todo.txt

- Fix shadowing ("redefinition of xxx")
- Fix `else if x := .... ; x {`
- Implement `if obj, ok := json.Data.(*js_ast.EObject); ok {`
             if str, ok := b.Data.(*js_ast.EString); ok {
- []u8(byteptr) cast ???
- `for x := ` variable shadowing
- `x := struct{}{}`
- `^uint32(chunkIndex)`
- `[]sourcemap.SourceMapShift{{}}`
- `const x = 1 << iota`




  The remaining errors are in categories that require deeper changes:
  - Option type handling (?int vs int for string methods) [DONE - see tests/option_type, map_lookup_ok, chan_recv_ok, strconv_atoi]
    - os.LookupEnv pattern: value, ok := os.LookupEnv("X")
    - Map lookup comma-ok: value, ok := m[key]
    - Channel receive comma-ok: value, ok := <-ch
    - strconv functions: value, err := strconv.Atoi("123")
  - Enum value scoping (need full enum name in comparisons)
  - Various void type initialization issues
  - Match exhaustiveness