[munificent]

Lisp is dynamically typed and macros are syntactic. The macro gets in an AST and spits out an AST with little in the way of semantic information involved beyond maybe some identifier resolution.

Dart is a statically typed language and we wanted macros to be able to introspect over the semantics of the code the macro is applied to, not just the semantics. For example, if a macro is generating code for serialization, we wanted the macro to be able to ask "Does the type of this field implement JsonSerializable?". Answering that means being able to look up the type of the field, possibly walk its inheritance hierarchy, etc.

It's a very different problem from just "give me a way to add pretty loop syntax".