diff --git a/purspgpp b/purspgpp
index faa4fe4..6ff6fa8 100644
--- a/purspgpp
+++ b/purspgpp
@@ -62,11 +62,11 @@ my Str:D %types{Int:D} =
     2950 => 'UUID',
 ;
 
-sub process-module($conn, Str:D $segment) {
+sub process-module(libpq::Connection:D $conn, Str:D $segment --> Str:D) {
     S:g/'[query|' (.*?) '|]'/&process-query($conn, ~$0)/ given $segment;
 }
 
-sub process-query($conn, Str:D $source) {
+sub process-query(libpq::Connection:D $conn, Str:D $source --> Str:D) {
     $conn.prepare('', $source);
     my $description = $conn.describe-prepared('');
     my &convert-types = { ($_.map({%types{$_}}), "Unit").flat.join(" × "); };