From b5d31950e5f99ae2e5be8d2468e24c54700ac507 Mon Sep 17 00:00:00 2001
From: Remco de Boer <29308176+redeboer@users.noreply.github.com>
Date: Thu, 25 Apr 2024 18:26:02 +0200
Subject: [PATCH] DX: lint type hints with MyPy (#109)

---
 .gitpod.yml                       |  1 +
 .pre-commit-config.yaml           | 11 ++++++
 .vscode/extensions.json           |  2 +-
 .vscode/settings.json             |  7 ++++
 docs/conf.py                      |  1 -
 pyproject.toml                    | 16 +++++++++
 src/ampform_dpd/__init__.py       | 58 ++++++++++++++++---------------
 src/ampform_dpd/_attrs.py         | 10 ++++--
 src/ampform_dpd/adapter/qrules.py | 14 ++++----
 src/ampform_dpd/decay.py          | 51 +++++++++++++++++++++------
 src/ampform_dpd/dynamics.py       |  4 +--
 src/ampform_dpd/io.py             | 19 +++++-----
 src/ampform_dpd/spin.py           |  2 +-
 tests/adapter/test_qrules.py      |  2 +-
 tests/test_angles.py              | 10 +++---
 tests/test_io.py                  |  2 +-
 16 files changed, 141 insertions(+), 69 deletions(-)

diff --git a/.gitpod.yml b/.gitpod.yml
index 866fb318..2e3ec8ef 100644
--- a/.gitpod.yml
+++ b/.gitpod.yml
@@ -22,6 +22,7 @@ vscode:
     - github.vscode-github-actions
     - github.vscode-pull-request-github
     - ms-python.python
+    - ms-python.mypy-type-checker
     - ms-python.vscode-pylance
     - ms-toolsai.vscode-jupyter-cell-tags
     - ms-vscode.live-server
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 2b4b76e2..0361bfbb 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -2,6 +2,7 @@ ci:
   autoupdate_commit_msg: "MAINT: update pip constraints and pre-commit"
   autoupdate_schedule: quarterly # already done by requirements-cron.yml
   skip:
+    - mypy
     - prettier
     - pyright
     - taplo
@@ -108,6 +109,16 @@ repos:
             .*\.py
           )$
 
+  - repo: local
+    hooks:
+      - id: mypy
+        name: mypy
+        entry: mypy
+        language: system
+        require_serial: true
+        types:
+          - python
+
   - repo: https://github.com/ComPWA/mirrors-pyright
     rev: v1.1.359
     hooks:
diff --git a/.vscode/extensions.json b/.vscode/extensions.json
index 44c0afda..d528453c 100644
--- a/.vscode/extensions.json
+++ b/.vscode/extensions.json
@@ -8,6 +8,7 @@
     "github.vscode-github-actions",
     "github.vscode-pull-request-github",
     "ms-python.python",
+    "ms-python.mypy-type-checker",
     "ms-python.vscode-pylance",
     "ms-toolsai.vscode-jupyter-cell-tags",
     "ms-vscode.live-server",
@@ -27,7 +28,6 @@
     "ms-python.black-formatter",
     "ms-python.flake8",
     "ms-python.isort",
-    "ms-python.mypy-type-checker",
     "ms-python.pylint",
     "travisillig.vscode-json-stable-stringify",
     "tyriar.sort-lines"
diff --git a/.vscode/settings.json b/.vscode/settings.json
index 0408778f..04642116 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -38,6 +38,8 @@
   "gitlens.telemetry.enabled": false,
   "livePreview.defaultPreviewPath": "docs/_build/html",
   "multiDiffEditor.experimental.enabled": true,
+  "mypy-type-checker.args": ["--config-file=${workspaceFolder}/pyproject.toml"],
+  "mypy-type-checker.importStrategy": "fromEnvironment",
   "notebook.codeActionsOnSave": {
     "notebook.source.organizeImports": "explicit"
   },
@@ -54,6 +56,11 @@
   "ruff.enable": true,
   "ruff.importStrategy": "fromEnvironment",
   "ruff.organizeImports": true,
+  "search.exclude": {
+    "**/tests/**/__init__.py": true,
+    ".constraints/*.txt": true,
+    "typings/**": true
+  },
   "telemetry.telemetryLevel": "off",
   "yaml.schemas": {
     "https://raw.githubusercontent.com/ComPWA/qrules/0.10.x/src/qrules/particle-validation.json": [
diff --git a/docs/conf.py b/docs/conf.py
index 9e88c084..fd54522f 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -67,7 +67,6 @@
     "show-inheritance": True,
 }
 autodoc_member_order = "bysource"
-autodoc_type_aliases = {}
 autodoc_typehints_format = "short"
 autosectionlabel_prefix_document = True
 autosectionlabel_maxdepth = 2
diff --git a/pyproject.toml b/pyproject.toml
index a6174d0f..d8ed943a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -86,6 +86,7 @@ numba = [
 ]
 sty = [
     "ampform-dpd[types]",
+    "mypy",
     "pre-commit >=1.4.0",
     "ruff",
 ]
@@ -134,6 +135,21 @@ where = ["src"]
 [tool.setuptools_scm]
 write_to = "src/ampform_dpd/version.py"
 
