From fc8becc431b22e3545812cfaa01a994f2500dcdd Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Mon, 15 Jan 2024 19:54:40 +0000
Subject: [PATCH 01/14] feat: Implicit local modules in @guppy

Tentatively adds a `compiled` option for directly generating a Hugr.
---
 guppy/decorator.py                  | 123 +++++++++++++++++++++++-----
 guppy/error.py                      |   4 +-
 poetry.lock                         |  36 ++++----
 tests/integration/test_decorator.py |  43 ++++++++++
 4 files changed, 165 insertions(+), 41 deletions(-)
 create mode 100644 tests/integration/test_decorator.py

diff --git a/guppy/decorator.py b/guppy/decorator.py
index d4518f7b..a2ef1dac 100644
--- a/guppy/decorator.py
+++ b/guppy/decorator.py
@@ -1,6 +1,8 @@
 import functools
+import inspect
 from collections.abc import Callable, Iterator, Sequence
 from dataclasses import dataclass
+from pathlib import Path
 from typing import Any, ClassVar, TypeVar
 
 from guppy.ast_util import AstNode, has_empty_body
@@ -23,44 +25,104 @@
 ClassDecorator = Callable[[type], type]
 
 
+@dataclass
+class CallerIdentifier:
+    """Identifier for the interpreter frame that called the decorator."""
+
+    filename: Path
+    function: str
+
+    @property
+    def name(self) -> str:
+        """Returns a user-friendly name for the caller.
+
+        If the called is not a function, uses the file name.
+        """
+        if self.function == "<module>":
+            return self.filename.name
+        return self.function
+
+    def __hash__(self) -> int:
+        return hash((self.filename, self.function))
+
+
 class _Guppy:
     """Class for the `@guppy` decorator."""
 
-    # The current module
-    _module: GuppyModule | None
+    # The currently-alive modules, associated with an element in the call stack.
+    _modules: dict[CallerIdentifier, GuppyModule]
 
     def __init__(self) -> None:
-        self._module = None
-
-    def set_module(self, module: GuppyModule) -> None:
-        self._module = module
+        self._modules = {}
 
     @pretty_errors
-    def __call__(self, arg: PyFunc | GuppyModule) -> Hugr | None | FuncDecorator:
+    def __call__(
+        self, arg: PyFunc | GuppyModule | None = None, *, compile: bool = False
+    ) -> Hugr | None | FuncDecorator:
         """Decorator to annotate Python functions as Guppy code.
 
-        Optionally, the `GuppyModule` in which the function should be placed can be
-        passed to the decorator.
+        Optionally, the `GuppyModule` in which the function should be placed can
+        be passed to the decorator.
+
+        If `compile` is set to `True` and no `GuppyModule` is passed, the
+        function is compiled immediately as an standalone module and the Hugr is
+        returned.
         """
+        if arg is not None and not isinstance(arg, GuppyModule):
+            # Decorator used without any arguments.
+            f = arg
+            return self.__call__(None)(f)
+
+        def make_dummy(wraps: PyFunc) -> Callable[..., Any]:
+            @functools.wraps(wraps)
+            def dummy(*args: Any, **kwargs: Any) -> Any:
+                raise GuppyError(
+                    "Guppy functions can only be called in a Guppy context"
+                )
+
+            return dummy
+
+        if arg is None and compile:
+            # No module passed, and compile option is set.
+            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
+                module = GuppyModule("module")
+                module.register_func_def(f)
+                return module.compile()
+
+            return dec
+
+        if arg is None and not compile:
+            # No module specified, and `compile` option is not set.
+            # We use a module associate with the caller of the decorator.
+            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
+                caller = self._get_python_caller()
+                if caller not in self._modules:
+                    self._modules[caller] = GuppyModule(caller.name)
+                module = self._modules[caller]
+                module.register_func_def(f)
+                return make_dummy(f)
+
+            return dec
+
         if isinstance(arg, GuppyModule):
+            # Module passed. Ignore `compile` option.
 
             def dec(f: Callable[..., Any]) -> Callable[..., Any]:
-                assert isinstance(arg, GuppyModule)
                 arg.register_func_def(f)
+                return make_dummy(f)
 
-                @functools.wraps(f)
-                def dummy(*args: Any, **kwargs: Any) -> Any:
-                    raise GuppyError(
-                        "Guppy functions can only be called in a Guppy context"
-                    )
+            return dec
 
-                return dummy
+        raise ValueError(f"Invalid arguments to `@guppy` decorator: {arg}")
 
-            return dec
-        else:
-            module = self._module or GuppyModule("module")
-            module.register_func_def(arg)
-            return module.compile()
+    def _get_python_caller(self) -> CallerIdentifier:
+        """Returns an identifier for the interpreter frame that called the decorator."""
+        for s in inspect.stack():
+            # Note the hacky check for the pretty errors wrapper,
+            # since @pretty_errors wraps the __call__ method.
+            if s.filename != __file__ and s.function != "pretty_errors_wrapped":
+                return CallerIdentifier(Path(s.filename), s.function)
+        raise GuppyError("Could not find caller of `@guppy` decorator")
 
     @pretty_errors
     def extend_type(self, module: GuppyModule, ty: type[GuppyType]) -> ClassDecorator:
@@ -204,5 +266,24 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
         return dec
 
+    def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule | None:
+        """Returns the local GuppyModule, removing it from the local state."""
+        if id is None:
+            id = self._get_python_caller()
+        if id not in self._modules:
+            return None
+        module = self._modules[id]
+        del self._modules[id]
+        return module
+
+    def compile(self, id: CallerIdentifier | None = None) -> Hugr | None:
+        """Compiles the local module into a Hugr."""
+        module = self.take_module(id)
+        return module.compile() if module else None
+
+    def registered_modules(self) -> list[CallerIdentifier]:
+        """Returns a list of all currently registered modules for local contexts."""
+        return list(self._modules.keys())
+
 
 guppy = _Guppy()
diff --git a/guppy/error.py b/guppy/error.py
index 14bb5813..3a0b4a94 100644
--- a/guppy/error.py
+++ b/guppy/error.py
@@ -166,7 +166,7 @@ def pretty_errors(f: FuncT) -> FuncT:
     """Decorator to print custom error banners when a `GuppyError` occurs."""
 
     @functools.wraps(f)
-    def wrapped(*args: Any, **kwargs: Any) -> Any:
+    def pretty_errors_wrapped(*args: Any, **kwargs: Any) -> Any:
         try:
             return f(*args, **kwargs)
         except GuppyError as err:
@@ -188,4 +188,4 @@ def wrapped(*args: Any, **kwargs: Any) -> Any:
                 sys.exit(1)
             return None
 
-    return cast(FuncT, wrapped)
+    return cast(FuncT, pretty_errors_wrapped)
diff --git a/poetry.lock b/poetry.lock
index 7616bebb..3fe7ff53 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -542,28 +542,28 @@ files = [
 
 [[package]]
 name = "ruff"
-version = "0.1.12"
+version = "0.1.13"
 description = "An extremely fast Python linter and code formatter, written in Rust."
 optional = false
 python-versions = ">=3.7"
 files = [
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-    {file = "ruff-0.1.12-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:8a0e3ef6299c4eab75a7740730e4b4bd4a36e0bd8102ded01553403cad088fd4"},
-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:47f6d939461e3273f10f4cd059fd0b83c249d73f1736032fffbac83a62939395"},
-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:25be18abc1fc3f3d3fb55855c41ed5d52063316defde202f413493bb3888218c"},
-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:d41e9f100b50526d80b076fc9c103c729387ff3f10f63606ed1038c30a372a40"},
-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_ppc64.manylinux2014_ppc64.whl", hash = "sha256:472a0548738d4711549c7874b43fab61aacafb1fede29c5232d4cfb8e2d13f69"},
-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:46685ef2f106b827705df876d38617741ed4f858bbdbc0817f94476c45ab6669"},
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-    {file = "ruff-0.1.12-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:4bdf26e5a2efab4c3aaf6b61648ea47a525dc12775810a85c285dc9ca03e5ac0"},
-    {file = "ruff-0.1.12-py3-none-musllinux_1_2_aarch64.whl", hash = "sha256:b631c6a95e4b6d5c4299e599067b5a89f5b18e2f2d9a6c22b879b3c4b077c96e"},
-    {file = "ruff-0.1.12-py3-none-musllinux_1_2_armv7l.whl", hash = "sha256:f193f460e231e63af5fc7516897cf5ab257cbda72ae83cf9a654f1c80c3b758a"},
-    {file = "ruff-0.1.12-py3-none-musllinux_1_2_i686.whl", hash = "sha256:718523c3a0b787590511f212d30cc9b194228ef369c8bdd72acd1282cc27c468"},
-    {file = "ruff-0.1.12-py3-none-musllinux_1_2_x86_64.whl", hash = "sha256:1c49e826de55d81a6ef93808b760925e492bad7cc470aaa114a3be158b2c7f99"},
-    {file = "ruff-0.1.12-py3-none-win32.whl", hash = "sha256:fbb1c002eeacb60161e51d77b2274c968656599477a1c8c65066953276e8ee2b"},
-    {file = "ruff-0.1.12-py3-none-win_amd64.whl", hash = "sha256:7fe06ba77e5b7b78db1d058478c47176810f69bb5be7c1b0d06876af59198203"},
-    {file = "ruff-0.1.12-py3-none-win_arm64.whl", hash = "sha256:bb29f8e3e6c95024902eaec5a9ce1fd5ac4e77f4594f4554e67fbb0f6d9a2f37"},
-    {file = "ruff-0.1.12.tar.gz", hash = "sha256:97189f38c655e573f6bea0d12e9f18aad5539fd08ab50651449450999f45383a"},
+    {file = "ruff-0.1.13-py3-none-macosx_10_12_x86_64.macosx_11_0_arm64.macosx_10_12_universal2.whl", hash = "sha256:e3fd36e0d48aeac672aa850045e784673449ce619afc12823ea7868fcc41d8ba"},
+    {file = "ruff-0.1.13-py3-none-macosx_10_12_x86_64.whl", hash = "sha256:9fb6b3b86450d4ec6a6732f9f60c4406061b6851c4b29f944f8c9d91c3611c7a"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:b13ba5d7156daaf3fd08b6b993360a96060500aca7e307d95ecbc5bb47a69296"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_armv7l.manylinux2014_armv7l.whl", hash = "sha256:9ebb40442f7b531e136d334ef0851412410061e65d61ca8ce90d894a094feb22"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_i686.manylinux2014_i686.whl", hash = "sha256:226b517f42d59a543d6383cfe03cccf0091e3e0ed1b856c6824be03d2a75d3b6"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_ppc64.manylinux2014_ppc64.whl", hash = "sha256:5f0312ba1061e9b8c724e9a702d3c8621e3c6e6c2c9bd862550ab2951ac75c16"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_ppc64le.manylinux2014_ppc64le.whl", hash = "sha256:2f59bcf5217c661254bd6bc42d65a6fd1a8b80c48763cb5c2293295babd945dd"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_s390x.manylinux2014_s390x.whl", hash = "sha256:e6894b00495e00c27b6ba61af1fc666f17de6140345e5ef27dd6e08fb987259d"},
+    {file = "ruff-0.1.13-py3-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:9a1600942485c6e66119da294c6294856b5c86fd6df591ce293e4a4cc8e72989"},
+    {file = "ruff-0.1.13-py3-none-musllinux_1_2_aarch64.whl", hash = "sha256:ee3febce7863e231a467f90e681d3d89210b900d49ce88723ce052c8761be8c7"},
+    {file = "ruff-0.1.13-py3-none-musllinux_1_2_armv7l.whl", hash = "sha256:dcaab50e278ff497ee4d1fe69b29ca0a9a47cd954bb17963628fa417933c6eb1"},
+    {file = "ruff-0.1.13-py3-none-musllinux_1_2_i686.whl", hash = "sha256:f57de973de4edef3ad3044d6a50c02ad9fc2dff0d88587f25f1a48e3f72edf5e"},
+    {file = "ruff-0.1.13-py3-none-musllinux_1_2_x86_64.whl", hash = "sha256:7a36fa90eb12208272a858475ec43ac811ac37e91ef868759770b71bdabe27b6"},
+    {file = "ruff-0.1.13-py3-none-win32.whl", hash = "sha256:a623349a505ff768dad6bd57087e2461be8db58305ebd5577bd0e98631f9ae69"},
+    {file = "ruff-0.1.13-py3-none-win_amd64.whl", hash = "sha256:f988746e3c3982bea7f824c8fa318ce7f538c4dfefec99cd09c8770bd33e6539"},
+    {file = "ruff-0.1.13-py3-none-win_arm64.whl", hash = "sha256:6bbbc3042075871ec17f28864808540a26f0f79a4478c357d3e3d2284e832998"},
+    {file = "ruff-0.1.13.tar.gz", hash = "sha256:e261f1baed6291f434ffb1d5c6bd8051d1c2a26958072d38dfbec39b3dda7352"},
 ]
 
 [[package]]
diff --git a/tests/integration/test_decorator.py b/tests/integration/test_decorator.py
new file mode 100644
index 00000000..205c2fdc
--- /dev/null
+++ b/tests/integration/test_decorator.py
@@ -0,0 +1,43 @@
+from guppy.decorator import guppy
+from guppy.module import GuppyModule
+
+
+def test_decorator():
+    module = GuppyModule("test")
+
+    @guppy
+    def a() -> None:
+        pass
+
+    @guppy(module)
+    def b() -> None:
+        pass
+
+    @guppy
+    def c() -> None:
+        pass
+
+    default_module = guppy.take_module()
+
+    assert not module.contains_function("a")
+    assert module.contains_function("b")
+    assert not module.contains_function("c")
+
+    assert default_module.contains_function("a")
+    assert not default_module.contains_function("b")
+    assert default_module.contains_function("c")
+
+
+def test_nested():
+    def make_module() -> GuppyModule:
+        @guppy
+        def a() -> None:
+            pass
+
+        return guppy.take_module()
+
+    module_a = make_module()
+    module_b = make_module()
+
+    assert module_a.contains_function("a")
+    assert module_b.contains_function("a")

From ec1c4b829d05981eccbe943fd791874580edd2f6 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Mon, 15 Jan 2024 19:55:12 +0000
Subject: [PATCH 02/14] Use `@guppy(compiled=True)` in tests

---
 .../error/errors_on_usage/and_not_defined.py  |  2 +-
 .../errors_on_usage/else_expr_not_defined.py  |  2 +-
 .../errors_on_usage/else_expr_type_change.py  |  2 +-
 .../error/errors_on_usage/else_not_defined.py |  2 +-
 .../else_not_defined_functional.py            |  2 +-
 .../error/errors_on_usage/else_type_change.py |  2 +-
 .../else_type_change_functional.py            |  2 +-
 .../errors_on_usage/if_different_types.py     |  2 +-
 .../if_different_types_functional.py          |  2 +-
 .../if_expr_cond_type_change.py               |  2 +-
 .../errors_on_usage/if_expr_not_defined.py    |  2 +-
 .../errors_on_usage/if_expr_type_change.py    |  2 +-
 .../errors_on_usage/if_expr_type_conflict.err |  2 +-
 .../errors_on_usage/if_expr_type_conflict.py  |  2 +-
 tests/error/errors_on_usage/if_not_defined.py |  2 +-
 .../if_not_defined_functional.py              |  2 +-
 tests/error/errors_on_usage/if_type_change.py |  2 +-
 .../if_type_change_functional.py              |  2 +-
 tests/error/errors_on_usage/or_not_defined.py |  2 +-
 tests/error/errors_on_usage/while_new_var.py  |  2 +-
 .../while_new_var_functional.py               |  2 +-
 .../errors_on_usage/while_type_change.py      |  2 +-
 .../while_type_change_functional.py           |  2 +-
 tests/error/misc_errors/arg_not_annotated.err |  2 +-
 tests/error/misc_errors/arg_not_annotated.py  |  2 +-
 tests/error/misc_errors/functional_break.py   |  2 +-
 .../error/misc_errors/functional_continue.py  |  2 +-
 tests/error/misc_errors/functional_return.py  |  2 +-
 tests/error/misc_errors/nested_functional.py  |  2 +-
 tests/error/misc_errors/no_return.err         |  2 +-
 tests/error/misc_errors/no_return.py          |  2 +-
 .../misc_errors/return_not_annotated.err      |  2 +-
 .../error/misc_errors/return_not_annotated.py |  2 +-
 .../return_not_annotated_none1.err            |  2 +-
 .../misc_errors/return_not_annotated_none1.py |  2 +-
 .../return_not_annotated_none2.err            |  2 +-
 .../misc_errors/return_not_annotated_none2.py |  2 +-
 tests/error/misc_errors/undefined_var.err     |  2 +-
 tests/error/misc_errors/undefined_var.py      |  2 +-
 tests/error/misc_errors/unreachable_1.py      |  2 +-
 tests/error/misc_errors/unreachable_2.py      |  2 +-
 tests/error/misc_errors/unreachable_3.py      |  2 +-
 tests/error/misc_errors/unreachable_4.py      |  2 +-
 tests/error/misc_errors/unreachable_5.py      |  2 +-
 .../error/nested_errors/different_types_if.py |  2 +-
 tests/error/nested_errors/not_defined_if.py   |  2 +-
 .../error/nested_errors/reassign_capture_1.py |  2 +-
 .../error/nested_errors/reassign_capture_2.py |  2 +-
 .../error/nested_errors/reassign_capture_3.py |  2 +-
 tests/error/nested_errors/var_not_defined.py  |  2 +-
 tests/error/py_errors/guppy_name1.err         |  2 +-
 tests/error/py_errors/guppy_name1.py          |  2 +-
 tests/error/py_errors/guppy_name2.err         |  2 +-
 tests/error/py_errors/guppy_name2.py          |  2 +-
 tests/error/py_errors/no_args.err             |  2 +-
 tests/error/py_errors/no_args.py              |  2 +-
 tests/error/py_errors/python_err.err          |  2 +-
 tests/error/py_errors/python_err.py           |  2 +-
 tests/error/py_errors/unsupported.err         |  2 +-
 tests/error/py_errors/unsupported.py          |  2 +-
 .../type_errors/binary_not_arith_left.err     |  2 +-
 .../type_errors/binary_not_arith_left.py      |  2 +-
 .../type_errors/binary_not_arith_right.err    |  2 +-
 .../type_errors/binary_not_arith_right.py     |  2 +-
 tests/error/type_errors/call_missing_arg.err  |  2 +-
 tests/error/type_errors/call_missing_arg.py   |  2 +-
 tests/error/type_errors/call_not_function.err |  2 +-
 tests/error/type_errors/call_not_function.py  |  2 +-
 .../error/type_errors/call_unexpected_arg.err |  2 +-
 .../error/type_errors/call_unexpected_arg.py  |  2 +-
 tests/error/type_errors/call_wrong_arg.err    |  2 +-
 tests/error/type_errors/call_wrong_arg.py     |  2 +-
 tests/error/type_errors/fun_ty_mismatch_1.py  |  2 +-
 tests/error/type_errors/fun_ty_mismatch_2.py  |  2 +-
 tests/error/type_errors/fun_ty_mismatch_3.py  |  2 +-
 .../type_errors/if_not_bool_functional.py     |  2 +-
 tests/error/type_errors/invert_not_int.err    |  2 +-
 tests/error/type_errors/invert_not_int.py     |  2 +-
 tests/error/type_errors/return_mismatch.err   |  2 +-
 tests/error/type_errors/return_mismatch.py    |  2 +-
 tests/error/type_errors/unary_not_arith.err   |  2 +-
 tests/error/type_errors/unary_not_arith.py    |  2 +-
 tests/error/type_errors/unpack_not_enough.err |  2 +-
 tests/error/type_errors/unpack_not_enough.py  |  2 +-
 tests/error/type_errors/unpack_too_many.err   |  2 +-
 tests/error/type_errors/unpack_too_many.py    |  2 +-
 .../type_errors/while_not_bool_functional.py  |  2 +-
 tests/integration/test_arithmetic.py          | 18 ++++----
 tests/integration/test_basic.py               | 16 +++----
 tests/integration/test_call.py                |  2 +-
 tests/integration/test_functional.py          | 14 +++---
 tests/integration/test_higher_order.py        |  2 +-
 tests/integration/test_if.py                  | 44 +++++++++----------
 tests/integration/test_nested.py              | 28 ++++++------
 tests/integration/test_programs.py            |  6 +--
 tests/integration/test_py.py                  | 12 ++---
 tests/integration/test_unused.py              | 16 +++----
 tests/integration/test_while.py               | 14 +++---
 98 files changed, 173 insertions(+), 173 deletions(-)

