diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 59fef63..5d1db83 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.10', '3.11', '3.12']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
 
     steps:
     - uses: actions/checkout@v4
diff --git a/.github/workflows/formatting-and-pyright.yml b/.github/workflows/formatting-and-pyright.yml
index be4eec6..ad01b68 100644
--- a/.github/workflows/formatting-and-pyright.yml
+++ b/.github/workflows/formatting-and-pyright.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.10']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
 
     steps:
     - uses: actions/checkout@v4
diff --git a/filecheck/matcher.py b/filecheck/matcher.py
index 5ad4a99..b7ecd63 100644
--- a/filecheck/matcher.py
+++ b/filecheck/matcher.py
@@ -370,15 +370,14 @@ def _approximate_uop_length(self, uops: Sequence[UOp]) -> int:
         """
         count = 0
         for op in uops:
-            match op:
-                case Subst(variable):
-                    count += len(str(self.ctx.live_variables.get(variable, "")))
-                case Literal(content):
-                    count += len(content)
-                case RE(content):
-                    count += len(content)
-                case Capture(pattern):
-                    count += len(pattern)
-                case _:
-                    continue
+            if isinstance(op, Subst):
+                count += len(str(self.ctx.live_variables.get(op.variable, "")))
+            elif isinstance(op, Literal):
+                count += len(op.content)
+            elif isinstance(op, RE):
+                count += len(op.content)
+            elif isinstance(op, Capture):
+                count += len(op.pattern)
+            else:
+                continue
         return count
diff --git a/filecheck/ops.py b/filecheck/ops.py
index 2273301..261e31e 100644
--- a/filecheck/ops.py
+++ b/filecheck/ops.py
@@ -1,13 +1,13 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from typing import Callable, TypeAlias
+from typing import Callable
 
 from filecheck.options import Options
 
 OP_KINDS = ("DAG", "COUNT", "NOT", "EMPTY", "NEXT", "SAME", "LABEL", "CHECK")
 
-VALUE_MAPPER_T: TypeAlias = Callable[[str], int] | Callable[[str], str]
+VALUE_MAPPER_T = Callable[[str], int] | Callable[[str], str]
 
 
 @dataclass(slots=True)
diff --git a/poetry.lock b/poetry.lock
index 48e7943..07e8ae3 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -254,13 +254,13 @@ virtualenv = ">=20.10.0"
 
 [[package]]
 name = "pyright"
-version = "1.1.373"
+version = "1.1.374"
 description = "Command line wrapper for pyright"
 optional = false
 python-versions = ">=3.7"
 files = [
-    {file = "pyright-1.1.373-py3-none-any.whl", hash = "sha256:b805413227f2c209f27b14b55da27fe5e9fb84129c9f1eb27708a5d12f6f000e"},
-    {file = "pyright-1.1.373.tar.gz", hash = "sha256:f41bcfc8b9d1802b09921a394d6ae1ce19694957b628bc657629688daf8a83ff"},
+    {file = "pyright-1.1.374-py3-none-any.whl", hash = "sha256:55752bcf7a3646d293cd76710a983b71e16f6128aab2d42468e6eb7e46c0a70d"},
+    {file = "pyright-1.1.374.tar.gz", hash = "sha256:d01b2daf864ba5e0362e56b844984865970d7204158e61eb685e2dab7804cb82"},
 ]
 
 [package.dependencies]
@@ -317,6 +317,7 @@ files = [
     {file = "PyYAML-6.0.1-cp311-cp311-win_amd64.whl", hash = "sha256:bf07ee2fef7014951eeb99f56f39c9bb4af143d8aa3c21b1677805985307da34"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:855fb52b0dc35af121542a76b9a84f8d1cd886ea97c84703eaa6d88e37a2ad28"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:40df9b996c2b73138957fe23a16a4f0ba614f4c0efce1e9406a184b6d07fa3a9"},
+    {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a08c6f0fe150303c1c6b71ebcd7213c2858041a7e01975da3a99aed1e7a378ef"},
     {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:6c22bec3fbe2524cde73d7ada88f6566758a8f7227bfbf93a408a9d86bcc12a0"},
     {file = "PyYAML-6.0.1-cp312-cp312-musllinux_1_1_x86_64.whl", hash = "sha256:8d4e9c88387b0f5c7d5f281e55304de64cf7f9c0021a3525bd3b1c542da3b0e4"},
     {file = "PyYAML-6.0.1-cp312-cp312-win32.whl", hash = "sha256:d483d2cdf104e7c9fa60c544d92981f12ad66a457afae824d146093b8c294c54"},
@@ -395,5 +396,5 @@ test = ["covdefaults (>=2.3)", "coverage (>=7.2.7)", "coverage-enable-subprocess
 
 [metadata]
 lock-version = "2.0"
-python-versions = "^3.10"
-content-hash = "b7b972f40548fcf82df353532b2b87f0e9d3680e87dddd2b582c282aa1ecff80"
+python-versions = "^3.8"
+content-hash = "e531f277074f1e1a005008328c7df1cff22e22ccc8d5a1d5048c3063f5420226"
diff --git a/pyproject.toml b/pyproject.toml
index 8b04a72..c36297f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,12 +14,12 @@ packages = [
 ]
 
 [tool.poetry.dependencies]
-python = "^3.10"
+python = "^3.8"
 
 [tool.poetry.group.dev.dependencies]
 black = "^24.4.2"
 lit = "^18.1.8"
-pre-commit = "^3.7.1"
+pre-commit = { version = "^3.7.1", python = "^3.9" }
 pyright = "^1.1.370"
 pytest = "^8.2.2"