Incorrect grammar for BlockExpression

[eggyal]

The grammar for BlockExpression is currently given as:

BlockExpression :
   {
      InnerAttribute^*
      Statements^?
   }

Statements :
      Statement⁺
   | Statement⁺ ExpressionWithoutBlock
   | ExpressionWithoutBlock

According to this grammar, the final operand of a BlockExpression (if present) can only be an ExpressionWithoutBlock. But surely this is not correct: it can be any Expression—i.e. including an ExpressionWithBlock.

For example, using the documented grammar to parse {{ 0 }} as a BlockExpression would result in the inner { 0 } block being a Statement within the outer block rather than its final operand; a consequence of this would be that such a statement must have unit type per the documentation of Expression statements; and even if a different type was permitted, its value would not be that of the outer block per the documentation of BlockExpression.

[ehuss]

Thanks for the report! Yea, the grammar isn't quite capturing what the "final operand" is, as answering that is a little complicated. I believe this is a duplicate of #762, so closing in favor of that.