Fix opaque type destructuring in code gen

examples/acceptance_tests/097/aiken.lock

@@ -0,0 +1,7 @@
+# This file was generated by Aiken
+# You typically do not need to edit this file
+
+requirements = []
+packages = []
+
+[etags]

examples/acceptance_tests/097/aiken.toml

@@ -0,0 +1,3 @@
+name = "aiken-lang/acceptance_test_097"
+version = "0.0.0"
+description = ""

examples/acceptance_tests/097/lib/foo.ak

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+pub opaque type Dict<a, b> {
+  inner: List<(a, b)>,
+}
+
+pub opaque type Value {
+  inner: Dict<ByteArray, Dict<ByteArray, Int>>,
+}
+
+fn to_dict(v: Value) {
+  v.inner
+}
+
+fn to_list(d: Dict<a, b>) {
+  d.inner
+}
+
+test opaque_destructure() {
+  let x = Value { inner: Dict { inner: [(#"", Dict { inner: [("ab", 3)] })] } }
+
+  expect [(policy_a, Dict{inner: [(asset_name_a, quantity_a), ..]}), ..] =
+    x |> to_dict() |> to_list()
+
+  quantity_a > 2
+}