diff --git a/tests/error/errors_on_usage/and_not_defined.py b/tests/error/errors_on_usage/and_not_defined.py
index 0f29fa58..eb77665d 100644
--- a/tests/error/errors_on_usage/and_not_defined.py
+++ b/tests/error/errors_on_usage/and_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool, y: int) -> int:
     if x and (z := y + 1):
         return z
diff --git a/tests/error/errors_on_usage/else_expr_not_defined.py b/tests/error/errors_on_usage/else_expr_not_defined.py
index 04aec300..ca3e127f 100644
--- a/tests/error/errors_on_usage/else_expr_not_defined.py
+++ b/tests/error/errors_on_usage/else_expr_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     (y := 1) if x else (z := 2)
     return z
diff --git a/tests/error/errors_on_usage/else_expr_type_change.py b/tests/error/errors_on_usage/else_expr_type_change.py
index 0f77ff1e..ae5a3aaf 100644
--- a/tests/error/errors_on_usage/else_expr_type_change.py
+++ b/tests/error/errors_on_usage/else_expr_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 3
     (y := y + 1) if x else (y := True)
diff --git a/tests/error/errors_on_usage/else_not_defined.py b/tests/error/errors_on_usage/else_not_defined.py
index a86d6cec..67f8f218 100644
--- a/tests/error/errors_on_usage/else_not_defined.py
+++ b/tests/error/errors_on_usage/else_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/else_not_defined_functional.py b/tests/error/errors_on_usage/else_not_defined_functional.py
index eac88f1b..75b24abb 100644
--- a/tests/error/errors_on_usage/else_not_defined_functional.py
+++ b/tests/error/errors_on_usage/else_not_defined_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/else_type_change.py b/tests/error/errors_on_usage/else_type_change.py
index ac3638a5..bb47734f 100644
--- a/tests/error/errors_on_usage/else_type_change.py
+++ b/tests/error/errors_on_usage/else_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 3
     if x:
diff --git a/tests/error/errors_on_usage/else_type_change_functional.py b/tests/error/errors_on_usage/else_type_change_functional.py
index 34a7a61d..328bf85f 100644
--- a/tests/error/errors_on_usage/else_type_change_functional.py
+++ b/tests/error/errors_on_usage/else_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 3
     _@functional
diff --git a/tests/error/errors_on_usage/if_different_types.py b/tests/error/errors_on_usage/if_different_types.py
index 5a871696..465f868b 100644
--- a/tests/error/errors_on_usage/if_different_types.py
+++ b/tests/error/errors_on_usage/if_different_types.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/if_different_types_functional.py b/tests/error/errors_on_usage/if_different_types_functional.py
index efe65c51..0f3c2073 100644
--- a/tests/error/errors_on_usage/if_different_types_functional.py
+++ b/tests/error/errors_on_usage/if_different_types_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/if_expr_cond_type_change.py b/tests/error/errors_on_usage/if_expr_cond_type_change.py
index 46af4085..38c14b7c 100644
--- a/tests/error/errors_on_usage/if_expr_cond_type_change.py
+++ b/tests/error/errors_on_usage/if_expr_cond_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 4
     0 if (y := x) else (y := 6)
diff --git a/tests/error/errors_on_usage/if_expr_not_defined.py b/tests/error/errors_on_usage/if_expr_not_defined.py
index b8b7f21f..270b4e6f 100644
--- a/tests/error/errors_on_usage/if_expr_not_defined.py
+++ b/tests/error/errors_on_usage/if_expr_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     (y := 1) if x else 0
     return y
diff --git a/tests/error/errors_on_usage/if_expr_type_change.py b/tests/error/errors_on_usage/if_expr_type_change.py
index 96e57658..37d26863 100644
--- a/tests/error/errors_on_usage/if_expr_type_change.py
+++ b/tests/error/errors_on_usage/if_expr_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool, a: int) -> int:
     y = 3
     (y := False) if x or a > 5 else 0
diff --git a/tests/error/errors_on_usage/if_expr_type_conflict.err b/tests/error/errors_on_usage/if_expr_type_conflict.err
index 3a1efcbb..98b2f422 100644
--- a/tests/error/errors_on_usage/if_expr_type_conflict.err
+++ b/tests/error/errors_on_usage/if_expr_type_conflict.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: bool) -> None:
 6:        y = True if x else 42
               ^^^^^^^^^^^^^^^^^
diff --git a/tests/error/errors_on_usage/if_expr_type_conflict.py b/tests/error/errors_on_usage/if_expr_type_conflict.py
index f2e921da..bd9eaa1d 100644
--- a/tests/error/errors_on_usage/if_expr_type_conflict.py
+++ b/tests/error/errors_on_usage/if_expr_type_conflict.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> None:
     y = True if x else 42
diff --git a/tests/error/errors_on_usage/if_not_defined.py b/tests/error/errors_on_usage/if_not_defined.py
index f613e168..6b6b6c22 100644
--- a/tests/error/errors_on_usage/if_not_defined.py
+++ b/tests/error/errors_on_usage/if_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/if_not_defined_functional.py b/tests/error/errors_on_usage/if_not_defined_functional.py
index 47aff403..7fd9e282 100644
--- a/tests/error/errors_on_usage/if_not_defined_functional.py
+++ b/tests/error/errors_on_usage/if_not_defined_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/if_type_change.py b/tests/error/errors_on_usage/if_type_change.py
index 1e688b5b..ef46c4e0 100644
--- a/tests/error/errors_on_usage/if_type_change.py
+++ b/tests/error/errors_on_usage/if_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 3
     if x:
diff --git a/tests/error/errors_on_usage/if_type_change_functional.py b/tests/error/errors_on_usage/if_type_change_functional.py
index 58ed7baa..605f9871 100644
--- a/tests/error/errors_on_usage/if_type_change_functional.py
+++ b/tests/error/errors_on_usage/if_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 3
     _@functional
diff --git a/tests/error/errors_on_usage/or_not_defined.py b/tests/error/errors_on_usage/or_not_defined.py
index 2435f624..167055d9 100644
--- a/tests/error/errors_on_usage/or_not_defined.py
+++ b/tests/error/errors_on_usage/or_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool, y: int) -> int:
     if x or (z := y + 1):
         return z
diff --git a/tests/error/errors_on_usage/while_new_var.py b/tests/error/errors_on_usage/while_new_var.py
index 28a63a58..f3c07672 100644
--- a/tests/error/errors_on_usage/while_new_var.py
+++ b/tests/error/errors_on_usage/while_new_var.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     while x:
         y = 5
diff --git a/tests/error/errors_on_usage/while_new_var_functional.py b/tests/error/errors_on_usage/while_new_var_functional.py
index d596834c..25844bc7 100644
--- a/tests/error/errors_on_usage/while_new_var_functional.py
+++ b/tests/error/errors_on_usage/while_new_var_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/errors_on_usage/while_type_change.py b/tests/error/errors_on_usage/while_type_change.py
index c8e565b1..3ee10443 100644
--- a/tests/error/errors_on_usage/while_type_change.py
+++ b/tests/error/errors_on_usage/while_type_change.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 5
     while x:
diff --git a/tests/error/errors_on_usage/while_type_change_functional.py b/tests/error/errors_on_usage/while_type_change_functional.py
index 343e4433..9bca1833 100644
--- a/tests/error/errors_on_usage/while_type_change_functional.py
+++ b/tests/error/errors_on_usage/while_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     y = 5
     _@functional
diff --git a/tests/error/misc_errors/arg_not_annotated.err b/tests/error/misc_errors/arg_not_annotated.err
index a607dc9b..5b588fda 100644
--- a/tests/error/misc_errors/arg_not_annotated.err
+++ b/tests/error/misc_errors/arg_not_annotated.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy
+3:    @guppy(compile=True)
 4:    def foo(x: bool, y) -> int:
                        ^
 GuppyError: Argument type must be annotated
diff --git a/tests/error/misc_errors/arg_not_annotated.py b/tests/error/misc_errors/arg_not_annotated.py
index 503393af..88e2f420 100644
--- a/tests/error/misc_errors/arg_not_annotated.py
+++ b/tests/error/misc_errors/arg_not_annotated.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool, y) -> int:
     return y
diff --git a/tests/error/misc_errors/functional_break.py b/tests/error/misc_errors/functional_break.py
index 2b03e316..8ba01169 100644
--- a/tests/error/misc_errors/functional_break.py
+++ b/tests/error/misc_errors/functional_break.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/functional_continue.py b/tests/error/misc_errors/functional_continue.py
index eced5d96..acaea8de 100644
--- a/tests/error/misc_errors/functional_continue.py
+++ b/tests/error/misc_errors/functional_continue.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/functional_return.py b/tests/error/misc_errors/functional_return.py
index 1821020e..9125d489 100644
--- a/tests/error/misc_errors/functional_return.py
+++ b/tests/error/misc_errors/functional_return.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/nested_functional.py b/tests/error/misc_errors/nested_functional.py
index 7094903c..b47d11a2 100644
--- a/tests/error/misc_errors/nested_functional.py
+++ b/tests/error/misc_errors/nested_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/no_return.err b/tests/error/misc_errors/no_return.err
index 21a5858e..36693946 100644
--- a/tests/error/misc_errors/no_return.err
+++ b/tests/error/misc_errors/no_return.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        pass
           ^^^^
diff --git a/tests/error/misc_errors/no_return.py b/tests/error/misc_errors/no_return.py
index 3f70926a..5eac1ffc 100644
--- a/tests/error/misc_errors/no_return.py
+++ b/tests/error/misc_errors/no_return.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     pass
diff --git a/tests/error/misc_errors/return_not_annotated.err b/tests/error/misc_errors/return_not_annotated.err
index dcce68ed..35e9e27f 100644
--- a/tests/error/misc_errors/return_not_annotated.err
+++ b/tests/error/misc_errors/return_not_annotated.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy
+3:    @guppy(compile=True)
 4:    def foo(x: bool):
       ^^^^^^^^^^^^^^^^^
 GuppyError: Return type must be annotated
diff --git a/tests/error/misc_errors/return_not_annotated.py b/tests/error/misc_errors/return_not_annotated.py
index 43ce1a8c..25444a56 100644
--- a/tests/error/misc_errors/return_not_annotated.py
+++ b/tests/error/misc_errors/return_not_annotated.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool):
     return x
diff --git a/tests/error/misc_errors/return_not_annotated_none1.err b/tests/error/misc_errors/return_not_annotated_none1.err
index 58d79a43..fc8ab7e9 100644
--- a/tests/error/misc_errors/return_not_annotated_none1.err
+++ b/tests/error/misc_errors/return_not_annotated_none1.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy
+3:    @guppy(compile=True)
 4:    def foo():
       ^^^^^^^^^^
 GuppyError: Return type must be annotated. Try adding a `-> None` annotation.
diff --git a/tests/error/misc_errors/return_not_annotated_none1.py b/tests/error/misc_errors/return_not_annotated_none1.py
index b85e6de1..81d8f9cd 100644
--- a/tests/error/misc_errors/return_not_annotated_none1.py
+++ b/tests/error/misc_errors/return_not_annotated_none1.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo():
     return
diff --git a/tests/error/misc_errors/return_not_annotated_none2.err b/tests/error/misc_errors/return_not_annotated_none2.err
index 58d79a43..fc8ab7e9 100644
--- a/tests/error/misc_errors/return_not_annotated_none2.err
+++ b/tests/error/misc_errors/return_not_annotated_none2.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy
+3:    @guppy(compile=True)
 4:    def foo():
       ^^^^^^^^^^
 GuppyError: Return type must be annotated. Try adding a `-> None` annotation.
diff --git a/tests/error/misc_errors/return_not_annotated_none2.py b/tests/error/misc_errors/return_not_annotated_none2.py
index ffd09c8c..72528695 100644
--- a/tests/error/misc_errors/return_not_annotated_none2.py
+++ b/tests/error/misc_errors/return_not_annotated_none2.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo():
     def bar(x: int) -> int:
         return x
diff --git a/tests/error/misc_errors/undefined_var.err b/tests/error/misc_errors/undefined_var.err
index b405ba4a..12c99cfd 100644
--- a/tests/error/misc_errors/undefined_var.err
+++ b/tests/error/misc_errors/undefined_var.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return x
                  ^
diff --git a/tests/error/misc_errors/undefined_var.py b/tests/error/misc_errors/undefined_var.py
index 6ff8e942..ea6e45f4 100644
--- a/tests/error/misc_errors/undefined_var.py
+++ b/tests/error/misc_errors/undefined_var.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return x
diff --git a/tests/error/misc_errors/unreachable_1.py b/tests/error/misc_errors/unreachable_1.py
index bf4948e5..d19aa08d 100644
--- a/tests/error/misc_errors/unreachable_1.py
+++ b/tests/error/misc_errors/unreachable_1.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return 0
     x = 42
diff --git a/tests/error/misc_errors/unreachable_2.py b/tests/error/misc_errors/unreachable_2.py
index 1a9722fd..31edf016 100644
--- a/tests/error/misc_errors/unreachable_2.py
+++ b/tests/error/misc_errors/unreachable_2.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     if x:
         return 4
diff --git a/tests/error/misc_errors/unreachable_3.py b/tests/error/misc_errors/unreachable_3.py
index 9bf3265e..aab12fcf 100644
--- a/tests/error/misc_errors/unreachable_3.py
+++ b/tests/error/misc_errors/unreachable_3.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     while x:
         break
diff --git a/tests/error/misc_errors/unreachable_4.py b/tests/error/misc_errors/unreachable_4.py
index 076c4e68..d0735436 100644
--- a/tests/error/misc_errors/unreachable_4.py
+++ b/tests/error/misc_errors/unreachable_4.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     while x:
         continue
diff --git a/tests/error/misc_errors/unreachable_5.py b/tests/error/misc_errors/unreachable_5.py
index ba3e5740..c9faee15 100644
--- a/tests/error/misc_errors/unreachable_5.py
+++ b/tests/error/misc_errors/unreachable_5.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: bool) -> int:
     while x:
         return 42
diff --git a/tests/error/nested_errors/different_types_if.py b/tests/error/nested_errors/different_types_if.py
index 7641d715..9068c0dd 100644
--- a/tests/error/nested_errors/different_types_if.py
+++ b/tests/error/nested_errors/different_types_if.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(b: bool) -> int:
     if b:
         def bar() -> int:
diff --git a/tests/error/nested_errors/not_defined_if.py b/tests/error/nested_errors/not_defined_if.py
index 40b0833d..6fb9d7a0 100644
--- a/tests/error/nested_errors/not_defined_if.py
+++ b/tests/error/nested_errors/not_defined_if.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(b: bool) -> int:
     if b:
         def bar() -> int:
diff --git a/tests/error/nested_errors/reassign_capture_1.py b/tests/error/nested_errors/reassign_capture_1.py
index 33151d92..d353e007 100644
--- a/tests/error/nested_errors/reassign_capture_1.py
+++ b/tests/error/nested_errors/reassign_capture_1.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/reassign_capture_2.py b/tests/error/nested_errors/reassign_capture_2.py
index 83769889..8f75b585 100644
--- a/tests/error/nested_errors/reassign_capture_2.py
+++ b/tests/error/nested_errors/reassign_capture_2.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/reassign_capture_3.py b/tests/error/nested_errors/reassign_capture_3.py
index b26fdd89..09ae0ed1 100644
--- a/tests/error/nested_errors/reassign_capture_3.py
+++ b/tests/error/nested_errors/reassign_capture_3.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/var_not_defined.py b/tests/error/nested_errors/var_not_defined.py
index 8d7abb7e..d991cc65 100644
--- a/tests/error/nested_errors/var_not_defined.py
+++ b/tests/error/nested_errors/var_not_defined.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     def bar() -> int:
         return x
diff --git a/tests/error/py_errors/guppy_name1.err b/tests/error/py_errors/guppy_name1.err
index f870fe12..2699fd77 100644
--- a/tests/error/py_errors/guppy_name1.err
+++ b/tests/error/py_errors/guppy_name1.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return py(x + 1)
                     ^
diff --git a/tests/error/py_errors/guppy_name1.py b/tests/error/py_errors/guppy_name1.py
index d1697d0a..13ef567c 100644
--- a/tests/error/py_errors/guppy_name1.py
+++ b/tests/error/py_errors/guppy_name1.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return py(x + 1)
diff --git a/tests/error/py_errors/guppy_name2.err b/tests/error/py_errors/guppy_name2.err
index fb0c8437..10dc8e38 100644
--- a/tests/error/py_errors/guppy_name2.err
+++ b/tests/error/py_errors/guppy_name2.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:9
 