+[tool.mypy]
+exclude = "_build"
+show_error_codes = true
+warn_unused_configs = true
+
+[[tool.mypy.overrides]]
+ignore_missing_imports = true
+module = ["cloudpickle.*"]
+
+[[tool.mypy.overrides]]
+check_untyped_defs = true
+disallow_incomplete_defs = false
+disallow_untyped_defs = false
+module = ["tests.*"]
+
 [tool.pyright]
 reportArgumentType = false
 reportAssignmentType = false
diff --git a/src/ampform_dpd/__init__.py b/src/ampform_dpd/__init__.py
index f316525a..4c5af6cb 100644
--- a/src/ampform_dpd/__init__.py
+++ b/src/ampform_dpd/__init__.py
@@ -22,6 +22,7 @@
     ThreeBodyDecay,
     ThreeBodyDecayChain,
     get_decay_product_ids,
+    get_particle,
 )
 from ampform_dpd.io import (
     simplify_latex_rendering,  # noqa: F401  # pyright:ignore[reportUnusedImport]
@@ -35,9 +36,9 @@ class AmplitudeModel:
     intensity: sp.Expr = sp.S.One
     amplitudes: dict[sp.Indexed, sp.Expr] = field(factory=dict)
     variables: dict[sp.Symbol, sp.Expr] = field(factory=dict)
-    parameter_defaults: dict[sp.Symbol, float] = field(factory=dict)
-    masses: dict[sp.Symbol, float] = field(factory=dict)
-    invariants: dict[sp.Symbol, float] = field(factory=dict)
+    parameter_defaults: dict[sp.Symbol, float | complex] = field(factory=dict)
+    masses: dict[sp.Symbol, float | complex] = field(factory=dict)
+    invariants: dict[sp.Symbol, sp.Expr] = field(factory=dict)
 
