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petrochenkovpetrochenkov
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AST/HIR: Introduce ExprKind::Err for better error recovery in the front-end
1 parent d298697 commit a5c52c7

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17 files changed

+51
-11
lines changed

17 files changed

+51
-11
lines changed

‎src/librustc/cfg/construct.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -392,7 +392,8 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
392392

393393
hir::ExprKind::Closure(..) |
394394
hir::ExprKind::Lit(..) |
395-
hir::ExprKind::Path(_) => {
395+
hir::ExprKind::Path(_) |
396+
hir::ExprKind::Err => {
396397
self.straightline(expr, pred, None::<hir::Expr>.iter())
397398
}
398399
}

‎src/librustc/hir/intravisit.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1099,6 +1099,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr) {
10991099
ExprKind::Yield(ref subexpression) => {
11001100
visitor.visit_expr(subexpression);
11011101
}
1102+
ExprKind::Err => {}
11021103
}
11031104
}
11041105

‎src/librustc/hir/lowering.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4117,6 +4117,8 @@ impl<'a> LoweringContext<'a> {
41174117
hir::ExprKind::Yield(P(expr))
41184118
}
41194119

4120+
ExprKind::Err => hir::ExprKind::Err,
4121+
41204122
// Desugar `ExprIfLet`
41214123
// from: `if let <pat> = <sub_expr> <body> [<else_opt>]`
41224124
ExprKind::IfLet(ref pats, ref sub_expr, ref body, ref else_opt) => {

‎src/librustc/hir/mod.rs

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1362,6 +1362,7 @@ impl Expr {
13621362
ExprKind::Struct(..) => ExprPrecedence::Struct,
13631363
ExprKind::Repeat(..) => ExprPrecedence::Repeat,
13641364
ExprKind::Yield(..) => ExprPrecedence::Yield,
1365+
ExprKind::Err => ExprPrecedence::Err,
13651366
}
13661367
}
13671368

@@ -1412,7 +1413,8 @@ impl Expr {
14121413
ExprKind::AddrOf(..) |
14131414
ExprKind::Binary(..) |
14141415
ExprKind::Yield(..) |
1415-
ExprKind::Cast(..) => {
1416+
ExprKind::Cast(..) |
1417+
ExprKind::Err => {
14161418
false
14171419
}
14181420
}
@@ -1525,6 +1527,9 @@ pub enum ExprKind {
15251527

15261528
/// A suspension point for generators. This is `yield <expr>` in Rust.
15271529
Yield(P<Expr>),
1530+
1531+
/// Placeholder for an expression that wasn't syntactically well formed in some way.
1532+
Err,
15281533
}
15291534

15301535
/// Optionally `Self`-qualified value/type path or associated extension.

‎src/librustc/hir/print.rs

Lines changed: 8 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -430,7 +430,9 @@ impl<'a> State<'a> {
430430
self.s.word("_")?;
431431
}
432432
hir::TyKind::Err => {
433-
self.s.word("?")?;
433+
self.popen()?;
434+
self.s.word("/*ERROR*/")?;
435+
self.pclose()?;
434436
}
435437
}
436438
self.end()
@@ -1540,6 +1542,11 @@ impl<'a> State<'a> {
15401542
self.word_space("yield")?;
15411543
self.print_expr_maybe_paren(&expr, parser::PREC_JUMP)?;
15421544
}
1545+
hir::ExprKind::Err => {
1546+
self.popen()?;
1547+
self.s.word("/*ERROR*/")?;
1548+
self.pclose()?;
1549+
}
15431550
}
15441551
self.ann.post(self, AnnNode::Expr(expr))?;
15451552
self.end()

‎src/librustc/ich/impls_hir.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -592,7 +592,8 @@ impl_stable_hash_for!(enum hir::ExprKind {
592592
InlineAsm(asm, inputs, outputs),
593593
Struct(path, fields, base),
594594
Repeat(val, times),
595-
Yield(val)
595+
Yield(val),
596+
Err
596597
});
597598

598599
impl_stable_hash_for!(enum hir::LocalSource {

‎src/librustc/middle/expr_use_visitor.rs

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -479,7 +479,8 @@ impl<'a, 'gcx, 'tcx> ExprUseVisitor<'a, 'gcx, 'tcx> {
479479
}
480480

481481
hir::ExprKind::Continue(..) |
482-
hir::ExprKind::Lit(..) => {}
482+
hir::ExprKind::Lit(..) |
483+
hir::ExprKind::Err => {}
483484

484485
hir::ExprKind::Loop(ref blk, _, _) => {
485486
self.walk_block(&blk);

‎src/librustc/middle/liveness.rs

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -515,6 +515,7 @@ fn visit_expr<'a, 'tcx>(ir: &mut IrMaps<'a, 'tcx>, expr: &'tcx Expr) {
515515
hir::ExprKind::Box(..) |
516516
hir::ExprKind::Yield(..) |
517517
hir::ExprKind::Type(..) |
518+
hir::ExprKind::Err |
518519
hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => {
519520
intravisit::walk_expr(ir, expr);
520521
}
@@ -1254,7 +1255,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
12541255
self.propagate_through_exprs(inputs, succ)
12551256
}
12561257

1257-
hir::ExprKind::Lit(..) | hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => {
1258+
hir::ExprKind::Lit(..) | hir::ExprKind::Err |
1259+
hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => {
12581260
succ
12591261
}
12601262

@@ -1521,7 +1523,7 @@ fn check_expr<'a, 'tcx>(this: &mut Liveness<'a, 'tcx>, expr: &'tcx Expr) {
15211523
hir::ExprKind::Block(..) | hir::ExprKind::AddrOf(..) |
15221524
hir::ExprKind::Struct(..) | hir::ExprKind::Repeat(..) |
15231525
hir::ExprKind::Closure(..) | hir::ExprKind::Path(_) | hir::ExprKind::Yield(..) |
1524-
hir::ExprKind::Box(..) | hir::ExprKind::Type(..) => {
1526+
hir::ExprKind::Box(..) | hir::ExprKind::Type(..) | hir::ExprKind::Err => {
15251527
intravisit::walk_expr(this, expr);
15261528
}
15271529
}

‎src/librustc/middle/mem_categorization.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -687,7 +687,7 @@ impl<'a, 'gcx, 'tcx> MemCategorizationContext<'a, 'gcx, 'tcx> {
687687
hir::ExprKind::Block(..) | hir::ExprKind::Loop(..) | hir::ExprKind::Match(..) |
688688
hir::ExprKind::Lit(..) | hir::ExprKind::Break(..) |
689689
hir::ExprKind::Continue(..) | hir::ExprKind::Struct(..) | hir::ExprKind::Repeat(..) |
690-
hir::ExprKind::InlineAsm(..) | hir::ExprKind::Box(..) => {
690+
hir::ExprKind::InlineAsm(..) | hir::ExprKind::Box(..) | hir::ExprKind::Err => {
691691
Ok(self.cat_rvalue_node(expr.hir_id, expr.span, expr_ty))
692692
}
693693
}

‎src/librustc_mir/hair/cx/expr.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -780,6 +780,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
780780
hir::ExprKind::Tup(ref fields) => ExprKind::Tuple { fields: fields.to_ref() },
781781

782782
hir::ExprKind::Yield(ref v) => ExprKind::Yield { value: v.to_ref() },
783+
hir::ExprKind::Err => unreachable!(),
783784
};
784785

785786
Expr {

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