internal: more reasonable grammar for blocks

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
      { ... }
This commit is contained in:
Aleksey Kladov 2021-09-26 12:12:57 +03:00
parent c51a3c78cf
commit 2bf81922f7
233 changed files with 11762 additions and 11343 deletions

View file

@ -721,7 +721,7 @@ impl ExpandTo {
match parent.kind() {
MACRO_ITEMS | SOURCE_FILE | ITEM_LIST => ExpandTo::Items,
MACRO_STMTS | EXPR_STMT | BLOCK_EXPR => ExpandTo::Statements,
MACRO_STMTS | EXPR_STMT | STMT_LIST => ExpandTo::Statements,
MACRO_PAT => ExpandTo::Pattern,
MACRO_TYPE => ExpandTo::Type,