     @property
     def full_expression(self) -> sp.Expr:
@@ -79,17 +80,20 @@ def formulate(
         reference_subsystem: Literal[1, 2, 3] = 1,
         cleanup_summations: bool = False,
     ) -> AmplitudeModel:
-        helicity_symbols = sp.symbols("lambda:4", rational=True)
+        helicity_symbols: tuple[sp.Symbol, sp.Symbol, sp.Symbol, sp.Symbol] = (
+            sp.symbols("lambda:4", rational=True)
+        )
         allowed_helicities = {
-            symbol: create_spin_range(self.decay.states[i].spin)
+            symbol: create_spin_range(self.decay.states[i].spin)  # type:ignore[index]
             for i, symbol in enumerate(helicity_symbols)
         }
         amplitude_definitions = {}
         angle_definitions = {}
         parameter_defaults = {}
-        for args in product(*allowed_helicities.values()):
-            for sub_system in [1, 2, 3]:
-                chain_model = self.formulate_subsystem_amplitude(*args, sub_system)
+        args: tuple[sp.Rational, sp.Rational, sp.Rational, sp.Rational]
+        for args in product(*allowed_helicities.values()):  # type:ignore[assignment]
+            for sub_system in (1, 2, 3):
+                chain_model = self.formulate_subsystem_amplitude(*args, sub_system)  # type:ignore[arg-type]
                 amplitude_definitions.update(chain_model.amplitudes)
                 angle_definitions.update(chain_model.variables)
                 parameter_defaults.update(chain_model.parameter_defaults)
@@ -100,13 +104,13 @@ def formulate(
         masses = create_mass_symbol_mapping(self.decay)
         parameter_defaults.update(masses)
         if cleanup_summations:
-            aligned_amp = aligned_amp.cleanup()
+            aligned_amp = aligned_amp.cleanup()  # type:ignore[assignment]
         intensity = PoolSum(
             sp.Abs(aligned_amp) ** 2,
             *allowed_helicities.items(),
         )
         if cleanup_summations:
-            intensity = intensity.cleanup()
+            intensity = intensity.cleanup()  # type:ignore[assignment]
         return AmplitudeModel(
             decay=self.decay,
             intensity=PoolSum(
@@ -165,8 +169,8 @@ def formulate_subsystem_amplitude(  # noqa: PLR0914
                     interaction=chain.outgoing_ls,
                     typ="decay",
                 )
-                parameter_defaults[h_prod] = 1 + 0j
-                parameter_defaults[h_dec] = 1
+                parameter_defaults[h_prod] = 1 + 0j  # type:ignore[index]
+                parameter_defaults[h_dec] = 1  # type:ignore[index]
             sub_amp_expr = (
                 sp.KroneckerDelta(λ[0], λR - λ[k])
                 * (-1) ** (spin[k] - λ[k])
@@ -189,9 +193,8 @@ def formulate_subsystem_amplitude(  # noqa: PLR0914
                 * (-1) ** (spin[j] - λ[j])
             )
             if not self.use_decay_helicity_couplings:
-                resonance_isobar = chain.decay.child1
                 sub_amp_expr *= _formulate_clebsch_gordan_factors(
-                    resonance_isobar,
+                    chain.decay_node,
                     helicities={
                         self.decay.final_state[i]: λ[i],
                         self.decay.final_state[j]: λ[j],
@@ -255,20 +258,23 @@ def formulate_aligned_amplitude(
             (_λ2, create_spin_range(j2)),
             (_λ3, create_spin_range(j3)),
         )
-        return amp_expr, wigner_generator.angle_definitions
+        return amp_expr, wigner_generator.angle_definitions  # type:ignore[return-value]
 
 
 def _create_coupling_symbol(
     helicity_coupling: bool,
     resonance: Str,
     helicities: tuple[sp.Basic, sp.Basic],
-    interaction: LSCoupling,
+    interaction: LSCoupling | None,
     typ: Literal["production", "decay"],
 ) -> sp.Indexed:
     H = _get_coupling_base(helicity_coupling, typ)
     if helicity_coupling:
         λi, λj = helicities
         return H[resonance, λi, λj]
+    if interaction is None:
+        msg = "Cannot formulate LS-coupling without LS combinations"
+        raise ValueError(msg)
     return H[resonance, interaction.L, interaction.S]
 
 
@@ -314,15 +320,9 @@ def _formulate_clebsch_gordan_factors(
     return sqrt_factor * cg_ll * cg_ss
 
 
-def get_particle(isobar: IsobarNode | Particle) -> Particle:
-    if isinstance(isobar, IsobarNode):
-        return isobar.parent
-    return isobar
-
-
 @lru_cache(maxsize=None)
 def _generate_amplitude_index_bases() -> dict[Literal[1, 2, 3], sp.IndexedBase]:
-    return dict(enumerate(sp.symbols(R"A^(1:4)", cls=sp.IndexedBase), 1))
+    return dict(enumerate(sp.symbols(R"A^(1:4)", cls=sp.IndexedBase), 1))  # type:ignore[arg-type]
 
 
 class _AlignmentWignerGenerator:
@@ -333,8 +333,8 @@ def __init__(self, reference_subsystem: Literal[1, 2, 3] = 1) -> None:
     def __call__(
         self,
         j: sp.Rational,
-        m: sp.Rational,
-        m_prime: sp.Rational,
+        m: sp.Rational | sp.Symbol,
+        m_prime: sp.Rational | sp.Symbol,
         rotated_state: int,
         aligned_subsystem: int,
     ) -> sp.Rational | WignerD:
@@ -380,16 +380,18 @@ def decay(self) -> ThreeBodyDecay:
 class DynamicsBuilder(Protocol):
     def __call__(
         self, decay_chain: ThreeBodyDecayChain
-    ) -> tuple[sp.Expr, dict[sp.Symbol, float]]: ...
+    ) -> tuple[sp.Expr, dict[sp.Symbol, float | complex]]: ...
 
