diff --git a/src/linalg.cpp b/src/linalg.cpp
index a7dec143..05403a0d 100644
--- a/src/linalg.cpp
+++ b/src/linalg.cpp
@@ -130,7 +130,7 @@ static Vec2 SmoothDamp(Vec2 current, Vec2 target, PyVec2& currentVelocity, float
             return VAR_T(PyVec2, self.rotate(radian));
         });
 
-        vm->bind_method<0>(type, "rotate_", [](VM* vm, ArgsView args){
+        vm->bind_method<1>(type, "rotate_", [](VM* vm, ArgsView args){
             PyVec2& self = _CAST(PyVec2&, args[0]);
             float radian = CAST(f64, args[1]);
             self = self.rotate(radian);
@@ -250,7 +250,7 @@ static Vec2 SmoothDamp(Vec2 current, Vec2 target, PyVec2& currentVelocity, float
                 return vm->heap.gcnew<PyMat3x3>(PK_OBJ_GET(Type, args[0]), mat);
             }
             vm->TypeError(fmt("Mat3x3.__new__ takes 0 or 1 or 9 arguments, got ", args.size()-1));
-            return vm->None;
+            PK_UNREACHABLE();
         });
 
         vm->bind_method<1>(type, "copy_", [](VM* vm, ArgsView args){
@@ -275,13 +275,11 @@ static Vec2 SmoothDamp(Vec2 current, Vec2 target, PyVec2& currentVelocity, float
             Tuple& t = CAST(Tuple&, index);
             if(t.size() != 2){
                 vm->TypeError("Mat3x3.__getitem__ takes a tuple of 2 integers");
-                return vm->None;
             }
             i64 i = CAST(i64, t[0]);
             i64 j = CAST(i64, t[1]);
             if(i < 0 || i >= 3 || j < 0 || j >= 3){
                 vm->IndexError("index out of range");
-                return vm->None;
             }
             return VAR(self.m[i][j]);
         });
@@ -291,13 +289,11 @@ static Vec2 SmoothDamp(Vec2 current, Vec2 target, PyVec2& currentVelocity, float
             const Tuple& t = CAST(Tuple&, index);
             if(t.size() != 2){
                 vm->TypeError("Mat3x3.__setitem__ takes a tuple of 2 integers");
-                return;
             }
             i64 i = CAST(i64, t[0]);
             i64 j = CAST(i64, t[1]);
             if(i < 0 || i >= 3 || j < 0 || j >= 3){
                 vm->IndexError("index out of range");
-                return;
             }
             self.m[i][j] = CAST_F(value);
         });
@@ -361,7 +357,7 @@ static Vec2 SmoothDamp(Vec2 current, Vec2 target, PyVec2& currentVelocity, float
             if(args[2] == vm->None){
                 return VAR_T(PyMat3x3, self.matmul(other));
             }else{
-                PyMat3x3& out = _CAST(PyMat3x3&, args[2]);
+                PyMat3x3& out = CAST(PyMat3x3&, args[2]);
                 out = self.matmul(other);
                 return vm->None;
             }
diff --git a/tests/80_linalg.py b/tests/80_linalg.py
index e5a6fd05..8a672ac4 100644
--- a/tests/80_linalg.py
+++ b/tests/80_linalg.py
@@ -38,11 +38,13 @@ assert element_value_list == copy_element_value_list
 test_vec2_copy = test_vec2.copy()
 radians = random.uniform(-10*math.pi, 10*math.pi)
 test_vec2_copy = rotated_vec2(test_vec2_copy, radians)
-assert test_vec2.rotate(radians).__dict__ == test_vec2_copy.__dict__
+assert test_vec2.rotate(radians) == test_vec2_copy
+test_vec2.rotate_(radians)
+assert test_vec2 == test_vec2_copy
 
 # test smooth_damp
 vel = vec2(0, 0)
-ret = vec2.smooth_damp(vec2(1, 2), vec2(3, 4), vel, 7, 8, 9)
+ret = vec2.smooth_damp(vec2(1, 2), vec2(3, 4), vel, 0.2, 0.001, 0.05)
 assert isinstance(ret, vec2)
 assert vel.length() > 0
 
@@ -342,10 +344,12 @@ except:
 
 # test transpose
 test_mat_copy = test_mat.copy()
+assert test_mat_copy.transpose_() is None
+assert test_mat_copy == test_mat.transpose()
 assert test_mat_copy.transpose() == test_mat_copy.transpose().transpose().transpose()
 
 # test inverse
-assert ~static_test_mat_float == static_test_mat_float_inv
+assert ~static_test_mat_float == static_test_mat_float_inv == static_test_mat_float.invert()
 assert static_test_mat_float.invert_() is None
 assert static_test_mat_float == static_test_mat_float_inv
 
@@ -467,3 +471,14 @@ d = mat3x3.identity()
 assert d.copy_(mat3x3.zeros()) is None
 assert d == mat3x3.zeros()
 
+d = mat3x3.identity()
+assert d.matmul(mat3x3.zeros()) == mat3x3.zeros()
+assert d == mat3x3.identity()
+assert d.matmul(mat3x3.zeros(), out=d) is None
+assert d == mat3x3.zeros()
+
+try:
+    assert d[6, 6]
+    exit(1)
+except IndexError:
+    pass
\ No newline at end of file