Auto merge of #46732 - estebank:silence-recovered-blocks, r=petrochenkov

Do not emit type errors on recovered blocks

When a parse error occurs on a block, the parser will recover and create
a block with the statements collected until that point. Now a flag
stating that a recovery has been performed in this block is propagated
so that the type checker knows that the type of the block (which will be
identified as `()`) shouldn't be checked against the expectation to
reduce the amount of irrelevant diagnostic errors shown to the user.

Fix #44579.

src/libsyntax/fold.rs

@@ -864,11 +864,12 @@ fn noop_fold_bounds<T: Folder>(bounds: TyParamBounds, folder: &mut T)
 }
 
 pub fn noop_fold_block<T: Folder>(b: P<Block>, folder: &mut T) -> P<Block> {
-    b.map(|Block {id, stmts, rules, span}| Block {
+    b.map(|Block {id, stmts, rules, span, recovered}| Block {
         id: folder.new_id(id),
         stmts: stmts.move_flat_map(|s| folder.fold_stmt(s).into_iter()),
         rules,
         span: folder.new_span(span),
+        recovered,
     })
 }