Auto merge of #66994 - Centril:stmt-polish, r=estebank

refactor expr & stmt parsing + improve recovery

Summary of important changes (best read commit-by-commit, ignoring whitespace changes):

- `AttrVec` is introduces as an alias for `ThinVec<Attribute>`
- `parse_expr_bottom` and `parse_stmt` are thoroughly refactored.
- Extract diagnostics logic for `vec![...]` in a pattern context.
- Recovery is added for `do catch { ... }`
- Recovery is added for `'label: non_block_expr`
- Recovery is added for `var $local`, `auto $local`, and `mut $local`. Fixes #65257.
- Recovery is added for `e1 and e2` and `e1 or e2`.
- ~~`macro_legacy_warnings` is turned into an error (has been a warning for 3 years!)~~
- Fixes #63396 by forward-porting #64105 which now works thanks to added recovery.
- `ui-fulldeps/ast_stmt_expr_attr.rs` is turned into UI and pretty tests.
- Recovery is fixed for `#[attr] if expr {}`

r? @estebank

1 files changed, 6 insertions, 12 deletions

diff --git a/src/librustc/hir/lowering/expr.rs b/src/librustc/hir/lowering/expr.rs
index f8465baeb13..04031710dc5 100644
--- a/src/librustc/hir/lowering/expr.rs
+++ b/src/librustc/hir/lowering/expr.rs
@@ -1318,8 +1318,7 @@ impl LoweringContext<'_> {
         &mut self,
         span: Span,
         expr: P<hir::Expr>,
-        attrs: ThinVec<Attribute>
-    ) -> hir::Expr {
+        attrs: AttrVec) -> hir::Expr {
         self.expr(span, hir::ExprKind::DropTemps(expr), attrs)
     }
 
@@ -1333,7 +1332,7 @@ impl LoweringContext<'_> {
         self.expr(span, hir::ExprKind::Match(arg, arms, source), ThinVec::new())
     }
 
-    fn expr_break(&mut self, span: Span, attrs: ThinVec<Attribute>) -> P<hir::Expr> {
+    fn expr_break(&mut self, span: Span, attrs: AttrVec) -> P<hir::Expr> {
         let expr_break = hir::ExprKind::Break(self.lower_loop_destination(None), None);
         P(self.expr(span, expr_break, attrs))
     }
@@ -1404,7 +1403,7 @@ impl LoweringContext<'_> {
         span: Span,
         components: &[Symbol],
         params: Option<P<hir::GenericArgs>>,
-        attrs: ThinVec<Attribute>,
+        attrs: AttrVec,
     ) -> hir::Expr {
         let path = self.std_path(span, components, params, true);
         self.expr(
@@ -1423,7 +1422,7 @@ impl LoweringContext<'_> {
         span: Span,
         ident: Ident,
         binding: hir::HirId,
-        attrs: ThinVec<Attribute>,
+        attrs: AttrVec,
     ) -> hir::Expr {
         let expr_path = hir::ExprKind::Path(hir::QPath::Resolved(
             None,
@@ -1459,16 +1458,11 @@ impl LoweringContext<'_> {
         self.expr_block(P(blk), ThinVec::new())
     }
 
-    pub(super) fn expr_block(&mut self, b: P<hir::Block>, attrs: ThinVec<Attribute>) -> hir::Expr {
+    pub(super) fn expr_block(&mut self, b: P<hir::Block>, attrs: AttrVec) -> hir::Expr {
         self.expr(b.span, hir::ExprKind::Block(b, None), attrs)
     }
 
-    pub(super) fn expr(
-        &mut self,
-        span: Span,
-        kind: hir::ExprKind,
-        attrs: ThinVec<Attribute>
-    ) -> hir::Expr {
+    pub(super) fn expr(&mut self, span: Span, kind: hir::ExprKind, attrs: AttrVec) -> hir::Expr {
         hir::Expr { hir_id: self.next_id(), kind, span, attrs }
     }