Add error position to an error message

Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/6e7aa4a1-be6a-1a75-b1f9-83a678e5184a@2ndquadrant.com

src/backend/commands/prepare.c

@@ -381,7 +381,8 @@ EvaluateParams(PreparedStatement *pstmt, List *params,
 							i + 1,
 							format_type_be(given_type_id),
 							format_type_be(expected_type_id)),
-					 errhint("You will need to rewrite or cast the expression.")));
+					 errhint("You will need to rewrite or cast the expression."),
+					 parser_errposition(pstate, exprLocation(lfirst(l)))));
 
 		/* Take care of collations in the finished expression. */
 		assign_expr_collations(pstate, expr);

src/test/regress/expected/prepare.out

@@ -113,6 +113,8 @@ DETAIL:  Expected 5 parameters but got 6.
 -- wrong param types
 EXECUTE q3(5::smallint, 10.5::float, false, 4::bigint, 'bytea');
 ERROR:  parameter $3 of type boolean cannot be coerced to the expected type double precision
+LINE 1: EXECUTE q3(5::smallint, 10.5::float, false, 4::bigint, 'byte...
+                                             ^
 HINT:  You will need to rewrite or cast the expression.
 -- invalid type
 PREPARE q4(nonexistenttype) AS SELECT $1;