttributeNumber + 1; i < 0; i++)
 		{
 			if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
 							  indexattrs))
@@ -1243,7 +1242,7 @@ DefineIndex(Oid relationId,
 			 * If none matches, build a new index by calling ourselves
 			 * recursively with the same options (except for the index name).
 			 */
-			for (i = 0; i < nparts; i++)
+			for (int i = 0; i < nparts; i++)
 			{
 				Oid			childRelid = part_oids[i];
 				Relation	childrel;

src/backend/executor/nodeAgg.c

@@ -1296,13 +1296,12 @@ finalize_aggregates(AggState *aggstate,
 	Datum	   *aggvalues = econtext->ecxt_aggvalues;
 	bool	   *aggnulls = econtext->ecxt_aggnulls;
 	int			aggno;
-	int			transno;
 
 	/*
 	 * If there were any DISTINCT and/or ORDER BY aggregates, sort their
 	 * inputs and run the transition functions.
 	 */
-	for (transno = 0; transno < aggstate->numtrans; transno++)
+	for (int transno = 0; transno < aggstate->numtrans; transno++)
 	{
 		AggStatePerTrans pertrans = &aggstate->pertrans[transno];
 		AggStatePerGroup pergroupstate;

src/backend/optimizer/path/costsize.c

@@ -2447,7 +2447,6 @@ append_nonpartial_cost(List *subpaths, int numpaths, int parallel_workers)
 	int			arrlen;
 	ListCell   *l;
 	ListCell   *cell;
-	int			i;
 	int			path_index;
 	int			min_index;
 	int			max_index;
@@ -2486,7 +2485,6 @@ append_nonpartial_cost(List *subpaths, int numpaths, int parallel_workers)
 	for_each_cell(l, subpaths, cell)
 	{
 		Path	   *subpath = (Path *) lfirst(l);
-		int			i;
 
 		/* Consider only the non-partial paths */
 		if (path_index++ == numpaths)
@@ -2495,7 +2493,8 @@ append_nonpartial_cost(List *subpaths, int numpaths, int parallel_workers)
 		costarr[min_index] += subpath->total_cost;
 
 		/* Update the new min cost array index */
-		for (min_index = i = 0; i < arrlen; i++)
+		min_index = 0;
+		for (int i = 0; i < arrlen; i++)
 		{
 			if (costarr[i] < costarr[min_index])
 				min_index = i;
@@ -2503,7 +2502,8 @@ append_nonpartial_cost(List *subpaths, int numpaths, int parallel_workers)
 	}
 
 	/* Return the highest cost from the array */
-	for (max_index = i = 0; i < arrlen; i++)
+	max_index = 0;
+	for (int i = 0; i < arrlen; i++)
 	{
 		if (costarr[i] > costarr[max_index])
 			max_index = i;

src/backend/statistics/mcv.c

@@ -1604,7 +1604,6 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 					 Bitmapset *keys, List *exprs,
 					 MCVList *mcvlist, bool is_or)
 {
-	int			i;
 	ListCell   *l;
 	bool	   *matches;
 
