Things missing:

* Attributes
- All types: @noreflect, @deprecated
- Struct: @packed, @aligned, @opaque
- Enums: @distinct, @noreflect
- Unions: @packed, @aligned, @opaque
- Functions: @inline, @reflect, @noreturn, @section, @unused, @used, @interrupt, @naked, @convention()
- Calls: @noinline, @inline
- Variables, parameters: @unused
- Constants, globals: @unused, @used, @section
- Labels: @unused

* Designated initializer
- Array initializer
- Array range initializer { [1..2] = 2 }

* Initializers
- Array initializers
- Union initializers
- Initializers with anonymous members

* Asserts
- assert, $assert
- @unreachable

* Types
- Vararrays
- Strings
- Array
- Slice
- Values: size, alignment, name, qualifiedName
- Functions: offsetof
- Distinct types
- Simd types?
- Complex types?
- Subtype casts
- Bitstruct
- Enumset
- Typeid

* Struct / union
- Cast to union?
- Structural typed anonymous structs and casts to them.

* Expressions
- Disallow x >= 0 and x < 0 on unsigned types unless in a macro.
- Range check arrays on debug
- Allow negating int if assigned to a larger type. E.g short x = 1; int y = -x;

* Switch
- String switch
- Range case

* Functions
- Varargs
- C ABI
- Safe varargs

* Pre-post conditions
- Breakdown here

* Error handling
- Error unions
- Catch/try
- Function return channel

* Enum
- Values: min, max, array
- Functions: fomOrdinal, ordinal, fromName, name, fromFullName, fullName, fromQualifiedName, qualifiedName, <value>(), fromValue()