Suggestion

In#9211: we are planning to enforce the following invariants in our AST forVariableDeclaration, specifically the declarators indeclarations:

• definite can only be true ifdeclare: false andkind: "let" | "var", so the following are all parsing errors:

  constx!=1;declareletx!:string;

• Ifdefinite: true, theninit: null, and the identifier has a type annotation:

  letx!=1;letx!;

• Ifdeclare: true andkind: "let" | "var", theninit: null:

  declareletx=1;

• Ifdeclare: false andkind: "const" theninit is non-null:

  constx;

@sosukesuzuki@fisker Do these look safe to you?