 
 def formulate_non_resonant(
     decay_chain: ThreeBodyDecayChain,
-) -> tuple[sp.Expr, dict[sp.Symbol, float]]:
+) -> tuple[sp.Expr, dict[sp.Symbol, float | complex]]:
     return sp.Rational(1), {}
 
 
-def create_mass_symbol_mapping(decay: ThreeBodyDecay) -> dict[sp.Symbol, float]:
+def create_mass_symbol_mapping(
+    decay: ThreeBodyDecay,
+) -> dict[sp.Symbol, float | complex]:
     return {
         sp.Symbol(f"m{i}", nonnegative=True): decay.states[i].mass
         for i in sorted(decay.states)  # ensure that dict keys are sorted by state ID
diff --git a/src/ampform_dpd/_attrs.py b/src/ampform_dpd/_attrs.py
index 19d5eb60..b85aaad3 100644
--- a/src/ampform_dpd/_attrs.py
+++ b/src/ampform_dpd/_attrs.py
@@ -2,14 +2,14 @@
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, SupportsFloat
+from typing import TYPE_CHECKING, Iterable, SupportsFloat
 
 import sympy as sp
 
 if TYPE_CHECKING:
     from attrs import Attribute
 
-    from ampform_dpd.decay import LSCoupling
+    from ampform_dpd.decay import LSCoupling, ThreeBodyDecayChain
 
 
 def assert_spin_value(instance, attribute: Attribute, value: sp.Rational) -> None:
@@ -18,7 +18,7 @@ def assert_spin_value(instance, attribute: Attribute, value: sp.Rational) -> Non
         raise ValueError(msg)
 
 
-def to_ls(obj: LSCoupling | tuple[int, SupportsFloat] | None) -> LSCoupling:
+def to_ls(obj: LSCoupling | tuple[int, SupportsFloat] | None) -> LSCoupling | None:
     from ampform_dpd.decay import LSCoupling  # noqa: PLC0415
 
     if obj is None:
@@ -32,5 +32,9 @@ def to_ls(obj: LSCoupling | tuple[int, SupportsFloat] | None) -> LSCoupling:
     raise TypeError(msg)
 
 
+def to_chains(obj: Iterable[ThreeBodyDecayChain]) -> tuple[ThreeBodyDecayChain, ...]:
+    return tuple(obj)
+
+
 def to_rational(obj: SupportsFloat) -> sp.Rational:
     return sp.Rational(obj)
diff --git a/src/ampform_dpd/adapter/qrules.py b/src/ampform_dpd/adapter/qrules.py
index d2a83e4f..9605a5f3 100644
--- a/src/ampform_dpd/adapter/qrules.py
+++ b/src/ampform_dpd/adapter/qrules.py
@@ -35,7 +35,7 @@ def to_three_body_decay(
         for i, idx in enumerate(sorted(some_transition.final_states), 1)
     }
     return ThreeBodyDecay(
-        states={0: initial_state, **final_states},
+        states={0: initial_state, **final_states},  # type:ignore[dict-item]
         chains=tuple(sorted(to_decay_chain(t) for t in transitions)),
     )
 
@@ -97,9 +97,9 @@ def _convert_edge(state: Any) -> Particle:
         raise NotImplementedError(msg)
     return Particle(
         name=particle.name,
-        latex=particle.latex,
+        latex=particle.name if particle.latex is None else particle.latex,
         spin=particle.spin,
-        parity=particle.parity,
+        parity=int(particle.parity),  # type:ignore[arg-type]
         mass=particle.mass,
         width=particle.width,
     )
@@ -131,11 +131,11 @@ def filter_min_ls(
     min_transitions = []
     for group in grouped_transitions.values():
         transition, *_ = group
-        min_transition = FrozenTransition(
+        min_transition: FrozenTransition[EdgeType, NodeType] = FrozenTransition(
             topology=transition.topology,
             states=transition.states,
             interactions={
-                i: min(t.interactions[i] for t in group)
+                i: min(t.interactions[i] for t in group)  # type:ignore[type-var]
                 for i in transition.interactions
             },
         )
@@ -146,6 +146,6 @@ def filter_min_ls(
 def load_particles() -> qrules.particle.ParticleCollection:
     src_dir = Path(__file__).parent.parent
     particle_database = qrules.load_default_particles()
-    additional_definitions = qrules.io.load(src_dir / "particle-definitions.yml")
-    particle_database.update(additional_definitions)
+    additional_definitions = qrules.io.load(src_dir / "particle-definitions.yml")  # type:ignore[arg-type]
+    particle_database.update(additional_definitions)  # type:ignore[arg-type]
     return particle_database
diff --git a/src/ampform_dpd/decay.py b/src/ampform_dpd/decay.py
index 2d538f1c..a4380603 100644
--- a/src/ampform_dpd/decay.py
+++ b/src/ampform_dpd/decay.py
@@ -2,12 +2,13 @@
 