-7:    @guppy
+7:    @guppy(compile=True)
 8:    def foo(x: int) -> int:
 9:        return py(x + 1)
                     ^
diff --git a/tests/error/py_errors/guppy_name2.py b/tests/error/py_errors/guppy_name2.py
index 44ca9852..7141a612 100644
--- a/tests/error/py_errors/guppy_name2.py
+++ b/tests/error/py_errors/guppy_name2.py
@@ -4,6 +4,6 @@
 x = 42
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return py(x + 1)
diff --git a/tests/error/py_errors/no_args.err b/tests/error/py_errors/no_args.err
index 5f8f43fb..28b70b9e 100644
--- a/tests/error/py_errors/no_args.err
+++ b/tests/error/py_errors/no_args.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return py()
                  ^^^^
diff --git a/tests/error/py_errors/no_args.py b/tests/error/py_errors/no_args.py
index 26bdda63..176fd688 100644
--- a/tests/error/py_errors/no_args.py
+++ b/tests/error/py_errors/no_args.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return py()
diff --git a/tests/error/py_errors/python_err.err b/tests/error/py_errors/python_err.err
index 9d4c1e70..85f2ff66 100644
--- a/tests/error/py_errors/python_err.err
+++ b/tests/error/py_errors/python_err.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return py(1 / 0)
                  ^^^^^^^^^
diff --git a/tests/error/py_errors/python_err.py b/tests/error/py_errors/python_err.py
index 803ec227..9fd5737f 100644
--- a/tests/error/py_errors/python_err.py
+++ b/tests/error/py_errors/python_err.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return py(1 / 0)
diff --git a/tests/error/py_errors/unsupported.err b/tests/error/py_errors/unsupported.err
index 22343611..d9310150 100644
--- a/tests/error/py_errors/unsupported.err
+++ b/tests/error/py_errors/unsupported.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return py({1, 2, 3})
                  ^^^^^^^^^^^^^
diff --git a/tests/error/py_errors/unsupported.py b/tests/error/py_errors/unsupported.py
index e238f300..68b1dd2b 100644
--- a/tests/error/py_errors/unsupported.py
+++ b/tests/error/py_errors/unsupported.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return py({1, 2, 3})
diff --git a/tests/error/type_errors/binary_not_arith_left.err b/tests/error/type_errors/binary_not_arith_left.err
index 4a532750..bbac107a 100644
--- a/tests/error/type_errors/binary_not_arith_left.err
+++ b/tests/error/type_errors/binary_not_arith_left.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return (1, 1) * 4
                  ^^^^^^^^^^
diff --git a/tests/error/type_errors/binary_not_arith_left.py b/tests/error/type_errors/binary_not_arith_left.py
index fd79799c..c9cda792 100644
--- a/tests/error/type_errors/binary_not_arith_left.py
+++ b/tests/error/type_errors/binary_not_arith_left.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return (1, 1) * 4
diff --git a/tests/error/type_errors/binary_not_arith_right.err b/tests/error/type_errors/binary_not_arith_right.err
index 0d9447c0..08ff77a7 100644
--- a/tests/error/type_errors/binary_not_arith_right.err
+++ b/tests/error/type_errors/binary_not_arith_right.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return x + True
                  ^^^^^^^^
diff --git a/tests/error/type_errors/binary_not_arith_right.py b/tests/error/type_errors/binary_not_arith_right.py
index 8240774c..d70b9424 100644
--- a/tests/error/type_errors/binary_not_arith_right.py
+++ b/tests/error/type_errors/binary_not_arith_right.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return x + True
diff --git a/tests/error/type_errors/call_missing_arg.err b/tests/error/type_errors/call_missing_arg.err
index 10ccaed5..7efbe771 100644
--- a/tests/error/type_errors/call_missing_arg.err
+++ b/tests/error/type_errors/call_missing_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return foo()
                  ^^^^^
diff --git a/tests/error/type_errors/call_missing_arg.py b/tests/error/type_errors/call_missing_arg.py
index 26160fbd..2aee1287 100644
--- a/tests/error/type_errors/call_missing_arg.py
+++ b/tests/error/type_errors/call_missing_arg.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return foo()
diff --git a/tests/error/type_errors/call_not_function.err b/tests/error/type_errors/call_not_function.err
index a2e5befb..e0a31066 100644
--- a/tests/error/type_errors/call_not_function.err
+++ b/tests/error/type_errors/call_not_function.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return x(42)
                  ^
diff --git a/tests/error/type_errors/call_not_function.py b/tests/error/type_errors/call_not_function.py
index 0dde7dc9..15b5ffe3 100644
--- a/tests/error/type_errors/call_not_function.py
+++ b/tests/error/type_errors/call_not_function.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return x(42)
diff --git a/tests/error/type_errors/call_unexpected_arg.err b/tests/error/type_errors/call_unexpected_arg.err
index c09395c5..38d4685e 100644
--- a/tests/error/type_errors/call_unexpected_arg.err
+++ b/tests/error/type_errors/call_unexpected_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return foo(x, x)
                         ^
diff --git a/tests/error/type_errors/call_unexpected_arg.py b/tests/error/type_errors/call_unexpected_arg.py
index 0d1f7975..5b87f4a6 100644
--- a/tests/error/type_errors/call_unexpected_arg.py
+++ b/tests/error/type_errors/call_unexpected_arg.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return foo(x, x)
diff --git a/tests/error/type_errors/call_wrong_arg.err b/tests/error/type_errors/call_wrong_arg.err
index 94daf5dc..30a2f122 100644
--- a/tests/error/type_errors/call_wrong_arg.err
+++ b/tests/error/type_errors/call_wrong_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo(x: int) -> int:
 6:        return foo(True)
                      ^^^^
diff --git a/tests/error/type_errors/call_wrong_arg.py b/tests/error/type_errors/call_wrong_arg.py
index 78d37c70..1115b40a 100644
--- a/tests/error/type_errors/call_wrong_arg.py
+++ b/tests/error/type_errors/call_wrong_arg.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     return foo(True)
diff --git a/tests/error/type_errors/fun_ty_mismatch_1.py b/tests/error/type_errors/fun_ty_mismatch_1.py
index 69ba1cfc..fc933a1b 100644
--- a/tests/error/type_errors/fun_ty_mismatch_1.py
+++ b/tests/error/type_errors/fun_ty_mismatch_1.py
@@ -3,7 +3,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> Callable[[int], int]:
     def bar(x: int) -> bool:
         return x > 0
diff --git a/tests/error/type_errors/fun_ty_mismatch_2.py b/tests/error/type_errors/fun_ty_mismatch_2.py
index 602c00f6..9f32a6bc 100644
--- a/tests/error/type_errors/fun_ty_mismatch_2.py
+++ b/tests/error/type_errors/fun_ty_mismatch_2.py
@@ -3,7 +3,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     def bar(f: Callable[[], int]) -> int:
         return f()
diff --git a/tests/error/type_errors/fun_ty_mismatch_3.py b/tests/error/type_errors/fun_ty_mismatch_3.py
index bfe5b742..3b697f75 100644
--- a/tests/error/type_errors/fun_ty_mismatch_3.py
+++ b/tests/error/type_errors/fun_ty_mismatch_3.py
@@ -3,7 +3,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo(x: int) -> int:
     def bar(f: Callable[[int], bool]) -> bool:
         return f(42)
diff --git a/tests/error/type_errors/if_not_bool_functional.py b/tests/error/type_errors/if_not_bool_functional.py
index 09ecd285..581eec63 100644
--- a/tests/error/type_errors/if_not_bool_functional.py
+++ b/tests/error/type_errors/if_not_bool_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     _@functional
     if 42:
diff --git a/tests/error/type_errors/invert_not_int.err b/tests/error/type_errors/invert_not_int.err
index fa1d83a2..e3317d5c 100644
--- a/tests/error/type_errors/invert_not_int.err
+++ b/tests/error/type_errors/invert_not_int.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return ~True
                   ^^^^
diff --git a/tests/error/type_errors/invert_not_int.py b/tests/error/type_errors/invert_not_int.py
index c18fd4e1..41d6f27f 100644
--- a/tests/error/type_errors/invert_not_int.py
+++ b/tests/error/type_errors/invert_not_int.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return ~True
diff --git a/tests/error/type_errors/return_mismatch.err b/tests/error/type_errors/return_mismatch.err
index a59582be..0f6dfa97 100644
--- a/tests/error/type_errors/return_mismatch.err
+++ b/tests/error/type_errors/return_mismatch.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> bool:
 6:        return 42
                  ^^
diff --git a/tests/error/type_errors/return_mismatch.py b/tests/error/type_errors/return_mismatch.py
index ca2fd8b5..7a517d61 100644
--- a/tests/error/type_errors/return_mismatch.py
+++ b/tests/error/type_errors/return_mismatch.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> bool:
     return 42
diff --git a/tests/error/type_errors/unary_not_arith.err b/tests/error/type_errors/unary_not_arith.err
index 5baf6757..f7c7daa7 100644
--- a/tests/error/type_errors/unary_not_arith.err
+++ b/tests/error/type_errors/unary_not_arith.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        return -True
                   ^^^^
diff --git a/tests/error/type_errors/unary_not_arith.py b/tests/error/type_errors/unary_not_arith.py
index 81134390..b5682c03 100644
--- a/tests/error/type_errors/unary_not_arith.py
+++ b/tests/error/type_errors/unary_not_arith.py
@@ -1,6 +1,6 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     return -True
diff --git a/tests/error/type_errors/unpack_not_enough.err b/tests/error/type_errors/unpack_not_enough.err
index 9628fc53..a1330755 100644
--- a/tests/error/type_errors/unpack_not_enough.err
+++ b/tests/error/type_errors/unpack_not_enough.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        a, b, c = 1, True
           ^^^^^^^^^^^^^^^^^
diff --git a/tests/error/type_errors/unpack_not_enough.py b/tests/error/type_errors/unpack_not_enough.py
index c022b692..1ec5a423 100644
--- a/tests/error/type_errors/unpack_not_enough.py
+++ b/tests/error/type_errors/unpack_not_enough.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     a, b, c = 1, True
     return a
diff --git a/tests/error/type_errors/unpack_too_many.err b/tests/error/type_errors/unpack_too_many.err
index aee08762..9590a2f4 100644
--- a/tests/error/type_errors/unpack_too_many.err
+++ b/tests/error/type_errors/unpack_too_many.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @guppy(compile=True)
 5:    def foo() -> int:
 6:        a, b = 1, True, 3.0
           ^^^^^^^^^^^^^^^^^^^
diff --git a/tests/error/type_errors/unpack_too_many.py b/tests/error/type_errors/unpack_too_many.py
index 71946970..12d3b402 100644
--- a/tests/error/type_errors/unpack_too_many.py
+++ b/tests/error/type_errors/unpack_too_many.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     a, b = 1, True, 3.0
     return a
diff --git a/tests/error/type_errors/while_not_bool_functional.py b/tests/error/type_errors/while_not_bool_functional.py
index 53c53bf1..43e40a9a 100644
--- a/tests/error/type_errors/while_not_bool_functional.py
+++ b/tests/error/type_errors/while_not_bool_functional.py
@@ -1,7 +1,7 @@
 from guppy.decorator import guppy
 
 
-@guppy
+@guppy(compile=True)
 def foo() -> int:
     _@functional
     while 42:
diff --git a/tests/integration/test_arithmetic.py b/tests/integration/test_arithmetic.py
index c4112fd1..fcef4a06 100644
--- a/tests/integration/test_arithmetic.py
+++ b/tests/integration/test_arithmetic.py
@@ -2,7 +2,7 @@
 
 
 def test_arith_basic(validate):
-    @guppy
+    @guppy(compile=True)
     def add(x: int, y: int) -> int:
         return x + y
 
@@ -10,7 +10,7 @@ def add(x: int, y: int) -> int:
 
 
 def test_constant(validate):
-    @guppy
+    @guppy(compile=True)
     def const() -> float:
         return 42.0
 
@@ -18,7 +18,7 @@ def const() -> float:
 
 
 def test_aug_assign(validate):
-    @guppy
+    @guppy(compile=True)
     def add(x: int) -> int:
         x += 1
         return x
@@ -27,7 +27,7 @@ def add(x: int) -> int:
 
 
 def test_float_coercion(validate):
-    @guppy
+    @guppy(compile=True)
     def coerce(x: int, y: float) -> float:
         return x * y
 
@@ -35,7 +35,7 @@ def coerce(x: int, y: float) -> float:
 
 
 def test_arith_big(validate):
-    @guppy
+    @guppy(compile=True)
     def arith(x: int, y: float, z: int) -> bool:
         a = x // y + 3 * z
         b = -8 >= a > 5 or (x * y == 0 and a % 3 < x)
@@ -45,7 +45,7 @@ def arith(x: int, y: float, z: int) -> bool:
 
 
 def test_shortcircuit_assign1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> bool:
         if (z := x) and y > 0:
             return z
@@ -55,7 +55,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> bool:
         if y > 0 and (z := x):
             return z
@@ -65,7 +65,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign3(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> bool:
         if (z := x) or y > 0:
             return z
@@ -75,7 +75,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign4(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> bool:
         if y > 0 or (z := x):
             return False
diff --git a/tests/integration/test_basic.py b/tests/integration/test_basic.py
index 487f0197..a7cffc99 100644
--- a/tests/integration/test_basic.py
+++ b/tests/integration/test_basic.py
@@ -4,7 +4,7 @@
 
 
 def test_id(validate):
-    @guppy
+    @guppy(compile=True)
     def identity(x: int) -> int:
         return x
 
@@ -12,7 +12,7 @@ def identity(x: int) -> int:
 
 
 def test_void(validate):
-    @guppy
+    @guppy(compile=True)
     def void() -> None:
         return
 
@@ -20,7 +20,7 @@ def void() -> None:
 
 
 def test_copy(validate):
-    @guppy
+    @guppy(compile=True)
     def copy(x: int) -> (int, int):
         return x, x
 
@@ -28,7 +28,7 @@ def copy(x: int) -> (int, int):
 
 
 def test_discard(validate):
-    @guppy
+    @guppy(compile=True)
     def discard(x: int) -> None:
         return
 
@@ -36,7 +36,7 @@ def discard(x: int) -> None:
 
 
 def test_implicit_return(validate):
-    @guppy
+    @guppy(compile=True)
     def ret() -> None:
         pass
 
@@ -44,7 +44,7 @@ def ret() -> None:
 
 
 def test_assign(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> bool:
         y = x
         return y
@@ -53,7 +53,7 @@ def foo(x: bool) -> bool:
 
 
 def test_assign_expr(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> bool:
         (y := x)
         return y
@@ -62,7 +62,7 @@ def foo(x: bool) -> bool:
 
 
 def test_func_def_name():
-    @guppy
+    @guppy(compile=True)
     def func_name() -> None:
         return
 
diff --git a/tests/integration/test_call.py b/tests/integration/test_call.py
index 2cb7ec80..63cfc954 100644
--- a/tests/integration/test_call.py
+++ b/tests/integration/test_call.py
@@ -31,7 +31,7 @@ def bar(x: int) -> int:
 
 
 def test_recursion(validate):
-    @guppy
+    @guppy(compile=True)
     def main(x: int) -> int:
         return main(x)
 
diff --git a/tests/integration/test_functional.py b/tests/integration/test_functional.py
index ae61a30d..2955b897 100644
--- a/tests/integration/test_functional.py
+++ b/tests/integration/test_functional.py
@@ -6,7 +6,7 @@
 
 @pytest.mark.skip()
 def test_if_no_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -18,7 +18,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -32,7 +32,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_elif(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -46,7 +46,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_elif_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -62,7 +62,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_infinite_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         while True:
             pass
@@ -73,7 +73,7 @@ def foo() -> int:
 
 @pytest.mark.skip()
 def test_counting_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(i: int) -> int:
         while i > 0:
             i -= 1
@@ -84,7 +84,7 @@ def foo(i: int) -> int:
 
 @pytest.mark.skip()
 def test_nested_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int, y: int) -> int:
         p = 0
         _ @ functional
diff --git a/tests/integration/test_higher_order.py b/tests/integration/test_higher_order.py
index fd8856d8..80e2ead3 100644
--- a/tests/integration/test_higher_order.py
+++ b/tests/integration/test_higher_order.py
@@ -55,7 +55,7 @@ def baz(y: int) -> None:
 
 
 def test_nested(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> Callable[[int], bool]:
         def bar(y: int) -> bool:
             return x > y
diff --git a/tests/integration/test_if.py b/tests/integration/test_if.py
index ac4f5f10..69f6938b 100644
--- a/tests/integration/test_if.py
+++ b/tests/integration/test_if.py
@@ -4,7 +4,7 @@
 
 
 def test_if_no_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -14,7 +14,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -26,7 +26,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_elif(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -38,7 +38,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_elif_else(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -52,7 +52,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         return y + 1 if x else 42
 
@@ -60,7 +60,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr_nested(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         a = y + 1 if x else y * y if 0 < y <= 10 else 42
         b = a if a < 5 or (not x and -7 >= a > 42) else -a
@@ -70,7 +70,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr_tuple(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> (int, int, int):
         t = (y + 1 if x else 42), 8, (y * 2 if x else 64)
         return t
@@ -79,7 +79,7 @@ def foo(x: bool, y: int) -> (int, int, int):
 
 
 def test_if_expr_assign_both(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         (z := 5) if x else (z := 42)
         return z
@@ -88,7 +88,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_assign_cond(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> bool:
         return z if (z := x) else False
 
@@ -96,7 +96,7 @@ def foo(x: bool) -> bool:
 
 
 def test_if_expr_reassign(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         y = 5
         (y := 1) if x else 6
@@ -108,7 +108,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_reassign_cond(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         y = 5
         return y if (y := 42) > 5 else 64 if x else y
@@ -117,7 +117,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_double_type_change(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         y = 4
         (y := 1) if (y := x) else (y := 6)
@@ -127,7 +127,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_return(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             return y
@@ -138,7 +138,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_else_return(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 3
@@ -151,7 +151,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_both_return(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool, y: int) -> int:
         if x:
             y += 3
@@ -164,7 +164,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_nested_return(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int, y: int) -> int:
         if x > 5:
             if y == 4:
@@ -177,7 +177,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_return_defined1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int, y: int) -> int:
         if x > 5:
             return y
@@ -189,7 +189,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_return_defined2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         if x > 5:
             z = 45
@@ -201,7 +201,7 @@ def foo(x: int) -> int:
 
 
 def test_break_different_types1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -217,7 +217,7 @@ def foo(x: int) -> int:
 
 
 def test_break_different_types2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -234,7 +234,7 @@ def foo(x: int) -> int:
 
