Improve parser error location for cases where an INSERT or UPDATE command

supplies an expression that can't be coerced to the target column type.
The code previously attempted to point at the target column name, which
doesn't work at all in an INSERT with omitted column name list, and is
also not remarkably helpful when the problem is buried somewhere in a
long INSERT-multi-VALUES command.  Make it point at the failed expression
instead.

2 files changed, 20 insertions, 9 deletions

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 8e762f824c2..2a99d099d8e 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -17,7 +17,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.381 2008/10/06 15:15:22 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.382 2008/10/07 01:47:54 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -426,11 +426,15 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 				exprType((Node *) tle->expr) == UNKNOWNOID)
 				expr = tle->expr;
 			else
-				expr = (Expr *) makeVar(rtr->rtindex,
-										tle->resno,
-										exprType((Node *) tle->expr),
-										exprTypmod((Node *) tle->expr),
-										0);
+			{
+				Var	   *var = makeVar(rtr->rtindex,
+									  tle->resno,
+									  exprType((Node *) tle->expr),
+									  exprTypmod((Node *) tle->expr),
+									  0);
+				var->location = exprLocation((Node *) tle->expr);
+				expr = (Expr *) var;
+			}
 			exprList = lappend(exprList, expr);
 		}
 
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index d83caab7e8c..c12201fff7d 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_target.c,v 1.167 2008/10/06 15:15:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_target.c,v 1.168 2008/10/07 01:47:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -343,6 +343,11 @@ markTargetListOrigin(ParseState *pstate, TargetEntry *tle,
  * location		error cursor position for the target column, or -1
  *
  * Returns the modified expression.
+ *
+ * Note: location points at the target column name (SET target or INSERT
+ * column name list entry), and must therefore be -1 in an INSERT that
+ * omits the column name list.  So we should usually prefer to use
+ * exprLocation(expr) for errors that can happen in a default INSERT.
  */
 Expr *
 transformAssignedExpr(ParseState *pstate,
@@ -446,9 +451,11 @@ transformAssignedExpr(ParseState *pstate,
 		 * For normal non-qualified target column, do type checking and
 		 * coercion.
 		 */
+		Node   *orig_expr = (Node *) expr;
+
 		expr = (Expr *)
 			coerce_to_target_type(pstate,
-								  (Node *) expr, type_id,
+								  orig_expr, type_id,
 								  attrtype, attrtypmod,
 								  COERCION_ASSIGNMENT,
 								  COERCE_IMPLICIT_CAST,
@@ -462,7 +469,7 @@ transformAssignedExpr(ParseState *pstate,
 							format_type_be(attrtype),
 							format_type_be(type_id)),
 				 errhint("You will need to rewrite or cast the expression."),
-					 parser_errposition(pstate, location)));
+					 parser_errposition(pstate, exprLocation(orig_expr))));
 	}
 
 	return expr;