Extend the parser location infrastructure to include a location field in

most node types used in expression trees (both before and after parse
analysis).  This allows us to place an error cursor in many situations
where we formerly could not, because the information wasn't available
beyond the very first level of parse analysis.  There's a fair amount
of work still to be done to persuade individual ereport() calls to actually
include an error location, but this gets the initdb-forcing part of the
work out of the way; and the situation is already markedly better than
before for complaints about unimplementable implicit casts, such as
CASE and UNION constructs with incompatible alternative data types.
Per my proposal of a few days ago.

1 files changed, 18 insertions, 10 deletions

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index aa0b9fd09e4..7097ef50582 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.176 2008/08/25 22:42:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_clause.c,v 1.177 2008/08/28 23:09:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -964,9 +964,10 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
 	outcoltypmod = l_colvar->vartypmod;
 	if (outcoltype != r_colvar->vartype)
 	{
-		outcoltype = select_common_type(list_make2_oid(l_colvar->vartype,
-													   r_colvar->vartype),
-										"JOIN/USING");
+		outcoltype = select_common_type(pstate,
+										list_make2(l_colvar, r_colvar),
+										"JOIN/USING",
+										NULL);
 		outcoltypmod = -1;		/* ie, unknown */
 	}
 	else if (outcoltypmod != r_colvar->vartypmod)
@@ -984,7 +985,7 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
 	if (l_colvar->vartype != outcoltype)
 		l_node = coerce_type(pstate, (Node *) l_colvar, l_colvar->vartype,
 							 outcoltype, outcoltypmod,
-							 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST);
+							 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
 	else if (l_colvar->vartypmod != outcoltypmod)
 		l_node = (Node *) makeRelabelType((Expr *) l_colvar,
 										  outcoltype, outcoltypmod,
@@ -995,7 +996,7 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
 	if (r_colvar->vartype != outcoltype)
 		r_node = coerce_type(pstate, (Node *) r_colvar, r_colvar->vartype,
 							 outcoltype, outcoltypmod,
-							 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST);
+							 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
 	else if (r_colvar->vartypmod != outcoltypmod)
 		r_node = (Node *) makeRelabelType((Expr *) r_colvar,
 										  outcoltype, outcoltypmod,
@@ -1038,6 +1039,7 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
 
 				c->coalescetype = outcoltype;
 				c->args = list_make2(l_node, r_node);
+				c->location = -1;
 				res_node = (Node *) c;
 				break;
 			}
@@ -1239,6 +1241,7 @@ findTargetlistEntry(ParseState *pstate, Node *node, List **tlist, int clause)
 	if (IsA(node, A_Const))
 	{
 		Value	   *val = &((A_Const *) node)->val;
+		int			location = ((A_Const *) node)->location;
 		int			targetlist_pos = 0;
 		int			target_pos;
 
@@ -1247,7 +1250,9 @@ findTargetlistEntry(ParseState *pstate, Node *node, List **tlist, int clause)
 					(errcode(ERRCODE_SYNTAX_ERROR),
 			/* translator: %s is name of a SQL construct, eg ORDER BY */
 					 errmsg("non-integer constant in %s",
-							clauseText[clause])));
+							clauseText[clause]),
+					 parser_errposition(pstate, location)));
+
 		target_pos = intVal(val);
 		foreach(tl, *tlist)
 		{
@@ -1263,7 +1268,8 @@ findTargetlistEntry(ParseState *pstate, Node *node, List **tlist, int clause)
 				(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
 		/* translator: %s is name of a SQL construct, eg ORDER BY */
 				 errmsg("%s position %d is not in select list",
-						clauseText[clause], target_pos)));
+						clauseText[clause], target_pos),
+				 parser_errposition(pstate, location)));
 	}
 
 	/*
@@ -1590,7 +1596,8 @@ addTargetToSortList(ParseState *pstate, TargetEntry *tle,
 		tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
 										 restype, TEXTOID, -1,
 										 COERCION_IMPLICIT,
-										 COERCE_IMPLICIT_CAST);
+										 COERCE_IMPLICIT_CAST,
+										 -1);
 		restype = TEXTOID;
 	}
 
@@ -1704,7 +1711,8 @@ addTargetToGroupList(ParseState *pstate, TargetEntry *tle,
 		tle->expr = (Expr *) coerce_type(pstate, (Node *) tle->expr,
 										 restype, TEXTOID, -1,
 										 COERCION_IMPLICIT,
-										 COERCE_IMPLICIT_CAST);
+										 COERCE_IMPLICIT_CAST,
+										 -1);
 		restype = TEXTOID;
 	}