 @pytest.mark.skip("Known bug")
 def test_continue_different_types1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -251,7 +251,7 @@ def foo(x: int) -> int:
 
 @pytest.mark.skip("Known bug")
 def test_continue_different_types2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         z = 0
         while True:
diff --git a/tests/integration/test_nested.py b/tests/integration/test_nested.py
index 23698f59..fe0892e8 100644
--- a/tests/integration/test_nested.py
+++ b/tests/integration/test_nested.py
@@ -2,7 +2,7 @@
 
 
 def test_basic(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y
@@ -13,7 +13,7 @@ def bar(y: int) -> int:
 
 
 def test_call_twice(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y + 3
@@ -27,7 +27,7 @@ def bar(y: int) -> int:
 
 
 def test_redefine(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y + 3
@@ -44,7 +44,7 @@ def bar(y: int) -> int:
 
 
 def test_define_twice(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         if x == 0:
 
@@ -61,7 +61,7 @@ def bar(y: int) -> int:
 
 
 def test_nested_deep(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             def baz(z: int) -> int:
@@ -75,7 +75,7 @@ def baz(z: int) -> int:
 
 
 def test_recurse(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             if y == 0:
@@ -88,7 +88,7 @@ def bar(y: int) -> int:
 
 
 def test_capture_arg(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar() -> int:
             return 1 + x
@@ -99,7 +99,7 @@ def bar() -> int:
 
 
 def test_capture_assigned(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         y = x + 1
 
@@ -112,7 +112,7 @@ def bar() -> int:
 
 
 def test_capture_multiple(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         if x > 5:
             y = 3
@@ -130,7 +130,7 @@ def bar() -> int:
 
 
 def test_capture_cfg(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         a = x + 4
         if x > 5:
@@ -146,7 +146,7 @@ def bar() -> int:
 
 
 def test_capture_deep(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         a = x * 2
 
@@ -165,7 +165,7 @@ def baz(y: int) -> int:
 
 
 def test_capture_recurse(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int, z: int) -> int:
             if y == 0:
@@ -178,7 +178,7 @@ def bar(y: int, z: int) -> int:
 
 
 def test_capture_recurse_nested(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         def bar(y: int, z: int) -> int:
             if y == 0:
@@ -197,7 +197,7 @@ def baz() -> int:
 
 
 def test_capture_while(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int) -> int:
         a = 0
         while x > 0:
diff --git a/tests/integration/test_programs.py b/tests/integration/test_programs.py
index ee7c87cc..345c2d20 100644
--- a/tests/integration/test_programs.py
+++ b/tests/integration/test_programs.py
@@ -3,7 +3,7 @@
 
 
 def test_factorial(validate):
-    @guppy
+    @guppy(compile=True)
     def factorial1(x: int) -> int:
         acc = 1
         while x > 0:
@@ -11,13 +11,13 @@ def factorial1(x: int) -> int:
             x -= 1
         return acc
 
-    @guppy
+    @guppy(compile=True)
     def factorial2(x: int) -> int:
         if x == 0:
             return 1
         return factorial2(x - 1) * x
 
-    @guppy
+    @guppy(compile=True)
     def factorial3(x: int, acc: int) -> int:
         if x == 0:
             return acc
diff --git a/tests/integration/test_py.py b/tests/integration/test_py.py
index 2e896aee..ced0e07f 100644
--- a/tests/integration/test_py.py
+++ b/tests/integration/test_py.py
@@ -5,7 +5,7 @@
 def test_basic(validate):
     x = 42
 
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         return py(x + 1)
 
@@ -13,7 +13,7 @@ def foo() -> int:
 
 
 def test_builtin(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         return py(len({"a": 1337, "b": None}))
 
@@ -23,7 +23,7 @@ def foo() -> int:
 def test_if(validate):
     b = True
 
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         if py(b or 1 > 6):
             return 0
@@ -35,7 +35,7 @@ def foo() -> int:
 def test_redeclare_after(validate):
     x = 1
 
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         return py(x)
 
@@ -45,7 +45,7 @@ def foo() -> int:
 
 
 def test_tuple(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         x, y = py((1, False))
         return x
@@ -54,7 +54,7 @@ def foo() -> int:
 
 
 def test_tuple_implicit(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         x, y = py(1, False)
         return x
diff --git a/tests/integration/test_unused.py b/tests/integration/test_unused.py
index b8592bc4..a62a506e 100644
--- a/tests/integration/test_unused.py
+++ b/tests/integration/test_unused.py
@@ -4,7 +4,7 @@
 
 
 def test_not_always_defined1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         if x:
             z = 5
@@ -14,7 +14,7 @@ def foo(x: bool) -> int:
 
 
 def test_not_always_defined2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         if x:
             pass
@@ -26,7 +26,7 @@ def foo(x: bool) -> int:
 
 
 def test_not_always_defined3(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         if x:
             y = True
@@ -38,7 +38,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types1(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         if x:
             z = True
@@ -50,7 +50,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types2(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         z = False
         if x:
@@ -63,7 +63,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types3(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> int:
         z = False
         if x:
@@ -76,7 +76,7 @@ def foo(x: bool) -> int:
 
 
 def test_while_change_type(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> None:
         x = 42
         while True:
@@ -86,7 +86,7 @@ def foo() -> None:
 
 
 def test_if_expr_different_types(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: bool) -> None:
         5 if x else False
 
diff --git a/tests/integration/test_while.py b/tests/integration/test_while.py
index 28d20dc0..6a5ec06b 100644
--- a/tests/integration/test_while.py
+++ b/tests/integration/test_while.py
@@ -2,7 +2,7 @@
 
 
 def test_infinite_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo() -> int:
         while True:
             pass
@@ -12,7 +12,7 @@ def foo() -> int:
 
 
 def test_counting_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(i: int) -> int:
         while i > 0:
             i -= 1
@@ -22,7 +22,7 @@ def foo(i: int) -> int:
 
 
 def test_break(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(i: int) -> int:
         while True:
             if i == 0:
@@ -34,7 +34,7 @@ def foo(i: int) -> int:
 
 
 def test_continue(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(i: int) -> int:
         x = 42
         while True:
@@ -47,7 +47,7 @@ def foo(i: int) -> int:
 
 
 def test_return_in_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(i: int) -> int:
         x = 42
         while i > 0:
@@ -61,7 +61,7 @@ def foo(i: int) -> int:
 
 
 def test_nested_loop(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int, y: int) -> int:
         p = 0
         while x > 0:
@@ -77,7 +77,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_nested_loop_break_continue(validate):
-    @guppy
+    @guppy(compile=True)
     def foo(x: int, y: int) -> int:
         p = 0
         while x > 0:

From a40fed50c99f572a68a7e6f1aeafd65894bf4124 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Mon, 15 Jan 2024 20:14:59 +0000
Subject: [PATCH 03/14] fix mypy

---
 guppy/decorator.py | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/guppy/decorator.py b/guppy/decorator.py
index a2ef1dac..c38e0ae4 100644
--- a/guppy/decorator.py
+++ b/guppy/decorator.py
@@ -20,7 +20,7 @@
 from guppy.hugr.hugr import Hugr
 from guppy.module import GuppyModule, PyFunc, parse_py_func
 
-FuncDecorator = Callable[[PyFunc], PyFunc]
+FuncDecorator = Callable[[PyFunc], PyFunc | Hugr]
 CustomFuncDecorator = Callable[[PyFunc], CustomFunction]
 ClassDecorator = Callable[[type], type]
 
@@ -71,7 +71,8 @@ def __call__(
         if arg is not None and not isinstance(arg, GuppyModule):
             # Decorator used without any arguments.
             f = arg
-            return self.__call__(None)(f)
+            decorator: FuncDecorator = self.__call__(None)  # type: ignore[assignment]
+            return decorator(f)
 
         def make_dummy(wraps: PyFunc) -> Callable[..., Any]:
             @functools.wraps(wraps)
@@ -84,17 +85,19 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
         if arg is None and compile:
             # No module passed, and compile option is set.
-            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
+            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 module = GuppyModule("module")
                 module.register_func_def(f)
-                return module.compile()
+                compiled = module.compile()
+                assert compiled is not None
+                return compiled
 
             return dec
 
         if arg is None and not compile:
             # No module specified, and `compile` option is not set.
             # We use a module associate with the caller of the decorator.
-            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
+            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 caller = self._get_python_caller()
                 if caller not in self._modules:
                     self._modules[caller] = GuppyModule(caller.name)
@@ -107,7 +110,7 @@ def dec(f: Callable[..., Any]) -> Callable[..., Any]:
         if isinstance(arg, GuppyModule):
             # Module passed. Ignore `compile` option.
 
-            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
+            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 arg.register_func_def(f)
                 return make_dummy(f)
 

From 12ec3f98fbce748d53d083fc44b3051f740b78b1 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Tue, 16 Jan 2024 13:39:20 +0000
Subject: [PATCH 04/14] review comments

---
 guppy/decorator.py | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/guppy/decorator.py b/guppy/decorator.py
index c38e0ae4..b41f0a72 100644
--- a/guppy/decorator.py
+++ b/guppy/decorator.py
@@ -25,7 +25,7 @@
 ClassDecorator = Callable[[type], type]
 
 
-@dataclass
+@dataclass(frozen=True)
 class CallerIdentifier:
     """Identifier for the interpreter frame that called the decorator."""
 
@@ -38,18 +38,20 @@ def name(self) -> str:
 
         If the called is not a function, uses the file name.
         """
-        if self.function == "<module>":
-            return self.filename.name
-        return self.function
-
-    def __hash__(self) -> int:
-        return hash((self.filename, self.function))
+        module_name = inspect.getmodulename(self.filename)
+        if self.function != "<module>":
+            return self.function
+        if module_name is not None:
+            return module_name
+        return self.filename.name
 
 
 class _Guppy:
     """Class for the `@guppy` decorator."""
 
     # The currently-alive modules, associated with an element in the call stack.
+    #
+    # Only contains **uncompiled** modules.
     _modules: dict[CallerIdentifier, GuppyModule]
 
     def __init__(self) -> None:
@@ -275,9 +277,7 @@ def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule | None:
             id = self._get_python_caller()
         if id not in self._modules:
             return None
-        module = self._modules[id]
-        del self._modules[id]
-        return module
+        return self._modules.pop(id)
 
     def compile(self, id: CallerIdentifier | None = None) -> Hugr | None:
         """Compiles the local module into a Hugr."""

From 4e521411318f0e50606a4863800d4e29ae18e36a Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:10:31 +0000
Subject: [PATCH 05/14] Move `compile=True` decorator to a test util. Update
 tests

---
 guppylang/decorator.py                        | 31 +++----------
 guppylang/hugr/__init__.py                    |  5 ++
 .../illegal_short_circuit.err                 |  2 +-
 .../illegal_short_circuit.py                  |  4 +-
 .../comprehension_errors/illegal_ternary.err  |  2 +-
 .../comprehension_errors/illegal_ternary.py   |  4 +-
 .../comprehension_errors/illegal_walrus.err   |  2 +-
 .../comprehension_errors/illegal_walrus.py    |  4 +-
 .../error/errors_on_usage/and_not_defined.py  |  4 +-
 .../errors_on_usage/else_expr_not_defined.py  |  4 +-
 .../errors_on_usage/else_expr_type_change.py  |  4 +-
 .../error/errors_on_usage/else_not_defined.py |  4 +-
 .../else_not_defined_functional.py            |  2 +-
 .../error/errors_on_usage/else_type_change.py |  4 +-
 .../else_type_change_functional.py            |  2 +-
 tests/error/errors_on_usage/for_new_var.py    |  4 +-
 tests/error/errors_on_usage/for_target.py     |  4 +-
 .../errors_on_usage/for_target_type_change.py |  4 +-
 .../error/errors_on_usage/for_type_change.py  |  4 +-
 .../errors_on_usage/if_different_types.py     |  4 +-
 .../if_different_types_functional.py          |  2 +-
 .../if_expr_cond_type_change.py               |  4 +-
 .../errors_on_usage/if_expr_not_defined.py    |  4 +-
 .../errors_on_usage/if_expr_type_change.py    |  4 +-
 .../errors_on_usage/if_expr_type_conflict.err |  2 +-
 .../errors_on_usage/if_expr_type_conflict.py  |  4 +-
 tests/error/errors_on_usage/if_not_defined.py |  4 +-
 .../if_not_defined_functional.py              |  2 +-
 tests/error/errors_on_usage/if_type_change.py |  4 +-
 .../if_type_change_functional.py              |  2 +-
 tests/error/errors_on_usage/or_not_defined.py |  4 +-
 tests/error/errors_on_usage/while_new_var.py  |  4 +-
 .../while_new_var_functional.py               |  2 +-
 .../errors_on_usage/while_type_change.py      |  4 +-
 .../while_type_change_functional.py           |  2 +-
 tests/error/misc_errors/arg_not_annotated.err |  2 +-
 tests/error/misc_errors/arg_not_annotated.py  |  4 +-
 tests/error/misc_errors/functional_break.py   |  2 +-
 .../error/misc_errors/functional_continue.py  |  2 +-
 tests/error/misc_errors/functional_return.py  |  2 +-
 tests/error/misc_errors/nested_functional.py  |  2 +-
 tests/error/misc_errors/no_return.err         |  2 +-
 tests/error/misc_errors/no_return.py          |  4 +-
 .../misc_errors/return_not_annotated.err      |  2 +-
 .../error/misc_errors/return_not_annotated.py |  4 +-
 .../return_not_annotated_none1.err            |  2 +-
 .../misc_errors/return_not_annotated_none1.py |  4 +-
 .../return_not_annotated_none2.err            |  2 +-
 .../misc_errors/return_not_annotated_none2.py |  4 +-
 tests/error/misc_errors/undefined_var.err     |  2 +-
 tests/error/misc_errors/undefined_var.py      |  4 +-
 tests/error/misc_errors/unreachable_1.py      |  4 +-
 tests/error/misc_errors/unreachable_2.py      |  4 +-
 tests/error/misc_errors/unreachable_3.py      |  4 +-
 tests/error/misc_errors/unreachable_4.py      |  4 +-
 tests/error/misc_errors/unreachable_5.py      |  4 +-
 .../error/nested_errors/different_types_if.py |  4 +-
 tests/error/nested_errors/not_defined_if.py   |  4 +-
 .../error/nested_errors/reassign_capture_1.py |  4 +-
 .../error/nested_errors/reassign_capture_2.py |  4 +-
 .../error/nested_errors/reassign_capture_3.py |  4 +-
 tests/error/nested_errors/var_not_defined.py  |  4 +-
 tests/error/py_errors/guppy_name1.err         |  2 +-
 tests/error/py_errors/guppy_name1.py          |  4 +-
 tests/error/py_errors/guppy_name2.err         |  2 +-
 tests/error/py_errors/guppy_name2.py          |  4 +-
 tests/error/py_errors/no_args.err             |  2 +-
 tests/error/py_errors/no_args.py              |  4 +-
 tests/error/py_errors/python_err.err          |  2 +-
 tests/error/py_errors/python_err.py           |  4 +-
 tests/error/py_errors/unsupported.err         |  2 +-
 tests/error/py_errors/unsupported.py          |  4 +-
 .../type_errors/binary_not_arith_left.err     |  2 +-
 .../type_errors/binary_not_arith_left.py      |  4 +-
 .../type_errors/binary_not_arith_right.err    |  2 +-
 .../type_errors/binary_not_arith_right.py     |  4 +-
 tests/error/type_errors/call_missing_arg.err  |  2 +-
 tests/error/type_errors/call_missing_arg.py   |  4 +-
 tests/error/type_errors/call_not_function.err |  2 +-
 tests/error/type_errors/call_not_function.py  |  4 +-
 .../error/type_errors/call_unexpected_arg.err |  2 +-
 .../error/type_errors/call_unexpected_arg.py  |  4 +-
 tests/error/type_errors/call_wrong_arg.err    |  2 +-
 tests/error/type_errors/call_wrong_arg.py     |  4 +-
 tests/error/type_errors/fun_ty_mismatch_1.py  |  4 +-
 tests/error/type_errors/fun_ty_mismatch_2.py  |  4 +-
 tests/error/type_errors/fun_ty_mismatch_3.py  |  4 +-
 .../type_errors/if_not_bool_functional.py     |  2 +-
 tests/error/type_errors/invert_not_int.err    |  2 +-
 tests/error/type_errors/invert_not_int.py     |  4 +-
 tests/error/type_errors/return_mismatch.err   |  2 +-
 tests/error/type_errors/return_mismatch.py    |  4 +-
 tests/error/type_errors/unary_not_arith.err   |  2 +-
 tests/error/type_errors/unary_not_arith.py    |  4 +-
 tests/error/type_errors/unpack_not_enough.err |  2 +-
 tests/error/type_errors/unpack_not_enough.py  |  4 +-
 tests/error/type_errors/unpack_too_many.err   |  2 +-
 tests/error/type_errors/unpack_too_many.py    |  4 +-
 .../type_errors/while_not_bool_functional.py  |  2 +-
 tests/error/util.py                           |  2 +-
 tests/integration/test_arithmetic.py          | 20 ++++----
 tests/integration/test_basic.py               | 17 +++----
 tests/integration/test_call.py                |  3 +-
 tests/integration/test_comprehension.py       | 19 ++++----
 tests/integration/test_for.py                 | 21 +++++----
 tests/integration/test_functional.py          | 15 +++---
 tests/integration/test_higher_order.py        |  3 +-
 tests/integration/test_if.py                  | 46 +++++++++----------
 tests/integration/test_list.py                | 12 ++---
 tests/integration/test_nested.py              | 30 ++++++------
 tests/integration/test_programs.py            |  7 +--
 tests/integration/test_py.py                  | 13 +++---
 tests/integration/test_unused.py              | 17 +++----
 tests/integration/test_while.py               | 15 +++---
 tests/util.py                                 | 18 ++++++++
 115 files changed, 310 insertions(+), 294 deletions(-)
 create mode 100644 tests/util.py

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 143abfb2..f6ab2c7f 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -58,9 +58,7 @@ def __init__(self) -> None:
         self._modules = {}
 
     @pretty_errors
-    def __call__(
-        self, arg: PyFunc | GuppyModule | None = None, *, compile: bool = False
-    ) -> Hugr | None | FuncDecorator:
+    def __call__(self, arg: PyFunc | GuppyModule) -> None | FuncDecorator:
         """Decorator to annotate Python functions as Guppy code.
 
