Remove some more useless assignments.

Found with clang's scan-build tool.  It also whines about a lot of
other dead stores that we should *not* change IMO, either as a matter
of style or future-proofing.  But these places seem like clear
oversights.

Discussion: https://postgr.es/m/CAEudQAo1+AcGppxDSg8k+zF4+Kv+eJyqzEDdbpDg58-=MQcerQ@mail.gmail.com

src/backend/access/brin/brin_tuple.c

@@ -243,7 +243,6 @@ brin_form_tuple(BrinDesc *brdesc, BlockNumber blkno, BrinMemTuple *tuple,
 
 			*bitP |= bitmask;
 		}
-		bitP = ((bits8 *) (rettuple + SizeOfBrinTuple)) - 1;
 	}
 
 	if (tuple->bt_placeholder)

src/backend/access/gin/ginbtree.c

@@ -241,7 +241,6 @@ ginFindParents(GinBtree btree, GinBtreeStack *stack)
 
 	blkno = root->blkno;
 	buffer = root->buffer;
-	offset = InvalidOffsetNumber;
 
 	ptr = (GinBtreeStack *) palloc(sizeof(GinBtreeStack));
 

src/backend/catalog/pg_depend.c

@@ -478,7 +478,7 @@ changeDependenciesOf(Oid classId, Oid oldObjectId,
 
 	while (HeapTupleIsValid((tup = systable_getnext(scan))))
 	{
-		Form_pg_depend depform = (Form_pg_depend) GETSTRUCT(tup);
+		Form_pg_depend depform;
 
 		/* make a modifiable copy */
 		tup = heap_copytuple(tup);
@@ -561,12 +561,12 @@ changeDependenciesOn(Oid refClassId, Oid oldRefObjectId,
 
 	while (HeapTupleIsValid((tup = systable_getnext(scan))))
 	{
-		Form_pg_depend depform = (Form_pg_depend) GETSTRUCT(tup);
-
 		if (newIsPinned)
 			CatalogTupleDelete(depRel, &tup->t_self);
 		else
 		{
+			Form_pg_depend depform;
+
 			/* make a modifiable copy */
 			tup = heap_copytuple(tup);
 			depform = (Form_pg_depend) GETSTRUCT(tup);

src/backend/optimizer/plan/planner.c

@@ -5097,7 +5097,7 @@ create_ordered_paths(PlannerInfo *root,
 			foreach(lc, input_rel->partial_pathlist)
 			{
 				Path	   *input_path = (Path *) lfirst(lc);
-				Path	   *sorted_path = input_path;
+				Path	   *sorted_path;
 				bool		is_sorted;
 				int			presorted_keys;
 				double		total_groups;

src/backend/parser/parse_utilcmd.c

@@ -1765,7 +1765,6 @@ generateClonedIndexStmt(RangeVar *heapRel, Relation source_idx,
 			char	   *attname;
 
 			attname = get_attname(indrelid, attnum, false);
-			keycoltype = get_atttype(indrelid, attnum);
 
 			iparam->name = attname;
 			iparam->expr = NULL;

src/backend/partitioning/partbounds.c

@@ -4259,10 +4259,6 @@ get_qual_for_range(Relation parent, PartitionBoundSpec *spec,
 		return result;
 	}
 
-	lower_or_start_datum = list_head(spec->lowerdatums);
-	upper_or_start_datum = list_head(spec->upperdatums);
-	num_or_arms = key->partnatts;
-
 	/*
 	 * If it is the recursive call for default, we skip the get_range_nulltest
 	 * to avoid accumulating the NullTest on the same keys for each partition.

src/backend/statistics/extended_stats.c

@@ -232,7 +232,7 @@ ComputeExtStatisticsRows(Relation onerel,
 	foreach(lc, lstats)
 	{
 		StatExtEntry *stat = (StatExtEntry *) lfirst(lc);
-		int			stattarget = stat->stattarget;
+		int			stattarget;
 		VacAttrStats **stats;
 		int			nattrs = bms_num_members(stat->columns);
 

src/backend/tsearch/spell.c

@@ -2124,7 +2124,6 @@ CheckAffix(const char *word, size_t len, AFFIX *Affix, int flagflags, char *neww
 	}
 	else
 	{
-		int			err;
 		pg_wchar   *data;
 		size_t		data_len;
 		int			newword_len;
@@ -2134,7 +2133,8 @@ CheckAffix(const char *word, size_t len, AFFIX *Affix, int flagflags, char *neww
 		data = (pg_wchar *) palloc((newword_len + 1) * sizeof(pg_wchar));
 		data_len = pg_mb2wchar_with_len(newword, data, newword_len);
 
-		if (!(err = pg_regexec(&(Affix->reg.regex), data, data_len, 0, NULL, 0, NULL, 0)))
+		if (pg_regexec(&(Affix->reg.regex), data, data_len,
+					   0, NULL, 0, NULL, 0) == REG_OKAY)
 		{
 			pfree(data);
 			return newword;