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, 2 insertions, 3 deletions

diff --git a/src/libsyntax/attr/mod.rs b/src/libsyntax/attr/mod.rs
index 13a9ed5f215..ae6d50ba083 100644
--- a/src/libsyntax/attr/mod.rs
+++ b/src/libsyntax/attr/mod.rs
@@ -9,7 +9,7 @@ pub use StabilityLevel::*;
 pub use crate::ast::Attribute;
 
 use crate::ast;
-use crate::ast::{AttrItem, AttrId, AttrKind, AttrStyle, Name, Ident, Path, PathSegment};
+use crate::ast::{AttrVec, AttrItem, AttrId, AttrKind, AttrStyle, Name, Ident, Path, PathSegment};
 use crate::ast::{MacArgs, MacDelimiter, MetaItem, MetaItemKind, NestedMetaItem};
 use crate::ast::{Lit, LitKind, Expr, Item, Local, Stmt, StmtKind, GenericParam};
 use crate::mut_visit::visit_clobber;
@@ -17,7 +17,6 @@ use crate::source_map::{BytePos, Spanned};
 use crate::token::{self, Token};
 use crate::ptr::P;
 use crate::symbol::{sym, Symbol};
-use crate::ThinVec;
 use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
 use crate::GLOBALS;
 
@@ -665,7 +664,7 @@ impl HasAttrs for Vec<Attribute> {
     }
 }
 
-impl HasAttrs for ThinVec<Attribute> {
+impl HasAttrs for AttrVec {
     fn attrs(&self) -> &[Attribute] {
         self
     }