Make a code-cleanup pass over the collations patch.

This patch is almost entirely cosmetic --- mostly cleaning up a lot of
neglected comments, and fixing code layout problems in places where the
patch made lines too long and then pgindent did weird things with that.
I did find a bug-of-omission in equalTupleDescs().

src/backend/parser/analyze.c

@@ -1357,9 +1357,9 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 
 	/*
 	 * Generate dummy targetlist for outer query using column names of
-	 * leftmost select and common datatypes of topmost set operation. Also
-	 * make lists of the dummy vars and their names for use in parsing ORDER
-	 * BY.
+	 * leftmost select and common datatypes/collations of topmost set
+	 * operation.  Also make lists of the dummy vars and their names for use
+	 * in parsing ORDER BY.
 	 *
 	 * Note: we use leftmostRTI as the varno of the dummy variables. It
 	 * shouldn't matter too much which RT index they have, as long as they
@@ -1371,7 +1371,9 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	targetnames = NIL;
 	left_tlist = list_head(leftmostQuery->targetList);
 
-	forthree(lct, sostmt->colTypes, lcm, sostmt->colTypmods, lcc, sostmt->colCollations)
+	forthree(lct, sostmt->colTypes,
+			 lcm, sostmt->colTypmods,
+			 lcc, sostmt->colCollations)
 	{
 		Oid			colType = lfirst_oid(lct);
 		int32		colTypmod = lfirst_int(lcm);

src/backend/parser/parse_cte.c

@@ -286,10 +286,10 @@ analyzeCTE(ParseState *pstate, CommonTableExpr *cte)
 	else
 	{
 		/*
-		 * Verify that the previously determined output column types match
-		 * what the query really produced.	We have to check this because the
-		 * recursive term could have overridden the non-recursive term, and we
-		 * don't have any easy way to fix that.
+		 * Verify that the previously determined output column types and
+		 * collations match what the query really produced.  We have to check
+		 * this because the recursive term could have overridden the
+		 * non-recursive term, and we don't have any easy way to fix that.
 		 */
 		ListCell   *lctlist,
 				   *lctyp,
@@ -366,11 +366,11 @@ analyzeCTETargetList(ParseState *pstate, CommonTableExpr *cte, List *tlist)
 	Assert(cte->ctecolnames == NIL);
 
 	/*
-	 * We need to determine column names and types.  The alias column names
-	 * override anything coming from the query itself.	(Note: the SQL spec
-	 * says that the alias list must be empty or exactly as long as the output
-	 * column set; but we allow it to be shorter for consistency with Alias
-	 * handling.)
+	 * We need to determine column names, types, and collations.  The alias
+	 * column names override anything coming from the query itself.  (Note:
+	 * the SQL spec says that the alias list must be empty or exactly as long
+	 * as the output column set; but we allow it to be shorter for consistency
+	 * with Alias handling.)
 	 */
 	cte->ctecolnames = copyObject(cte->aliascolnames);
 	cte->ctecoltypes = cte->ctecoltypmods = cte->ctecolcollations = NIL;

src/backend/parser/parse_relation.c

@@ -1174,7 +1174,8 @@ addRangeTableEntryForFunction(ParseState *pstate,
 			eref->colnames = lappend(eref->colnames, makeString(attrname));
 			rte->funccoltypes = lappend_oid(rte->funccoltypes, attrtype);
 			rte->funccoltypmods = lappend_int(rte->funccoltypmods, attrtypmod);
-			rte->funccolcollations = lappend_oid(rte->funccolcollations, attrcollation);
+			rte->funccolcollations = lappend_oid(rte->funccolcollations,
+												 attrcollation);
 		}
 	}
 	else
@@ -1902,7 +1903,8 @@ expandTupleDesc(TupleDesc tupdesc, Alias *eref,
 			Var		   *varnode;
 
 			varnode = makeVar(rtindex, attr->attnum,
-						 attr->atttypid, attr->atttypmod, attr->attcollation,
+							  attr->atttypid, attr->atttypmod,
+							  attr->attcollation,
 							  sublevels_up);
 			varnode->location = location;
 
@@ -2009,7 +2011,7 @@ get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
 
 /*
  * get_rte_attribute_type
- *		Get attribute type information from a RangeTblEntry
+ *		Get attribute type/typmod/collation information from a RangeTblEntry
  */
 void
 get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,

src/backend/parser/parse_target.c

@@ -372,7 +372,7 @@ transformAssignedExpr(ParseState *pstate,
 	Oid			type_id;		/* type of value provided */
 	Oid			attrtype;		/* type of target column */
 	int32		attrtypmod;
-	Oid			attrcollation;
+	Oid			attrcollation;	/* collation of target column */
 	Relation	rd = pstate->p_target_relation;
 
 	Assert(rd != NULL);
@@ -388,11 +388,12 @@ transformAssignedExpr(ParseState *pstate,
 
 	/*
 	 * If the expression is a DEFAULT placeholder, insert the attribute's
-	 * type/typmod into it so that exprType will report the right things. (We
-	 * expect that the eventually substituted default expression will in fact
-	 * have this type and typmod.)	Also, reject trying to update a subfield
-	 * or array element with DEFAULT, since there can't be any default for
-	 * portions of a column.
+	 * type/typmod/collation into it so that exprType etc will report the
+	 * right things.  (We expect that the eventually substituted default
+	 * expression will in fact have this type and typmod.  The collation
+	 * likely doesn't matter, but let's set it correctly anyway.)  Also,
+	 * reject trying to update a subfield or array element with DEFAULT, since
+	 * there can't be any default for portions of a column.
 	 */
 	if (expr && IsA(expr, SetToDefault))
 	{