Assembly should be strict than currently defined. Issues should be warned about for now and turn into errors later. Only the following aspects of assembly should be allowed:

• directly below a block, only the following is allowed:
  • function definition
  • variable declaration
  • functional assignment
  • function call with zero returns
  • functional instruction that has zero returns
  • block
  • for
  • switch
  • break
  • continue
  • subassembly
• invalidJumpTag should be replaced by revert() / invalid()
• jumps are disallowed
• DUP and SWAP instructions are disallowed
• labels are disallowed
• statements (elements of a block) are disallowed if they return something onto the stack at the end.