I don't like our macro tests -- they are brittle and don't inspire
confidence. I think the reason for that is that we try to unit-test
them, but that is at odds with reality, where macro expansion
fundamentally depends on name resolution.
Consider these expples
{ 92 }
async { 92 }
'a: { 92 }
#[a] { 92 }
Previously the tree for them were
BLOCK_EXPR
{ ... }
EFFECT_EXPR
async
BLOCK_EXPR
{ ... }
EFFECT_EXPR
'a:
BLOCK_EXPR
{ ... }
BLOCK_EXPR
#[a]
{ ... }
As you see, it gets progressively worse :) The last two items are
especially odd. The last one even violates the balanced curleys
invariant we have (#10357) The new approach is to say that the stuff in
`{}` is stmt_list, and the block is stmt_list + optional modifiers
BLOCK_EXPR
STMT_LIST
{ ... }
BLOCK_EXPR
async
STMT_LIST
{ ... }
BLOCK_EXPR
'a:
STMT_LIST
{ ... }
BLOCK_EXPR
#[a]
STMT_LIST
{ ... }
FragmentKind played two roles:
* entry point to the parser
* syntactic category of a macro call
These are different use-cases, and warrant different types. For example,
macro can't expand to visibility, but we have such fragment today.
This PR introduces `ExpandsTo` enum to separate this two use-cases.
I suspect we might further split `FragmentKind` into `$x:specifier` enum
specific to MBE, and a general parser entry point, but that's for
another PR!
9970: feat: Implement attribute input token mapping, fix attribute item token mapping r=Veykril a=Veykril
![image](https://user-images.githubusercontent.com/3757771/130328577-4c1ad72c-51b1-47c3-8d3d-3242ec44a355.png)
The token mapping for items with attributes got overwritten partially by the attributes non-item input, since attributes have two different inputs, the item and the direct input both.
This PR gives attributes a second TokenMap for its direct input. We now shift all normal input IDs by the item input maximum(we maybe wanna swap this see below) similar to what we do for macro-rules/def. For mapping down we then have to figure out whether we are inside the direct attribute input or its item input to pick the appropriate mapping which can be done with some token range comparisons.
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/9867
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>