Use new syntax more consistently in error msgs
Use List[X] instead of X[] in error messages
Use Dict[...], not dict[...] in error messages
Rename test case file
Add comments to test cases
Fix explicit type for attribute in __init__
Add type checker test case
Add type checker test case
Add basic type checking of Undefined(type)
Add type checker test case
Add type checker test cases
Add type checker test case
Add type checker test cases
Add type checker test case
Add type checker test case
Add type checker test case
Let multiple variable declaration be in parens
Verify tuple item counts in multiple variable decl
Disallow simple type in multiple variable decl
Update exception error message