diff --git a/src/protocol/parser/pass_definitions.rs b/src/protocol/parser/pass_definitions.rs
index ab2b18ad81aa014acecabc50db0c7b131aa6c945..0436245808a05644b981900a7705735ba1f7457b 100644
--- a/src/protocol/parser/pass_definitions.rs
+++ b/src/protocol/parser/pass_definitions.rs
@@ -1317,15 +1317,38 @@ impl PassDefinitions {
                     ));
                 }
             } else {
+                // Can be a select expression for struct fields, or a select
+                // for a tuple element.
                 debug_assert_eq!(token, TokenKind::Dot);
                 let subject = result;
-                let field_name = consume_ident_interned(&module.source, iter, ctx)?;
 
-                let full_span = InputSpan::from_positions(
-                    ctx.heap[subject].full_span().begin, field_name.span.end
-                );
+                let next = iter.next();
+                let (select_kind, full_span) = if Some(TokenKind::Integer) == next {
+                    // Tuple member
+                    let (index, index_span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
+                    let full_span = InputSpan::from_positions(
+                        ctx.heap[subject].full_span().begin, index_span.end
+                    );
+
+                    (SelectKind::TupleMember(index), full_span)
+                } else if Some(TokenKind::Ident) == next {
+                    // Struct field
+                    let field_name = consume_ident_interned(&module.source, iter, ctx)?;
+
+                    let full_span = InputSpan::from_positions(
+                        ctx.heap[subject].full_span().begin, field_name.span.end
+                    );
+
+                    (SelectKind::StructField(field_name), full_span)
+                } else {
+                    return Err(ParseError::new_error_str_at_pos(
+                        &module.source, iter.last_valid_pos(), "unexpected token: expected integer or identifier"
+                    ));
+                };
+
                 result = ctx.heap.alloc_select_expression(|this| SelectExpression{
-                    this, operator_span, full_span, subject, field_name,
+                    this, operator_span, full_span, subject,
+                    kind: select_kind,
                     parent: ExpressionParent::None,
                     unique_id_in_definition: -1,
                 }).upcast();