         Optionally, the `GuppyModule` in which the function should be placed can
@@ -70,11 +68,6 @@ def __call__(
         function is compiled immediately as an standalone module and the Hugr is
         returned.
         """
-        if arg is not None and not isinstance(arg, GuppyModule):
-            # Decorator used without any arguments.
-            f = arg
-            decorator: FuncDecorator = self.__call__(None)  # type: ignore[assignment]
-            return decorator(f)
 
         def make_dummy(wraps: PyFunc) -> Callable[..., Any]:
             @functools.wraps(wraps)
@@ -85,20 +78,11 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
             return dummy
 
-        if arg is None and compile:
-            # No module passed, and compile option is set.
-            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
-                module = GuppyModule("module")
-                module.register_func_def(f)
-                compiled = module.compile()
-                assert compiled is not None
-                return compiled
-
-            return dec
+        if not isinstance(arg, GuppyModule):
+            # Decorator used without any arguments.
+            # We default to a module associated with the caller of the decorator.
+            f = arg
 
-        if arg is None and not compile:
-            # No module specified, and `compile` option is not set.
-            # We use a module associate with the caller of the decorator.
             def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 caller = self._get_python_caller()
                 if caller not in self._modules:
@@ -107,11 +91,10 @@ def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 module.register_func_def(f)
                 return make_dummy(f)
 
-            return dec
+            return dec(f)
 
         if isinstance(arg, GuppyModule):
-            # Module passed. Ignore `compile` option.
-
+            # Module passed.
             def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
                 arg.register_func_def(f)
                 return make_dummy(f)
diff --git a/guppylang/hugr/__init__.py b/guppylang/hugr/__init__.py
index e69de29b..0f6535c5 100644
--- a/guppylang/hugr/__init__.py
+++ b/guppylang/hugr/__init__.py
@@ -0,0 +1,5 @@
+"""Python definitions for the Hierarchical Unified Graph Representation."""
+
+from .hugr import Hugr
+
+__all__ = ["Hugr"]
diff --git a/tests/error/comprehension_errors/illegal_short_circuit.err b/tests/error/comprehension_errors/illegal_short_circuit.err
index 6c8bfb78..d05dc6a8 100644
--- a/tests/error/comprehension_errors/illegal_short_circuit.err
+++ b/tests/error/comprehension_errors/illegal_short_circuit.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @compile_guppy
 5:    def foo(xs: list[int]) -> None:
 6:        [x for x in xs if x < 5 and x != 6]
                             ^^^^^^^^^^^^^^^^
diff --git a/tests/error/comprehension_errors/illegal_short_circuit.py b/tests/error/comprehension_errors/illegal_short_circuit.py
index f54d5209..103d72f5 100644
--- a/tests/error/comprehension_errors/illegal_short_circuit.py
+++ b/tests/error/comprehension_errors/illegal_short_circuit.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int]) -> None:
     [x for x in xs if x < 5 and x != 6]
diff --git a/tests/error/comprehension_errors/illegal_ternary.err b/tests/error/comprehension_errors/illegal_ternary.err
index b7e9e7a9..d99720ac 100644
--- a/tests/error/comprehension_errors/illegal_ternary.err
+++ b/tests/error/comprehension_errors/illegal_ternary.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @compile_guppy
 5:    def foo(xs: list[int], ys: list[int], b: bool) -> None:
 6:        [x for x in (xs if b else ys)]
                        ^^^^^^^^^^^^^^^
diff --git a/tests/error/comprehension_errors/illegal_ternary.py b/tests/error/comprehension_errors/illegal_ternary.py
index 7c1a7715..d3136514 100644
--- a/tests/error/comprehension_errors/illegal_ternary.py
+++ b/tests/error/comprehension_errors/illegal_ternary.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int], ys: list[int], b: bool) -> None:
     [x for x in (xs if b else ys)]
diff --git a/tests/error/comprehension_errors/illegal_walrus.err b/tests/error/comprehension_errors/illegal_walrus.err
index 2fbb77d7..4b19d4ba 100644
--- a/tests/error/comprehension_errors/illegal_walrus.err
+++ b/tests/error/comprehension_errors/illegal_walrus.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy
+4:    @compile_guppy
 5:    def foo(xs: list[int]) -> None:
 6:        [y := x for x in xs]
            ^^^^^^
diff --git a/tests/error/comprehension_errors/illegal_walrus.py b/tests/error/comprehension_errors/illegal_walrus.py
index cf252b96..ea168ab2 100644
--- a/tests/error/comprehension_errors/illegal_walrus.py
+++ b/tests/error/comprehension_errors/illegal_walrus.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int]) -> None:
     [y := x for x in xs]
diff --git a/tests/error/errors_on_usage/and_not_defined.py b/tests/error/errors_on_usage/and_not_defined.py
index 5fa5c9dc..ebe2a498 100644
--- a/tests/error/errors_on_usage/and_not_defined.py
+++ b/tests/error/errors_on_usage/and_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool, y: int) -> int:
     if x and (z := y + 1):
         return z
diff --git a/tests/error/errors_on_usage/else_expr_not_defined.py b/tests/error/errors_on_usage/else_expr_not_defined.py
index b3fb80d8..c348a85e 100644
--- a/tests/error/errors_on_usage/else_expr_not_defined.py
+++ b/tests/error/errors_on_usage/else_expr_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     (y := 1) if x else (z := 2)
     return z
diff --git a/tests/error/errors_on_usage/else_expr_type_change.py b/tests/error/errors_on_usage/else_expr_type_change.py
index ab03bff0..0c93cae7 100644
--- a/tests/error/errors_on_usage/else_expr_type_change.py
+++ b/tests/error/errors_on_usage/else_expr_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 3
     (y := y + 1) if x else (y := True)
diff --git a/tests/error/errors_on_usage/else_not_defined.py b/tests/error/errors_on_usage/else_not_defined.py
index de4e31d6..0c48ba75 100644
--- a/tests/error/errors_on_usage/else_not_defined.py
+++ b/tests/error/errors_on_usage/else_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/else_not_defined_functional.py b/tests/error/errors_on_usage/else_not_defined_functional.py
index 3f4a08dc..e3aae879 100644
--- a/tests/error/errors_on_usage/else_not_defined_functional.py
+++ b/tests/error/errors_on_usage/else_not_defined_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/else_type_change.py b/tests/error/errors_on_usage/else_type_change.py
index d506f4af..e1623f32 100644
--- a/tests/error/errors_on_usage/else_type_change.py
+++ b/tests/error/errors_on_usage/else_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 3
     if x:
diff --git a/tests/error/errors_on_usage/else_type_change_functional.py b/tests/error/errors_on_usage/else_type_change_functional.py
index 561225f1..5f96b5ca 100644
--- a/tests/error/errors_on_usage/else_type_change_functional.py
+++ b/tests/error/errors_on_usage/else_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 3
     _@functional
diff --git a/tests/error/errors_on_usage/for_new_var.py b/tests/error/errors_on_usage/for_new_var.py
index f3c29ab1..42d4d917 100644
--- a/tests/error/errors_on_usage/for_new_var.py
+++ b/tests/error/errors_on_usage/for_new_var.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int]) -> int:
     for _ in xs:
         y = 5
diff --git a/tests/error/errors_on_usage/for_target.py b/tests/error/errors_on_usage/for_target.py
index b2876dc2..cfca2ee1 100644
--- a/tests/error/errors_on_usage/for_target.py
+++ b/tests/error/errors_on_usage/for_target.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int]) -> int:
     for x in xs:
         pass
diff --git a/tests/error/errors_on_usage/for_target_type_change.py b/tests/error/errors_on_usage/for_target_type_change.py
index 4f5f3b08..90af80d6 100644
--- a/tests/error/errors_on_usage/for_target_type_change.py
+++ b/tests/error/errors_on_usage/for_target_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[bool]) -> int:
     x = 5
     for x in xs:
diff --git a/tests/error/errors_on_usage/for_type_change.py b/tests/error/errors_on_usage/for_type_change.py
index e4be618d..c12a5d59 100644
--- a/tests/error/errors_on_usage/for_type_change.py
+++ b/tests/error/errors_on_usage/for_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy
+@compile_guppy
 def foo(xs: list[int]) -> int:
     y = 5
     for x in xs:
diff --git a/tests/error/errors_on_usage/if_different_types.py b/tests/error/errors_on_usage/if_different_types.py
index 15a31700..4723e9d0 100644
--- a/tests/error/errors_on_usage/if_different_types.py
+++ b/tests/error/errors_on_usage/if_different_types.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/if_different_types_functional.py b/tests/error/errors_on_usage/if_different_types_functional.py
index 50e523a7..0b364870 100644
--- a/tests/error/errors_on_usage/if_different_types_functional.py
+++ b/tests/error/errors_on_usage/if_different_types_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/if_expr_cond_type_change.py b/tests/error/errors_on_usage/if_expr_cond_type_change.py
index 6d6102c4..809999a4 100644
--- a/tests/error/errors_on_usage/if_expr_cond_type_change.py
+++ b/tests/error/errors_on_usage/if_expr_cond_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 4
     0 if (y := x) else (y := 6)
diff --git a/tests/error/errors_on_usage/if_expr_not_defined.py b/tests/error/errors_on_usage/if_expr_not_defined.py
index 079b6937..570ef5a7 100644
--- a/tests/error/errors_on_usage/if_expr_not_defined.py
+++ b/tests/error/errors_on_usage/if_expr_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     (y := 1) if x else 0
     return y
diff --git a/tests/error/errors_on_usage/if_expr_type_change.py b/tests/error/errors_on_usage/if_expr_type_change.py
index afeff682..65b5132b 100644
--- a/tests/error/errors_on_usage/if_expr_type_change.py
+++ b/tests/error/errors_on_usage/if_expr_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool, a: int) -> int:
     y = 3
     (y := False) if x or a > 5 else 0
diff --git a/tests/error/errors_on_usage/if_expr_type_conflict.err b/tests/error/errors_on_usage/if_expr_type_conflict.err
index 98b2f422..239b9059 100644
--- a/tests/error/errors_on_usage/if_expr_type_conflict.err
+++ b/tests/error/errors_on_usage/if_expr_type_conflict.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: bool) -> None:
 6:        y = True if x else 42
               ^^^^^^^^^^^^^^^^^
diff --git a/tests/error/errors_on_usage/if_expr_type_conflict.py b/tests/error/errors_on_usage/if_expr_type_conflict.py
index 1b4d1a43..9dfec99a 100644
--- a/tests/error/errors_on_usage/if_expr_type_conflict.py
+++ b/tests/error/errors_on_usage/if_expr_type_conflict.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> None:
     y = True if x else 42
diff --git a/tests/error/errors_on_usage/if_not_defined.py b/tests/error/errors_on_usage/if_not_defined.py
index d30c958c..11dd7e99 100644
--- a/tests/error/errors_on_usage/if_not_defined.py
+++ b/tests/error/errors_on_usage/if_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     if x:
         y = 1
diff --git a/tests/error/errors_on_usage/if_not_defined_functional.py b/tests/error/errors_on_usage/if_not_defined_functional.py
index ad03eb70..a3ff1a46 100644
--- a/tests/error/errors_on_usage/if_not_defined_functional.py
+++ b/tests/error/errors_on_usage/if_not_defined_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     if x:
diff --git a/tests/error/errors_on_usage/if_type_change.py b/tests/error/errors_on_usage/if_type_change.py
index 43d92e22..9a1c8928 100644
--- a/tests/error/errors_on_usage/if_type_change.py
+++ b/tests/error/errors_on_usage/if_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 3
     if x:
diff --git a/tests/error/errors_on_usage/if_type_change_functional.py b/tests/error/errors_on_usage/if_type_change_functional.py
index 6bb2ee6e..9bb0a814 100644
--- a/tests/error/errors_on_usage/if_type_change_functional.py
+++ b/tests/error/errors_on_usage/if_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 3
     _@functional
diff --git a/tests/error/errors_on_usage/or_not_defined.py b/tests/error/errors_on_usage/or_not_defined.py
index 03a6c7b9..4e6d4283 100644
--- a/tests/error/errors_on_usage/or_not_defined.py
+++ b/tests/error/errors_on_usage/or_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool, y: int) -> int:
     if x or (z := y + 1):
         return z
diff --git a/tests/error/errors_on_usage/while_new_var.py b/tests/error/errors_on_usage/while_new_var.py
index 9e2096f7..1d230852 100644
--- a/tests/error/errors_on_usage/while_new_var.py
+++ b/tests/error/errors_on_usage/while_new_var.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     while x:
         y = 5
diff --git a/tests/error/errors_on_usage/while_new_var_functional.py b/tests/error/errors_on_usage/while_new_var_functional.py
index fff1d570..33604b36 100644
--- a/tests/error/errors_on_usage/while_new_var_functional.py
+++ b/tests/error/errors_on_usage/while_new_var_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/errors_on_usage/while_type_change.py b/tests/error/errors_on_usage/while_type_change.py
index 93a7dc26..4086422c 100644
--- a/tests/error/errors_on_usage/while_type_change.py
+++ b/tests/error/errors_on_usage/while_type_change.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 5
     while x:
diff --git a/tests/error/errors_on_usage/while_type_change_functional.py b/tests/error/errors_on_usage/while_type_change_functional.py
index 4450c8ad..fcc3c302 100644
--- a/tests/error/errors_on_usage/while_type_change_functional.py
+++ b/tests/error/errors_on_usage/while_type_change_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     y = 5
     _@functional
diff --git a/tests/error/misc_errors/arg_not_annotated.err b/tests/error/misc_errors/arg_not_annotated.err
index 5b588fda..0e680b48 100644
--- a/tests/error/misc_errors/arg_not_annotated.err
+++ b/tests/error/misc_errors/arg_not_annotated.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy(compile=True)
+3:    @compile_guppy
 4:    def foo(x: bool, y) -> int:
                        ^
 GuppyError: Argument type must be annotated
diff --git a/tests/error/misc_errors/arg_not_annotated.py b/tests/error/misc_errors/arg_not_annotated.py
index 3a099936..608a1c01 100644
--- a/tests/error/misc_errors/arg_not_annotated.py
+++ b/tests/error/misc_errors/arg_not_annotated.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool, y) -> int:
     return y
diff --git a/tests/error/misc_errors/functional_break.py b/tests/error/misc_errors/functional_break.py
index 93564ecf..3dd1b6d5 100644
--- a/tests/error/misc_errors/functional_break.py
+++ b/tests/error/misc_errors/functional_break.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/functional_continue.py b/tests/error/misc_errors/functional_continue.py
index 78f4c675..8e5f04d4 100644
--- a/tests/error/misc_errors/functional_continue.py
+++ b/tests/error/misc_errors/functional_continue.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/functional_return.py b/tests/error/misc_errors/functional_return.py
index d4b5da94..835a3afe 100644
--- a/tests/error/misc_errors/functional_return.py
+++ b/tests/error/misc_errors/functional_return.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/nested_functional.py b/tests/error/misc_errors/nested_functional.py
index 4399e488..0008dc0d 100644
--- a/tests/error/misc_errors/nested_functional.py
+++ b/tests/error/misc_errors/nested_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     _@functional
     while x:
diff --git a/tests/error/misc_errors/no_return.err b/tests/error/misc_errors/no_return.err
index 36693946..676e2bf1 100644
--- a/tests/error/misc_errors/no_return.err
+++ b/tests/error/misc_errors/no_return.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        pass
           ^^^^
diff --git a/tests/error/misc_errors/no_return.py b/tests/error/misc_errors/no_return.py
index e08cdacb..3c853d95 100644
--- a/tests/error/misc_errors/no_return.py
+++ b/tests/error/misc_errors/no_return.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     pass
diff --git a/tests/error/misc_errors/return_not_annotated.err b/tests/error/misc_errors/return_not_annotated.err
index 35e9e27f..e66c67e0 100644
--- a/tests/error/misc_errors/return_not_annotated.err
+++ b/tests/error/misc_errors/return_not_annotated.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy(compile=True)
+3:    @compile_guppy
 4:    def foo(x: bool):
       ^^^^^^^^^^^^^^^^^
 GuppyError: Return type must be annotated
diff --git a/tests/error/misc_errors/return_not_annotated.py b/tests/error/misc_errors/return_not_annotated.py
index e76085d8..fd0389f9 100644
--- a/tests/error/misc_errors/return_not_annotated.py
+++ b/tests/error/misc_errors/return_not_annotated.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool):
     return x
diff --git a/tests/error/misc_errors/return_not_annotated_none1.err b/tests/error/misc_errors/return_not_annotated_none1.err
index fc8ab7e9..2798749f 100644
--- a/tests/error/misc_errors/return_not_annotated_none1.err
+++ b/tests/error/misc_errors/return_not_annotated_none1.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy(compile=True)
+3:    @compile_guppy
 4:    def foo():
       ^^^^^^^^^^
 GuppyError: Return type must be annotated. Try adding a `-> None` annotation.
diff --git a/tests/error/misc_errors/return_not_annotated_none1.py b/tests/error/misc_errors/return_not_annotated_none1.py
index 74daa3ec..29f10063 100644
--- a/tests/error/misc_errors/return_not_annotated_none1.py
+++ b/tests/error/misc_errors/return_not_annotated_none1.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo():
     return
diff --git a/tests/error/misc_errors/return_not_annotated_none2.err b/tests/error/misc_errors/return_not_annotated_none2.err
index fc8ab7e9..2798749f 100644
--- a/tests/error/misc_errors/return_not_annotated_none2.err
+++ b/tests/error/misc_errors/return_not_annotated_none2.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:5
 
