Submitted by: @cincuranet

Calling ".GetSchema("Procedures", new[] { null, "dbo", "test" });" results into:
SELECT
null AS PROCEDURE_CATALOG,
null AS PROCEDURE_SCHEMA,
rdb$procedure_name AS PROCEDURE_NAME,
rdb$procedure_inputs AS INPUTS,
rdb$procedure_outputs AS OUTPUTS,
rdb$system_flag AS IS_SYSTEM_PROCEDURE,
rdb$procedure_source AS SOURCE,
rdb$description AS DESCRIPTION
FROM rdb$procedures WHERE rdb$procedure_name = @p0 ORDER BY rdb$procedure_name
FirebirdSql.Data.FirebirdClient Information: 0 : Parameters:

FirebirdSql.Data.FirebirdClient Information: 0 : Name:@p0 Type:VarChar Used Value:dbo
FirebirdSql.Data.FirebirdClient Information: 0 : Name:@p1 Type:VarChar Used Value:test

So the wrong parameter is used and another parameter is generated even if nod needed nor used.

It should be i.e.:
SELECT
null AS PROCEDURE_CATALOG,
'Firebird' AS PROCEDURE_SCHEMA,
rdb$procedure_name AS PROCEDURE_NAME,
rdb$procedure_inputs AS INPUTS,
rdb$procedure_outputs AS OUTPUTS,
rdb$system_flag AS IS_SYSTEM_PROCEDURE,
rdb$procedure_source AS SOURCE,
rdb$description AS DESCRIPTION
FROM rdb$procedures WHERE rdb$procedure_name = @p0 ORDER BY rdb$procedure_name
Parameters:
Name:@p0 Type:VarChar Used Value:test

Commits: dbdce38