diff --git a/pydust/src/modules.zig b/pydust/src/modules.zig
index d86a8ae0..699e777e 100644
--- a/pydust/src/modules.zig
+++ b/pydust/src/modules.zig
@@ -50,7 +50,7 @@ pub fn Module(comptime name: [:0]const u8, comptime definition: type) type {
 
         /// A function to initialize the Python module from its definition.
         pub fn init() !py.PyObject {
-            var pyModuleDef = try py.allocator.create(ffi.PyModuleDef);
+            const pyModuleDef = try py.allocator.create(ffi.PyModuleDef);
             pyModuleDef.* = ffi.PyModuleDef{
                 .m_base = ffi.PyModuleDef_Base{
                     .ob_base = ffi.PyObject{
diff --git a/pydust/src/pytypes.zig b/pydust/src/pytypes.zig
index d3c95f30..4e28b101 100644
--- a/pydust/src/pytypes.zig
+++ b/pydust/src/pytypes.zig
@@ -509,7 +509,7 @@ fn GC(comptime definition: type) type {
         }
 
         fn tp_clear(pyself: *ffi.PyObject) callconv(.C) c_int {
-            var self: *PyTypeStruct(definition) = @ptrCast(pyself);
+            const self: *PyTypeStruct(definition) = @ptrCast(pyself);
             clearFields(self.state);
             return 0;
         }
@@ -562,7 +562,7 @@ fn GC(comptime definition: type) type {
         }
 
         inline fn pyClear(obj: *ffi.PyObject) void {
-            var objRef = @constCast(&obj);
+            const objRef = @constCast(&obj);
             const objOld = objRef.*;
             objRef.* = undefined;
             py.decref(objOld);
@@ -665,7 +665,7 @@ fn Members(comptime definition: type) type {
 
                 // We compute the offset of the attribute within the type, and then the value field within the attribute.
                 // Although the value within the attribute should always be 0 since it's the only field.
-                var offset = @offsetOf(PyTypeStruct(definition), "state") + @offsetOf(definition, field.name) + @offsetOf(field.type, "value");
+                const offset = @offsetOf(PyTypeStruct(definition), "state") + @offsetOf(definition, field.name) + @offsetOf(field.type, "value");
 
                 const T = @typeInfo(field.type).Struct.fields[0].type;
 
diff --git a/pydust/src/types/bytes.zig b/pydust/src/types/bytes.zig
index 8c8429a8..149b153a 100644
--- a/pydust/src/types/bytes.zig
+++ b/pydust/src/types/bytes.zig
@@ -60,7 +60,7 @@ test "PyBytes" {
     var ps = try PyBytes.create(a);
     defer ps.decref();
 
-    var ps_slice = try ps.asSlice();
+    const ps_slice = try ps.asSlice();
     try testing.expectEqual(a.len, ps_slice.len);
     try testing.expectEqual(a.len, try ps.length());
     try testing.expectEqual(@as(u8, 0), ps_slice[ps_slice.len]);
diff --git a/pydust/src/types/str.zig b/pydust/src/types/str.zig
index 52762b03..f2d85c3d 100644
--- a/pydust/src/types/str.zig
+++ b/pydust/src/types/str.zig
@@ -105,7 +105,7 @@ test "PyString" {
     ps = try ps.appendSlice(b);
     defer ps.decref();
 
-    var ps_slice = try ps.asSlice();
+    const ps_slice = try ps.asSlice();
 
     // Null-terminated strings have len == non-null bytes, but are guaranteed to have a null byte
     // when indexed by their length.