Add exceptions for ExprKind::Err/TyKind::Error.

Author: Centril

src/librustc_passes/ast_validation.rs

@@ -287,7 +287,7 @@ impl<'a> AstValidator<'a> {
     // ```
     fn check_expr_within_pat(&self, expr: &Expr, allow_paths: bool) {
         match expr.node {
-            ExprKind::Lit(..) => {}
+            ExprKind::Lit(..) | ExprKind::Err => {}
             ExprKind::Path(..) if allow_paths => {}
             ExprKind::Unary(UnOp::Neg, ref inner)
                 if match inner.node { ExprKind::Lit(_) => true, _ => false } => {}

src/librustc_typeck/check/_match.rs

@@ -196,7 +196,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 let rhs_ty = self.check_expr(end);
 
                 // Check that both end-points are of numeric or char type.
-                let numeric_or_char = |ty: Ty<'_>| ty.is_numeric() || ty.is_char();
+                let numeric_or_char = |ty: Ty<'_>| {
+                    ty.is_numeric()
+                    || ty.is_char()
+                    || ty.references_error()
+                };
                 let lhs_compat = numeric_or_char(lhs_ty);
                 let rhs_compat = numeric_or_char(rhs_ty);