@@ -1659,7 +1658,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			 * can skip items that were already ruled out, and terminate if
 			 * there are no remaining MCV items that might possibly match.
 			 */
-			for (i = 0; i < mcvlist->nitems; i++)
+			for (int i = 0; i < mcvlist->nitems; i++)
 			{
 				bool		match = true;
 				MCVItem    *item = &mcvlist->items[i];
@@ -1766,7 +1765,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			 * can skip items that were already ruled out, and terminate if
 			 * there are no remaining MCV items that might possibly match.
 			 */
-			for (i = 0; i < mcvlist->nitems; i++)
+			for (int i = 0; i < mcvlist->nitems; i++)
 			{
 				int			j;
 				bool		match = !expr->useOr;
@@ -1837,7 +1836,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			 * can skip items that were already ruled out, and terminate if
 			 * there are no remaining MCV items that might possibly match.
 			 */
-			for (i = 0; i < mcvlist->nitems; i++)
+			for (int i = 0; i < mcvlist->nitems; i++)
 			{
 				bool		match = false;	/* assume mismatch */
 				MCVItem    *item = &mcvlist->items[i];
@@ -1930,7 +1929,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			 * can skip items that were already ruled out, and terminate if
 			 * there are no remaining MCV items that might possibly match.
 			 */
-			for (i = 0; i < mcvlist->nitems; i++)
+			for (int i = 0; i < mcvlist->nitems; i++)
 			{
 				MCVItem    *item = &mcvlist->items[i];
 				bool		match = false;
@@ -1956,7 +1955,7 @@ mcv_get_match_bitmap(PlannerInfo *root, List *clauses,
 			 * can skip items that were already ruled out, and terminate if
 			 * there are no remaining MCV items that might possibly match.
 			 */
-			for (i = 0; i < mcvlist->nitems; i++)
+			for (int i = 0; i < mcvlist->nitems; i++)
 			{
 				bool		match;
 				MCVItem    *item = &mcvlist->items[i];

src/backend/storage/buffer/bufmgr.c

@@ -3183,7 +3183,6 @@ void
 DropRelationsAllBuffers(SMgrRelation *smgr_reln, int nlocators)
 {
 	int			i;
-	int			j;
 	int			n = 0;
 	SMgrRelation *rels;
 	BlockNumber (*block)[MAX_FORKNUM + 1];
@@ -3232,7 +3231,7 @@ DropRelationsAllBuffers(SMgrRelation *smgr_reln, int nlocators)
 	 */
 	for (i = 0; i < n && cached; i++)
 	{
-		for (j = 0; j <= MAX_FORKNUM; j++)
+		for (int j = 0; j <= MAX_FORKNUM; j++)
 		{
 			/* Get the number of blocks for a relation's fork. */
 			block[i][j] = smgrnblocks_cached(rels[i], j);
@@ -3259,7 +3258,7 @@ DropRelationsAllBuffers(SMgrRelation *smgr_reln, int nlocators)
 	{
 		for (i = 0; i < n; i++)
 		{
-			for (j = 0; j <= MAX_FORKNUM; j++)
+			for (int j = 0; j <= MAX_FORKNUM; j++)
 			{
 				/* ignore relation forks that doesn't exist */
 				if (!BlockNumberIsValid(block[i][j]))

src/bin/pg_dump/pg_dump.c

@@ -11576,7 +11576,6 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 	char	  **configitems = NULL;
 	int			nconfigitems = 0;
 	const char *keyword;
-	int			i;
 
 	/* Do nothing in data-only dump */
 	if (dopt->dataOnly)
@@ -11853,7 +11852,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 					 finfo->dobj.name);
 	}
 
-	for (i = 0; i < nconfigitems; i++)
+	for (int i = 0; i < nconfigitems; i++)
 	{
 		/* we feel free to scribble on configitems[] here */
 		char	   *configitem = configitems[i];

src/interfaces/ecpg/pgtypeslib/numeric.c

@@ -1062,7 +1062,6 @@ PGTYPESnumeric_div(numeric *var1, numeric *var2, numeric *result)
 	int			weight_tmp;
 	int			rscale_tmp;
 	int			ri;
-	int			i;
 	long		guess;
 	long		first_have;
 	long		first_div;
@@ -1109,7 +1108,7 @@ PGTYPESnumeric_div(numeric *var1, numeric *var2, numeric *result)
 	 * Initialize local variables
 	 */
 	init_var(&dividend);
-	for (i = 1; i < 10; i++)
+	for (int i = 1; i < 10; i++)
 		init_var(&divisor[i]);
 
 	/*
@@ -1268,7 +1267,7 @@ done:
 	if (dividend.buf != NULL)
 		digitbuf_free(dividend.buf);
 
-	for (i = 1; i < 10; i++)
+	for (int i = 1; i < 10; i++)
 	{
 		if (divisor[i].buf != NULL)
 			digitbuf_free(divisor[i].buf);