Function parameterize_statement_variables 

pub fn parameterize_statement_variables(
    statement: &Statement,
    resolver: &mut dyn VariableResolver,
    conflict: VariableConflict,
    resolve_sites: VariableSiteResolver<'_>,
) -> Result<PLpgSQLVariableBindings, SQLError>

Reuse the ordinary PL name/column conflict resolver, then number only names it selected as variables. Repeated reads receive fresh invocation values.