Remove vestigial resolveUnknown arguments from transformSortClause etc.

There's really no situation where we don't want these unknown-to-text
conversions to happen.  The alternative is failure anyway, and the one
caller that was passing "false" did so only because it expected the
case could not arise.  Might as well simplify the code.

Discussion: https://postgr.es/m/CAH2L28uwwbL9HUM-WR=hromW1Cvamkn7O-g8fPY2m=_7muJ0oA@mail.gmail.com

src/backend/parser/analyze.c

@@ -1232,7 +1232,6 @@ transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
 										  stmt->sortClause,
 										  &qry->targetList,
 										  EXPR_KIND_ORDER_BY,
-										  true /* fix unknowns */ ,
 										  false /* allow SQL92 rules */ );
 
 	qry->groupClause = transformGroupClause(pstate,
@@ -1512,7 +1511,6 @@ transformValuesClause(ParseState *pstate, SelectStmt *stmt)
 										  stmt->sortClause,
 										  &qry->targetList,
 										  EXPR_KIND_ORDER_BY,
-										  true /* fix unknowns */ ,
 										  false /* allow SQL92 rules */ );
 
 	qry->limitOffset = transformLimitClause(pstate, stmt->limitOffset,
@@ -1736,7 +1734,6 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 										  sortClause,
 										  &qry->targetList,
 										  EXPR_KIND_ORDER_BY,
-										  false /* no unknowns expected */ ,
 										  false /* allow SQL92 rules */ );
 
 	/* restore namespace, remove jrte from rtable */

src/backend/parser/parse_agg.c

@@ -155,8 +155,7 @@ transformAggregateCall(ParseState *pstate, Aggref *agg,
 			tlist = lappend(tlist, tle);
 
 			torder = addTargetToSortList(pstate, tle,
-										 torder, tlist, sortby,
-										 true /* fix unknowns */ );
+										 torder, tlist, sortby);
 		}
 
 		/* Never any DISTINCT in an ordered-set agg */
@@ -196,7 +195,6 @@ transformAggregateCall(ParseState *pstate, Aggref *agg,
 									 aggorder,
 									 &tlist,
 									 EXPR_KIND_ORDER_BY,
-									 true /* fix unknowns */ ,
 									 true /* force SQL99 rules */ );
 
 		/*

src/backend/parser/parse_clause.c

@@ -89,8 +89,7 @@ static int get_matching_location(int sortgroupref,
 static List *resolve_unique_index_expr(ParseState *pstate, InferClause *infer,
 						  Relation heapRel);
 static List *addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
-					 List *grouplist, List *targetlist, int location,
-					 bool resolveUnknown);
+					 List *grouplist, List *targetlist, int location);
 static WindowClause *findWindowClause(List *wclist, const char *name);
 static Node *transformFrameOffset(ParseState *pstate, int frameOptions,
 					 Node *clause);
@@ -2011,8 +2010,7 @@ transformGroupClauseExpr(List **flatresult, Bitmapset *seen_local,
 	if (!found)
 		*flatresult = addTargetToGroupList(pstate, tle,
 										   *flatresult, *targetlist,
-										   exprLocation(gexpr),
-										   true);
+										   exprLocation(gexpr));
 
 	/*
 	 * _something_ must have assigned us a sortgroupref by now...
@@ -2300,7 +2298,6 @@ transformSortClause(ParseState *pstate,
 					List *orderlist,
 					List **targetlist,
 					ParseExprKind exprKind,
-					bool resolveUnknown,
 					bool useSQL99)
 {
 	List	   *sortlist = NIL;
@@ -2319,8 +2316,7 @@ transformSortClause(ParseState *pstate,
 										   targetlist, exprKind);
 
 		sortlist = addTargetToSortList(pstate, tle,
-									   sortlist, *targetlist, sortby,
-									   resolveUnknown);
+									   sortlist, *targetlist, sortby);
 	}
 
 	return sortlist;
@@ -2382,7 +2378,6 @@ transformWindowDefinitions(ParseState *pstate,
 										  windef->orderClause,
 										  targetlist,
 										  EXPR_KIND_WINDOW_ORDER,
-										  true /* fix unknowns */ ,
 										  true /* force SQL99 rules */ );
 		partitionClause = transformGroupClause(pstate,
 											   windef->partitionClause,
@@ -2553,8 +2548,7 @@ transformDistinctClause(ParseState *pstate,
 			continue;			/* ignore junk */
 		result = addTargetToGroupList(pstate, tle,
 									  result, *targetlist,
-									  exprLocation((Node *) tle->expr),
-									  true);
+									  exprLocation((Node *) tle->expr));
 	}
 
