Macros in match blocks can't expand to a pattern *and* block

[reem]

Example of incorrect behavior: http://is.gd/WmvsML

In the above example, the branch! macro should expand to a pattern and block, but rustc insists that it only expands into a pattern, and still expects further patterns or a block.

[reem]

@cmr told me on IRC this is because macros must produce a single valid AST node, and we don't have an AST node for "match arm".

[lambda-fairy]

Is there any workaround for this? A macro that I'm writing works this way.

[Mark-Simulacrum]

Closing in favor of #12832.