-3:    @guppy(compile=True)
+3:    @compile_guppy
 4:    def foo():
       ^^^^^^^^^^
 GuppyError: Return type must be annotated. Try adding a `-> None` annotation.
diff --git a/tests/error/misc_errors/return_not_annotated_none2.py b/tests/error/misc_errors/return_not_annotated_none2.py
index 51571cfe..861342b8 100644
--- a/tests/error/misc_errors/return_not_annotated_none2.py
+++ b/tests/error/misc_errors/return_not_annotated_none2.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo():
     def bar(x: int) -> int:
         return x
diff --git a/tests/error/misc_errors/undefined_var.err b/tests/error/misc_errors/undefined_var.err
index 12c99cfd..d5cf6925 100644
--- a/tests/error/misc_errors/undefined_var.err
+++ b/tests/error/misc_errors/undefined_var.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return x
                  ^
diff --git a/tests/error/misc_errors/undefined_var.py b/tests/error/misc_errors/undefined_var.py
index 46bfbb06..753bd4ed 100644
--- a/tests/error/misc_errors/undefined_var.py
+++ b/tests/error/misc_errors/undefined_var.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return x
diff --git a/tests/error/misc_errors/unreachable_1.py b/tests/error/misc_errors/unreachable_1.py
index 00653c9f..2a2c264b 100644
--- a/tests/error/misc_errors/unreachable_1.py
+++ b/tests/error/misc_errors/unreachable_1.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return 0
     x = 42
diff --git a/tests/error/misc_errors/unreachable_2.py b/tests/error/misc_errors/unreachable_2.py
index 9826262e..6a4a2750 100644
--- a/tests/error/misc_errors/unreachable_2.py
+++ b/tests/error/misc_errors/unreachable_2.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     if x:
         return 4
diff --git a/tests/error/misc_errors/unreachable_3.py b/tests/error/misc_errors/unreachable_3.py
index a2c50eef..f14290eb 100644
--- a/tests/error/misc_errors/unreachable_3.py
+++ b/tests/error/misc_errors/unreachable_3.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     while x:
         break
diff --git a/tests/error/misc_errors/unreachable_4.py b/tests/error/misc_errors/unreachable_4.py
index 0fb2f6e3..10b9fac3 100644
--- a/tests/error/misc_errors/unreachable_4.py
+++ b/tests/error/misc_errors/unreachable_4.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     while x:
         continue
diff --git a/tests/error/misc_errors/unreachable_5.py b/tests/error/misc_errors/unreachable_5.py
index 56e26d03..7875e472 100644
--- a/tests/error/misc_errors/unreachable_5.py
+++ b/tests/error/misc_errors/unreachable_5.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: bool) -> int:
     while x:
         return 42
diff --git a/tests/error/nested_errors/different_types_if.py b/tests/error/nested_errors/different_types_if.py
index c5e653df..2dcd722e 100644
--- a/tests/error/nested_errors/different_types_if.py
+++ b/tests/error/nested_errors/different_types_if.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(b: bool) -> int:
     if b:
         def bar() -> int:
diff --git a/tests/error/nested_errors/not_defined_if.py b/tests/error/nested_errors/not_defined_if.py
index 131dc577..fe9f9a4f 100644
--- a/tests/error/nested_errors/not_defined_if.py
+++ b/tests/error/nested_errors/not_defined_if.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(b: bool) -> int:
     if b:
         def bar() -> int:
diff --git a/tests/error/nested_errors/reassign_capture_1.py b/tests/error/nested_errors/reassign_capture_1.py
index 9a6bb21e..78d60ec2 100644
--- a/tests/error/nested_errors/reassign_capture_1.py
+++ b/tests/error/nested_errors/reassign_capture_1.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/reassign_capture_2.py b/tests/error/nested_errors/reassign_capture_2.py
index 9a05f977..70f83748 100644
--- a/tests/error/nested_errors/reassign_capture_2.py
+++ b/tests/error/nested_errors/reassign_capture_2.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/reassign_capture_3.py b/tests/error/nested_errors/reassign_capture_3.py
index 197ea695..0a597a42 100644
--- a/tests/error/nested_errors/reassign_capture_3.py
+++ b/tests/error/nested_errors/reassign_capture_3.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     y = x + 1
 
diff --git a/tests/error/nested_errors/var_not_defined.py b/tests/error/nested_errors/var_not_defined.py
index 48efc3ae..0fb7e3fb 100644
--- a/tests/error/nested_errors/var_not_defined.py
+++ b/tests/error/nested_errors/var_not_defined.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     def bar() -> int:
         return x
diff --git a/tests/error/py_errors/guppy_name1.err b/tests/error/py_errors/guppy_name1.err
index 2699fd77..1b8d8b62 100644
--- a/tests/error/py_errors/guppy_name1.err
+++ b/tests/error/py_errors/guppy_name1.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return py(x + 1)
                     ^
diff --git a/tests/error/py_errors/guppy_name1.py b/tests/error/py_errors/guppy_name1.py
index 13bd3ccd..87994b92 100644
--- a/tests/error/py_errors/guppy_name1.py
+++ b/tests/error/py_errors/guppy_name1.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return py(x + 1)
diff --git a/tests/error/py_errors/guppy_name2.err b/tests/error/py_errors/guppy_name2.err
index 10dc8e38..73d2d298 100644
--- a/tests/error/py_errors/guppy_name2.err
+++ b/tests/error/py_errors/guppy_name2.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:9
 
-7:    @guppy(compile=True)
+7:    @compile_guppy
 8:    def foo(x: int) -> int:
 9:        return py(x + 1)
                     ^
diff --git a/tests/error/py_errors/guppy_name2.py b/tests/error/py_errors/guppy_name2.py
index e1ffe9aa..6558c20f 100644
--- a/tests/error/py_errors/guppy_name2.py
+++ b/tests/error/py_errors/guppy_name2.py
@@ -1,9 +1,9 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 x = 42
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return py(x + 1)
diff --git a/tests/error/py_errors/no_args.err b/tests/error/py_errors/no_args.err
index 28b70b9e..7c30ee04 100644
--- a/tests/error/py_errors/no_args.err
+++ b/tests/error/py_errors/no_args.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return py()
                  ^^^^
diff --git a/tests/error/py_errors/no_args.py b/tests/error/py_errors/no_args.py
index 1e38fb5f..074479e8 100644
--- a/tests/error/py_errors/no_args.py
+++ b/tests/error/py_errors/no_args.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return py()
diff --git a/tests/error/py_errors/python_err.err b/tests/error/py_errors/python_err.err
index 85f2ff66..5d21c3e8 100644
--- a/tests/error/py_errors/python_err.err
+++ b/tests/error/py_errors/python_err.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return py(1 / 0)
                  ^^^^^^^^^
diff --git a/tests/error/py_errors/python_err.py b/tests/error/py_errors/python_err.py
index 42b631d3..68b874d3 100644
--- a/tests/error/py_errors/python_err.py
+++ b/tests/error/py_errors/python_err.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return py(1 / 0)
diff --git a/tests/error/py_errors/unsupported.err b/tests/error/py_errors/unsupported.err
index d9310150..4de7be8c 100644
--- a/tests/error/py_errors/unsupported.err
+++ b/tests/error/py_errors/unsupported.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return py({1, 2, 3})
                  ^^^^^^^^^^^^^
diff --git a/tests/error/py_errors/unsupported.py b/tests/error/py_errors/unsupported.py
index a7d9c918..08c0daeb 100644
--- a/tests/error/py_errors/unsupported.py
+++ b/tests/error/py_errors/unsupported.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return py({1, 2, 3})
diff --git a/tests/error/type_errors/binary_not_arith_left.err b/tests/error/type_errors/binary_not_arith_left.err
index bbac107a..36bb9a57 100644
--- a/tests/error/type_errors/binary_not_arith_left.err
+++ b/tests/error/type_errors/binary_not_arith_left.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return (1, 1) * 4
                  ^^^^^^^^^^
diff --git a/tests/error/type_errors/binary_not_arith_left.py b/tests/error/type_errors/binary_not_arith_left.py
index 8bc6761d..0fddfc17 100644
--- a/tests/error/type_errors/binary_not_arith_left.py
+++ b/tests/error/type_errors/binary_not_arith_left.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return (1, 1) * 4
diff --git a/tests/error/type_errors/binary_not_arith_right.err b/tests/error/type_errors/binary_not_arith_right.err
index 08ff77a7..7bd8ce2d 100644
--- a/tests/error/type_errors/binary_not_arith_right.err
+++ b/tests/error/type_errors/binary_not_arith_right.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return x + True
                  ^^^^^^^^
diff --git a/tests/error/type_errors/binary_not_arith_right.py b/tests/error/type_errors/binary_not_arith_right.py
index 5b07a409..7222dba3 100644
--- a/tests/error/type_errors/binary_not_arith_right.py
+++ b/tests/error/type_errors/binary_not_arith_right.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return x + True
diff --git a/tests/error/type_errors/call_missing_arg.err b/tests/error/type_errors/call_missing_arg.err
index 7efbe771..9562fd5a 100644
--- a/tests/error/type_errors/call_missing_arg.err
+++ b/tests/error/type_errors/call_missing_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return foo()
                  ^^^^^
diff --git a/tests/error/type_errors/call_missing_arg.py b/tests/error/type_errors/call_missing_arg.py
index 7cabd523..301afc4c 100644
--- a/tests/error/type_errors/call_missing_arg.py
+++ b/tests/error/type_errors/call_missing_arg.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return foo()
diff --git a/tests/error/type_errors/call_not_function.err b/tests/error/type_errors/call_not_function.err
index e0a31066..f04efe2b 100644
--- a/tests/error/type_errors/call_not_function.err
+++ b/tests/error/type_errors/call_not_function.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return x(42)
                  ^
diff --git a/tests/error/type_errors/call_not_function.py b/tests/error/type_errors/call_not_function.py
index 9cda081c..cb912bfe 100644
--- a/tests/error/type_errors/call_not_function.py
+++ b/tests/error/type_errors/call_not_function.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return x(42)
diff --git a/tests/error/type_errors/call_unexpected_arg.err b/tests/error/type_errors/call_unexpected_arg.err
index 38d4685e..8fe6436d 100644
--- a/tests/error/type_errors/call_unexpected_arg.err
+++ b/tests/error/type_errors/call_unexpected_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return foo(x, x)
                         ^
diff --git a/tests/error/type_errors/call_unexpected_arg.py b/tests/error/type_errors/call_unexpected_arg.py
index e2d0977a..99c901ff 100644
--- a/tests/error/type_errors/call_unexpected_arg.py
+++ b/tests/error/type_errors/call_unexpected_arg.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return foo(x, x)
diff --git a/tests/error/type_errors/call_wrong_arg.err b/tests/error/type_errors/call_wrong_arg.err
index 30a2f122..8642b137 100644
--- a/tests/error/type_errors/call_wrong_arg.err
+++ b/tests/error/type_errors/call_wrong_arg.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo(x: int) -> int:
 6:        return foo(True)
                      ^^^^
diff --git a/tests/error/type_errors/call_wrong_arg.py b/tests/error/type_errors/call_wrong_arg.py
index db8504bb..ab9b98ee 100644
--- a/tests/error/type_errors/call_wrong_arg.py
+++ b/tests/error/type_errors/call_wrong_arg.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     return foo(True)
diff --git a/tests/error/type_errors/fun_ty_mismatch_1.py b/tests/error/type_errors/fun_ty_mismatch_1.py
index cffa16bf..d7e956b8 100644
--- a/tests/error/type_errors/fun_ty_mismatch_1.py
+++ b/tests/error/type_errors/fun_ty_mismatch_1.py
@@ -1,9 +1,9 @@
 from collections.abc import Callable
 
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> Callable[[int], int]:
     def bar(x: int) -> bool:
         return x > 0
diff --git a/tests/error/type_errors/fun_ty_mismatch_2.py b/tests/error/type_errors/fun_ty_mismatch_2.py
index 35313a85..fc3af13e 100644
--- a/tests/error/type_errors/fun_ty_mismatch_2.py
+++ b/tests/error/type_errors/fun_ty_mismatch_2.py
@@ -1,9 +1,9 @@
 from collections.abc import Callable
 
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     def bar(f: Callable[[], int]) -> int:
         return f()
diff --git a/tests/error/type_errors/fun_ty_mismatch_3.py b/tests/error/type_errors/fun_ty_mismatch_3.py
index e6dd23a6..e9dc0b48 100644
--- a/tests/error/type_errors/fun_ty_mismatch_3.py
+++ b/tests/error/type_errors/fun_ty_mismatch_3.py
@@ -1,9 +1,9 @@
 from collections.abc import Callable
 
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo(x: int) -> int:
     def bar(f: Callable[[int], bool]) -> bool:
         return f(42)
diff --git a/tests/error/type_errors/if_not_bool_functional.py b/tests/error/type_errors/if_not_bool_functional.py
index bab50ace..0b240fab 100644
--- a/tests/error/type_errors/if_not_bool_functional.py
+++ b/tests/error/type_errors/if_not_bool_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     _@functional
     if 42:
diff --git a/tests/error/type_errors/invert_not_int.err b/tests/error/type_errors/invert_not_int.err
index e3317d5c..16524a1f 100644
--- a/tests/error/type_errors/invert_not_int.err
+++ b/tests/error/type_errors/invert_not_int.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return ~True
                   ^^^^
diff --git a/tests/error/type_errors/invert_not_int.py b/tests/error/type_errors/invert_not_int.py
index a348bf1f..39399e81 100644
--- a/tests/error/type_errors/invert_not_int.py
+++ b/tests/error/type_errors/invert_not_int.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return ~True
diff --git a/tests/error/type_errors/return_mismatch.err b/tests/error/type_errors/return_mismatch.err
index 0f6dfa97..0d9a0605 100644
--- a/tests/error/type_errors/return_mismatch.err
+++ b/tests/error/type_errors/return_mismatch.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> bool:
 6:        return 42
                  ^^
diff --git a/tests/error/type_errors/return_mismatch.py b/tests/error/type_errors/return_mismatch.py
index 65af0e99..9328972e 100644
--- a/tests/error/type_errors/return_mismatch.py
+++ b/tests/error/type_errors/return_mismatch.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> bool:
     return 42
diff --git a/tests/error/type_errors/unary_not_arith.err b/tests/error/type_errors/unary_not_arith.err
index f7c7daa7..ae82206b 100644
--- a/tests/error/type_errors/unary_not_arith.err
+++ b/tests/error/type_errors/unary_not_arith.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        return -True
                   ^^^^
diff --git a/tests/error/type_errors/unary_not_arith.py b/tests/error/type_errors/unary_not_arith.py
index 9813943a..bf9ce2cb 100644
--- a/tests/error/type_errors/unary_not_arith.py
+++ b/tests/error/type_errors/unary_not_arith.py
@@ -1,6 +1,6 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     return -True
diff --git a/tests/error/type_errors/unpack_not_enough.err b/tests/error/type_errors/unpack_not_enough.err
index a1330755..d9523c30 100644
--- a/tests/error/type_errors/unpack_not_enough.err
+++ b/tests/error/type_errors/unpack_not_enough.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        a, b, c = 1, True
           ^^^^^^^^^^^^^^^^^
diff --git a/tests/error/type_errors/unpack_not_enough.py b/tests/error/type_errors/unpack_not_enough.py
index 792cb634..389b9fd9 100644
--- a/tests/error/type_errors/unpack_not_enough.py
+++ b/tests/error/type_errors/unpack_not_enough.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     a, b, c = 1, True
     return a
diff --git a/tests/error/type_errors/unpack_too_many.err b/tests/error/type_errors/unpack_too_many.err
index 9590a2f4..44ffb60f 100644
--- a/tests/error/type_errors/unpack_too_many.err
+++ b/tests/error/type_errors/unpack_too_many.err
@@ -1,6 +1,6 @@
 Guppy compilation failed. Error in file $FILE:6
 
-4:    @guppy(compile=True)
+4:    @compile_guppy
 5:    def foo() -> int:
 6:        a, b = 1, True, 3.0
           ^^^^^^^^^^^^^^^^^^^
diff --git a/tests/error/type_errors/unpack_too_many.py b/tests/error/type_errors/unpack_too_many.py
index 472aa000..b252cf7d 100644
--- a/tests/error/type_errors/unpack_too_many.py
+++ b/tests/error/type_errors/unpack_too_many.py
@@ -1,7 +1,7 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     a, b = 1, True, 3.0
     return a
diff --git a/tests/error/type_errors/while_not_bool_functional.py b/tests/error/type_errors/while_not_bool_functional.py
index 4c74b1b2..78c66c40 100644
--- a/tests/error/type_errors/while_not_bool_functional.py
+++ b/tests/error/type_errors/while_not_bool_functional.py
@@ -1,7 +1,7 @@
 from guppylang.decorator import guppy
 
 
-@guppy(compile=True)
+@compile_guppy
 def foo() -> int:
     _@functional
     while 42:
diff --git a/tests/error/util.py b/tests/error/util.py
index 821aa2f4..88c3182c 100644
--- a/tests/error/util.py
+++ b/tests/error/util.py
@@ -26,7 +26,7 @@ def run_error_test(file, capsys):
         exp_err = f.read()
 
     exp_err = exp_err.replace("$FILE", str(file))
-    assert err == exp_err
+    assert err == exp_err, f"Expected error '{err}', but got '{exp_err}'."
 
 
 util = GuppyModule("test")
diff --git a/tests/integration/test_arithmetic.py b/tests/integration/test_arithmetic.py
index 7eeda1b9..a31db662 100644
--- a/tests/integration/test_arithmetic.py
+++ b/tests/integration/test_arithmetic.py
@@ -1,8 +1,8 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_arith_basic(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def add(x: int, y: int) -> int:
         return x + y
 
@@ -10,7 +10,7 @@ def add(x: int, y: int) -> int:
 
 
 def test_constant(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def const() -> float:
         return 42.0
 
@@ -18,7 +18,7 @@ def const() -> float:
 
 
 def test_aug_assign(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def add(x: int) -> int:
         x += 1
         return x
@@ -27,7 +27,7 @@ def add(x: int) -> int:
 
 
 def test_float_coercion(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def coerce(x: int, y: float) -> float:
         return x * y
 
@@ -35,7 +35,7 @@ def coerce(x: int, y: float) -> float:
 
 
 def test_arith_big(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def arith(x: int, y: float, z: int) -> bool:
         a = x // y + 3 * z
         b = -8 >= a > 5 or (x * y == 0 and a % 3 < x)
@@ -45,7 +45,7 @@ def arith(x: int, y: float, z: int) -> bool:
 
 
 def test_shortcircuit_assign1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> bool:
         if (z := x) and y > 0:
             return z
@@ -55,7 +55,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> bool:
         if y > 0 and (z := x):
             return z
@@ -65,7 +65,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign3(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> bool:
         if (z := x) or y > 0:
             return z
@@ -75,7 +75,7 @@ def foo(x: bool, y: int) -> bool:
 
 
 def test_shortcircuit_assign4(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> bool:
         if y > 0 or (z := x):
             return False
diff --git a/tests/integration/test_basic.py b/tests/integration/test_basic.py
index 7bcb48cc..bb57695e 100644
--- a/tests/integration/test_basic.py
+++ b/tests/integration/test_basic.py
@@ -1,10 +1,11 @@
 from guppylang.decorator import guppy
 from guppylang.hugr import ops
 from guppylang.module import GuppyModule
+from tests.util import compile_guppy
 
 
 def test_id(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def identity(x: int) -> int:
         return x
 
