plpgsql_check is next generation of plpgsql_lint. It allows to check source code
by explicit call plpgsql_check_function. PostgreSQL 9.4, 9.5, 9.6, 10, 11 are
supported (Develop 12 is supported too). The SQL statements inside PL/pgSQL
functions are checked by validator for semantic errors. These errors can be
found by plpgsql_check_function.

Features:
- check fields of referenced database objects and types inside embedded SQL
- using correct types of function parameters
- unused variables and function argumens, unmodified OUT argumens
- partially detection of dead code (due RETURN command)
- detection of missing RETURN command in function
- try to identify unwanted hidden casts, that can be performance issue like
  unused indexes
- possibility to collect relations and functions used by function
- possibility to check EXECUTE stmt agaist SQL injection vulnerability