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Dict, Literal
+from functools import lru_cache
+from typing import TYPE_CHECKING, Dict, Literal, TypeVar
 
 from attrs import field, frozen
 from attrs.validators import instance_of
 
-from ampform_dpd._attrs import assert_spin_value, to_ls, to_rational
+from ampform_dpd._attrs import assert_spin_value, to_chains, to_ls, to_rational
 
 if TYPE_CHECKING:
     import sympy as sp
@@ -31,14 +32,19 @@ class IsobarNode:
     interaction: LSCoupling | None = field(default=None, converter=to_ls)
 
     @property
-    def children(self) -> tuple[Particle, Particle]:
+    def children(
+        self,
+    ) -> tuple[
+        Particle | IsobarNode,
+        Particle | IsobarNode,
+    ]:
         return self.child1, self.child2
 
 
 @frozen
 class ThreeBodyDecay:
     states: OuterStates
-    chains: tuple[ThreeBodyDecayChain, ...]
+    chains: tuple[ThreeBodyDecayChain, ...] = field(converter=to_chains)
 
     def __attrs_post_init__(self) -> None:
         expected_initial_state = self.initial_state
@@ -89,7 +95,9 @@ def get_subsystem(self, subsystem_id: Literal[1, 2, 3]) -> ThreeBodyDecay:
         return ThreeBodyDecay(self.states, filtered_chains)
 
 
-def get_decay_product_ids(spectator_id: Literal[1, 2, 3]) -> tuple[int, int]:
+def get_decay_product_ids(
+    spectator_id: Literal[1, 2, 3],
+) -> tuple[Literal[1, 2, 3], Literal[1, 2, 3]]:
     if spectator_id == 1:
         return 2, 3
     if spectator_id == 2:  # noqa: PLR2004
@@ -128,18 +136,31 @@ def parent(self) -> Particle:
 
     @property
     def resonance(self) -> Particle:
-        return self.decay.child1.parent
+        decay_node: IsobarNode = self._get_child_of_type(IsobarNode)
+        return get_particle(decay_node)
+
+    @property
+    def decay_node(self) -> IsobarNode:
+        return self._get_child_of_type(IsobarNode)
 
     @property
     def decay_products(self) -> tuple[Particle, Particle]:
         return (
-            self.decay.child1.child1,
-            self.decay.child1.child2,
+            get_particle(self.decay_node.child1),
+            get_particle(self.decay_node.child2),
         )
 
     @property
     def spectator(self) -> Particle:
-        return self.decay.child2
+        return self._get_child_of_type(Particle)
+
+    @lru_cache(maxsize=None)  # noqa: B019
+    def _get_child_of_type(self, typ: type[T]) -> T:
+        for child in self.decay.children:
+            if isinstance(child, typ):
+                return child
+        msg = f"The production node does not have any children that are of type {typ.__name__}"
+        raise ValueError(msg)
 
     @property
     def incoming_ls(self) -> LSCoupling | None:
@@ -147,10 +168,20 @@ def incoming_ls(self) -> LSCoupling | None:
 
     @property
     def outgoing_ls(self) -> LSCoupling | None:
-        return self.decay.child1.interaction
+        decay_node: IsobarNode = self._get_child_of_type(IsobarNode)
+        return decay_node.interaction
+
+
+T = TypeVar("T", Particle, IsobarNode)
 
