Fix validator's fallback handler generation

Fixes #1015.

examples/acceptance_tests/script_context/v3/validators/simple_else.ak

@@ -0,0 +1,95 @@
+use aiken/collection/dict
+use cardano/address.{Address, Script}
+use cardano/assets
+use cardano/script_context.{ScriptContext, Spending}
+use cardano/transaction.{
+  InlineDatum, Input, Output, OutputReference, ScriptPurpose, Spend, Transaction,
+}
+
+validator simple_else {
+  else(ctx: ScriptContext) {
+    expect Spending(output_ref, _) = ctx.info
+
+    let transaction = ctx.transaction
+
+    assert_transaction_id(transaction.id)
+
+    assert_script_info(output_ref)
+
+    assert_inputs(transaction.inputs)
+
+    expect [] = transaction.outputs
+
+    expect [] = transaction.reference_inputs
+
+    expect [] = transaction.extra_signatories
+
+    expect 42 == transaction.fee
+
+    assert_redeemers(transaction.redeemers)
+
+    expect [] == dict.to_pairs(transaction.datums)
+
+    True
+  }
+}
+
+fn assert_transaction_id(id: ByteArray) {
+  expect
+    #"c6fbd346681a8f8337f6b3e51e6ec973f1509367eabc3a44c849af58a1d8471b" == id
+  Void
+}
+
+fn assert_script_info(info: OutputReference) {
+  expect
+    OutputReference {
+      transaction_id: #"0000000000000000000000000000000000000000000000000000000000000000",
+      output_index: 0,
+    } == info
+  Void
+}
+
+fn assert_inputs(inputs: List<Input>) {
+  expect [
+    Input {
+      output_reference: OutputReference { transaction_id, output_index: 0 },
+      output: Output {
+        address,
+        value: resolved_input_value,
+        datum: InlineDatum(_),
+        reference_script: None,
+      },
+    },
+  ] = inputs
+
+  expect
+    transaction_id == #"0000000000000000000000000000000000000000000000000000000000000000"
+
+  expect resolved_input_value == assets.from_lovelace(1000000000)
+
+  expect Address { payment_credential: Script(_), stake_credential: None } =
+    address
+
+  Void
+}
+
+fn assert_redeemers(redeemers: Pairs<ScriptPurpose, Data>) {
+  expect
+    [
+      Pair(
+        Spend(
+          OutputReference {
+            transaction_id: #"0000000000000000000000000000000000000000000000000000000000000000",
+            output_index: 0,
+          },
+        ),
+        void(),
+      ),
+    ] == redeemers
+  Void
+}
+
+fn void() -> Data {
+  let void: Data = Void
+  void
+}