From 87eb4ca3b406c8e75263bbc9c160c4046e95af09 Mon Sep 17 00:00:00 2001
From: Kasey White <kwhitemsg@gmail.com>
Date: Mon, 20 Feb 2023 00:51:03 -0500
Subject: [PATCH] feat: handle single constr when with multiple branches

Add case to acceptance test 40
Add special case for top level single constr in a when.
---
 crates/aiken-lang/src/uplc.rs              | 29 +++++++++++++++++-----
 examples/acceptance_tests/040/lib/tests.ak |  9 +++++++
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/crates/aiken-lang/src/uplc.rs b/crates/aiken-lang/src/uplc.rs
index 0e451146..31407969 100644
--- a/crates/aiken-lang/src/uplc.rs
+++ b/crates/aiken-lang/src/uplc.rs
@@ -756,12 +756,29 @@ impl<'a> CodeGenerator<'a> {
                         scope.clone(),
                     );
 
-                    ir_stack.push(Air::Clause {
-                        scope,
-                        tipo: subject_type.clone(),
-                        complex_clause: *clause_properties.is_complex_clause(),
-                        subject_name,
-                    });
+                    let data_type =
+                        lookup_data_type_by_tipo(self.data_types.clone(), &subject_type).unwrap();
+
+                    if data_type.constructors.len() > 1 {
+                        ir_stack.push(Air::Clause {
+                            scope,
+                            tipo: subject_type.clone(),
+                            complex_clause: *clause_properties.is_complex_clause(),
+                            subject_name,
+                        });
+                    } else {
+                        ir_stack.push(Air::Clause {
+                            scope: scope.clone(),
+                            tipo: subject_type.clone(),
+                            complex_clause: *clause_properties.is_complex_clause(),
+                            subject_name,
+                        });
+
+                        ir_stack.push(Air::Int {
+                            scope,
+                            value: "0".to_string(),
+                        });
+                    }
                 }
                 ClauseProperties::ListClause {
                     original_subject_name,
diff --git a/examples/acceptance_tests/040/lib/tests.ak b/examples/acceptance_tests/040/lib/tests.ak
index 0367517b..23903b7c 100644
--- a/examples/acceptance_tests/040/lib/tests.ak
+++ b/examples/acceptance_tests/040/lib/tests.ak
@@ -73,3 +73,12 @@ test single_field_expect() {
   expect CreateVoteBatch { id } = redeemer
   id == #""
 }
+
+test single_when() {
+  let redeemer = CreateVoteBatch { id: #"" }
+  let x = when redeemer is {
+    CreateVoteBatch { id } -> id == #""
+    _ -> False
+  }
+  x == True
+}