@@ -12,7 +13,7 @@ def identity(x: int) -> int:
 
 
 def test_void(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def void() -> None:
         return
 
@@ -20,7 +21,7 @@ def void() -> None:
 
 
 def test_copy(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def copy(x: int) -> (int, int):
         return x, x
 
@@ -28,7 +29,7 @@ def copy(x: int) -> (int, int):
 
 
 def test_discard(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def discard(x: int) -> None:
         return
 
@@ -36,7 +37,7 @@ def discard(x: int) -> None:
 
 
 def test_implicit_return(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def ret() -> None:
         pass
 
@@ -44,7 +45,7 @@ def ret() -> None:
 
 
 def test_assign(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> bool:
         y = x
         return y
@@ -53,7 +54,7 @@ def foo(x: bool) -> bool:
 
 
 def test_assign_expr(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> bool:
         (y := x)
         return y
@@ -62,7 +63,7 @@ def foo(x: bool) -> bool:
 
 
 def test_func_def_name():
-    @guppy(compile=True)
+    @compile_guppy
     def func_name() -> None:
         return
 
diff --git a/tests/integration/test_call.py b/tests/integration/test_call.py
index eee02085..01a520c9 100644
--- a/tests/integration/test_call.py
+++ b/tests/integration/test_call.py
@@ -1,5 +1,6 @@
 from guppylang.decorator import guppy
 from guppylang.module import GuppyModule
+from tests.util import compile_guppy
 
 
 def test_call(validate):
@@ -31,7 +32,7 @@ def bar(x: int) -> int:
 
 
 def test_recursion(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def main(x: int) -> int:
         return main(x)
 
diff --git a/tests/integration/test_comprehension.py b/tests/integration/test_comprehension.py
index 3b5c0774..76da7749 100644
--- a/tests/integration/test_comprehension.py
+++ b/tests/integration/test_comprehension.py
@@ -5,10 +5,11 @@
 from guppylang.prelude.quantum import Qubit, h, cx
 
 import guppylang.prelude.quantum as quantum
+from tests.util import compile_guppy
 
 
 def test_basic(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[float]) -> list[int]:
         return [int(x) for x in xs]
 
@@ -27,7 +28,7 @@ def test(qs: linst[Qubit]) -> linst[Qubit]:
 
 
 def test_guarded(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int]) -> list[int]:
         return [2 * x for x in xs if x > 0 if x < 20]
 
@@ -35,7 +36,7 @@ def test(xs: list[int]) -> list[int]:
 
 
 def test_multiple(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int], ys: list[int]) -> list[int]:
         return [x + y for x in xs for y in ys if x + y > 42]
 
@@ -43,7 +44,7 @@ def test(xs: list[int], ys: list[int]) -> list[int]:
 
 
 def test_tuple_pat(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[tuple[int, int, float]]) -> list[float]:
         return [x + y * z for x, y, z in xs if x - y > z]
 
@@ -62,7 +63,7 @@ def test(qs: linst[tuple[int, Qubit, Qubit]]) -> linst[tuple[Qubit, Qubit]]:
 
 
 def test_tuple_return(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int], ys: list[float]) -> list[tuple[int, float]]:
         return [(x, y) for x in xs for y in ys]
 
@@ -84,7 +85,7 @@ def test(xs: list[float]) -> list[float]:
 
 
 def test_capture(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int], y: int) -> list[int]:
         return [x + y for x in xs if x > y]
 
@@ -92,7 +93,7 @@ def test(xs: list[int], y: int) -> list[int]:
 
 
 def test_scope(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[None]) -> float:
         x = 42.0
         [x for x in xs]
@@ -102,7 +103,7 @@ def test(xs: list[None]) -> float:
 
 
 def test_nested_left(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int], ys: list[float]) -> list[list[float]]:
         return [[x + y for y in ys] for x in xs]
 
@@ -110,7 +111,7 @@ def test(xs: list[int], ys: list[float]) -> list[list[float]]:
 
 
 def test_nested_right(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int]) -> list[int]:
         return [-x for x in [2 * x for x in xs]]
 
diff --git a/tests/integration/test_for.py b/tests/integration/test_for.py
index 08a26e96..57a9f750 100644
--- a/tests/integration/test_for.py
+++ b/tests/integration/test_for.py
@@ -1,8 +1,9 @@
 from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_basic(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         for x in xs:
             pass
@@ -12,7 +13,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_counting_loop(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         s = 0
         for x in xs:
@@ -23,7 +24,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_multi_targets(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[tuple[int, float]]) -> float:
         s = 0.0
         for x, y in xs:
@@ -34,7 +35,7 @@ def foo(xs: list[tuple[int, float]]) -> float:
 
 
 def test_multi_targets_same(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[tuple[int, float]]) -> float:
         s = 1.0
         for x, x in xs:
@@ -45,7 +46,7 @@ def foo(xs: list[tuple[int, float]]) -> float:
 
 
 def test_reassign_iter(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         s = 1
         for x in xs:
@@ -57,7 +58,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_break(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         i = 1
         for x in xs:
@@ -70,7 +71,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_continue(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         i = len(xs)
         for x in xs:
@@ -83,7 +84,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_return_in_loop(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int]) -> int:
         y = 42
         for x in xs:
@@ -96,7 +97,7 @@ def foo(xs: list[int]) -> int:
 
 
 def test_nested_loop(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int], ys: list[int]) -> int:
         p = 0
         for x in xs:
@@ -110,7 +111,7 @@ def foo(xs: list[int], ys: list[int]) -> int:
 
 
 def test_nested_loop_break_continue(validate):
-    @guppy
+    @compile_guppy
     def foo(xs: list[int], ys: list[int]) -> int:
         p = 0
         for x in xs:
diff --git a/tests/integration/test_functional.py b/tests/integration/test_functional.py
index d0c90d70..7f994e4a 100644
--- a/tests/integration/test_functional.py
+++ b/tests/integration/test_functional.py
@@ -2,11 +2,12 @@
 
 from guppylang.decorator import guppy
 from tests.integration.util import functional, _
+from tests.util import compile_guppy
 
 
 @pytest.mark.skip()
 def test_if_no_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -18,7 +19,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -32,7 +33,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_elif(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -46,7 +47,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_if_elif_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         _ @ functional
         if x:
@@ -62,7 +63,7 @@ def foo(x: bool, y: int) -> int:
 
 @pytest.mark.skip()
 def test_infinite_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         while True:
             pass
@@ -73,7 +74,7 @@ def foo() -> int:
 
 @pytest.mark.skip()
 def test_counting_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(i: int) -> int:
         while i > 0:
             i -= 1
@@ -84,7 +85,7 @@ def foo(i: int) -> int:
 
 @pytest.mark.skip()
 def test_nested_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int, y: int) -> int:
         p = 0
         _ @ functional
diff --git a/tests/integration/test_higher_order.py b/tests/integration/test_higher_order.py
index 3fa857a4..94de2b31 100644
--- a/tests/integration/test_higher_order.py
+++ b/tests/integration/test_higher_order.py
@@ -2,6 +2,7 @@
 
 from guppylang.decorator import guppy
 from guppylang.module import GuppyModule
+from tests.util import compile_guppy
 
 
 def test_basic(validate):
@@ -55,7 +56,7 @@ def baz(y: int) -> None:
 
 
 def test_nested(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> Callable[[int], bool]:
         def bar(y: int) -> bool:
             return x > y
diff --git a/tests/integration/test_if.py b/tests/integration/test_if.py
index 4a7752a7..67dfb7be 100644
--- a/tests/integration/test_if.py
+++ b/tests/integration/test_if.py
@@ -1,10 +1,10 @@
 import pytest
 
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_if_no_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -14,7 +14,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -26,7 +26,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_elif(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -38,7 +38,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_elif_else(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 1
@@ -52,7 +52,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         return y + 1 if x else 42
 
@@ -60,7 +60,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr_nested(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         a = y + 1 if x else y * y if 0 < y <= 10 else 42
         b = a if a < 5 or (not x and -7 >= a > 42) else -a
@@ -70,7 +70,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_if_expr_tuple(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> (int, int, int):
         t = (y + 1 if x else 42), 8, (y * 2 if x else 64)
         return t
@@ -79,7 +79,7 @@ def foo(x: bool, y: int) -> (int, int, int):
 
 
 def test_if_expr_assign_both(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         (z := 5) if x else (z := 42)
         return z
@@ -88,7 +88,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_assign_cond(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> bool:
         return z if (z := x) else False
 
@@ -96,7 +96,7 @@ def foo(x: bool) -> bool:
 
 
 def test_if_expr_reassign(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         y = 5
         (y := 1) if x else 6
@@ -108,7 +108,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_reassign_cond(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         y = 5
         return y if (y := 42) > 5 else 64 if x else y
@@ -117,7 +117,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_expr_double_type_change(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         y = 4
         (y := 1) if (y := x) else (y := 6)
@@ -127,7 +127,7 @@ def foo(x: bool) -> int:
 
 
 def test_if_return(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             return y
@@ -138,7 +138,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_else_return(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 3
@@ -151,7 +151,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_both_return(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool, y: int) -> int:
         if x:
             y += 3
@@ -164,7 +164,7 @@ def foo(x: bool, y: int) -> int:
 
 
 def test_nested_return(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int, y: int) -> int:
         if x > 5:
             if y == 4:
@@ -177,7 +177,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_return_defined1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int, y: int) -> int:
         if x > 5:
             return y
@@ -189,7 +189,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_return_defined2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         if x > 5:
             z = 45
@@ -201,7 +201,7 @@ def foo(x: int) -> int:
 
 
 def test_break_different_types1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -217,7 +217,7 @@ def foo(x: int) -> int:
 
 
 def test_break_different_types2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -234,7 +234,7 @@ def foo(x: int) -> int:
 
 @pytest.mark.skip("Known bug")
 def test_continue_different_types1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         z = 0
         while True:
@@ -251,7 +251,7 @@ def foo(x: int) -> int:
 
 @pytest.mark.skip("Known bug")
 def test_continue_different_types2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         z = 0
         while True:
diff --git a/tests/integration/test_list.py b/tests/integration/test_list.py
index 9bee4016..e90f1bfe 100644
--- a/tests/integration/test_list.py
+++ b/tests/integration/test_list.py
@@ -1,8 +1,8 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_types(validate):
-    @guppy
+    @compile_guppy
     def test(
         xs: list[int], ys: list[tuple[int, float]]
     ) -> tuple[list[int], list[tuple[int, float]]]:
@@ -12,7 +12,7 @@ def test(
 
 
 def test_len(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int]) -> int:
         return len(xs)
 
@@ -20,7 +20,7 @@ def test(xs: list[int]) -> int:
 
 
 def test_literal(validate):
-    @guppy
+    @compile_guppy
     def test(x: float) -> list[float]:
         return [1.0, 2.0, 3.0, 4.0 + x]
 
@@ -28,7 +28,7 @@ def test(x: float) -> list[float]:
 
 
 def test_arith(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[int]) -> list[int]:
         xs += xs + [42]
         xs = 3 * xs
@@ -38,7 +38,7 @@ def test(xs: list[int]) -> list[int]:
 
 
 def test_subscript(validate):
-    @guppy
+    @compile_guppy
     def test(xs: list[float], i: int) -> float:
         return xs[2 * i]
 
diff --git a/tests/integration/test_nested.py b/tests/integration/test_nested.py
index 9e445f84..aac788ba 100644
--- a/tests/integration/test_nested.py
+++ b/tests/integration/test_nested.py
@@ -1,8 +1,8 @@
-from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_basic(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y
@@ -13,7 +13,7 @@ def bar(y: int) -> int:
 
 
 def test_call_twice(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y + 3
@@ -27,7 +27,7 @@ def bar(y: int) -> int:
 
 
 def test_redefine(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             return y + 3
@@ -44,7 +44,7 @@ def bar(y: int) -> int:
 
 
 def test_define_twice(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         if x == 0:
 
@@ -61,7 +61,7 @@ def bar(y: int) -> int:
 
 
 def test_nested_deep(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             def baz(z: int) -> int:
@@ -75,7 +75,7 @@ def baz(z: int) -> int:
 
 
 def test_recurse(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int) -> int:
             if y == 0:
@@ -88,7 +88,7 @@ def bar(y: int) -> int:
 
 
 def test_capture_arg(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar() -> int:
             return 1 + x
@@ -99,7 +99,7 @@ def bar() -> int:
 
 
 def test_capture_assigned(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         y = x + 1
 
@@ -112,7 +112,7 @@ def bar() -> int:
 
 
 def test_capture_multiple(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         if x > 5:
             y = 3
@@ -130,7 +130,7 @@ def bar() -> int:
 
 
 def test_capture_cfg(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         a = x + 4
         if x > 5:
@@ -146,7 +146,7 @@ def bar() -> int:
 
 
 def test_capture_deep(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         a = x * 2
 
@@ -165,7 +165,7 @@ def baz(y: int) -> int:
 
 
 def test_capture_recurse(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int, z: int) -> int:
             if y == 0:
@@ -178,7 +178,7 @@ def bar(y: int, z: int) -> int:
 
 
 def test_capture_recurse_nested(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         def bar(y: int, z: int) -> int:
             if y == 0:
@@ -197,7 +197,7 @@ def baz() -> int:
 
 
 def test_capture_while(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int) -> int:
         a = 0
         while x > 0:
diff --git a/tests/integration/test_programs.py b/tests/integration/test_programs.py
index 47caf96f..44c7968d 100644
--- a/tests/integration/test_programs.py
+++ b/tests/integration/test_programs.py
@@ -1,9 +1,10 @@
 from guppylang.decorator import guppy
 from guppylang.module import GuppyModule
+from tests.util import compile_guppy
 
 
 def test_factorial(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def factorial1(x: int) -> int:
         acc = 1
         while x > 0:
@@ -11,13 +12,13 @@ def factorial1(x: int) -> int:
             x -= 1
         return acc
 
-    @guppy(compile=True)
+    @compile_guppy
     def factorial2(x: int) -> int:
         if x == 0:
             return 1
         return factorial2(x - 1) * x
 
-    @guppy(compile=True)
+    @compile_guppy
     def factorial3(x: int, acc: int) -> int:
         if x == 0:
             return acc
diff --git a/tests/integration/test_py.py b/tests/integration/test_py.py
index feaee3dc..ac983942 100644
--- a/tests/integration/test_py.py
+++ b/tests/integration/test_py.py
@@ -1,11 +1,12 @@
 from guppylang.decorator import guppy
 from tests.integration.util import py
+from tests.util import compile_guppy
 
 
 def test_basic(validate):
     x = 42
 
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         return py(x + 1)
 
@@ -13,7 +14,7 @@ def foo() -> int:
 
 
 def test_builtin(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         return py(len({"a": 1337, "b": None}))
 
@@ -23,7 +24,7 @@ def foo() -> int:
 def test_if(validate):
     b = True
 
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         if py(b or 1 > 6):
             return 0
@@ -35,7 +36,7 @@ def foo() -> int:
 def test_redeclare_after(validate):
     x = 1
 
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         return py(x)
 
@@ -45,7 +46,7 @@ def foo() -> int:
 
 
 def test_tuple(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         x, y = py((1, False))
         return x
@@ -54,7 +55,7 @@ def foo() -> int:
 
 
 def test_tuple_implicit(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         x, y = py(1, False)
         return x
diff --git a/tests/integration/test_unused.py b/tests/integration/test_unused.py
index d16664ff..9c36aa80 100644
--- a/tests/integration/test_unused.py
+++ b/tests/integration/test_unused.py
@@ -1,10 +1,11 @@
 """ All sorts of weird stuff is allowed when variables are not used. """
 
 from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_not_always_defined1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         if x:
             z = 5
@@ -14,7 +15,7 @@ def foo(x: bool) -> int:
 
 
 def test_not_always_defined2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         if x:
             pass
@@ -26,7 +27,7 @@ def foo(x: bool) -> int:
 
 
 def test_not_always_defined3(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         if x:
             y = True
@@ -38,7 +39,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types1(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         if x:
             z = True
@@ -50,7 +51,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types2(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         z = False
         if x:
@@ -63,7 +64,7 @@ def foo(x: bool) -> int:
 
 
 def test_different_types3(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> int:
         z = False
         if x:
@@ -76,7 +77,7 @@ def foo(x: bool) -> int:
 
 
 def test_while_change_type(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> None:
         x = 42
         while True:
@@ -86,7 +87,7 @@ def foo() -> None:
 
 
 def test_if_expr_different_types(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: bool) -> None:
         5 if x else False
 
diff --git a/tests/integration/test_while.py b/tests/integration/test_while.py
index f7e21678..b97fbd61 100644
--- a/tests/integration/test_while.py
+++ b/tests/integration/test_while.py
@@ -1,8 +1,9 @@
 from guppylang.decorator import guppy
+from tests.util import compile_guppy
 
 
 def test_infinite_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo() -> int:
         while True:
             pass
@@ -12,7 +13,7 @@ def foo() -> int:
 
 
 def test_counting_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(i: int) -> int:
         while i > 0:
             i -= 1
@@ -22,7 +23,7 @@ def foo(i: int) -> int:
 
 
 def test_break(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(i: int) -> int:
         while True:
             if i == 0:
@@ -34,7 +35,7 @@ def foo(i: int) -> int:
 
 
 def test_continue(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(i: int) -> int:
         x = 42
         while True:
@@ -47,7 +48,7 @@ def foo(i: int) -> int:
 
 
 def test_return_in_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(i: int) -> int:
         x = 42
         while i > 0:
@@ -61,7 +62,7 @@ def foo(i: int) -> int:
 
 
 def test_nested_loop(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int, y: int) -> int:
         p = 0
         while x > 0:
@@ -77,7 +78,7 @@ def foo(x: int, y: int) -> int:
 
 
 def test_nested_loop_break_continue(validate):
-    @guppy(compile=True)
+    @compile_guppy
     def foo(x: int, y: int) -> int:
         p = 0
         while x > 0:
diff --git a/tests/util.py b/tests/util.py
new file mode 100644
index 00000000..36cc3175
--- /dev/null
+++ b/tests/util.py
@@ -0,0 +1,18 @@
+import guppylang
+from guppylang.hugr import Hugr
+from guppylang.module import GuppyModule
+
+
+def compile_guppy(fn) -> Hugr:
+    """A decorator that combines @guppy with HUGR compilation.
+
+    Creates a temporary module that only contains the defined function.
+    """
+    assert not isinstance(
+        fn,
+        GuppyModule,
+    ), "`@compile_guppy` does not support extra arguments."
+
+    module = GuppyModule("module")
+    guppylang.decorator.guppy(module)(fn)
+    return module.compile()