 	/*
@@ -2671,8 +2665,7 @@ transformDistinctOnClause(ParseState *pstate, List *distinctlist,
 					 parser_errposition(pstate, exprLocation(dexpr))));
 		result = addTargetToGroupList(pstate, tle,
 									  result, *targetlist,
-									  exprLocation(dexpr),
-									  true);
+									  exprLocation(dexpr));
 	}
 
 	/*
@@ -2906,17 +2899,11 @@ transformOnConflictArbiter(ParseState *pstate,
  *		list, add it to the end of the list, using the given sort ordering
  *		info.
  *
- * If resolveUnknown is TRUE, convert TLEs of type UNKNOWN to TEXT.  If not,
- * do nothing (which implies the search for a sort operator will fail).
- * pstate should be provided if resolveUnknown is TRUE, but can be NULL
- * otherwise.
- *
  * Returns the updated SortGroupClause list.
  */
 List *
 addTargetToSortList(ParseState *pstate, TargetEntry *tle,
-					List *sortlist, List *targetlist, SortBy *sortby,
-					bool resolveUnknown)
+					List *sortlist, List *targetlist, SortBy *sortby)
 {
 	Oid			restype = exprType((Node *) tle->expr);
 	Oid			sortop;
@@ -2927,7 +2914,7 @@ addTargetToSortList(ParseState *pstate, TargetEntry *tle,
 	ParseCallbackState pcbstate;
 
 	/* if tlist item is an UNKNOWN literal, change it to TEXT */
-	if (restype == UNKNOWNOID && resolveUnknown)
+	if (restype == UNKNOWNOID)
 	{
 		tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
 										 restype, TEXTOID, -1,
@@ -3055,22 +3042,16 @@ addTargetToSortList(ParseState *pstate, TargetEntry *tle,
  * to a SELECT item that matches the GROUP BY item; it'd be pretty confusing
  * to report such a location.
  *
- * If resolveUnknown is TRUE, convert TLEs of type UNKNOWN to TEXT.  If not,
- * do nothing (which implies the search for an equality operator will fail).
- * pstate should be provided if resolveUnknown is TRUE, but can be NULL
- * otherwise.
- *
  * Returns the updated SortGroupClause list.
  */
 static List *
 addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
-					 List *grouplist, List *targetlist, int location,
-					 bool resolveUnknown)
+					 List *grouplist, List *targetlist, int location)
 {
 	Oid			restype = exprType((Node *) tle->expr);
 
 	/* if tlist item is an UNKNOWN literal, change it to TEXT */
-	if (restype == UNKNOWNOID && resolveUnknown)
+	if (restype == UNKNOWNOID)
 	{
 		tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
 										 restype, TEXTOID, -1,

src/include/parser/parse_clause.h

@@ -31,7 +31,7 @@ extern List *transformGroupClause(ParseState *pstate, List *grouplist,
 					 ParseExprKind exprKind, bool useSQL99);
 extern List *transformSortClause(ParseState *pstate, List *orderlist,
 					List **targetlist, ParseExprKind exprKind,
-					bool resolveUnknown, bool useSQL99);
+					bool useSQL99);
 
 extern List *transformWindowDefinitions(ParseState *pstate,
 						   List *windowdefs,
@@ -47,8 +47,7 @@ extern void transformOnConflictArbiter(ParseState *pstate,
 						   Oid *constraint);
 
 extern List *addTargetToSortList(ParseState *pstate, TargetEntry *tle,
-					List *sortlist, List *targetlist, SortBy *sortby,
-					bool resolveUnknown);
+					List *sortlist, List *targetlist, SortBy *sortby);
 extern Index assignSortGroupRef(TargetEntry *tle, List *tlist);
 extern bool targetIsInSortList(TargetEntry *tle, Oid sortop, List *sortList);