 
 @frozen(order=True)
 class LSCoupling:
     L: int
     S: sp.Rational = field(converter=to_rational, validator=assert_spin_value)
+
+
+def get_particle(isobar: IsobarNode | Particle) -> Particle:
+    if isinstance(isobar, IsobarNode):
+        return isobar.parent
+    return isobar
diff --git a/src/ampform_dpd/dynamics.py b/src/ampform_dpd/dynamics.py
index 00f7e7d8..13a5a118 100644
--- a/src/ampform_dpd/dynamics.py
+++ b/src/ampform_dpd/dynamics.py
@@ -144,8 +144,8 @@ def evaluate(self) -> sp.Piecewise:
         z, L = self.args
         cases = {
             0: 1,
-            1: 1 / (1 + z**2),
-            2: 1 / (9 + 3 * z**2 + z**4),
+            1: 1 / (1 + z**2),  # type:ignore[operator]
+            2: 1 / (9 + 3 * z**2 + z**4),  # type:ignore[operator]
         }
         return sp.Piecewise(*[
             (sp.sqrt(expr), sp.Eq(L, l_val)) for l_val, expr in cases.items()
diff --git a/src/ampform_dpd/io.py b/src/ampform_dpd/io.py
index 6b4d1766..5fce8fc9 100644
--- a/src/ampform_dpd/io.py
+++ b/src/ampform_dpd/io.py
@@ -23,7 +23,7 @@
 from collections import abc
 from importlib.metadata import version
 from pathlib import Path
-from typing import TYPE_CHECKING, Iterable, Mapping, Sequence, overload
+from typing import TYPE_CHECKING, Any, Iterable, Mapping, Sequence, overload
 
 import cloudpickle
 import sympy as sp
@@ -136,11 +136,11 @@ def _render_jp(particle: Particle) -> str:
 
 def as_markdown_table(obj: Sequence) -> str:
     """Render objects a `str` suitable for generating a table."""
+    if isinstance(obj, ThreeBodyDecay):
+        return _as_decay_markdown_table(obj.chains)
     item_type = _determine_item_type(obj)
     if item_type is Particle:
         return _as_resonance_markdown_table(obj)
-    if item_type is ThreeBodyDecay:
-        return _as_decay_markdown_table(obj.chains)
     if item_type is ThreeBodyDecayChain:
         return _as_decay_markdown_table(obj)
     msg = (
@@ -175,7 +175,7 @@ def _as_resonance_markdown_table(items: Sequence[Particle]) -> str:
         row_items = [
             f"`{particle.name}`",
             f"${particle.latex}$",
-            Rf"${aslatex(particle, only_jp=True)}$",
+            Rf"${aslatex(particle, only_jp=True)}$",  # type:ignore[call-arg]
             f"{int(1e3 * particle.mass):,.0f}",
             f"{int(1e3 * particle.width):,.0f}",
         ]
@@ -195,9 +195,9 @@ def _as_decay_markdown_table(decay_chains: Sequence[ThreeBodyDecayChain]) -> str
     src = _create_markdown_table_header(column_names)
     for chain in decay_chains:
         child1, child2 = map(aslatex, chain.decay_products)
-        row_items = [
+        row_items: list = [
             Rf"${chain.resonance.latex} \to {child1} {child2}$",
-            Rf"${aslatex(chain.resonance, only_jp=True)}$",
+            Rf"${aslatex(chain.resonance, only_jp=True)}$",  # type:ignore[call-arg]
             f"{int(1e3 * chain.resonance.mass):,.0f}",
             f"{int(1e3 * chain.resonance.width):,.0f}",
         ]
@@ -236,7 +236,7 @@ def perform_cached_lambdify(
 ) -> ParametrizedBackendFunction: ...
 
 
-def perform_cached_lambdify(  # pyright: ignore[reportInconsistentOverload]
+def perform_cached_lambdify(  # type:ignore[misc]  # pyright:ignore[reportInconsistentOverload]
     expr: sp.Expr,
     parameters: Mapping[sp.Symbol, ParameterValue] | None = None,
     backend: str = "jax",
@@ -276,7 +276,7 @@ def perform_cached_lambdify(  # pyright: ignore[reportInconsistentOverload]
         cache_directory = Path(cache_directory)
     cache_directory.mkdir(exist_ok=True, parents=True)
     if parameters is None:
-        hash_obj = expr
+        hash_obj: Any = expr
     else:
         hash_obj = (
             expr,
@@ -288,6 +288,7 @@ def perform_cached_lambdify(  # pyright: ignore[reportInconsistentOverload]
         with open(filename, "rb") as f:
             return pickle.load(f)
     _LOGGER.warning(f"Cached function file {filename} not found, lambdifying...")
+    func: ParametrizedFunction | Function
     if parameters is None:
         func = create_function(expr, backend)
     else:
@@ -305,4 +306,4 @@ def _print_Indexed_latex(self, printer, *args):  # noqa: N802
         indices = ", ".join(map(printer._print, self.indices))
         return f"{base}_{{{indices}}}"
 
