diff --git a/py2wasm/ourlang.py b/py2wasm/ourlang.py
index 622a321..ba87aec 100644
--- a/py2wasm/ourlang.py
+++ b/py2wasm/ourlang.py
@@ -97,7 +97,7 @@ class TupleMember:
 
 class OurTypeTuple(OurType):
     """
-    The tuple type, 64 bits wide
+    The tuple type
     """
     __slots__ = ('members', )
 
@@ -842,8 +842,14 @@ class OurVisitor:
             if not isinstance(node.ctx, ast.Load):
                 _raise_static_error(node, 'Must be load context')
 
-            if node.id in our_locals:
-                return VariableReference(our_locals[node.id], node.id)
+            if node.id not in our_locals:
+                _raise_static_error(node, 'Undefined variable')
+
+            act_type = our_locals[node.id]
+            if exp_type != act_type:
+                _raise_static_error(node, f'Expected {exp_type.render()}, {node.id} is actually {act_type.render()}')
+
+            return VariableReference(act_type, node.id)
 
         if isinstance(node, ast.Tuple):
             if not isinstance(node.ctx, ast.Load):
@@ -884,7 +890,7 @@ class OurVisitor:
             func = module.functions[struct_constructor.name]
         elif node.func.id in WEBASSEMBLY_BUILDIN_FLOAT_OPS:
             if not isinstance(exp_type, (OurTypeFloat32, OurTypeFloat64, )):
-                _raise_static_error(node, f'Cannot make square root result in {exp_type}')
+                _raise_static_error(node, f'Cannot make {node.func.id} result in {exp_type}')
 
             if 1 != len(node.args):
                 _raise_static_error(node, f'Function {node.func.id} requires 1 arguments but {len(node.args)} are given')
@@ -901,7 +907,7 @@ class OurVisitor:
             func = module.functions[node.func.id]
 
         if func.returns != exp_type:
-            _raise_static_error(node, f'Function {node.func.id} does not return {exp_type.render()}')
+            _raise_static_error(node, f'Expected {exp_type.render()}, {func.name} actually returns {func.returns.render()}')
 
         if len(func.posonlyargs) != len(node.args):
             _raise_static_error(node, f'Function {node.func.id} requires {len(func.posonlyargs)} arguments but {len(node.args)} are given')
@@ -932,7 +938,7 @@ class OurVisitor:
             _raise_static_error(node, f'{node_typ.name} has no attribute {node.attr}')
 
         if exp_type != member.type:
-            _raise_static_error(node, f'Expected {exp_type.render()}, got {member.type.render()} instead')
+            _raise_static_error(node, f'Expected {exp_type.render()}, {node.value.id}.{member.name} is actually {member.type.render()}')
 
         return AccessStructMember(
             VariableReference(node_typ, node.value.id),
@@ -949,7 +955,8 @@ class OurVisitor:
         if not isinstance(node.slice.value, ast.Constant):
             _raise_static_error(node, 'Must subscript using a constant index') # FIXME: Implement variable indexes
 
-        if not isinstance(node.slice.value.value, int):
+        idx = node.slice.value.value
+        if not isinstance(idx, int):
             _raise_static_error(node, 'Must subscript using a constant integer index')
 
         if not isinstance(node.ctx, ast.Load):
@@ -962,12 +969,12 @@ class OurVisitor:
         if not isinstance(node_typ, OurTypeTuple):
             _raise_static_error(node, f'Cannot take index of non-tuple {node.value.id}')
 
-        if len(node_typ.members) <= node.slice.value.value:
-            _raise_static_error(node, f'Index {node.slice.value.value} out of bounds for tuple {node.value.id}')
+        if len(node_typ.members) <= idx:
+            _raise_static_error(node, f'Index {idx} out of bounds for tuple {node.value.id}')
 
-        member = node_typ.members[node.slice.value.value]
+        member = node_typ.members[idx]
         if exp_type != member.type:
-            _raise_static_error(node, f'Expected {exp_type.render()}, got {member.type.render()} instead')
+            _raise_static_error(node, f'Expected {exp_type.render()}, {node.value.id}[{idx}] is actually {member.type.render()}')
 
         return AccessTupleMember(
             VariableReference(node_typ, node.value.id),
diff --git a/tests/integration/test_static_checking.py b/tests/integration/test_static_checking.py
new file mode 100644
index 0000000..f3de90b
--- /dev/null
+++ b/tests/integration/test_static_checking.py
@@ -0,0 +1,56 @@
+import pytest
+
+from py2wasm.utils import our_process
+
+from py2wasm.ourlang import StaticError
+
+@pytest.mark.integration_test
+@pytest.mark.parametrize('type_', ['i32', 'i64', 'f32', 'f64'])
+def test_type_mismatch_function_argument(type_):
+    code_py = f"""
+def helper(a: {type_}) -> (i32, i32, ):
+    return a
+"""
+
+    with pytest.raises(StaticError, match=f'Static error on line 3: Expected \\(i32, i32, \\), a is actually {type_}'):
+        our_process(code_py, 'test')
+
+@pytest.mark.integration_test
+@pytest.mark.parametrize('type_', ['i32', 'i64', 'f32', 'f64'])
+def test_type_mismatch_struct_member(type_):
+    code_py = f"""
+class Struct:
+    param: {type_}
+
+def testEntry(arg: Struct) -> (i32, i32, ):
+    return arg.param
+"""
+
+    with pytest.raises(StaticError, match=f'Static error on line 6: Expected \\(i32, i32, \\), arg.param is actually {type_}'):
+        our_process(code_py, 'test')
+
+@pytest.mark.integration_test
+@pytest.mark.parametrize('type_', ['i32', 'i64', 'f32', 'f64'])
+def test_type_mismatch_tuple_member(type_):
+    code_py = f"""
+def testEntry(arg: ({type_}, )) -> (i32, i32, ):
+    return arg[0]
+"""
+
+    with pytest.raises(StaticError, match=f'Static error on line 3: Expected \\(i32, i32, \\), arg\\[0\\] is actually {type_}'):
+        our_process(code_py, 'test')
+
+@pytest.mark.integration_test
+@pytest.mark.parametrize('type_', ['i32', 'i64', 'f32', 'f64'])
+def test_type_mismatch_function_result(type_):
+    code_py = f"""
+def helper() -> {type_}:
+    return 1
+
+@exported
+def testEntry() -> (i32, i32, ):
+    return helper()
+"""
+
+    with pytest.raises(StaticError, match=f'Static error on line 7: Expected \\(i32, i32, \\), helper actually returns {type_}'):
+        our_process(code_py, 'test')