From 1213256b543f317510a3bff139ac507e3dc7f79f Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:16:24 +0000
Subject: [PATCH 06/14] fix lints

---
 tests/integration/test_for.py        | 1 -
 tests/integration/test_functional.py | 1 -
 tests/integration/test_py.py         | 1 -
 tests/integration/test_unused.py     | 1 -
 tests/integration/test_while.py      | 1 -
 5 files changed, 5 deletions(-)

diff --git a/tests/integration/test_for.py b/tests/integration/test_for.py
index 57a9f750..0d82c357 100644
--- a/tests/integration/test_for.py
+++ b/tests/integration/test_for.py
@@ -1,4 +1,3 @@
-from guppylang.decorator import guppy
 from tests.util import compile_guppy
 
 
diff --git a/tests/integration/test_functional.py b/tests/integration/test_functional.py
index 7f994e4a..238a04b0 100644
--- a/tests/integration/test_functional.py
+++ b/tests/integration/test_functional.py
@@ -1,6 +1,5 @@
 import pytest
 
-from guppylang.decorator import guppy
 from tests.integration.util import functional, _
 from tests.util import compile_guppy
 
diff --git a/tests/integration/test_py.py b/tests/integration/test_py.py
index ac983942..be3353ac 100644
--- a/tests/integration/test_py.py
+++ b/tests/integration/test_py.py
@@ -1,4 +1,3 @@
-from guppylang.decorator import guppy
 from tests.integration.util import py
 from tests.util import compile_guppy
 
diff --git a/tests/integration/test_unused.py b/tests/integration/test_unused.py
index 9c36aa80..f4b5b01f 100644
--- a/tests/integration/test_unused.py
+++ b/tests/integration/test_unused.py
@@ -1,6 +1,5 @@
 """ All sorts of weird stuff is allowed when variables are not used. """
 
-from guppylang.decorator import guppy
 from tests.util import compile_guppy
 
 
diff --git a/tests/integration/test_while.py b/tests/integration/test_while.py
index b97fbd61..c351481a 100644
--- a/tests/integration/test_while.py
+++ b/tests/integration/test_while.py
@@ -1,4 +1,3 @@
-from guppylang.decorator import guppy
 from tests.util import compile_guppy
 
 

From ad8b49ba82cedc57afa580b95e3a070c50bc4f32 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:16:38 +0000
Subject: [PATCH 07/14] Raise errors when compiling decorator without modules

---
 guppylang/decorator.py | 12 ++++++++----
 guppylang/error.py     |  4 ++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index f6ab2c7f..25bb9029 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -14,7 +14,7 @@
     DefaultCallCompiler,
     OpCompiler,
 )
-from guppylang.error import GuppyError, pretty_errors
+from guppylang.error import GuppyError, MissingModuleError, pretty_errors
 from guppylang.gtypes import GuppyType, TypeTransformer
 from guppylang.hugr import ops, tys
 from guppylang.hugr.hugr import Hugr
@@ -258,17 +258,21 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
         return dec
 
-    def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule | None:
+    def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
         """Returns the local GuppyModule, removing it from the local state."""
         if id is None:
             id = self._get_python_caller()
         if id not in self._modules:
-            return None
+            err = f"Module {id.name} not found." if id else "No module found."
+            raise MissingModuleError(err)
         return self._modules.pop(id)
 
-    def compile(self, id: CallerIdentifier | None = None) -> Hugr | None:
+    def compile(self, id: CallerIdentifier | None = None) -> Hugr:
         """Compiles the local module into a Hugr."""
         module = self.take_module(id)
+        if not module:
+            err = f"Module {id.name} not found." if id else "No module found."
+            raise MissingModuleError(err)
         return module.compile() if module else None
 
     def registered_modules(self) -> list[CallerIdentifier]:
diff --git a/guppylang/error.py b/guppylang/error.py
index 91c4d54f..8e8ae4bc 100644
--- a/guppylang/error.py
+++ b/guppylang/error.py
@@ -76,6 +76,10 @@ class GuppyTypeInferenceError(GuppyError):
     """Special Guppy exception for type inference errors."""
 
 
+class MissingModuleError(GuppyError):
+    """Special Guppy exception for operations that require a guppy module."""
+
+
 class InternalGuppyError(Exception):
     """Exception for internal problems during compilation."""
 

From 816fb6d12b876a457e0cd53d6d4971a0e502acc3 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:18:02 +0000
Subject: [PATCH 08/14] s/guppy.compile/guppy.compile_module

---
 guppylang/decorator.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 25bb9029..0b833fdd 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -267,7 +267,7 @@ def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
             raise MissingModuleError(err)
         return self._modules.pop(id)
 
-    def compile(self, id: CallerIdentifier | None = None) -> Hugr:
+    def compile_module(self, id: CallerIdentifier | None = None) -> Hugr:
         """Compiles the local module into a Hugr."""
         module = self.take_module(id)
         if not module:

From 7d7690be9afd50cb4ee4217986a24ab7c51ec873 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:18:49 +0000
Subject: [PATCH 09/14] Update docs

---
 guppylang/decorator.py | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 0b833fdd..8900f056 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -63,10 +63,6 @@ def __call__(self, arg: PyFunc | GuppyModule) -> None | FuncDecorator:
 
         Optionally, the `GuppyModule` in which the function should be placed can
         be passed to the decorator.
-
-        If `compile` is set to `True` and no `GuppyModule` is passed, the
-        function is compiled immediately as an standalone module and the Hugr is
-        returned.
         """
 
         def make_dummy(wraps: PyFunc) -> Callable[..., Any]:
@@ -192,7 +188,7 @@ def __str__(self) -> str:
     def type_var(self, module: GuppyModule, name: str, linear: bool = False) -> TypeVar:
         """Creates a new type variable in a module."""
         module.register_type_var(name, linear)
-        return TypeVar(name)
+        return TypeVar(name)  # type: ignore[parameter]
 
     @pretty_errors
     def custom(
@@ -263,7 +259,11 @@ def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
         if id is None:
             id = self._get_python_caller()
         if id not in self._modules:
-            err = f"Module {id.name} not found." if id else "No module found."
+            err = (
+                f"Module {id.name} not found."
+                if id
+                else "No Guppy functions or types defined in this module."
+            )
             raise MissingModuleError(err)
         return self._modules.pop(id)
 
@@ -271,7 +271,11 @@ def compile_module(self, id: CallerIdentifier | None = None) -> Hugr:
         """Compiles the local module into a Hugr."""
         module = self.take_module(id)
         if not module:
-            err = f"Module {id.name} not found." if id else "No module found."
+            err = (
+                f"Module {id.name} not found."
+                if id
+                else "No Guppy functions or types defined in this module."
+            )
             raise MissingModuleError(err)
         return module.compile() if module else None
 

From 008782caf38ac59ecffe3e7ad0ea534f0274a333 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 13:54:27 +0000
Subject: [PATCH 10/14] Associate GuppyModules with the py module, not the
 function

---
 guppylang/decorator.py | 41 ++++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 8900f056..2bd48771 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -30,7 +30,7 @@ class CallerIdentifier:
     """Identifier for the interpreter frame that called the decorator."""
 
     filename: Path
-    function: str
+    module: str | None
 
     @property
     def name(self) -> str:
@@ -38,11 +38,8 @@ def name(self) -> str:
 
         If the called is not a function, uses the file name.
         """
-        module_name = inspect.getmodulename(self.filename)
-        if self.function != "<module>":
-            return self.function
-        if module_name is not None:
-            return module_name
+        if self.module is not None:
+            return self.module.__name__
         return self.filename.name
 
 
@@ -80,7 +77,7 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
             f = arg
 
             def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
-                caller = self._get_python_caller()
+                caller = self._get_python_caller(f)
                 if caller not in self._modules:
                     self._modules[caller] = GuppyModule(caller.name)
                 module = self._modules[caller]
@@ -99,14 +96,23 @@ def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
 
         raise ValueError(f"Invalid arguments to `@guppy` decorator: {arg}")
 
-    def _get_python_caller(self) -> CallerIdentifier:
-        """Returns an identifier for the interpreter frame that called the decorator."""
-        for s in inspect.stack():
-            # Note the hacky check for the pretty errors wrapper,
-            # since @pretty_errors wraps the __call__ method.
-            if s.filename != __file__ and s.function != "pretty_errors_wrapped":
-                return CallerIdentifier(Path(s.filename), s.function)
-        raise GuppyError("Could not find caller of `@guppy` decorator")
+    def _get_python_caller(self, fn: PyFunc | None = None) -> CallerIdentifier:
+        """Returns an identifier for the interpreter frame that called the decorator.
+
+        :param fn: Optional. The function that was decorated.
+        """
+        if fn is not None:
+            filename = inspect.getfile(fn)
+            module = inspect.getmodule(fn)
+        else:
+            for s in inspect.stack():
+                if s.filename != __file__:
+                    filename = s.filename
+                    module = inspect.getmodule(s.frame)
+                    break
+            else:
+                raise GuppyError("Could not find a caller for the `@guppy` decorator")
+        return CallerIdentifier(Path(filename), module)
 
     @pretty_errors
     def extend_type(self, module: GuppyModule, ty: type[GuppyType]) -> ClassDecorator:
@@ -256,12 +262,13 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
     def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
         """Returns the local GuppyModule, removing it from the local state."""
+        orig_id = id
         if id is None:
             id = self._get_python_caller()
         if id not in self._modules:
             err = (
-                f"Module {id.name} not found."
-                if id
+                f"Module {orig_id.name} not found."
+                if orig_id
                 else "No Guppy functions or types defined in this module."
             )
             raise MissingModuleError(err)

From 3d303a9590e7053ffebc09bc73c639e68785f8bf Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 14:01:19 +0000
Subject: [PATCH 11/14] fix mypy

---
 guppylang/decorator.py | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 2bd48771..7dcd1fde 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -3,6 +3,7 @@
 from collections.abc import Callable, Iterator, Sequence
 from dataclasses import dataclass
 from pathlib import Path
+from types import ModuleType
 from typing import Any, ClassVar, TypeVar
 
 from guppylang.ast_util import AstNode, has_empty_body
@@ -30,7 +31,7 @@ class CallerIdentifier:
     """Identifier for the interpreter frame that called the decorator."""
 
     filename: Path
-    module: str | None
+    module: ModuleType | None
 
     @property
     def name(self) -> str:
@@ -39,7 +40,7 @@ def name(self) -> str:
         If the called is not a function, uses the file name.
         """
         if self.module is not None:
-            return self.module.__name__
+            return str(self.module.__name__)
         return self.filename.name
 
 
@@ -55,7 +56,7 @@ def __init__(self) -> None:
         self._modules = {}
 
     @pretty_errors
-    def __call__(self, arg: PyFunc | GuppyModule) -> None | FuncDecorator:
+    def __call__(self, arg: PyFunc | GuppyModule) -> FuncDecorator:
         """Decorator to annotate Python functions as Guppy code.
 
         Optionally, the `GuppyModule` in which the function should be placed can
@@ -76,7 +77,7 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
             # We default to a module associated with the caller of the decorator.
             f = arg
 
-            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
+            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
                 caller = self._get_python_caller(f)
                 if caller not in self._modules:
                     self._modules[caller] = GuppyModule(caller.name)
@@ -88,7 +89,7 @@ def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
 
         if isinstance(arg, GuppyModule):
             # Module passed.
-            def dec(f: Callable[..., Any]) -> Callable[..., Any] | Hugr:
+            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
                 arg.register_func_def(f)
                 return make_dummy(f)
 
@@ -194,7 +195,7 @@ def __str__(self) -> str:
     def type_var(self, module: GuppyModule, name: str, linear: bool = False) -> TypeVar:
         """Creates a new type variable in a module."""
         module.register_type_var(name, linear)
-        return TypeVar(name)  # type: ignore[parameter]
+        return TypeVar(name)
 
     @pretty_errors
     def custom(
@@ -274,7 +275,7 @@ def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
             raise MissingModuleError(err)
         return self._modules.pop(id)
 
-    def compile_module(self, id: CallerIdentifier | None = None) -> Hugr:
+    def compile_module(self, id: CallerIdentifier | None = None) -> Hugr | None:
         """Compiles the local module into a Hugr."""
         module = self.take_module(id)
         if not module:
@@ -284,7 +285,7 @@ def compile_module(self, id: CallerIdentifier | None = None) -> Hugr:
                 else "No Guppy functions or types defined in this module."
             )
             raise MissingModuleError(err)
-        return module.compile() if module else None
+        return module.compile()
 
     def registered_modules(self) -> list[CallerIdentifier]:
         """Returns a list of all currently registered modules for local contexts."""

From 4ac68a59fab102a4aab239f40fd6c1de0ad72da3 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 15:07:38 +0000
Subject: [PATCH 12/14] Review comments: Better docs for the identifier

---
 guppylang/decorator.py | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/guppylang/decorator.py b/guppylang/decorator.py
index 7dcd1fde..77538f9e 100644
--- a/guppylang/decorator.py
+++ b/guppylang/decorator.py
@@ -27,8 +27,8 @@
 
 
 @dataclass(frozen=True)
-class CallerIdentifier:
-    """Identifier for the interpreter frame that called the decorator."""
+class ModuleIdentifier:
+    """Identifier for the Python file/module that called the decorator."""
 
     filename: Path
     module: ModuleType | None
@@ -47,10 +47,10 @@ def name(self) -> str:
 class _Guppy:
     """Class for the `@guppy` decorator."""
 
-    # The currently-alive modules, associated with an element in the call stack.
+    # The currently-alive GuppyModules, associated with a Python file/module.
     #
     # Only contains **uncompiled** modules.
-    _modules: dict[CallerIdentifier, GuppyModule]
+    _modules: dict[ModuleIdentifier, GuppyModule]
 
     def __init__(self) -> None:
         self._modules = {}
@@ -77,15 +77,12 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
             # We default to a module associated with the caller of the decorator.
             f = arg
 
-            def dec(f: Callable[..., Any]) -> Callable[..., Any]:
-                caller = self._get_python_caller(f)
-                if caller not in self._modules:
-                    self._modules[caller] = GuppyModule(caller.name)
-                module = self._modules[caller]
-                module.register_func_def(f)
-                return make_dummy(f)
-
-            return dec(f)
+            caller = self._get_python_caller(f)
+            if caller not in self._modules:
+                self._modules[caller] = GuppyModule(caller.name)
+            module = self._modules[caller]
+            module.register_func_def(f)
+            return make_dummy(f)
 
         if isinstance(arg, GuppyModule):
             # Module passed.
@@ -97,8 +94,8 @@ def dec(f: Callable[..., Any]) -> Callable[..., Any]:
 
         raise ValueError(f"Invalid arguments to `@guppy` decorator: {arg}")
 
-    def _get_python_caller(self, fn: PyFunc | None = None) -> CallerIdentifier:
-        """Returns an identifier for the interpreter frame that called the decorator.
+    def _get_python_caller(self, fn: PyFunc | None = None) -> ModuleIdentifier:
+        """Returns an identifier for the Python file/module that called the decorator.
 
         :param fn: Optional. The function that was decorated.
         """
@@ -113,7 +110,7 @@ def _get_python_caller(self, fn: PyFunc | None = None) -> CallerIdentifier:
                     break
             else:
                 raise GuppyError("Could not find a caller for the `@guppy` decorator")
-        return CallerIdentifier(Path(filename), module)
+        return ModuleIdentifier(Path(filename), module)
 
     @pretty_errors
     def extend_type(self, module: GuppyModule, ty: type[GuppyType]) -> ClassDecorator:
@@ -261,7 +258,7 @@ def dummy(*args: Any, **kwargs: Any) -> Any:
 
         return dec
 
-    def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
+    def take_module(self, id: ModuleIdentifier | None = None) -> GuppyModule:
         """Returns the local GuppyModule, removing it from the local state."""
         orig_id = id
         if id is None:
@@ -275,7 +272,7 @@ def take_module(self, id: CallerIdentifier | None = None) -> GuppyModule:
             raise MissingModuleError(err)
         return self._modules.pop(id)
 
-    def compile_module(self, id: CallerIdentifier | None = None) -> Hugr | None:
+    def compile_module(self, id: ModuleIdentifier | None = None) -> Hugr | None:
         """Compiles the local module into a Hugr."""
         module = self.take_module(id)
         if not module:
@@ -287,7 +284,7 @@ def compile_module(self, id: CallerIdentifier | None = None) -> Hugr | None:
             raise MissingModuleError(err)
         return module.compile()
 
-    def registered_modules(self) -> list[CallerIdentifier]:
+    def registered_modules(self) -> list[ModuleIdentifier]:
         """Returns a list of all currently registered modules for local contexts."""
         return list(self._modules.keys())
 

From a75ac5001ab09aeb3c68de1eb7fe2d2996365a37 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 15:16:02 +0000
Subject: [PATCH 13/14] Drop assert message

---
 tests/error/util.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/error/util.py b/tests/error/util.py
index 88c3182c..821aa2f4 100644
--- a/tests/error/util.py
+++ b/tests/error/util.py
@@ -26,7 +26,7 @@ def run_error_test(file, capsys):
         exp_err = f.read()
 
     exp_err = exp_err.replace("$FILE", str(file))
-    assert err == exp_err, f"Expected error '{err}', but got '{exp_err}'."
+    assert err == exp_err
 
 
 util = GuppyModule("test")

From 3042071170d83b263401456d516f6a646e9b4c47 Mon Sep 17 00:00:00 2001
From: Agustin Borgna <agustin.borgna@quantinuum.com>
Date: Thu, 18 Jan 2024 15:43:11 +0000
Subject: [PATCH 14/14] Avoid a circular dependency

`hugr` uses `gtypes`, which uses `hugr.tys`
---
 guppylang/hugr/__init__.py | 5 -----
 tests/util.py              | 2 +-
 2 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/guppylang/hugr/__init__.py b/guppylang/hugr/__init__.py
index 0f6535c5..e69de29b 100644
--- a/guppylang/hugr/__init__.py
+++ b/guppylang/hugr/__init__.py
@@ -1,5 +0,0 @@
-"""Python definitions for the Hierarchical Unified Graph Representation."""
-
-from .hugr import Hugr
-
-__all__ = ["Hugr"]
diff --git a/tests/util.py b/tests/util.py
index 36cc3175..3a45073e 100644
--- a/tests/util.py
+++ b/tests/util.py
@@ -1,5 +1,5 @@
 import guppylang
-from guppylang.hugr import Hugr
+from guppylang.hugr.hugr import Hugr
 from guppylang.module import GuppyModule