-    sp.Indexed._latex = _print_Indexed_latex
+    sp.Indexed._latex = _print_Indexed_latex  # type:ignore[attr-defined]
diff --git a/src/ampform_dpd/spin.py b/src/ampform_dpd/spin.py
index f583f0ef..df8f8ad0 100644
--- a/src/ampform_dpd/spin.py
+++ b/src/ampform_dpd/spin.py
@@ -60,7 +60,7 @@ def create_spin_range(spin: SupportsFloat) -> list[sp.Rational]:
     >>> create_spin_range(1.5)
     [-3/2, -1/2, 1/2, 3/2]
     """
-    return create_rational_range(-spin, spin)
+    return create_rational_range(-float(spin), +float(spin))
 
 
 def create_rational_range(
diff --git a/tests/adapter/test_qrules.py b/tests/adapter/test_qrules.py
index b97b7c3e..f2d9b51e 100644
--- a/tests/adapter/test_qrules.py
+++ b/tests/adapter/test_qrules.py
@@ -73,7 +73,7 @@ def test_to_three_body_decay(reaction: ReactionInfo, min_ls: bool):
 
 
 def _get_couplings(transition: StateTransition) -> tuple[dict, dict]:
-    return tuple(
+    return tuple(  # type:ignore[return-value]
         {"L": node.l_magnitude, "S": node.s_magnitude}
         for node in transition.interactions.values()
     )
diff --git a/tests/test_angles.py b/tests/test_angles.py
index cbdbb708..7d4ffffe 100644
--- a/tests/test_angles.py
+++ b/tests/test_angles.py
@@ -49,7 +49,7 @@ def test_formulate_zeta_angle_equation_A6():  # noqa: N802
 
 
 @pytest.mark.parametrize(
-    ("ζ1", "ζ2", "ζ3"),
+    ("ζ1_expr", "ζ2_expr", "ζ3_expr"),
     [
         (
             formulate_zeta_angle(1, 2, 3)[1],
@@ -68,14 +68,14 @@ def test_formulate_zeta_angle_equation_A6():  # noqa: N802
         ),
     ],
 )
-def test_formulate_zeta_angle_sum_rule(ζ1: sp.Expr, ζ2: sp.Expr, ζ3: sp.Expr):
+def test_formulate_zeta_angle_sum(ζ1_expr: sp.Expr, ζ2_expr: sp.Expr, ζ3_expr: sp.Expr):
     """Test Eq.
 
     (A9), https://journals.aps.org/prd/pdf/10.1103/PhysRevD.101.034033#page=11.
     """
     σ3_expr = compute_third_mandelstam(σ1, σ2, m0, m1, m2, m3)
     masses = {m0: 2.3, m1: 0.94, m2: 0.14, m3: 0.49, σ1: 1.2, σ2: 3.0, σ3: σ3_expr}
-    ζ1 = float(ζ1.doit().xreplace(masses).xreplace(masses))
-    ζ2 = float(ζ2.doit().xreplace(masses).xreplace(masses))
-    ζ3 = float(ζ3.doit().xreplace(masses).xreplace(masses))
+    ζ1 = float(ζ1_expr.doit().xreplace(masses).xreplace(masses))
+    ζ2 = float(ζ2_expr.doit().xreplace(masses).xreplace(masses))
+    ζ3 = float(ζ3_expr.doit().xreplace(masses).xreplace(masses))
     np.testing.assert_almost_equal(ζ1, ζ2 + ζ3, decimal=14)
diff --git a/tests/test_io.py b/tests/test_io.py
index c3700498..b5a883ba 100644
--- a/tests/test_io.py
+++ b/tests/test_io.py
@@ -75,7 +75,7 @@ def test_get_readable_hash(
             caplog.clear()
     elif python_hash_seed == "0":
         if sys.version_info < (3, 11):
-            expected_hash = expected_hash[0]
+            expected_hash = expected_hash[0]  # type:ignore[assignment]
         else:
             expected_hash = expected_hash[1]
         expected = f"pythonhashseed-0{expected_hash:+d}"